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Stem
A 22-year-old man presents to a hospital in Delhi with eight days of fever that has risen progressively in a step-ladder pattern, now 39.6°C. He has a severe dull frontal headache, constipation for four days (now loose stools), a dry cough, anorexia and malaise. He is a student who drinks tap water and eats street food. On examination: pulse 74/min, BP 110/68 mmHg, RR 18/min, SpO₂ 97%. He is mildly confused. There are 8–10 blanching salmon-pink macules, 2–4 mm, on his upper abdomen and lower chest. The tongue is coated white with red edges. Abdomen is softly distended with diffuse tenderness and a palpable spleen 2 cm below the costal margin. WCC 3.6 ×10⁹/L (neutrophils 52%, lymphocytes 44%, eosinophils 0%), haemoglobin 11.2 g/dL, platelets 130 ×10⁹/L, ALT 96 U/L, AST 88 U/L. Blood culture is pending.
Questions
a) What is the most likely diagnosis and give three clinical features from the stem that support it. (3 marks)
Diagnosis: enteric (typhoid) fever due to Salmonella Typhi.
Three supporting clinical features:
- Step-ladder (stepwise-rising) fever over 8 days, now sustained at ~40°C — the classical fever pattern.
- Relative bradycardia — pulse only 74/min for a temperature of 39.6°C (pulse–temperature dissociation; Faget sign).
- Rose spots — blanching salmon-pink macules on the trunk, which are bacterial (septic) emboli to dermal capillaries.
Additional supporting features worth one mark each: coated "typhoid" tongue with red edges; constipation then diarrhoea; dry cough; splenomegaly; headache and confusion; leucopenia with relative lymphocytosis and eosinopenia; mild transaminitis; endemic-exposure history (tap water, street food).
b) Justify the diagnosis with two investigations, stating which is the gold standard, the most sensitive, and why. (3 marks)
- Blood culture — the gold standard in the first week. Sensitivity ~60–90% before antibiotics; take ~10 mL into aerobic and anaerobic bottles before the first antibiotic dose. Positive culture confirms typhoid and allows susceptibility testing (critical given XDR spread).
- Bone marrow culture — the most sensitive (~90%) and remains positive even after antibiotics have been started, because S. Typhi persists intracellularly in macrophages of the reticuloendothelial system. Preferred when the patient is already pretreated or blood cultures are negative.
(Stool culture is useful in week 2–3 and in chronic carriers; the Widal test is at best supportive — a four-fold rise in anti-O/anti-H titre — and must not be used alone in an endemic region.)
c) Outline the definitive stepwise management of this patient, including the antibiotic you would start today (with dose and route) and one drug you would add if he became confused and hypotensive. (4 marks)
- Admit, hydrate with IV crystalloid, antipyretics (paracetamol), correct electrolytes; monitor for perforation/haemorrhage (hourly observations, abdominal exam). Take blood AND marrow culture before antibiotics.
- Empirical IV antibiotic — given quinolone resistance is very high in India, start IV ceftriaxone 2 g once daily (alternative: oral cefixime 200 mg twice daily if tolerating oral and uncomplicated). Review once susceptibilities return; switch to azithromycin 500–1000 mg once daily if XDR.
- Duration 7–14 days; switch IV to oral once afebrile and improving.
- Severe typhoid (if he becomes confused/obtunded and hypotensive) — add dexamethasone, Hoffman regimen: 3 mg/kg IV loading over 30 minutes, then 1 mg/kg IV every 6 hours for 8 doses (reduces mortality from ~40% to ~10% by damping the macrophage cytokine cascade).
- Escalation triggers: new rigid abdomen + free gas = intestinal perforation → resuscitate, broad-spectrum antibiotics (ceftriaxone + metronidazole), urgent laparotomy; melaena/haematemesis = intestinal haemorrhage → transfuse, NBM, PPI.
- Public health: notify, trace household contacts, exclude from food-handling until three negative stool cultures; offer household vaccination.