The "Why It Makes Sense" Guide
Every condition walked through: pathophysiology β clinical findings (and why they appear) β diagnostics (and why we pick them) β treatment (and why it works). Built for application-level questions.
Gastrointestinal & Genitourinary
Pyloric Stenosis
Hypertrophy and hyperplasia of the circular muscle of the pylorus narrows the gastric outlet. The thickened muscle acts like a closed valve β milk enters the stomach but cannot pass into the duodenum. Over days to weeks, the baby vomits more forcefully, becomes dehydrated, and loses HCl and KβΊ through vomited gastric contents.
Classic: firstborn male, 3β6 weeks old, previously feeding well, now with non-bilious projectile vomiting after feeds. Hungry immediately after vomiting ("hungry vomiter"). Weight loss, dehydration, decreased wet diapers.
Exam: olive-shaped mass palpable in RUQ (hypertrophied pylorus). Visible peristaltic waves across epigastrium.
Abdominal US (first line): pyloric muscle thickness > 3 mm, channel length > 15 mm.
Labs: hypochloremic, hypokalemic metabolic alkalosis (classic).
Pyloromyotomy (Ramstedt procedure) β surgeon splits the hypertrophied muscle longitudinally without cutting mucosa. Correct electrolytes and dehydration first β anesthesia is dangerous with alkalosis.
Umbilical Hernia
Incomplete closure of the fascial ring at the umbilicus after cord separation allows abdominal contents (usually omentum or bowel) to bulge through. Much more common in African American infants and preemies.
Soft, reducible bulge at the umbilicus that protrudes with crying, straining, or standing. Usually painless. Size usually < 1β2 cm.
Observation until age 4β5. Surgical repair if: persists past 5 yrs, defect > 1.5β2 cm, symptomatic, or incarcerated. Do not tape/bind β no evidence it helps and can cause skin breakdown.
Appendicitis
The appendiceal lumen gets obstructed (fecalith, lymphoid hyperplasia after viral illness, rarely tumor). Mucus and bacteria accumulate behind the obstruction β pressure rises β venous and then arterial compromise β wall ischemia β bacterial invasion β perforation within 24β72 hrs if untreated.
- Classic sequence: anorexia β periumbilical pain β nausea/vomiting β pain migrates to RLQ β low-grade fever
- McBurney's point tenderness (1/3 way from ASIS to umbilicus)
- Rovsing sign (LLQ palpation β RLQ pain), psoas sign, obturator sign
- Children under 5 often present atypically with diffuse pain and perforate early (delayed dx)
- CBC: WBC 10β18K with left shift; > 20K suggests perforation
- CRP elevated
- US first in kids (no radiation); CT if US equivocal
- UA to rule out UTI / pyelonephritis (can mimic)
Appendectomy + IV antibiotics. NPO, fluids, pain management. Perforated appendicitis may need drainage and longer abx course.
Constipation & Encopresis
A painful stool (illness, dehydration, toilet training, dietary change) β child withholds β stool sits in the rectum β water is reabsorbed β stool becomes harder β next BM hurts more β withholding cycle. Over time, the rectum distends and loses sensation; liquid stool leaks around the impaction = encopresis (involuntary soiling).
- Infrequent, painful, hard stools; straining; blood-streaked stool (anal fissure)
- Posturing (heel-standing, stiffening) that parents often misread as trying to poop β actually withholding
- Abdominal pain, decreased appetite
- Encopresis in older children (after age 4)
- Palpable stool mass in LLQ or suprapubic area
- Onset in neonate or delayed passage of meconium > 48 hrs β Hirschsprung
- FTT, bilious vomiting, ribbon stools, tight empty rectum on exam
- Spine abnormalities (tuft of hair, dimple) β tethered cord
- No response to aggressive therapy
Step 1 β Disimpaction: PEG 3350 (Miralax) 1β1.5 g/kg/day Γ 3β6 days, or enemas.
Step 2 β Maintenance: PEG 0.4β0.8 g/kg/day for months. Goal: 1β2 soft stools daily until the rectum regains tone.
Step 3 β Behavior: toilet sits 5β10 min after meals (takes advantage of gastrocolic reflex), reward the sitting not the producing, fiber + fluids.
GERD (vs. Physiologic Reflux)
Lower esophageal sphincter (LES) tone is immature in infants; transient LES relaxations allow gastric contents to reflux. Physiologic reflux ("happy spitter") = normal; resolves by 12β18 months as LES matures. GERD = reflux causing complications β esophagitis, poor growth, respiratory symptoms.
- Physiologic: effortless spit-up, thriving, happy
- GERD: poor weight gain, feeding refusal, arching/irritability with feeds, recurrent aspiration/pneumonia, apnea, Sandifer syndrome (back arching)
- Older kids: heartburn, regurgitation, chest/epigastric pain, nocturnal cough
Clinical. Consider upper GI (r/o anatomic β malrotation, pyloric stenosis), pH probe or impedance study for atypical presentations, endoscopy if esophagitis suspected.
Conservative first: thickened feeds (rice cereal), smaller more frequent feeds, upright 20β30 min after, left-side positioning, elevate head of bed (older kids), avoid tobacco smoke exposure.
Pharm (only if true GERD): H2 blocker (famotidine) or PPI (omeprazole). Avoid empiric PPIs in happy spitters β no benefit, and they increase risk of infection and fracture.
Functional Abdominal Pain
Visceral hypersensitivity β the gut-brain axis is dysregulated. Normal gut distention or motility is perceived as painful. Often worsened by stress, anxiety, and poor sleep. Not psychosomatic, not "faking" β the pain is real but without structural disease.
- Recurrent abdominal pain, often periumbilical, > 2 months
- No weight loss, no nocturnal pain, no blood, normal growth
- Normal physical exam, normal labs
- Often in 5β12 year olds; school avoidance pattern
Limited workup: CBC, ESR/CRP, CMP, UA, celiac screen, stool studies if diarrhea. Extensive workup is usually low-yield and reinforces illness behavior.
Validation + school attendance + CBT + regular meals, sleep, exercise. Treat anxiety/depression if present. Peppermint oil helpful for IBS-type. Avoid extensive workup β it reinforces the sick role.
Urinary Tract Infection
Ascending bacterial colonization from the perineum β urethra β bladder (cystitis) β ureters/kidneys (pyelonephritis). E. coli is the dominant pathogen; others include Klebsiella, Proteus, Enterococcus. Girls are at higher risk (short urethra, proximity to anus); uncircumcised boys in the first year.
- Infants: fever without a source, poor feeding, irritability, vomiting, jaundice (newborns)
- Toddlers/preschool: fever, abdominal pain, new-onset enuresis
- School-age: classic dysuria, urgency, frequency, suprapubic pain
- Pyelonephritis: high fever, flank/CVA tenderness, vomiting, ill-appearing
- Cath UA + Cx in pre-continent children (bag specimens = 85% false positive β skin contamination)
- Midstream clean catch if toilet-trained
- Positive UA: leukocyte esterase, nitrites, WBC > 5/hpf
- Positive Cx: β₯ 50,000 CFU/mL from cath, β₯ 100,000 from clean catch
- After first febrile UTI in < 24 mo: renal/bladder ultrasound
- VCUG: only if recurrent febrile UTIs or abnormal US
Outpatient: cephalexin, cefixime, TMP-SMX, or nitrofurantoin Γ 7β14 days (longer for febrile/pyelo). Admit if: < 2 mo old, toxic, vomiting, dehydrated, immunocompromised, or failing outpatient therapy.
Vesicoureteral Reflux (VUR)
Normally, ureters enter the bladder at an oblique angle β bladder pressure during voiding closes the ureteral orifice. In VUR, the ureter-bladder junction is abnormal (short tunnel) and urine flows backward up the ureter during voiding. Primary VUR = congenital anatomic defect. Retrograde urine carries bacteria to kidneys β pyelonephritis β renal scarring β HTN and CKD long-term.
Often silent β diagnosed after a child presents with febrile UTI. Suspect in any child with recurrent febrile UTIs or pyelonephritis.
- I: reflux into distal ureter only
- II: into renal pelvis, no dilation
- III: mild dilation
- IV: moderate dilation + blunting of calyces
- V: severe dilation, tortuous ureter, intrarenal reflux
VCUG = gold standard; performed after recurrent febrile UTI or abnormal renal US.
Low grade (IβIII): often spontaneously resolves as the child grows. Observation Β± prophylactic antibiotics (amoxicillin or TMP-SMX).
High grade (IVβV): surgical correction (ureteral reimplantation, Deflux injection).
Nocturnal Enuresis
Three mechanisms β often combined:
- Delayed arousal: child doesn't wake to a full bladder
- Nocturnal polyuria: insufficient nighttime ADH release β large urine volumes
- Small functional bladder capacity
Primary enuresis: child was never dry (most common). Secondary: dry β₯ 6 mo, now wetting β look for trigger (UTI, new stressor, DM, constipation, OSA, abuse).
Involuntary nighttime wetting in a child β₯ 5 years, at least 2Γ/week for 3 months, not explained by a medical condition. Strong family history (if both parents were bedwetters, child has ~75% risk).
UA to rule out UTI, DM, DI. History focused on daytime symptoms (if daytime wetting or dysfunctional voiding β different workup). Screen for constipation (hugely underdiagnosed contributor) and OSA.
Age < 6β7: reassure, avoid treatment β most outgrow it.
Age β₯ 6β7 when child is bothered:
- First-line: bedwetting alarm (60β70% cure; relapse low)
- DDAVP (desmopressin): for short-term use (sleepovers, camp). Works by mimicking ADH β reduces nighttime urine production
- Treat any constipation or OSA first β often fixes it
- Motivation + bladder-stretching exercises
Labial Adhesions
In the hypoestrogenic state between infancy and puberty, inflammation of the vulvar skin (from chronic moisture, diapers, mild irritation) causes the labia minora to stick together midline. The fusion is epithelial, not fibrous.
Midline raphe where labia minora fuse. Usually asymptomatic and incidental. Occasional complications: post-void dribbling, UTI, vulvitis.
- Asymptomatic: observation. Resolves at puberty when estrogen rises.
- Symptomatic: topical estrogen cream to the raphe nightly Γ 2β6 weeks. Betamethasone cream is an alternative.
- Never forcibly separate β traumatic and will re-adhere.
Vulvovaginitis (Prepubertal)
The prepubertal vagina is hypoestrogenic (thin, alkaline epithelium, no protective lactobacilli), making it vulnerable to irritants and infections. Most cases are nonspecific β from poor perineal hygiene, wiping back-to-front, bubble baths, tight clothing, soaps.
- Vulvar erythema, itching, burning, dysuria
- Discharge (usually minimal in nonspecific; thick/purulent suggests infection)
- Consider foreign body (toilet paper) if foul, bloody discharge
- Consider group A strep if beefy erythema (esp. after strep pharyngitis)
- Consider pinworms if nocturnal itching
- Consider sexual abuse if STI pathogen isolated
Hygiene education (front-to-back wiping, cotton underwear, no bubble baths, loose clothing, sitz baths). Treat specific infections as identified. Candida is uncommon prepubertally β don't reach for fluconazole reflexively.
Cryptorchidism (Undescended Testis)
The testes normally descend from the abdominal cavity through the inguinal canal into the scrotum between 7β9 months gestation. Descent can arrest anywhere along this path. ~3% of term and 30% of preterm males have undescended testes at birth; 75% descend spontaneously by 3β6 months.
Empty or small hemiscrotum; testis may be palpable in the inguinal canal or not palpable at all. Bilateral non-palpable testes β workup for DSD.
Retractile testis (cremaster pulls testis up but it returns to scrotum) is normal β differentiate carefully.
Watchful waiting until 6 months (most descend by then). Refer to urology at 6 months if still undescended. Orchiopexy by 12β18 months.
Musculoskeletal & Genetic Conditions
Developmental Dysplasia of the Hip (DDH)
A spectrum of abnormal hip development β from mild acetabular dysplasia (shallow socket) to frank dislocation. The femoral head and acetabulum are a complementary pair; each shapes the other during development. If the femoral head sits outside the socket, the acetabulum doesn't form properly β progressive dysplasia β early osteoarthritis if untreated.
- Female (4β6Γ more common β maternal estrogens loosen ligaments more in female fetuses)
- First-born (tight uterus)
- Family history
- Frank breech (most significant β hip held flexed + externally rotated in utero)
- Fluid (oligohydramnios)
- "Footling" and other non-vertex positions
- Barlow (dislocates a dislocatable hip): adduct + push posteriorly β feel "clunk" OUT
- Ortolani (relocates a dislocated hip): abduct + lift anteriorly β feel "clunk" IN
- Older infant (> 3 mo): Barlow/Ortolani become negative; look for asymmetric thigh/gluteal folds, limited abduction, Galeazzi sign (knees at unequal heights when hips flexed β short femur on affected side)
- Walking child: Trendelenburg gait, waddling (bilateral)
- < 4β6 months: ultrasound (femoral head is mostly cartilage β not yet ossified β invisible on X-ray)
- > 4β6 months: X-ray (femoral head ossification center appears)
- Universal US screening in breech girls and high-risk infants at 4β6 weeks
- < 6 months: Pavlik harness β holds hips flexed and abducted (the "frog-leg" position that encourages proper socket formation)
- 6β18 months: closed reduction + spica cast
- > 18 months: open reduction Β± femoral/pelvic osteotomy
Talipes Equinovarus (Clubfoot)
A complex congenital foot deformity with four components (remember CAVE):
- Cavus (high arch)
- Adductus (forefoot turned inward)
- Varus (hindfoot inverted)
- Equinus (ankle pointed down β "horse-like")
Soft tissues (tendons, ligaments) are short on the medial and posterior side; bones are malpositioned. Can be isolated (idiopathic) or syndromic (spina bifida, arthrogryposis).
Obvious at birth β foot looks like a golf club. Rigid (true clubfoot) vs flexible (positional β corrects passively; benign).
Ponseti method β serial casting starting in the first 1β2 weeks of life. Weekly manipulation + casting for 5β8 weeks β percutaneous Achilles tenotomy β bracing (boots-and-bar) for several years to prevent recurrence.
Osgood-Schlatter Disease
Traction apophysitis of the tibial tubercle. Repetitive quadriceps contraction pulls on the patellar tendon, which inserts on the tibial tubercle β an active growth plate in adolescents. Repeated traction causes microavulsion, inflammation, and bony prominence.
- 10β15 yo, active boy (or girl) in jumping/running sports (basketball, soccer, gymnastics)
- Anterior knee pain, worse with activity
- Tender, enlarged tibial tubercle
- Pain reproduced with resisted knee extension
Self-limited β resolves when growth plate closes. Ice, NSAIDs, quad stretching, activity modification (not full rest β partial is fine). Patellar strap may help. Residual bony prominence may persist.
Nursemaid's Elbow (Radial Head Subluxation)
Sudden axial traction on a pronated, extended arm (adult pulls child by the hand) slips the annular ligament partially off the radial head. The ligament gets trapped in the radiohumeral joint. Peak age 1β4 yrs β after age 5 the annular ligament thickens and it becomes rare.
- Toddler who refuses to use one arm, holds it slightly flexed and pronated at side
- Cries only when the arm is moved; otherwise seems fine
- No swelling, no deformity, no bruising
- Classic history: "I pulled him up by the hand" or "he slipped off the couch while I was holding his hand"
Clinical. X-ray not needed if history is classic β just reduce. Get X-rays if history inconsistent, swelling, or deformity (r/o fracture, abuse).
Reduction: supinate and flex (or hyperpronate) β feel a click. Child uses the arm within 10β15 min. No immobilization needed.
Idiopathic Toe Walking
Walking on the balls of the feet without heel strike. Common and benign in children under 3 as part of gait development. Persistent toe walking > 3 yrs needs evaluation to rule out:
- Cerebral palsy (hyperreflexia, spasticity)
- Muscular dystrophy (Gower sign, calf hypertrophy, CK elevation)
- Tethered cord (spine findings)
- Autism (associated sensory/behavioral findings)
- Short Achilles tendon (limited passive dorsiflexion)
Idiopathic: observation, stretching, heel-cord exercises. Serial casting or botulinum toxin if persistent/painful. Surgery (tendon lengthening) rare.
Legg-CalvΓ©-Perthes Disease (LCPD)
Idiopathic avascular necrosis of the femoral head. Blood supply to the ossification center is interrupted β bone dies β over months, bone is resorbed β new bone remodels (reossification). The softened head can deform during this vulnerable phase, leading to a misshapen hip and early osteoarthritis.
- Boys 4β8 years (5:1 M:F), typically short, thin, and very active
- Painless limp or intermittent pain referred to the knee, thigh, or groin
- Limited hip abduction and internal rotation
- Bilateral in ~15%
- Delayed bone age
X-ray: AP and frog-leg lateral. Findings evolve β early: increased femoral head density, joint space widening. Later: fragmentation, flattening. MRI if X-ray normal but suspicion high.
Goal: containment β keep the femoral head seated in the acetabulum during healing so it remodels round. NSAIDs, activity restriction, PT for range of motion. Bracing or surgery (osteotomy) for more severe cases.
Slipped Capital Femoral Epiphysis (SCFE)
During the adolescent growth spurt, the femoral head "slips" posteriorly and medially off the femoral neck at the growth plate (physis), like a scoop of ice cream sliding off a cone. Mechanical weakness + hormonal factors during puberty weaken the physis.
- Obese adolescents, typically 10β15 years old
- Boys > girls, African American children at higher risk
- Endocrine associations: hypothyroidism, growth hormone therapy, renal osteodystrophy (think about SCFE in short/young-looking or unusual stature kids)
- Bilateral in ~40% β screen the other side
- Hip, groin, thigh, or KNEE pain (often only knee pain!)
- Limp, antalgic gait
- Leg held in external rotation when hip flexed (pathognomonic β the displaced head forces external rotation)
- Limited internal rotation and abduction
- Stable: able to bear weight. Unstable: cannot bear weight β high risk of AVN.
Bilateral AP + frog-leg lateral X-rays. Look for widening/lucency of the physis (pre-slip) or the "ice cream slipping off the cone" sign. Draw Klein's line along the superior femoral neck β it should cross some of the femoral head. If it doesn't cross, think SCFE.
Urgent orthopedic referral. Non-weight-bearing on crutches immediately. In situ screw fixation β one screw through the femoral neck into the head prevents further slippage while the physis fuses.
Osteomyelitis
Bacterial infection of bone, almost always from hematogenous seeding in children (bacteremia β bone). The metaphysis of long bones has sluggish blood flow and abundant vessels β bacteria get trapped there. Infection spreads into bone, forms an abscess, and can track to the joint (especially in infants whose metaphysis is intracapsular at the hip).
S. aureus is the dominant pathogen across all ages. Others: Group A strep, Kingella (< 5 yrs), Salmonella (in sickle cell), Pseudomonas (puncture wound through sneaker).
- Fever + focal bone pain + refusal to use/bear weight on the limb
- Point tenderness over the bone β cardinal feature that differentiates from joint infection
- Warmth, erythema, swelling over the affected bone
- Limp if in the lower extremity
- CBC with diff, ESR, CRP β all elevated. CRP rises within 6β8 hrs and trends with response.
- Blood culture β positive in ~50%
- X-ray β normal in first 7β10 days (bone changes lag behind). Useful to r/o fracture or tumor.
- MRI β study of choice; shows marrow edema within days
- Bone aspiration/biopsy for definitive organism + sensitivities
IV antibiotics covering S. aureus (MSSA: cefazolin; MRSA coverage: clindamycin or vancomycin), usually 4β6 weeks total (can transition to PO after clinical response). Surgical drainage if abscess, failure to respond, or joint involvement.
Transient Synovitis (Toxic Synovitis)
Self-limited inflammation of the hip synovium, most often post-viral (URI in the preceding 1β2 weeks) or reactive. Most common cause of hip pain in children 3β10 years. Exactly the scenario from Case Study #1.
- 3β10 yo, recent URI or viral illness
- Acute hip pain, limp, or refusal to bear weight
- Hip held flexed, abducted, externally rotated β position of lowest intracapsular pressure
- Afebrile or low-grade fever (high fever suggests septic arthritis)
- Not systemically ill β this is the key clinical distinction from septic arthritis
Four predictors of septic arthritis:
- History of fever (> 38.5Β°C)
- Non-weight-bearing
- ESR β₯ 40
- WBC > 12,000
All 4 present β ~99% probability of septic arthritis. 0 present β < 0.2%. Add CRP > 2.0 mg/dL for improved sensitivity (rises within 6β8 hrs of inflammation).
- X-ray hip (AP + frog-leg) β usually normal; r/o other causes
- CBC with diff, ESR, CRP, blood Cx
- Hip US Β± aspiration if septic arthritis suspected β effusion > 2 mm suspicious; aspirate and send fluid for cell count, Gram stain, culture
Rest + ibuprofen 7β10 days. Often improves within 24β48 hrs. Follow up in 24 hrs if uncertain β septic arthritis worsens while transient synovitis improves. Return immediately for high fever, worsening pain, or inability to move the joint.
Down Syndrome (Trisomy 21)
Three copies of chromosome 21 β 95% from maternal meiotic nondisjunction (risk rises with maternal age), 4% from translocation, 1% mosaic. Extra dose of chromosome 21 genes causes the multisystem phenotype.
- Facies: upslanting palpebral fissures, epicanthal folds, flat nasal bridge, small ears, protruding tongue (relative macroglossia), brachycephaly
- Hands: single transverse palmar crease, short fifth finger with clinodactyly, wide gap between 1st and 2nd toes ("sandal gap")
- Tone: hypotonia (the "floppy baby")
- Growth: short stature, use Down-specific growth charts
- Intellectual disability (mild to moderate usually)
- Cardiac: ~50% have CHD β AV canal (AVSD) most characteristic; also VSD, ASD, tetralogy. Echo at birth.
- GI: duodenal atresia (double-bubble sign), Hirschsprung, celiac disease
- Thyroid: hypothyroidism (congenital + acquired) β screen at birth, 6 mo, 12 mo, then annually
- Hematologic: 10β20Γ risk of leukemia (ALL and AML); transient myeloproliferative disorder in newborns
- Atlantoaxial instability β screen before contact sports; avoid cervical manipulation
- Hearing & vision: OME, cataracts, refractive errors β screen regularly
- OSA β polysomnography by age 4
- Alzheimer disease β early onset (chromosome 21 carries APP gene)
Early intervention (PT/OT/ST), educational support, treatment of comorbidities, regular surveillance per AAP guidelines. Genetic counseling for family.
Marfan Syndrome
Mutation in FBN1 (fibrillin-1), a connective tissue protein that provides structural support in elastic tissues (aorta, lens zonules, periosteum, skin). Defective fibrillin weakens these tissues β aortic dilation, lens subluxation, tall stature with long limbs.
- Skeletal: tall, long limbs (dolichostenomelia), arachnodactyly (long spider-like fingers), pectus excavatum or carinatum, scoliosis, high-arched palate, joint hypermobility
- Positive wrist sign (Walker-Murdoch β thumb and 5th finger overlap when gripping wrist) and thumb sign (Steinberg β thumb protrudes past ulnar border of fist)
- Cardiovascular: aortic root dilation β aneurysm β dissection (main cause of death). Mitral valve prolapse.
- Ocular: ectopia lentis (upward lens subluxation), myopia, retinal detachment
Echocardiogram (aortic root dimension, Z-score), slit lamp, genetic testing (FBN1). Family history key.
- Annual echo to monitor aortic root
- Beta blockers (atenolol) or ARBs (losartan) to slow aortic dilation
- Avoid contact sports and isometric/max-effort activities (weightlifting) β aortic dissection risk
- Prophylactic aortic root replacement when diameter reaches threshold
- Annual eye exam; genetic counseling
Fragile X Syndrome
CGG trinucleotide repeat expansion in the FMR1 gene on the X chromosome. Normal: < 45 repeats. Premutation: 55β200. Full mutation: > 200 β gene is silenced (methylated) β no FMRP protein β abnormal synaptic plasticity. Anticipation β the repeat expands from generation to generation, so symptoms worsen across generations.
- Intellectual disability (most common inherited cause; Down is most common overall but not inherited)
- Autism features (Fragile X is one of the most common identifiable genetic causes of autism)
- Facies: long face, prominent jaw, large ears (often protruding)
- Macroorchidism β large testes, emerges post-pubertally
- Joint hypermobility, flat feet, mitral valve prolapse
- Anxiety, hyperactivity, gaze aversion, stereotyped hand movements, tactile defensiveness
DNA testing for CGG repeat number (direct gene testing). Recommended for any child with unexplained ID, developmental delay, or autism.
Early intervention, educational support, SSRI for anxiety, stimulants for ADHD symptoms, treat comorbid epilepsy. Genetic counseling for family β mother is at minimum a carrier; sisters, aunts, cousins need testing.
Nutritional & Endocrine Conditions
Food Allergy
IgE-mediated (immediate): prior sensitization β food-specific IgE on mast cells/basophils β re-exposure β crosslinking β histamine and cytokine release within minutes to 2 hours. Non-IgE-mediated: cell-mediated, delayed (hours to days) β e.g., FPIES, eosinophilic esophagitis, milk protein proctocolitis.
Top 9 allergens: milk, egg, peanut, tree nuts, soy, wheat, fish, shellfish, sesame.
- Skin: urticaria, angioedema, flushing, pruritus
- GI: vomiting, abdominal pain, diarrhea
- Respiratory: wheeze, stridor, cough
- Cardiovascular: hypotension, tachycardia (anaphylaxis)
- Onset within minutes, peaks within 2 hours
- Skin prick test or food-specific IgE (RAST/ImmunoCAP) β support diagnosis but don't diagnose alone (false positives common)
- Oral food challenge = gold standard (in a controlled setting)
- Detailed history is most important β timing, reproducibility, dose
- Avoidance of the trigger
- Epinephrine auto-injector Γ 2 (always prescribe two β biphasic reactions)
- Action plan for home, school, caregivers
- Early introduction of peanut in high-risk infants (LEAP trial) β starting 4β6 months reduces peanut allergy
- Consider oral immunotherapy for selected patients
Celiac Disease
In genetically predisposed children (HLA-DQ2 or HLA-DQ8), ingestion of gluten (wheat, barley, rye) triggers an autoimmune reaction in the small intestine. Gluten peptides are modified by tissue transglutaminase (tTG) β presented to T cells β inflammation β villous atrophy β malabsorption. The damage is entirely reversible with strict gluten avoidance.
- Classic (infants/toddlers after gluten introduction): chronic diarrhea, abdominal distension, FTT, irritability
- Older children: short stature, delayed puberty, iron-deficiency anemia refractory to iron, dental enamel defects, dermatitis herpetiformis (grouped pruritic vesicles on elbows/knees)
- Silent celiac: asymptomatic but serology +, damage present
- Associated conditions: T1DM, Down syndrome, Turner syndrome, autoimmune thyroiditis, IgA deficiency, first-degree relatives
- tTG-IgA + total IgA (check total IgA because IgA deficiency is common in celiac and would give a false negative tTG-IgA)
- If IgA deficient: use tTG-IgG or DGP-IgG
- Gold standard: duodenal biopsy showing villous atrophy + crypt hyperplasia + intraepithelial lymphocytes
- Must be on gluten-containing diet when testing β gluten-free diet normalizes labs and biopsy
Strict lifelong gluten-free diet. Referral to dietitian essential. Screen for nutrient deficiencies (iron, vitamin D, folate, B12) and treat. Monitor growth and tTG to confirm adherence. Screen first-degree relatives.
Malnutrition / Failure to Thrive
Inadequate nutritional intake, absorption, or utilization for the child's growth needs. Defined as:
- Weight-for-age < 5th percentile
- Weight-for-length < 5th percentile
- Downward crossing of β₯ 2 major percentile lines
Categorized as: inadequate intake (most common β feeding problems, poverty, neglect, food refusal), inadequate absorption (celiac, CF, milk protein allergy), increased metabolic demand (CHD, chronic infection, hyperthyroidism), or defective utilization (metabolic disorders).
- Detailed feeding history β what, how much, how often, who feeds, mealtime behavior
- Plot growth on standardized curves β pattern often reveals cause (head circumference spared suggests nutritional; all parameters affected suggests genetic/structural)
- Observe a feeding
- Psychosocial assessment β caregiver mental health, food security, family stress
Address underlying cause. Increase caloric density (add fats, oils; concentrate formula carefully). Feeding therapy. Multidisciplinary approach β pediatrician, dietitian, social work, behavioral health. Admit if severe, dehydrated, or social concerns. Watch for refeeding syndrome (hypophosphatemia, hypokalemia, hypomagnesemia) in severely malnourished children.
Pediatric Obesity
- Overweight: BMI 85thβ94th percentile for age/sex
- Obesity (class 1): BMI β₯ 95th percentile
- Class 2 obesity: β₯ 120% of 95th percentile (or BMI β₯ 35)
- Class 3 (severe): β₯ 140% of 95th percentile (or BMI β₯ 40)
Energy imbalance β intake > expenditure, modulated by genetics, early-life programming, sleep, stress, gut microbiome, food environment, and activity. Adipose tissue is an active endocrine organ β excess fat produces inflammatory cytokines and disrupts insulin signaling, leading to insulin resistance and the metabolic consequences.
- Metabolic: T2DM, dyslipidemia, HTN, NAFLD
- Respiratory: OSA, asthma
- Orthopedic: SCFE, Blount disease (tibia vara)
- Dermatologic: acanthosis nigricans (marker of insulin resistance)
- Reproductive: PCOS in adolescent girls, precocious puberty
- Mental health: depression, anxiety, disordered eating, bullying
- GI: GERD, gallstones
- Fasting lipid panel
- ALT (NAFLD screen β most common cause of chronic liver disease in kids now)
- Fasting glucose or HbA1c if BMI β₯ 85th + risk factors
- BP at every visit
- Intensive health behavior and lifestyle treatment (IHBLT) β β₯ 26 contact hours over 3β12 months, family-based
- Pharmacotherapy β₯ 12 yrs with obesity: metformin, GLP-1 agonists (liraglutide, semaglutide), orlistat
- Metabolic and bariatric surgery β₯ 13 yrs with severe obesity
- Do not use "watchful waiting" as a default strategy β early intervention works better
Hypothyroidism
Congenital hypothyroidism (CH): thyroid dysgenesis (aplasia, ectopy β 85%), dyshormonogenesis, transient (maternal antibodies, iodine exposure). Universal newborn screening catches nearly all cases. Untreated CH causes irreversible intellectual disability and growth failure.
Acquired hypothyroidism: most commonly Hashimoto thyroiditis (autoimmune lymphocytic infiltration destroying thyroid tissue). Associated with T1DM, Down syndrome, Turner syndrome, celiac.
Congenital (if screening missed or late): large fontanelles, poor feeding, lethargy, constipation, prolonged jaundice, macroglossia, umbilical hernia, cool/mottled skin, hoarse cry, hypotonia.
Acquired: growth failure + delayed bone age, fatigue, cold intolerance, constipation, weight gain (usually modest β not as dramatic as adults), dry skin/hair, bradycardia, delayed puberty or precocious pseudopuberty, goiter.
- Primary hypothyroidism: β TSH, β free T4
- Central hypothyroidism: β or inappropriately normal TSH, β free T4
- Subclinical: β TSH, normal free T4
- Antibodies: anti-TPO, anti-thyroglobulin (Hashimoto)
- Bone age X-ray β delayed in hypothyroidism
Levothyroxine daily, on empty stomach. Start full replacement immediately in CH (10β15 mcg/kg/day); lower doses for acquired. Recheck TSH in 4β6 weeks after dose change. Goal: TSH in normal range. Do not take with calcium, iron, or soy (reduces absorption).
Hyperthyroidism
Graves disease β autoimmune, TSH receptor antibodies (TRAb) stimulate the thyroid β excess T3/T4 + goiter. Most common cause in children, peaks in adolescence, 5:1 female:male. Can also occur in neonates born to mothers with Graves (antibodies cross the placenta β transient).
- Weight loss with increased appetite, hyperphagia
- Heat intolerance, sweating
- Tachycardia, palpitations, HTN with widened pulse pressure
- Tremor, anxiety, emotional lability, poor concentration (often misdiagnosed as ADHD)
- Declining school performance despite hyperactivity
- Goiter (diffuse, firm, possible bruit)
- Ophthalmopathy (exophthalmos, lid lag β Graves specific)
- Growth acceleration, advanced bone age
β TSH, β free T4/T3. TRAb or TSI confirms Graves. Thyroid US or uptake scan if nodular. Bone age advanced.
- Methimazole = first-line in peds (avoid PTU in kids β hepatotoxicity risk; exception: first trimester pregnancy)
- Beta blocker (propranolol or atenolol) for symptomatic relief of tachycardia/tremor while methimazole works
- Radioactive iodine or thyroidectomy for definitive treatment in refractory cases or adolescents
- Monitor CBC (methimazole can cause agranulocytosis) and LFTs
Type 1 Diabetes Mellitus
Autoimmune destruction of pancreatic Ξ²-cells (T-cell mediated, with autoantibodies as markers: GAD65, IA-2, insulin, ZnT8). > 90% of Ξ²-cells must be destroyed before symptoms appear. Without insulin, glucose can't enter cells β cells starve β the body shifts to fat breakdown for fuel β ketone bodies accumulate β diabetic ketoacidosis (DKA). About 30% of new-onset T1DM presents in DKA.
- Classic triad: polyuria, polydipsia, polyphagia β with weight loss
- New-onset nocturnal enuresis in a previously dry child
- Fatigue, blurred vision
- DKA (emergency): nausea, vomiting, abdominal pain, altered mental status, fruity breath (acetone), Kussmaul respirations (deep, rapid β compensatory for acidosis), tachycardia, hypotension, dehydration signs (tenting, poor cap refill, tachypnea)
- Random glucose > 200 + symptoms, or
- Fasting glucose > 126, or
- HbA1c β₯ 6.5%, or
- 2-hr OGTT > 200
- UA: glucose + ketones
- Confirmatory / typing: C-peptide (low in T1), islet cell antibodies (GAD65, IA-2)
- CMP in DKA: metabolic acidosis, hyponatremia (often pseudo β glucose pulls water into vessels), normal-or-β K (total body K is depleted but acidosis shifts K extracellularly), elevated BUN/Cr from dehydration
- CBC: WBC often elevated
New-onset or DKA: ED/hospital admission. IV fluids (careful β too fast = cerebral edema), IV regular insulin drip, potassium replacement as acidosis corrects, gradual glucose correction.
Ongoing: basal-bolus insulin (long-acting glargine/detemir + rapid-acting aspart/lispro with meals), or insulin pump. Carb counting. CGM. Target HbA1c < 7%. Multidisciplinary diabetes team.
Type 2 Diabetes Mellitus
Peripheral tissues become resistant to insulin β the pancreas initially compensates with hyperinsulinemia, but Ξ²-cells eventually fatigue. Associated with obesity, family history, certain ethnicities (Hispanic, Black, AI/AN, Asian), puberty (normal physiologic insulin resistance worsens), and PCOS.
- Obese adolescent (typically at or after puberty)
- Asymptomatic on screening, or mild polyuria/polydipsia
- Acanthosis nigricans (velvety hyperpigmented skin, neck/axilla) β marker of insulin resistance
- Can rarely present with DKA or hyperosmolar hyperglycemic state
- Family history of T2DM common
BMI β₯ 85% + β₯ 1 risk factor (family hx, high-risk race/ethnicity, signs of insulin resistance, maternal DM/GDM). Start at age 10 or onset of puberty. Screen every 3 years.
Same criteria as T1DM (HbA1c β₯ 6.5%, fasting β₯ 126, random β₯ 200 + symptoms). Differentiation: C-peptide normal or high (Ξ²-cells still working), no autoantibodies, usually obese.
- Lifestyle: nutrition, exercise, weight management
- First-line pharmacotherapy: metformin (improves insulin sensitivity). If HbA1c > 8.5% or symptomatic β start insulin + metformin.
- Second-line (if metformin alone fails): GLP-1 agonists (liraglutide) approved β₯ 10 yrs; insulin
- Screen for comorbidities: NAFLD, dyslipidemia, HTN, PCOS, OSA, microalbuminuria, retinopathy
Constitutional Delay of Growth & Puberty (CDGP)
A variation of normal β the child is on a delayed tempo. Growth velocity is normal, but the child enters puberty late. Bone age is delayed (matches the delayed growth), and final adult height is usually normal.
- Short stature relative to peers
- Delayed pubertal onset (no breast budding by 13 in girls, no testicular enlargement by 14 in boys)
- Family history of "late bloomers" β dad shaved late, mom had late menarche
- Normal growth velocity, delayed bone age
- Usually self-conscious about being shorter/less developed than peers
Bone age X-ray (delayed), TSH/free T4, IGF-1, CBC, CMP, ESR, celiac screen, karyotype in girls (r/o Turner). Normal workup + family history + delayed bone age = CDGP.
Reassurance is primary. For significant psychosocial distress, a short course of low-dose testosterone (boys) or estrogen (girls) can kick-start puberty without affecting final height. Not usually needed.
Precocious Puberty
- Girls: secondary sexual characteristics before age 8 (or menarche before 9.5)
- Boys: secondary sexual characteristics before age 9
Central (GnRH-dependent, "true"): early activation of the HPG axis β all sex hormones rise together, orderly Tanner progression. In girls, ~90% is idiopathic. In boys, ~50% has a pathologic cause (CNS lesion, hamartoma) β always work up boys carefully.
Peripheral (GnRH-independent, "pseudo"): sex hormones from somewhere other than the HPG axis β adrenal (CAH, tumor), gonadal (McCune-Albright, ovarian cyst, Leydig cell tumor), exogenous (topical estrogen/testosterone exposure). Progression is often out of order.
- Breast development (thelarche) in girls
- Testicular enlargement (> 4 mL or 2.5 cm) in boys β earliest sign
- Pubic/axillary hair, body odor, acne
- Accelerated growth velocity and advanced bone age β tall as a child, short as an adult (early growth plate closure)
- Psychosocial distress, early menarche
- Bone age X-ray of left hand/wrist β first step; advanced > chronological
- LH, FSH (baseline + GnRH-stimulation test β pubertal response = central)
- Estradiol (girls), testosterone (boys)
- TSH (primary hypothyroidism can cause incomplete precocious puberty β Van Wyk-Grumbach)
- 17-OHP (r/o CAH), DHEAS (adrenal source)
- Pelvic US (ovarian size, uterine changes)
- Brain MRI for central precocious puberty in boys, or girls < 6
- Central: GnRH agonist (leuprolide) β continuous stimulation desensitizes the pituitary, shutting down LH/FSH pulses β stops progression and preserves adult height
- Peripheral: treat the underlying cause (tumor removal, hormone replacement for CAH, etc.)
Neurodevelopmental & Mental Health Conditions
Specific Learning Disability
A heterogeneous group of neurologically-based disorders in which a child's academic achievement is substantially below expected for age and IQ, despite adequate instruction. Involves differences in brain processing of specific academic skills β reading (dyslexia β most common), math (dyscalculia), written expression (dysgraphia).
- Normal IQ
- Persistent difficulty in one or more academic areas despite adequate instruction β₯ 6 months
- Academic skills substantially and measurably below age-expected
- Begins in school-age years, emerges when demands exceed capacities
- Not explained by ID, vision/hearing deficit, neurologic disorder, lack of instruction, language barrier
Psychoeducational evaluation β IQ test + achievement testing, demonstrating the discrepancy. Schools are required under IDEA to evaluate if parents request. Audiology/vision screening to rule out sensory contributors.
IEP or 504 plan β individualized educational interventions, accommodations (extended time, text-to-speech, oral testing). Screen for and treat comorbid ADHD (co-occurs in 30β50%), anxiety, depression. Early intervention = best outcomes.
ADHD (Attention-Deficit/Hyperactivity Disorder)
Neurodevelopmental disorder of executive function β dysregulation in prefrontal cortex dopamine and norepinephrine circuits. Prefrontal cortex governs attention, working memory, impulse control, and task initiation. Highly heritable (~75%).
Three presentations: predominantly inattentive, predominantly hyperactive/impulsive, or combined.
β₯ 6 symptoms of inattention AND/OR hyperactivity/impulsivity, persisting β₯ 6 months, inconsistent with developmental level. Several symptoms present before age 12. Symptoms in β₯ 2 settings (home + school). Interfering with functioning. Not better explained by another disorder.
Adolescents/adults β₯ 17: only 5 symptoms needed.
Careless mistakes, trouble sustaining attention, doesn't listen, doesn't follow through, poor organization, avoids sustained mental effort, loses things, easily distracted, forgetful.
Fidgeting, leaves seat, runs/climbs inappropriately, unable to play quietly, "on the go" / "driven by motor," talks excessively, blurts answers, can't wait turn, interrupts.
- Vanderbilt Rating Scales β from both parent and teacher (symptoms in β₯ 2 settings is a diagnostic requirement)
- Other validated tools: Conners, SNAP-IV
- Comprehensive history β developmental, medical, psychosocial, academic
- Rule out mimics: sleep deprivation/OSA, hearing/vision problems, absence seizures, anxiety, depression, learning disability, lead poisoning, thyroid dysfunction, trauma
- Ages 4β5: behavioral therapy/parent training first. Consider methylphenidate only if behavioral fails and symptoms severe.
- Ages β₯ 6: stimulant medication + behavioral therapy (the combination outperforms either alone β MTA study).
- First-line stimulants: methylphenidate (Ritalin, Concerta) or amphetamines (Adderall, Vyvanse). Start low, titrate to effect.
- Non-stimulants: atomoxetine (Strattera β SNRI), alpha-2 agonists (guanfacine, clonidine) β useful for stimulant side effects, comorbid tics, or sleep issues
- Monitor: growth (weight, height), BP, HR, sleep, appetite, tics, mood
Autism Spectrum Disorder
A neurodevelopmental disorder with strong genetic contribution (twin concordance ~90% MZ) and altered brain connectivity β differences in social cognition networks, sensory processing, and executive function. Onset before age 3 (though diagnosis may come later). Not caused by vaccines, parenting, or anything the family did.
Domain A β Persistent deficits in social communication and interaction (all 3 required):
- Deficits in social-emotional reciprocity (back-and-forth conversation, sharing interests/emotions)
- Deficits in nonverbal communication (eye contact, gestures, facial expressions)
- Deficits in developing, maintaining, understanding relationships
Domain B β Restricted, repetitive patterns of behavior/interests (β₯ 2 of 4):
- Stereotyped or repetitive motor movements (hand flapping), use of objects, or speech (echolalia)
- Insistence on sameness, rigid routines, ritualized behavior
- Highly restricted, fixated interests of abnormal intensity
- Hyper- or hyporeactivity to sensory input (fascination with lights, aversion to textures/sounds)
Symptoms in early developmental period; cause functional impairment; not better explained by ID.
- 6 mo: no joyful expressions, limited eye contact
- 9 mo: no back-and-forth sounds or facial expressions
- 12 mo: no babbling, no pointing/gestures, no response to name
- 16 mo: no words
- 24 mo: no 2-word phrases
- Any age: loss of skills (regression)
- M-CHAT-R/F at 18 and 24 months β universal screening
- Any concern at any age β refer for formal evaluation and early intervention simultaneously β don't wait
- Early intensive behavioral intervention (ABA, NDBI), speech-language therapy, OT, special education
- No medications for core features
- Treat comorbidities: irritability/aggression (risperidone, aripiprazole β only FDA-approved meds for autism, for irritability), ADHD symptoms, anxiety, sleep disturbance (melatonin), GI issues
- Family support, parent training, respite care
Anorexia Nervosa
Multifactorial β genetic, neurobiologic, psychological, sociocultural. Dysregulation of hunger/satiety circuits, reward processing, and body image perception. Restriction becomes reinforcing (both psychologically and neurobiologically β starvation itself alters serotonin and dopamine signaling).
- Restriction of energy intake β significantly low body weight
- Intense fear of weight gain or behavior that interferes with weight gain
- Disturbance in body image, self-evaluation unduly influenced by weight/shape, or denial of seriousness
- Subtypes: restricting vs. binge-eating/purging
- Vitals: bradycardia, hypotension, orthostatic changes, hypothermia
- Skin: dry, lanugo (fine downy hair β body insulation response), yellowish (hypercarotenemia), acrocyanosis
- Cardiac: prolonged QTc, arrhythmias, mitral valve prolapse, pericardial effusion
- Endocrine: amenorrhea, low T3 (sick euthyroid), delayed puberty, osteoporosis
- GI: delayed gastric emptying, constipation
- Labs: β WBC, β platelets, low electrolytes, low albumin, transaminitis
- < 75% median BMI or rapid weight loss
- HR < 50 daytime or < 45 nighttime
- BP < 90/45
- Temp < 35.6Β°C
- Orthostatic HR increase > 20 or BP drop > 20/10
- Electrolyte abnormalities, arrhythmia, syncope, dehydration, acute food refusal
- Family-Based Therapy (FBT / Maudsley) = first-line for adolescents β parents take charge of refeeding
- Nutritional rehabilitation with slow caloric advancement
- Watch for refeeding syndrome: after prolonged starvation, sudden refeeding causes insulin surge β cells take up phosphate, potassium, magnesium β severe hypophosphatemia, hypokalemia, hypomagnesemia β cardiac arrhythmias, delirium, seizures. Prevent with slow advancement + electrolyte monitoring/supplementation.
- SSRIs don't work for anorexia until weight is restored
- Multidisciplinary team: pediatrics, psychiatry, dietitian, therapy
Bulimia Nervosa
- Recurrent binge eating (large amount + loss of control)
- Recurrent compensatory behavior β vomiting, laxatives, diuretics, fasting, excessive exercise
- β₯ 1Γ/week for β₯ 3 months
- Self-evaluation unduly influenced by weight/shape
- Does not occur exclusively during anorexia
- Weight often normal or slightly elevated β doesn't exclude diagnosis
- Russell's sign β calluses/scars on knuckles from self-induced vomiting
- Parotid gland enlargement ("chipmunk cheeks") β from chronic purging
- Dental erosion β lingual surfaces of upper teeth (perimolysis) from gastric acid
- Esophagitis, Mallory-Weiss tears, aspiration
- Electrolyte derangements: hypokalemia, metabolic alkalosis (from vomiting), hypochloremia
- Menstrual irregularity but usually not amenorrhea
- CBT-E (Enhanced CBT for eating disorders) = first-line
- Fluoxetine (FDA approved; only SSRI with indication) β works for bulimia even at normal weight
- Nutritional counseling, regular meal structure
- Treat electrolyte abnormalities, dental referrals
Binge Eating Disorder
- Recurrent binge eating episodes (large amount + loss of control)
- Associated with β₯ 3 of: eating rapidly, eating until uncomfortably full, eating when not hungry, eating alone (embarrassment), feeling disgusted/guilty after
- Marked distress
- β₯ 1Γ/week for β₯ 3 months
- No compensatory behaviors (distinguishes from bulimia)
Often associated with obesity, depression, shame. Most common eating disorder in adults; also in adolescents. CBT = first-line. Lisdexamfetamine (Vyvanse) is FDA-approved for BED in adults (not first-line in adolescents). SSRIs may help mood symptoms.
ARFID (Avoidant/Restrictive Food Intake Disorder)
- Eating disturbance β significant weight loss, nutritional deficiency, dependence on supplements, or marked psychosocial impairment
- Not about body image or weight concerns (this is the key distinction from anorexia)
- Not explained by food scarcity or a medical/psych condition
- Sensory aversion β extreme picky eating (texture, smell, color)
- Lack of interest in food β low appetite drive
- Fear of consequences β choking, vomiting, allergic reaction (often after a traumatic episode)
Strongly associated with autism spectrum and anxiety disorders.
CBT for ARFID, feeding therapy, OT for sensory issues, nutritional rehabilitation, treat comorbid anxiety. Very different approach than anorexia β weight restoration alone isn't the goal; the underlying driver must be addressed.
Separation Anxiety Disorder
Separation anxiety is normal from 8 months to ~3 years (stranger/separation anxiety develops with object permanence). It becomes a disorder when it's developmentally inappropriate (persisting past expected age or resurfacing), excessive, and functionally impairing.
β₯ 3 of the following, for β₯ 4 weeks in children:
- Excessive distress when separation occurs or is anticipated
- Persistent worry about losing attachment figures (accident, illness, death)
- Persistent worry that an event will cause separation (getting lost, kidnapped)
- Reluctance or refusal to go to school or elsewhere alone
- Reluctance to sleep away from home or without attachment figure nearby
- Nightmares about separation
- Physical symptoms (headaches, stomachaches) when separation occurs or is anticipated
- CBT with graduated exposure = first-line
- SSRI (fluoxetine, sertraline) if moderate-severe or CBT inadequate
- School re-entry plan; don't allow prolonged school avoidance (deepens the pattern)
- Parent training β avoid reinforcing avoidance with excessive accommodation
Generalized Anxiety Disorder
- Excessive anxiety/worry about multiple events, more days than not, for β₯ 6 months
- Difficult to control the worry
- β₯ 1 (in children) of: restlessness, fatigue, difficulty concentrating, irritability, muscle tension, sleep disturbance (adults need 3)
- Clinically significant distress/impairment
- The "worrier" β worries about school, family, future, world events
- Perfectionism, reassurance-seeking
- Somatic: headaches, abdominal pain, fatigue, sleep disturbance
- Often misattributed to "stress" for years before diagnosis
- CBT = first-line
- SSRIs (fluoxetine, sertraline, escitalopram) β all first-line for moderate-severe
- Combination CBT + SSRI = best outcomes (CAMS study)
- Avoid benzodiazepines in pediatrics β dependence risk, disinhibition
Major Depressive Disorder
Complex interaction of genetic vulnerability, neurotransmitter dysregulation (serotonin, norepinephrine, dopamine), stress/HPA axis, and psychosocial factors. In adolescents, hormonal changes, social/academic stress, and developing identity all contribute.
β₯ 5 of the following, β₯ 2 weeks, with at least one being low mood OR anhedonia. Mnemonic: SIGECAPS + mood.
- Sleep disturbance (insomnia or hypersomnia)
- Interest loss (anhedonia)
- Guilt or worthlessness
- Energy loss / fatigue
- Concentration impaired
- Appetite/weight changes
- Psychomotor agitation or retardation
- Suicidal ideation
- Mood (sad/depressed) β or irritability in children/adolescents
In kids/teens, irritability can substitute for depressed mood. "Failure to make expected weight gain" can substitute for weight loss.
- PHQ-A (modified PHQ-9 for adolescents) β 9 symptom questions + 4 follow-ups (duration, impairment, SI in past month, lifetime SI attempt)
- Interview the adolescent privately β essential before anything else (Case 3 step 1)
- Rule out medical: CBC, TSH, CMP, B12, urine tox, mono if indicated
- Rule out substance use (marijuana, alcohol, other)
- Rule out medications β steroids, clonidine, Accutane, beta blockers, OCPs, benzos, thyroid supplements
- Rule out psychiatric comorbidities β ADHD, bipolar, anxiety, substance use disorder
- Screen for suicidality β direct, non-judgmental
- Mild: psychoeducation, CBT, supportive care, regular exercise/sleep/nutrition, follow-up in 1β2 weeks
- Moderateβsevere: SSRI + CBT (TADS study showed combination superior)
- First-line SSRIs in adolescents: fluoxetine (FDA approved β₯ 8 yrs) and escitalopram (β₯ 12 yrs). (Review said you just need to know SSRIs are first-line.)
- Dosing rule: start low, go slow. Increase every 5β7 days to target dose; hold dose 4β6 weeks before further increases.
- Black box warning β SSRIs can transiently increase suicidal ideation in youth; weekly contact for first 4 weeks, every 2 weeks for next month, monthly thereafter for the first 12 weeks.
- Refer to psychiatry if severe, suicidal, multiple diagnoses, or not comfortable managing
Disruptive Mood Dysregulation Disorder (DMDD)
DMDD was added to DSM-5 specifically to reduce overdiagnosis of pediatric bipolar disorder. Kids with chronic irritability and outbursts were being labeled bipolar (and treated with mood stabilizers), but long-term follow-up showed most develop depression or anxiety, not bipolar. DMDD captures this group correctly.
- Severe recurrent temper outbursts (verbal or behavioral) grossly out of proportion to situation
- β₯ 3 times per week
- Persistently irritable/angry mood between outbursts
- Present for β₯ 12 months, no symptom-free period > 3 months
- Present in β₯ 2 settings
- Diagnosis only between ages 6 and 18
- Onset before age 10
Limited evidence base. Psychotherapy (parent management training, CBT). Medications target comorbidities β SSRIs for depression/anxiety symptoms, stimulants for comorbid ADHD. Atypical antipsychotics only for severe aggression.
Oppositional Defiant Disorder & Conduct Disorder
A pattern of angry/irritable mood, argumentative/defiant behavior, or vindictiveness lasting β₯ 6 months, with β₯ 4 symptoms from these categories:
- Angry/irritable mood: loses temper, touchy/annoyed, angry/resentful
- Argumentative/defiant: argues with authority, actively defies rules, deliberately annoys, blames others
- Vindictive: spiteful at least twice in 6 months
ODD does NOT include aggression toward people/animals, destruction, theft, or serious rule violations.
A repetitive pattern of violating rights of others or major age-appropriate norms, with β₯ 3 symptoms in past 12 months from these categories:
- Aggression toward people or animals (bullying, fights, weapons, cruelty, forced sex)
- Destruction of property (fire-setting, vandalism)
- Deceitfulness / theft (breaking in, lying to obtain, shoplifting)
- Serious rule violations (staying out despite parental prohibition before age 13, running away, truancy)
Childhood-onset (< 10) = worse prognosis; adolescent-onset = better. CD can progress to antisocial personality disorder in adulthood (but not always).
- Parent Management Training (PMT) = first-line for ODD
- Multisystemic therapy (MST), functional family therapy for CD
- School-based interventions, mentoring, skills training
- Treat comorbid ADHD (high overlap β treating ADHD alone can resolve ODD in many cases)
- Treat comorbid mood/anxiety disorders
- No medication specifically for ODD or CD β target comorbidities
Neurologic Conditions
Pediatric Headaches (Migraine & Tension)
Migraine: cortical spreading depression + activation of the trigeminovascular system β release of CGRP and other neuropeptides β meningeal inflammation + vasodilation + pain. Genetic (~60% have FH). Tension-type: pericranial muscle contraction, stress, poor sleep, posture; mechanism less well defined.
- Duration in kids: 2β72 hrs (shorter than adults)
- Location: often bilateral in kids (in adults more typically unilateral)
- Quality: throbbing/pulsating
- Severity: moderate-to-severe, interferes with activity
- Associated: photo- and phonophobia (may be inferred from behavior in young kids β seeking dark quiet room), nausea/vomiting
- Aura (sensory, visual, motor) in ~25% β precedes headache by up to 1 hr
Bilateral, band-like, pressing/tightening, mild-moderate, not aggravated by activity, no nausea/vomiting, possibly mild photo- or phonophobia but not both.
Clinical diagnosis β headache diary. Neuroimaging (MRI preferred over CT for peds) only if red flags, abnormal neuro exam, change in pattern, or recent trauma. Routine neuroimaging for recurrent migraines with normal exam = not indicated.
- Acute/abortive:
- First-line: ibuprofen 10 mg/kg or acetaminophen 15 mg/kg β at onset (don't wait to see if it gets bad)
- Triptans: almotriptan β₯ 12 yrs, rizatriptan β₯ 6 yrs, sumatriptan nasal spray β₯ 12 yrs
- Antiemetic (ondansetron) for nausea
- Lifestyle triggers: regular sleep, hydration, regular meals, stress management, identify food triggers (chocolate, cheese, nitrates, MSG) β but individual variation
- Prophylaxis (β₯ 4 headaches/mo or severely disabling): amitriptyline, topiramate, propranolol, cyproheptadine. Riboflavin/magnesium/CoQ10 nutritional supplements
- Medication overuse headache β analgesics > 2β3x/week perpetuate headaches
Breath-Holding Spells
Reflexive response, not volitional. Two types:
- Cyanotic: triggered by anger, frustration, or crying. Child cries forcefully β exhales β breath-holds at end-expiration β cyanosis β brief LOC. More common.
- Pallid: triggered by pain or sudden fright (minor head bump). Vagally mediated bradycardia/asystole β pallor β LOC. Less common.
- Consistent trigger β single cry (cyanotic) or no cry (pallid) β color change β LOC (lasts seconds) β possible brief tonic posturing or myoclonic jerk β spontaneous recovery β tired but otherwise fine
- Peak age 1β3 yrs; resolves by 4β6 yrs
- Family history common
Check iron β iron deficiency anemia is strongly associated with breath-holding; iron supplementation reduces spells in many kids even with only borderline labs. EKG (r/o long QT if pallid/syncopal). EEG only if atypical.
- Reassurance β benign, self-limited, no long-term sequelae, outgrown by school age
- Iron supplementation if deficient or borderline ferritin (< 50)
- Don't reinforce with overreaction β the cyanotic type especially can become a behavior pattern if the child learns it produces a panicked caregiver response
- Keep the child safe during the spell (cushion fall)
Febrile Seizures
Age-dependent susceptibility β immature brain has a lower seizure threshold when body temperature rises rapidly. It's the rate of temperature rise, not the absolute temperature, that's most important. Strong genetic component.
Seizure in a child 6 months to 5 years with fever, without CNS infection, metabolic disturbance, prior afebrile seizure, or other identifiable cause.
Simple febrile seizure (all of the following):
- Generalized (tonic-clonic)
- Duration < 15 minutes
- Single event in 24 hours
- Prior neurologically normal child
Complex febrile seizure (any of the following):
- Focal features
- Duration > 15 minutes
- Recurs within 24 hours
- Postictal neurologic abnormality (e.g., Todd's paralysis)
- Simple febrile seizure with identifiable source of fever: no routine labs, no EEG, no neuroimaging. Focus on the source of fever.
- LP considerations: any child < 12 mo with incomplete or absent Hib/pneumococcal vaccination, any concern for meningitis (irritability, bulging fontanelle, neck stiffness, petechiae), any child on antibiotics (could partially treat meningitis)
- Complex febrile seizure: consider further workup β EEG, labs, imaging depending on features
- Most (> 95%) resolve spontaneously within 5 minutes
- > 5 min or persistent: benzodiazepine (IV lorazepam, IM/rectal midazolam, rectal diazepam)
- Treat the fever source
- Antipyretics for comfort β but they do not prevent recurrence; don't oversell
- Chronic anticonvulsants not indicated for simple febrile seizures
- ~30% recur with future febrile illness; higher if first seizure < 18 mo
- Risk of later epilepsy after simple FS: ~1% (same as general population slightly)
- Complex febrile seizures carry somewhat higher epilepsy risk (~4β15%)
- No long-term neurodevelopmental effects from simple febrile seizures
Epilepsy
Any of:
- β₯ 2 unprovoked seizures > 24 hrs apart, OR
- 1 unprovoked seizure + probability of recurrence β₯ 60% over next 10 yrs, OR
- Diagnosis of an epilepsy syndrome
- Focal onset β one brain region; may have motor or nonmotor signs; may impair awareness or not; may spread to bilateral tonic-clonic
- Generalized onset β bilateral networks from the start: tonic-clonic, absence, myoclonic, atonic, tonic, clonic
- Unknown onset
- Childhood absence epilepsy: 4β10 yrs, brief staring spells (5β10 sec), multiple daily, subtle eye fluttering; EEG = 3 Hz spike-and-wave; triggered by hyperventilation in clinic. Often remits by adolescence. Tx: ethosuximide first-line.
- Benign rolandic epilepsy (BECTS): 3β13 yrs, nocturnal facial/oropharyngeal twitching, drooling, speech arrest; EEG = centrotemporal spikes; outgrown by puberty.
- Juvenile myoclonic epilepsy (JME): adolescent onset, morning myoclonic jerks (drops toothbrush, spills cereal), GTC seizures, sometimes absence; lifelong treatment needed; levetiracetam or valproate.
- Infantile spasms (West syndrome): sudden flexor/extensor "jackknife" spasms in clusters, 3β12 mo; EEG = hypsarrhythmia; developmental regression; urgent β ACTH or vigabatrin.
EEG (awake + sleep, often with hyperventilation and photic stimulation), MRI brain (preferred over CT; CT only for acute setting β bleed, mass). Labs if metabolic cause suspected. Genetic testing for specific syndromes.
- AED selection based on seizure type + syndrome
- Monotherapy preferred; 2/3 seizure-free on first or second agent
- Goal: seizure freedom with minimal side effects
- Refractory (2 drugs failed) β refer to epileptologist; consider ketogenic diet, VNS, epilepsy surgery
- Counsel about driving, bathing safety, seizure action plan, medication adherence
Concussion / Mild Traumatic Brain Injury
Traumatic force (direct or inertial) β axonal stretch β neurometabolic cascade: KβΊ efflux, glutamate release, ionic imbalance, mitochondrial dysfunction, vasoreactivity changes β energy crisis. Imaging is normal β this is a functional disturbance, not a structural injury.
Any combination of:
- Physical: headache, nausea/vomiting, dizziness, light/noise sensitivity, balance problems, fatigue, blurred vision
- Cognitive: slowed thinking, difficulty concentrating, memory problems, feeling "foggy"
- Emotional: irritability, sadness, anxiety, emotional lability
- Sleep: sleeping more or less, trouble falling asleep
Loss of consciousness is not required for diagnosis β most concussions have no LOC.
Age < 2 years β CT if any of:
- AMS or signs of AMS
- Palpable skull fracture
- Scalp hematoma (non-frontal, in infants)
- LOC > 5 seconds
- Severe mechanism (MVC, fall > 3 ft, high-impact object)
- Not acting normally per parent
Age β₯ 2 years β CT if any of:
- AMS or signs of AMS
- Signs of basilar skull fracture (hemotympanum, Battle's sign, raccoon eyes, CSF otorrhea/rhinorrhea)
- LOC
- Vomiting
- Severe headache
- Severe mechanism
- Initial relative rest 24β48 hrs (physical AND cognitive β limit screens, schoolwork)
- Avoid strict prolonged rest β older "sit in a dark room until symptoms resolve" approach is outdated and actually prolongs recovery
- Gradual symptom-limited return to activity after 24β48 hrs β light aerobic activity (walking, stationary bike) below symptom threshold actually speeds recovery
- Return to school before return to play β graduated academic accommodations
- Stepwise return-to-play protocol β each step takes β₯ 24 hrs; any symptom return β step back and rest 24 hrs
- Acetaminophen for headache (avoid NSAIDs in the first 24β48 hrs due to bleeding concerns, then OK)
You've got this, Sasha.
Every condition here maps to the exam review transcript and Dr. [reviewer]'s emphasis. Walk through the three case studies one more time before exam day β the reasoning is the content.