A 35-year-old woman from rural Uttar Pradesh presents with a 3-week history of fever, rose-colored rash, and hepatosplenomegaly. She is suspected to have enteric fever. Which is the most common site of intestinal perforation in typhoid fever?

Explanation

## Intestinal Perforation in Typhoid Fever ### Pathophysiology of Perforation **Key Point:** The terminal ileum is the most common site of intestinal perforation in typhoid fever, accounting for >90% of perforations. This occurs due to Peyer's patch hyperplasia and necrosis in the terminal ileum, which is the primary site of bacterial invasion and multiplication. ### Anatomical Basis 1. **Peyer's patches** in the terminal ileum are the primary lymphoid tissue targeted by S. typhi 2. Bacterial invasion → hyperplasia → ulceration → necrosis 3. Transmural inflammation → perforation, typically in the third to fourth week of illness 4. Single or multiple perforations may occur ### Comparison of Perforation Sites | Site | Frequency | Pathophysiology | Clinical Significance | |------|-----------|-----------------|----------------------| | **Terminal ileum** | >90% | Peyer's patch necrosis | Most common, highest mortality | | **Jejunum** | <5% | Rare involvement | Uncommon | | **Duodenum** | <2% | Minimal lymphoid tissue | Very rare | | **Sigmoid colon** | <2% | Not primary site of invasion | Unusual | ### Clinical Presentation of Perforation **High-Yield:** Perforation typically occurs in the third to fourth week of untreated typhoid fever and presents with: - Sudden onset of severe abdominal pain - Acute peritonitis (guarding, rigidity, rebound tenderness) - Pneumoperitoneum on X-ray (free air under diaphragm) - Septic shock and high mortality if not treated urgently **Clinical Pearl:** Perforation is a medical emergency requiring immediate surgical intervention (primary repair or resection). Mortality is significantly higher in perforated typhoid (20–40%) compared to uncomplicated typhoid (<1% with appropriate antibiotics). **Warning:** Do not confuse perforation site with the primary site of bacterial invasion — both are the terminal ileum, but perforation can occasionally occur at other sites due to extensive mucosal damage. **Mnemonic:** **ILEUM** = **I**nvasion site, **L**ymphoid tissue (Peyer's patches), **E**xtensive ulceration, **U**lceration → necrosis, **M**ost common perforation site [cite:Robbins 10e Ch 8]