Pediatrics

Clinical Presentation

Most common in young children (typically 1–3 years), reflecting oral exploration behavior combined with immature airway protective reflexes and molar teeth not yet developed for adequate chewing (peanuts/nuts classically implicated, along with other small food items and toy components). Classic presentation: a witnessed or strongly suspected choking episode, followed by coughing, wheezing, or stridor depending on obstruction level — though a significant proportion present with a more insidious, delayed history (unwitnessed choking or a child too young to communicate), leading to delayed diagnosis presenting as recurrent/persistent unilateral wheeze, recurrent pneumonia in the same lung segment, or chronic cough. This delayed/atypical pattern is a frequently-tested pearl, since foreign body aspiration must remain on the differential for persistent unilateral respiratory findings even without a clear witnessed choking history.

Radiological Features

Since most aspirated foreign bodies in children are radiolucent (food items, plastic toy fragments), plain chest X-ray is frequently normal or shows only indirect signs — a normal chest X-ray does not exclude aspiration:

• Air trapping/hyperinflation on the affected side, best demonstrated on an expiratory film (or lateral decubitus film with the suspected side dependent, in a young child unable to cooperate with breath-holding) — a ball-valve obstruction mechanism analogous to that in meconium aspiration
• Atelectasis distal to a completely obstructing foreign body
• Mediastinal shift — away from the affected side with air trapping, or toward it with complete obstruction/atelectasis
• Directly visible radiopaque foreign body, when the object itself is radiopaque (a minority of cases)

Emergency Maneuvers (acute, witnessed choking with severe/complete obstruction)

For an infant: back blows and chest thrusts (not abdominal thrusts, avoided given risk of visceral injury) — alternating cycles until the object is expelled or the infant becomes unresponsive. For a child beyond infancy: the Heimlich maneuver (abdominal thrusts), as in adult choking emergencies. If the child becomes unresponsive, standard CPR is initiated, with rescuers checking the mouth for a visible object before each set of rescue breaths and removing it if directly visualized (blind finger sweeps avoided, given risk of pushing the object further into the airway).

Rigid Bronchoscopy — Definitive Management

Rigid bronchoscopy under general anesthesia is the definitive diagnostic and therapeutic procedure, allowing both visualization/confirmation and retrieval using specialized grasping instruments — generally preferred over flexible bronchoscopy for retrieval in children, given superior instrument channel size and ability to simultaneously ventilate through the rigid scope. Indications: strongly suggestive clinical history (even with a normal CXR, given frequent radiolucency) combined with supportive radiological findings (air trapping, atelectasis), or, in acute severe respiratory distress with a witnessed/strongly suspected aspiration event, emergency bronchoscopy without extensive prior imaging where clinical urgency warrants immediate intervention.

Definition

Pediatric hypertension is defined using age-, sex-, and height-specific percentile-based BP norms (rather than fixed absolute values as in adults), reflecting substantial normal variation across childhood growth. A hypertensive emergency refers to severely elevated BP accompanied by evidence of acute target organ damage (hypertensive encephalopathy, acute heart failure/pulmonary edema, AKI, or retinal hemorrhage/papilledema) — requiring prompt, controlled BP reduction, distinguished from hypertensive urgency (severely elevated BP without acute end-organ damage, allowing more gradual correction).

Etiology — Secondary Causes Predominate in Children

Unlike adults, where primary (essential) hypertension predominates, children — particularly younger children and those with more severe hypertension — much more frequently have an identifiable secondary cause:

• Renal causes (most common category overall) — glomerulonephritis, hemolytic uremic syndrome, renal artery stenosis, reflux nephropathy, polycystic kidney disease
• Renovascular causes — renal artery stenosis (fibromuscular dysplasia; associated with neurofibromatosis or Takayasu arteritis in some regions)
• Endocrine causes — pheochromocytoma, Cushing syndrome, congenital adrenal hyperplasia, hyperthyroidism
• Cardiovascular causes — coarctation of the aorta (classic presentation with hypertension and reduced/absent femoral pulses — an essential examination finding to check in any hypertensive child)
• Medication/substance-induced — corticosteroids, certain immunosuppressants, sympathomimetic drug use/toxicity

Target Organ Damage Assessment

Neurological assessment for hypertensive encephalopathy (headache, altered mental status, visual disturbance, seizures — related to failure of cerebral autoregulation causing hyperperfusion/edema, conceptually related to PRES); cardiovascular assessment for acute heart failure/pulmonary edema; renal function for AKI; and fundoscopic examination for papilledema/hemorrhage.

Choice of Intravenous Antihypertensive Agents

Controlled, gradual BP reduction using continuously titratable IV agents in a monitored setting, avoiding overly rapid correction (which risks cerebral hypoperfusion/ischemic injury given adapted cerebral autoregulation) — a general target of reducing BP by no more than ~25% within the first 8 hours, with further gradual correction over 24–48 hours.

Choice among these is individualized based on clinical scenario, comorbid conditions, and institutional familiarity, with continuous BP monitoring (arterial line preferred in the most severe cases) essential throughout for precise, safe titration.

Kussmaul Breathing

A distinctive, deep, labored, typically rapid respiratory pattern representing a physiological compensatory response to severe metabolic acidosis — increasing alveolar ventilation to “blow off” CO₂, reducing PaCO₂ and partially compensating for the metabolic acidosis by raising pH via the respiratory component. Its presence should immediately prompt evaluation for an underlying cause, most classically (though not exclusively) diabetic ketoacidosis.

Differential Diagnosis of High Anion Gap Metabolic Acidosis

The anion gap (Na⁺ − [Cl⁻ + HCO₃⁻], normal ~8–12 mEq/L) distinguishes accumulation of unmeasured acid anions (high anion gap) from bicarbonate loss with compensatory chloride retention (normal/hyperchloremic gap, e.g., diarrhea, renal tubular acidosis). The classic mnemonic (“MUDPILES” or similar variants):

• Methanol
• Uremia (renal failure — accumulation of unmeasured anions from impaired excretion)
• Diabetic ketoacidosis (and other ketoacidoses — alcoholic, starvation)
• Propylene glycol / Paraldehyde
• Isoniazid / Iron toxicity
• Lactic acidosis (any cause of tissue hypoperfusion/hypoxia — sepsis, shock, seizures, inborn errors of metabolism with impaired lactate clearance)
• Ethylene glycol
• Salicylates

In pediatric emergency practice specifically, the most commonly encountered causes are diabetic ketoacidosis, sepsis/shock-associated lactic acidosis, inborn errors of metabolism (particularly infants with unexplained severe acidosis), and toxic ingestions (salicylates, and less commonly methanol/ethylene glycol).

Indications for Sodium Bicarbonate Therapy

A genuinely important, frequently-tested nuanced point: sodium bicarbonate is NOT a routine or first-line treatment for metabolic acidosis in most contexts, and indiscriminate use carries recognized harms — paradoxical worsening of intracellular acidosis (CO₂ diffuses more rapidly across cell membranes than bicarbonate), hypernatremia/hyperosmolality, and, specifically in DKA management, an established association with increased cerebral edema risk (see Q26) — a favorite examiner cross-link.

Appropriate, evidence-supported indications:

• Severe, life-threatening acidosis with hemodynamic compromise — particularly where acidosis itself impairs cardiac contractility/catecholamine responsiveness (a relative indication, individualized to severity)
• Specific toxicological indications — salicylate poisoning (bicarbonate corrects acidosis AND alkalinizes urine to enhance renal salicylate elimination via ion trapping, and alkalinizes serum to reduce the CNS-penetrant non-ionized fraction) and tricyclic antidepressant overdose (narrows a widened QRS/treats cardiotoxicity via a sodium-channel-related mechanism) — both genuinely mechanistically-targeted, distinct from generic acidosis correction
• Severe hyperkalemia with life-threatening ECG changes, as one component of broader hyperkalemia management (shifting potassium intracellularly)
• DKA specifically — bicarbonate is now explicitly NOT routinely recommended even with quite severe acidosis, given the cerebral edema association; contemporary protocols reserve consideration only for the most extreme, life-threatening circumstances (e.g., severe acidosis with hemodynamic compromise/impending cardiac arrest)

Throughout, the overarching management principle remains identification and treatment of the underlying cause of acidosis (fluid/insulin for DKA, resuscitation and source control for sepsis-associated lactic acidosis, specific antidotal therapy for toxin-induced acidosis), with bicarbonate reserved as an adjunct for specific, defined indications rather than a generic, reflexive “buffer.”

The Two Parallel Frameworks

India operates two related but distinct immunization frameworks: the Universal Immunization Programme (UIP), the government-funded schedule delivered free of cost through the public health system, and the IAP (Indian Academy of Pediatrics) Advisory Committee on Vaccines and Immunization Practices (ACVIP) schedule, representing the professional body's evidence-based recommendations, including a broader range of vaccines not currently funded under UIP, intended for private-sector/individual family decision-making.

UIP Schedule — Current Structure

• At Birth: BCG, OPV-0, Hepatitis B birth dose
• 6, 10, 14 weeks: Pentavalent vaccine (DPT + Hepatitis B + Hib) ×3 doses, OPV ×3 doses, Fractional IPV (fIPV) at 6 and 14 weeks (intradermal, dose-sparing), Rotavirus vaccine ×3 doses, Pneumococcal Conjugate Vaccine (PCV) ×3 doses (recent, phased national rollout addition, now covering all states)
• 9–12 months: Measles-Rubella (MR) first dose, Japanese Encephalitis (JE) vaccine in endemic districts, Vitamin A first dose
• 16–24 months: DPT booster-1, OPV booster, MR second dose, JE second dose (endemic areas), Vitamin A subsequent doses (up to 5 years, every 6 months)
• 5–6 years: DPT booster-2
• 10 and 16 years: Td (Tetanus-diphtheria, adult formulation, replacing earlier TT-only approach)
• Pregnant women: Td vaccination included as part of UIP

Newly Introduced/Recently Expanded UIP Vaccines — High-Yield Specifics

• nOPV2 (novel OPV type 2): genetically modified for greater stability, substantially reducing reversion risk vs original Sabin OPV2; used specifically for outbreak response to cVDPV2, not routine scheduled immunization.
• PCV: phased introduction, now nationally available (PCV10/PCV13), given at 6, 10, 14 weeks — 3-primary-dose schedule under UIP, no separate booster (unlike some private 3+1 schedules).
• Rotavirus vaccine: oral, live-attenuated, now universally available across all states, given at 6, 10, 14 weeks.
• HPV vaccine: not yet universal in UIP; India's indigenous Cervavac (quadrivalent) introduced in select state programs, targeting adolescent girls (and boys per IAP).
• DTaP combinations: whole-cell DPT (wP) remains UIP-standard (lower cost, comparable/superior pertussis efficacy despite reactogenicity); DTaP is IAP-recommended/private-sector, favored for boosters and children with prior significant wP reactions.

IAP ACVIP-Specific Additional Recommendations (Not in UIP)

Hepatitis A vaccine, Varicella (chickenpox) vaccine, Typhoid Conjugate Vaccine (TCV) (usable from 6 months, longer immunity than polysaccharide Vi vaccine), Meningococcal conjugate vaccine, Influenza vaccine (annual), and HPV vaccine for adolescents.

Comparing UIP and IAP Philosophies

UIP reflects a population-level, cost-effectiveness-driven, programmatically feasible approach prioritizing vaccines with greatest demonstrated public health impact within resource constraints, while IAP ACVIP reflects an individual-patient, evidence-based, comprehensive protection philosophy less constrained by programmatic cost — examiners often ask candidates to articulate this distinction explicitly.

Pathophysiology of Plasma Leakage

The defining feature distinguishing DHF/DSS from uncomplicated dengue fever is increased vascular permeability leading to plasma leakage from the intravascular compartment into extravascular spaces (pleural, peritoneal, interstitial) — a capillary leak syndrome, not primarily a hemorrhagic process. Mechanism involves direct viral endothelial effects, immune-mediated injury (notably antibody-dependent enhancement, ADE in secondary heterologous-serotype infection, where pre-existing non-neutralizing antibodies enhance viral uptake into Fc-receptor cells), and a cytokine storm (TNF-α, IL-6). Plasma leakage is most pronounced around defervescence (day 3–7) — a critical timing point since resolving fever can falsely reassure.

WHO 2009 Revised Classification

• Dengue without warning signs
• Dengue with warning signs: abdominal pain/tenderness, persistent vomiting, clinical fluid accumulation (ascites, pleural effusion), mucosal bleeding, lethargy/restlessness, liver enlargement >2cm, and rising hematocrit with concurrently falling platelets (reliable early indicator of impending plasma leakage)
• Severe dengue: severe plasma leakage (shock/DSS or fluid accumulation with respiratory distress), severe bleeding, or severe organ involvement (liver AST/ALT ≥1000, CNS impaired consciousness, heart or other organs)

Staging/Phases of Illness

Triphasic course: febrile phase (2–7 days), critical phase (begins around defervescence, lasts 24–48 hrs, maximal leakage/shock risk), recovery/convalescent phase (spontaneous reabsorption over 48–72 hrs with diuresis).

Fluid Management Algorithm — The Core of Severe Dengue Management

Principle: give just enough fluid to compensate for ongoing leakage without over-resuscitating — excess fluid during the critical phase cannot be retained intravascularly and worsens effusions/ascites once recovery-phase reabsorption occurs.

Monitoring & Red Flag Signs

Serial hematocrit (rising = ongoing leakage needing more fluid; falling in an unstable patient may indicate hemorrhage, not successful resuscitation), platelet trend, vital signs, urine output, vigilance for both inadequate resuscitation and fluid overload.

Pathogenesis

TBM results from hematogenous dissemination of Mycobacterium tuberculosis during primary infection, seeding the meninges and forming Rich foci (subpial/subependymal). TBM develops when a Rich focus ruptures into the subarachnoid space, triggering intense inflammatory exudate accumulating predominantly at the base of the brain (basal exudate) — explaining cranial nerve palsies (CN III, IV, VI, VII), obliterative vasculitis (infarction of basal ganglia/internal capsule), and obstructive/communicating hydrocephalus.

Modified British MRC (BMRC) Staging

Stage III at presentation is strongly associated with significantly worse outcomes (higher mortality and disability) — a frequently-tested prognostic anchor.

CSF Diagnostic Markers

• Lymphocytic pleocytosis (early neutrophilic predominance can occur, mimicking bacterial meningitis)
• Markedly elevated protein (sometimes xanthochromic or spontaneously clotting)
• Low CSF glucose (low CSF:blood glucose ratio)

Specific Diagnostic Tests

• GeneXpert MTB/RIF (Ultra): rapid PCR-based test detecting M. tuberculosis DNA and rifampicin resistance within hours; sensitivity improved with Ultra but remains imperfect — negative result does not fully exclude TBM.
• CSF Adenosine Deaminase (ADA): T-lymphocyte activity marker; elevated in TBM (also lymphoma — specificity limitation); useful when molecular testing unavailable/equivocal.
• CSF culture: traditional gold standard with full drug-susceptibility testing, but weeks-long turnaround limits acute utility — treatment started empirically.

Neuroimaging Features

MRI (preferred over CT) shows: basal meningeal enhancement (most characteristic finding), hydrocephalus, infarcts (basal ganglia/internal capsule), and tuberculomas (which may paradoxically enlarge/appear during effective ATT — immune reconstitution phenomenon, distinct from true treatment failure).

Anti-Tubercular Therapy (ATT) Regimens

Intensive phase: 2 months, four drugs — Isoniazid, Rifampicin, Pyrazinamide, Ethambutol (INH/PZA good CSF penetration even without inflammation; RIF/EMB penetration more inflammation-dependent). Continuation phase: Isoniazid + Rifampicin. Total duration: 9–12 months (longer than standard 6-month pulmonary TB course).

Role of Corticosteroids and Thalidomide

Dexamethasone is a well-established adjunct across essentially all disease stages/severities in pediatric TBM (broader role than in adult TBM/pericarditis), shown to reduce mortality by limiting inflammation-mediated secondary injury.

Thalidomide is a specific adjunct for tuberculomas with mass effect/paradoxical enlargement and for TBM-associated optochiasmatic arachnoiditis, via anti-TNF-α immunomodulation — a complication-specific, not routine, role.

WHO Clinical Staging

Early Infant Diagnosis (EID) — A Distinct Diagnostic Challenge

Standard antibody-based serology is unreliable in infants because maternal IgG (including anti-HIV antibodies) crosses the placenta and can persist up to 18 months. Virological testing is required for definitive early diagnosis:

• HIV-DNA PCR / HIV-RNA PCR: detects virus itself, unconfounded by maternal antibody, allows accurate diagnosis from a younger age.
• Standard protocol: initial virological test at 4–6 weeks of age, confirmatory second test if positive, continued follow-up testing for ongoing-exposure infants (e.g., breastfeeding).
• Antibody testing is reliable only after 18 months of age, once maternal antibody has cleared.

First-Line ART — Indications and Regimens

Reflecting the global 'test and treat' philosophy, ART is recommended in ALL children diagnosed with HIV regardless of clinical stage/CD4, as soon as possible after diagnosis and family readiness.

• Regimen: two NRTIs + a third agent, with the third agent age/weight-dependent.
• Younger children/infants below weight threshold: LPV/r (Lopinavir/ritonavir)-based regimens historically preferred (limited dolutegravir formulations available for youngest ages).
• Increasing availability of pediatric dolutegravir (including dispersible tablets) is making DTG-based regimens preferred across a broader age range, mirroring the adult shift.
• NRTI backbone: commonly abacavir/lamivudine or zidovudine/lamivudine depending on regional protocol.

Management of Opportunistic Infections

• PCP: high-dose co-trimoxazole; prophylaxis for all HIV-exposed infants from 4–6 weeks until infection excluded (or continued per age/immunological criteria if confirmed).
• Tuberculosis: major co-morbidity; attention to rifampicin–ART drug interactions and timing of ART initiation to balance efficacy against IRIS risk.
• Other OIs: recurrent bacterial infections, oral/esophageal candidiasis, and, in advanced disease, additional AIDS-defining conditions per WHO Stage 4.

CDC/WHO Diagnostic Criteria

• Age: typically <18–21 years (CDC) or <19 years (WHO)
• Fever: ≥3 days (WHO) or ≥24 hrs subjective/objective (CDC)
• Evidence of multisystem (≥2 organ systems) involvement: cardiac, renal, respiratory, hematologic, gastrointestinal, dermatologic, or neurological
• Elevated inflammatory markers: CRP, ESR, procalcitonin, ferritin, others
• No alternative plausible diagnosis
• Evidence of current/recent SARS-CoV-2 infection or close contact within preceding weeks — MIS-C is a delayed, post-infectious phenomenon, manifesting 2–6 weeks after acute infection (which may have been mild/asymptomatic)

Clinical Features

Persistent fever is essentially universal. GI symptoms are particularly prominent (abdominal pain, vomiting, diarrhea — can mimic acute appendicitis). Cardiovascular involvement is defining: myocardial dysfunction, shock (more common/severe than in classic Kawasaki disease, often requiring ICU/inotropic support), coronary artery abnormalities, arrhythmias. Mucocutaneous features overlap with Kawasaki disease but are often less complete. Neurological involvement (headache, altered mental status) can occur.

Differentiation from Kawasaki Disease

Therapeutic Management

• IVIG: first-line, single high-dose infusion (2 g/kg), drawing on Kawasaki disease evidence base.
• Corticosteroids: increasingly used upfront with IVIG (not just for refractory cases as in classic KD) — a notable practice divergence.
• Biologic agents (anakinra, less commonly infliximab): escalation therapy for IVIG/steroid-refractory cases.
• Supportive/critical care: fluid resuscitation, vasoactive/inotropic support, mechanical circulatory support in severe cases.
• Antithrombotic therapy: low-dose aspirin; therapeutic anticoagulation for significant coronary aneurysm/ventricular dysfunction risk.
• Long-term follow-up: serial echocardiography for coronary artery surveillance.

Clinical Presentation

Scrub typhus, caused by Orientia tsutsugamushi, transmitted via infected trombiculid mites (chiggers), presents with acute fever, headache, myalgia, malaise. The eschar — a painless, black, necrotic ulcer with erythematous halo at the bite site — is the classic, pathognomonic finding, though not universally present (often in occult sites: axilla, groin, skin folds). Generalized lymphadenopathy and a later-appearing maculopapular rash are additional features. Untreated disease can progress to ARDS, myocarditis, hepatic dysfunction, AKI, meningoencephalitis, and DIC.

Diagnostic Tests

• Weil-Felix test: older, low-cost indirect agglutination test; poor sensitivity/specificity, largely superseded.
• IgM ELISA: current preferred test, better sensitivity/specificity; antibody response may not be detectable until ~1st week of illness (early false negatives possible).
• PCR-based testing: earlier/more specific diagnosis where available, limited outside reference labs.

Treatment

Doxycycline is the treatment of choice across all age groups including young children — short-course use (typically 7 days, or until afebrile for a defined period) is supported even under 8 years given severe mortality risk of undertreated disease vs largely theoretical dental staining risk. Azithromycin is an effective alternative, particularly favored in pregnancy and in young children where doxycycline reluctance persists. Response is typically rapid and dramatic, with defervescence within 24–48 hours — sometimes used as a pragmatic diagnostic/therapeutic trial in endemic areas.

Etiology Across Age Groups

CSF Interpretation

Neutrophilic pleocytosis (vs lymphocytic in viral meningitis/TBM, though early overlap can occur), elevated protein, markedly reduced glucose (CSF:blood ratio typically <0.4). This combination is the classic bacterial signature.

Empiric Antibiotic Regimens

• Neonates: Ampicillin + third-generation cephalosporin (Cefotaxime preferred over ceftriaxone given biliary sludging/kernicterus risk) or an aminoglycoside — ampicillin essential for Listeria coverage.
• Infants and older children: Third-generation cephalosporin (Ceftriaxone/Cefotaxime) backbone, with Vancomycin commonly added empirically pending susceptibility given resistant S. pneumoniae concern.

Role of Adjunctive Dexamethasone

Established evidence for reducing hearing loss, best demonstrated for Hib meningitis, less robust for pneumococcal, and less clear for meningococcal meningitis. Critical timing point: dexamethasone must be given before or concurrently with the first antibiotic dose — giving it after does not confer the same benefit.

Complications

• Subdural effusion (common in young infants, usually managed conservatively)
• SIADH (careful fluid management to avoid both under- and over-hydration)
• Sensorineural hearing loss (most common significant sequela — mandates formal audiological assessment for every child post-meningitis)
• Seizures (acute and long-term epilepsy risk)
• Hydrocephalus, cerebral infarction, long-term neurodevelopmental impairment (most severe cases)