Typhoid

📘 TYPHOID FEVER – SHORT NOTES

🔹 Introduction

• Also called enteric fever
• Caused by:
• Salmonella typhi (main)
• Salmonella paratyphi (milder)
• Transmission: Feco-oral route (contaminated food & water)
• Spread by carriers
• Major public health issue in developing countries

🔹 Pathophysiology

Stepwise mechanism:

1.     Entry

• Through contaminated food/water → reaches intestine

2.     Intestinal invasion

• Bacteria attach to intestinal epithelium (Peyer’s patches)
• Invade mucosa

3.     Phagocytosis

• Engulfed by macrophages but survive inside them

4.     Lymphatic spread

• Travel via:
• Mesenteric lymph nodes
• Lymphatics → bloodstream

5.     Systemic spread

• Reach:
• Liver
• Spleen
• Bone marrow
• Reticuloendothelial system

6.     Multiplication

• Multiply inside macrophages

7.     Bacteremia

• Released into blood → systemic infection

8.     Gallbladder infection

• Enter bile → reinfect intestine
• Shed in stool → infect others

🔬 Special feature

• Vi antigen (capsule) → helps bacteria evade immune response
• Reduces neutrophil-mediated inflammation

🔹 Life Cycle Summary

• Feco-oral transmission
• Incubation: 7–14 days
• Intestinal invasion → lymphatics → bloodstream → organs → reinfection via bile

🔹 Symptoms

Common symptoms:

• High sustained fever (~40°C / 104°F)
• Weakness / fatigue
• Headache
• Loss of appetite
• Abdominal pain
• Constipation
• Cough
• Sore throat

Characteristic signs:

• Coated tongue
• Rose spots (pink rash on chest/abdomen)
• Enlarged liver & spleen

Rare symptoms:

• Diarrhea
• Delirium
• Rectal bleeding

🔹 Complications (Important for exams ⚠️)

• Intestinal ulceration (Peyer’s patches)
• Intestinal perforation
• Peritonitis
• Sepsis
• Toxic encephalopathy
• Myocarditis
• Hemodynamic shock

🔹 Key Exam Points 🧠

• Mode of transmission → Feco-oral
• Organism survives in macrophages
• Important antigen → Vi antigen
• Common site of ulcer → Peyer’s patches (ileum)
• Carrier state → Gallbladder involvement

📘 DIAGNOSIS

🔹 Differential Diagnosis (Clinical Features)

Typical symptom cluster suggesting typhoid:

• Gradually rising fever
• Evening ↑, morning ↓ (step-ladder pattern)
• Malaise + headache
• Furred tongue with red edges & tip
• Epistaxis (nose bleeding)
• Relative bradycardia (slow pulse vs fever)
• Abdominal distension + ↑ bowel sounds
• Right iliac fossa tenderness
• Rose spots (rash on chest & abdomen)
• Splenomegaly
• Bronchial catarrh

⚠️ Always rule out:

• Malaria
• Schistosomiasis
• Other tropical fevers

🔹 Organism Culture (Gold Standard)

• Caused by Salmonella typhi
• Samples:
• Blood
• Stool
• Bone marrow (most sensitive)

Key points:

• Blood culture positivity: 40–60%
• With repeated cultures → >80%
• Bone marrow culture sensitivity: ~90% (highest)
• Best detection: 1st week of illness

🔹 Serology

Widal Test:

• Detects antibodies against:
• O antigen (somatic)
• H antigen (flagellar)

Interpretation:

• High/rising titers → acute infection
• Limitations:
• Variable sensitivity & specificity
• False positives common

💊 TREATMENT

🔹 Antibiotic Therapy

Common drugs:

1.     Fluoroquinolones

• Ciprofloxacin
• Ofloxacin
• Gatifloxacin

2.     Cephalosporins

• Ceftriaxone (preferred in pregnancy)

3.     Others:

• Ampicillin
• Trimethoprim-sulfamethoxazole (TMP-SMX)
  ⚠️ Resistance increasing

4.     Old drug (rarely used):

• Chloramphenicol (due to serious side effects)

🔹 Supportive Treatment

• Antipyretics (fever control)
• Hydration
• Nutrition

🔹 Severe Cases

• Steroids (rare, severe toxicity cases only)
• Surgery:
• Required in intestinal perforation
• Procedure: closure + drainage

🔹 Prognosis

• Without treatment → mortality ~20%
• With treatment → 1–2% mortality
• Recovery: 7–10 days

⚠️ COMPLICATIONS

🔹 Major complications:

• Intestinal hemorrhage
• Intestinal perforation (high mortality)

🔹 Other complications:

• Hepatitis → jaundice
• Cholecystitis / cholangitis
• Pancreatitis (rare)
• Acute kidney injury

🔹 Cardiac:

• Toxic myocarditis (1–5%) → major cause of death

🔹 CNS:

• Delirium
• Confusion
• Psychiatric symptoms

🛡️ PREVENTION

🔹 Hygiene & Sanitation

• Hand washing (after toilet, before food)
• Safe drinking water:
• Boiled / disinfected
• Bottled (prefer carbonated)

🔹 Food Safety

• Eat well-cooked hot food
• Avoid:
• Street food
• Raw vegetables & salads
• Unpasteurized milk
• Ice cubes

🔹 Other Measures

• Peel fruits before eating
• Protect food from flies
• Avoid contaminated seafood

🧠 QUICK REVISION POINTS

• Gold standard → Culture (bone marrow best)
• Widal → supportive, not confirmatory
• Drug of choice → Ceftriaxone / Fluoroquinolones
• Most serious complication → Intestinal perforation
• Prevention → Hygiene + safe food & water