A 35-year-old man from Delhi presents with a 3-week history of fever, weight loss, and abdominal distension. On examination, he has a palpable spleen 4 cm below the costal margin and a soft, non-tender abdomen. Blood investigations show Hb 9.8 g/dL, WBC 3,200/μL with relative lymphocytosis, and platelets 95,000/μL. Blood culture grows *Salmonella typhi*. What is the most likely complication if he does not receive prompt antibiotic therapy?

Explanation

## Enteric Fever: Third-Week Complications ### Clinical Context This patient is in the **third week** of enteric fever with: - Prolonged fever (3 weeks) - Hepatosplenomegaly (spleen 4 cm) - Pancytopenia (anemia, leukopenia, thrombocytopenia) - Positive blood culture confirming *Salmonella typhi* **Key Point:** The third week of untreated enteric fever carries the highest risk of life-threatening complications, particularly **intestinal perforation**. ### Pathophysiology of Intestinal Perforation ```mermaid flowchart TD A["Salmonella typhi infection<br/>of Peyer's patches"]:::outcome --> B["Week 1-2: Hyperplasia<br/>and edema"]:::outcome B --> C["Week 2-3: Necrosis and<br/>ulceration of mucosa"]:::outcome C --> D{"Depth of ulceration?"}:::decision D -->|"Superficial<br/>mucosa only"| E["Continued fever,<br/>diarrhea"]:::outcome D -->|"Full thickness<br/>through submucosa"| F["Perforation of<br/>intestinal wall"]:::urgent F --> G["Peritonitis, sepsis,<br/>shock"]:::urgent H["Untreated enteric fever<br/>in week 3"]:::outcome --> F ``` **High-Yield:** Intestinal perforation occurs in 1–3% of untreated enteric fever cases, predominantly in the **third week**. The terminal ileum (site of Peyer's patches) is the most common site. ### Why This Patient Is at High Risk 1. **Duration:** 3 weeks of fever = peak risk period 2. **Pancytopenia:** Suggests bone marrow involvement and prolonged severe infection 3. **Splenomegaly:** Indicates systemic infection 4. **No mention of antibiotics:** Untreated disease ### Clinical Presentation of Perforation - Sudden onset of severe, diffuse abdominal pain - Acute peritonitis (rigid abdomen, rebound tenderness, guarding) - Septic shock (hypotension, tachycardia, altered mental status) - Mortality: 20–40% even with treatment; >90% if untreated **Clinical Pearl:** A patient with enteric fever who suddenly develops severe abdominal pain and peritoneal signs has perforated until proven otherwise. This is a surgical emergency. ### Why Other Complications Are Less Likely | Complication | Frequency | Timing | Notes | |--------------|-----------|--------|-------| | **Intestinal perforation** | 1–3% | Week 3 (peak) | Most common serious complication | | Myocarditis | <1% | Week 2–3 | Rare; usually subclinical | | Splenic rupture | <0.1% | Rare | Requires trauma or massive infarction | | DIC | <1% | Late/severe | Seen in fulminant sepsis, not typical | **Key Point:** While myocarditis, splenic rupture, and DIC can occur in severe enteric fever, they are much rarer than intestinal perforation, which is the most common life-threatening complication in the third week.