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PE31.1-14 | Tuberculosis and Febrile Infections — Practice Quiz
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A 5-year-old girl presents with 3-week history of low-grade fever, weight loss, and fatigue. Her father was diagnosed with pulmonary tuberculosis 2 months ago. On examination, there is no BCG scar, she has mild cervical lymphadenopathy, and her Mantoux test shows 12 mm induration. Chest X-ray shows right hilar enlargement. Which of the following best describes the Mantoux cut-off for a strongly positive result in this child?
Correct. In immunocompetent children with TB contact (or other risk factors), Mantoux ≥10 mm is considered positive. The ≥5 mm cut-off applies to immunocompromised children (HIV-positive, on immunosuppressants) or those with very high-risk exposure.
Mantoux ≥10 mm = positive in immunocompetent children at risk; ≥5 mm in immunocompromised. BCG vaccination alone does not change interpretation when there is definite TB contact.
The standard cut-off is ≥10 mm for immunocompetent children with risk factors. The ≥5 mm threshold is reserved for immunocompromised children. A 15–20 mm threshold would miss many true positives.
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A 4-year-old boy is diagnosed with primary pulmonary tuberculosis. His weight is 16 kg. According to India's NTEP weight-band dosing for the 2HRZE/4HRE regimen, which of the following describes the correct treatment approach?
Correct. NTEP (formerly RNTCP) now uses daily fixed-dose combination (FDC) tablets dosed by weight band: 2 months of HRZE (intensive) + 4 months of HRE (continuation). Use the appropriate weight-band FDC tablet count for this 16 kg child.
NTEP (National Tuberculosis Elimination Programme, the new name — never RNTCP in current practice) mandates daily FDC weight-band therapy: 2HRZE + 4HRE for drug-susceptible TB in children.
Thrice-weekly regimens are no longer recommended by NTEP. NTEP uses the abbreviation NTEP (not RNTCP). Streptomycin injections are not part of first-line childhood TB therapy. All four drugs (HRZE) are used in the intensive phase.
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A 3-year-old child, a household contact of a smear-positive pulmonary TB patient, has a Mantoux of 8 mm and a normal chest X-ray. She is asymptomatic and well-nourished. What is the recommended action under NTEP guidelines?
Correct. Under NTEP, all children under 5 years who are household contacts of smear-positive TB, regardless of Mantoux result or BCG status, should receive Isoniazid Preventive Therapy (IPT) for 6 months to prevent progression to active TB.
IPT (isoniazid 6 months) for ALL children <5 years and HIV-positive children of any age who are household contacts of smear-positive TB — regardless of Mantoux result.
This child has latent TB infection risk (under 5, household contact) — she needs IPT not full treatment. Waiting and repeating Mantoux delays necessary prophylaxis. BCG alone is not sufficient management for a young TB contact.
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An 8-year-old boy presents with 3 weeks of fever, abdominal pain, and constipation. He is from a rural area. Blood culture grows Salmonella typhi. The Widal test shows TO titre 1:80. Which statement regarding diagnosis and management is most accurate?
Correct. Blood culture (Salmonella typhi) is the gold standard for typhoid diagnosis. Widal test has poor sensitivity and specificity, varies with prior immunization and background endemic titres, and should not be used alone for diagnosis. Ceftriaxone is first-line IV therapy for enteric fever in children.
For typhoid: blood culture = gold standard. Widal = unreliable (endemic background, prior vaccination). Use ceftriaxone IV for moderate-severe disease. Watch for complications (intestinal perforation) typically in week 3.
Widal cut-offs vary by endemic region and are unreliable. Amoxicillin is no longer recommended due to widespread resistance. Blood culture is definitive and should always be sought.
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A 7-year-old girl presents with 4 days of high fever, severe headache, retro-orbital pain, and myalgia. Her platelet count is 68,000/mm³. NS1 antigen is positive. She has no bleeding manifestations. Which management step is most appropriate at this stage?
Correct. In dengue without warning signs, treatment is supportive — oral/IV paracetamol for fever, adequate hydration, and close monitoring for warning signs (abdominal pain, persistent vomiting, rapid decline in platelet count, mucosal bleeding). NSAIDs (ibuprofen, aspirin) are contraindicated as they worsen bleeding risk.
Dengue management: paracetamol ONLY for fever (no aspirin, no NSAIDs), adequate hydration, monitor warning signs. No prophylactic platelets. NS1 antigen = early (days 1–5); IgM = later (day 5+).
Prophylactic platelet transfusion is NOT recommended unless there is active significant bleeding or platelet count <10,000/mm³ with haemorrhagic risk. Ibuprofen and aspirin are contraindicated in dengue.
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A 2-year-old unvaccinated boy develops high fever, coryza, and conjunctivitis. On day 3, white spots are seen on the buccal mucosa opposite the lower molars. By day 5, a maculopapular rash appears starting at the face and spreading downward. Which is the most important specific intervention?
Correct. This is measles. Koplik spots (white spots on buccal mucosa) are pathognomonic. WHO and IAP recommend Vitamin A 200,000 IU orally for 2 consecutive days for all children with measles ≥12 months, as it reduces severity and mortality significantly.
Measles: Koplik spots (pathognomonic), coryza + conjunctivitis, head-to-toe rash. Treatment: Vitamin A 200,000 IU × 2 days. Complications: pneumonia, encephalitis, keratoconjunctivitis. Notifiable disease.
Acyclovir is for varicella (chickenpox), not measles. IM immunoglobulin is for post-exposure prophylaxis within 6 days, not for established disease. Corticosteroids are not routinely used for measles and may worsen secondary infections.
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A 6-year-old child develops fever with barking cough that sounds like a seal's bark, followed by inspiratory stridor. Subsequently, her parents note she has paroxysms of cough followed by a whooping sound, post-tussive vomiting, and facial petechiae. She is unvaccinated. Which causative organism and most appropriate antibiotic match correctly?
Correct. The paroxysmal cough with whoop, post-tussive vomiting, and petechiae describe whooping cough caused by Bordetella pertussis. Azithromycin (10 mg/kg/day × 5 days) is the preferred macrolide — better tolerated than erythromycin. Erythromycin (14 days) is an alternative. Antibiotics reduce infectivity but may not shorten illness if started late.
Pertussis: paroxysmal cough + inspiratory whoop + post-tussive vomiting + petechiae (unvaccinated child). Azithromycin 5 days = preferred macrolide. Antibiotics reduce transmission, not necessarily illness duration if given late. DPT vaccination prevents it.
The clinical picture is whooping cough (pertussis), not diphtheria. Diphtheria causes a greyish pseudomembrane in the throat. Ampicillin is not standard for pertussis. HiB causes epiglottitis/meningitis, not whooping cough.
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A 10-year-old boy returns from a malaria-endemic forest area with high-grade fever with chills and rigors, every 48 hours. Peripheral blood smear shows ring-trophozoites with Schuffner's dots. He weighs 30 kg. What is the correct treatment?
Correct. Schuffner's dots with 48-hour periodicity = Plasmodium vivax (tertian malaria). Treatment: Chloroquine (25 mg/kg over 3 days) PLUS primaquine (0.25 mg/kg/day for 14 days) to eliminate liver hypnozoites and prevent relapse. Check G6PD status before primaquine — contraindicated in G6PD deficiency.
Vivax malaria (Schuffner's dots, 48-hr periodicity): chloroquine + primaquine 14 days. Always check G6PD before primaquine. Falciparum: ACT. Severe malaria: IV artesunate.
Artemether-lumefantrine (ACT) is for falciparum malaria. Chloroquine alone without primaquine will not prevent vivax relapse from liver hypnozoites. IV artesunate is for severe malaria, not uncomplicated vivax.
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A child is being evaluated for suspected pulmonary tuberculosis. The clinician wants to collect a sample for mycobacterial culture and CBNAAT. The child is 4 years old and cannot produce sputum spontaneously. Which sample collection technique is most appropriate?
Correct. Young children (under 5–6 years) cannot produce sputum voluntarily. Early morning gastric aspirate (GA) — obtained before the child sits up — collects swallowed respiratory secretions and is the standard sample for smear, culture, and CBNAAT in young children. Three consecutive morning samples improve yield.
Young children (<6 years) cannot produce sputum — use early morning gastric aspirate × 3 consecutive days. CBNAAT (GeneXpert MTB/RIF) simultaneously detects M. tuberculosis AND rifampicin resistance.
Induced sputum is an alternative but requires special equipment and expertise. BAL under GA is invasive and reserved for specific indications. Nasopharyngeal swabs are not validated for TB diagnosis.
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A 7-year-old child presents with fever for 10 days, rash on the trunk sparing palms and soles, abdominal distension, and relative bradycardia. Blood culture is positive for Salmonella typhi. On day 21 of illness, the child suddenly develops severe abdominal pain and rigidity. What is the most likely complication?
Correct. Intestinal perforation is the most feared complication of enteric fever (typhoid), typically occurring in week 3 of illness (day 15–21). Peyer's patches in the terminal ileum become necrotic and perforate, causing peritonitis. It requires emergency surgical management.
Typhoid complications by week: Week 1 — bacteraemia; Week 2 — rose spots, hepatosplenomegaly; Week 3 — intestinal perforation (emergency). Relative bradycardia (Faget sign) is a classic feature. Rose spots = faint salmon-coloured macules on trunk.
While appendicitis must be considered, the timing (week 3), fever history, positive blood culture, and rose spots strongly point to typhoid intestinal perforation. Mesenteric adenitis does not typically cause peritonitis signs.
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