Typhoid and Paratyphoid fever (Enteric Fever)
🌡️ About
- Typhoid Fever: Caused by Salmonella typhi.
- Paratyphoid Fever: Caused by Salmonella paratyphi (A, B, C).
🦠 Aetiology
- Transmission: Faeco-oral (contaminated food/water).
- Children aged 1–5 yrs particularly vulnerable.
- Gallbladder = reservoir in chronic carriers.
- Pathology: Peyer’s patches in ileum → swelling, ulceration → intestinal bleeding/perforation in severe cases.
🔬 Key Microbiology
- Gram-negative, motile rod, facultative anaerobe.
- Ferments glucose, oxidase-negative, catalase-positive.
- Reduces nitrates → nitrites.
- Non-lactose fermenter → pale colonies on MacConkey agar.
- Resistant to bile salts (sodium deoxycholate).
🩺 Clinical Presentation
- Incubation: 10–14 days (typhoid); shorter in paratyphoid.
- Week 1: Dry cough, malaise, headache, stepwise fever (→ 39°C), constipation/diarrhoea, relative bradycardia 🚨.
- Week 2: Rose spots (trunk), splenomegaly, hepatomegaly, lymphadenopathy, epistaxis, persistent bradycardia.
- Week 3: Complications – bowel haemorrhage, perforation, toxaemia, cholecystitis, osteomyelitis (esp. sickle cell), myocarditis, nephritis, meningitis, pneumonia.
- Week 4: Recovery (if untreated), but some → prolonged illness or carrier state.
- Paratyphoid: Shorter, milder, rash more prominent, intestinal complications less common.
⚠️ Clinical clue: Relative bradycardia + low WCC despite fever.
🧒 Sickle cell children → high risk of Salmonella osteomyelitis.
🧪 Investigations
- FBC: Low WCC, raised AST/ALT.
- Blood cultures: Positive in 1st–2nd week.
- Stool cultures: Positive from 2nd week onward.
- Urine cultures: May also be positive.
- Widal test: Obsolete/unreliable.
💊 Management
- Duration untreated: Typically ≥4 weeks.
- Infection control: Side room isolation, strict hygiene.
- First-line antibiotics:
- Ciprofloxacin 500–750 mg BD PO × 10 days (up to 500 mg QDS).
- Alternative if resistance suspected → Azithromycin 500 mg OD × 10–14 days.
- Chronic carriers: Ciprofloxacin 500 mg BD PO × 4 weeks.
If fails → consider cholecystectomy.
- Public health: Notifiable disease 🚨 → inform HPA/UKHSA.
- Food handling: No return until 3 consecutive negative stool cultures.
🛡️ Prevention
- Vaccination (IM polysaccharide) recommended for travellers to endemic regions.
- Safe food, clean water, strict hygiene.
