321|Hypoglycemia|Low blood glucose in infants and children: definitions, causes from ketotic fasting hypoglycemia to hyperinsulinism, clinical recognition, and treatment goals.
322|Undescended Testis|[[356|Cryptorchidism]]: epidemiology, evaluation distinguishing true UDT from retractile testis, red flags for disorders of sex development, and timing of orchiopexy.
324|Nasal Fracture|Pediatric nasal fractures: recognizing septal hematoma as an emergency, why imaging is rarely needed, and timing of closed reduction.
327|Splenic Injury|Pediatric blunt splenic injury: mechanisms, AAST grading, the shift to nonoperative management, and the lifelong infection risk of resulting asplenia.
331|Epiglottitis|Epiglottitis/supraglottitis: the abrupt drooling-dysphagia-distress triad, why it must not be confused with croup, and controlled airway management plus antibiotics.
333|Metabolic Syndrome|Metabolic syndrome as cardiometabolic risk factor clustering: the adult NCEP ATP III criteria, why pediatrics avoids a fixed definition, and the AAP-recommended screen-and-treat-each-component approach.
337|Thyroid Nodule|Pediatric thyroid nodules: why they carry higher malignancy risk than in adults, the TSH-and-ultrasound evaluation pathway, FNAB indications, and MEN2/RET considerations.
338|Toxic Ingestion|The general approach to a child with a suspected poisoning: who is at risk, the wide range of presentations, and why ingestion belongs on the differential for almost any unexplained symptom complex.
339|Tinea Capitis|Tinea capitis: T. tonsurans vs M. canis epidemiology, endothrix/ectothrix pathophysiology, kerion recognition, and why systemic (not topical) antifungal therapy is required.
341|Toxoplasmosis|Congenital and acquired toxoplasmosis: trimester-dependent transmission and severity, the classic triad, hydrocephalus management, and serologic diagnosis of ocular disease.
343|Visual Impairment|Pediatric visual impairment: acuity-based grading, the developed-vs-developing world etiology split, cortical visual impairment as the leading cause in developed countries, and infancy red flags for early detection.
347|Acute Pancreatitis|Pediatric acute pancreatitis: the 2-of-3 diagnostic criteria, drug and multisystem-disease causes, and the favorable prognosis versus the minority who progress to recurrent or chronic disease.
353|Cellulitis|Pediatric cellulitis: exposure-based pathogen clues, distinguishing it from erysipelas, red flags for parenteral therapy, and first-line oral antibiotic choices.
355|Chorioamnionitis|Chorioamnionitis / Triple I: clinical diagnostic criteria, GBS/E. coli as the key neonatal pathogens, and the tiered newborn evaluation pathway based on gestational age and clinical appearance.
357|Chronic Sinusitis|Pediatric chronic sinusitis: the 90-day threshold distinguishing it from acute/subacute disease, its milder presentation and distinct microbiology, and the empiric-antibiotic-then-ENT-referral treatment pathway.
360|Dilated Cardiomyopathy|Pediatric dilated cardiomyopathy: age-dependent presentation (GI symptoms and failure to thrive in young children vs adult-like heart failure in adolescents), genetic and acquired causes, and the heart-failure treatment ladder toward transplantation.
362|Exercise-Induced Asthma|Exercise-induced bronchoconstriction: the exercise-challenge (not methacholine) diagnostic pathway, the 15% FEV1 drop criterion, mimicking conditions, and pre-exercise versus controller-step-up treatment decisions.
364|Fetal Alcohol Syndrome|Fetal alcohol syndrome within the FASD spectrum: the exact 4-part diagnostic criteria, why no alcohol amount in pregnancy is safe, and the lifelong but improvable neurobehavioral course.
366|Fragile X Syndrome|Fragile X syndrome: the FMR1 CGG-repeat mechanism and genetic anticipation, why physical features and macro-orchidism appear late, and the case for early molecular testing over exam-based screening.
369|Glomerulonephritis|Pediatric glomerulonephritis: the nephritic syndrome, APSGN as the dominant acute cause versus RPGN and chronic MPGN, and the C3-guided diagnostic approach.
370|Hair Loss|Pediatric alopecia: distinguishing [[346|alopecia areata]], telogen effluvium, [[339|tinea capitis]], and trichotillomania by pattern and history, plus neonatal causes and Wood-lamp diagnostic pitfalls.
371|Influenza A|Seasonal [[298|influenza]] A infection in children: antigenic subtyping and drift, the age-dependent clinical picture from classic myalgic illness to infant sepsis-like presentation, and antiviral treatment indications.
372|Hiv Infection|Pediatric HIV: transmission routes, early manifestations including AIDS-defining illness in the first months of life, pediatric-specific findings like chronic parotid swelling and LIP, and the CD4-based classification and ART-based management approach.
375|Idiopathic Intracranial Hypertension|Pediatric IIH/pseudotumor cerebri: the normal-imaging-plus-elevated-opening-pressure diagnostic criteria, why false-positive diagnosis is common, medication/obesity associations, and the vision-preservation treatment goal.
377|Insomnia|Pediatric insomnia: behavioral insomnia of childhood subtypes (sleep-onset association, limit-setting), the ICSD-3 subtype list, and why behavioral management, not medication, is first-line.
379|Intracranial Hemorrhage|Intracranial hemorrhage across the pediatric age spectrum: neonatal germinal matrix/IVH and subarachnoid/cerebellar hemorrhage by gestational age, versus childhood hemorrhagic stroke from vascular anomalies, coagulopathy, and SCD.
381|Juvenile Dermatomyositis|Juvenile dermatomyositis: the Bohan-Peter diagnostic criteria, its vasculopathic pathophysiology distinguishing it from adult disease, MRI-first work-up, and extramuscular complications including ILD and calcinosis.
383|Laceration|Pediatric laceration management: hemostasis and deep-structure risk (especially neck and lateral palatal injuries), LET topical anesthesia, dog-bite cervicofacial repair, and abuse-pattern red flags.
385|Laryngomalacia|Laryngomalacia: the omega-shaped epiglottis on laryngoscopy, typical timing and positional pattern of stridor, GERD/dysphagia associations, and when expectant management gives way to supraglottoplasty.
387|Metabolic Acidosis|Pediatric metabolic acidosis: distinguishing acute (diarrhea, shock, DKA) from chronic (RTA, renal insufficiency, inborn errors) causes, the anion-gap work-up, and why bicarbonate bolus therapy is risky and reserved for last resort.
391|Oligohydramnios|Oligohydramnios and the Potter sequence: MVP-based definition, renal versus non-renal causes, the pulmonary hypoplasia and compression-deformity consequences, and anticipated newborn findings.
393|Peanut Allergy|Peanut allergy prevention and management: LEAP-trial-based early introduction guidelines by [[288|eczema]]/egg-allergy risk tier, skin-prick/IgE risk stratification, and [[143|anaphylaxis]] treatment.
396|Pneumothorax|Pediatric pneumothorax: spontaneous (primary vs secondary) vs traumatic/iatrogenic classification, neonatal incidence and tension-pneumothorax risk, and needle/chest-tube decompression technique.
398|Polytrauma|Pediatric polytrauma: unique anatomic/physiologic vulnerabilities (blood-loss compensation, thin padding, cervical spine), the ABCDE approach, causes of persistent shock beyond hemorrhage, and multidisciplinary trauma team management.
399|Posterior Urethral Valves|Posterior urethral valves: presentation across the diagnostic spectrum from prenatal hydronephrosis to delayed childhood UTI, VCUG-based diagnosis, endoscopic ablation, and long-term renal prognosis by VUR pattern.
404|Vulvovaginitis|Prepubertal vulvovaginitis: why unestrogenized anatomy predisposes to nonspecific disease, the discharge-versus-irritation distinction that flags a specific infectious cause, and when a finding should trigger a sexual abuse evaluation.