## Clinical Presentation of Enteric Fever **Key Point:** The constellation of high-grade fever, relative bradycardia, rose spots, hepatosplenomegaly, and abdominal pain in a patient from an endemic region (Delhi) is pathognomonic for enteric fever caused by *Salmonella typhi*. ### Distinguishing Features of *S. typhi* Enteric Fever | Feature | *S. typhi* | *S. paratyphi A* | |---------|-----------|------------------| | **Incubation period** | 7–14 days | 1–10 days (shorter) | | **Rose spots** | Present (classic) | Less common | | **Relative bradycardia** | Characteristic | May occur | | **Hepatosplenomegaly** | Marked | Mild to moderate | | **Severity** | More severe, prolonged | Milder, shorter course | | **Geographic prevalence** | Worldwide endemic | South Asia, Middle East | **High-Yield:** Rose spots (blanching, maculopapular rash on trunk) are a classic sign of *S. typhi* infection and appear in the second week of illness in ~30% of cases. **Clinical Pearl:** Relative bradycardia (pulse-temperature dissociation) is a hallmark of enteric fever and helps distinguish it from other febrile illnesses. The fever follows a characteristic step-ladder pattern in the first week, then becomes sustained. ### Pathogenesis 1. Ingestion of contaminated food/water 2. Invasion of small intestine (Peyer's patches) 3. Translocation to mesenteric lymph nodes 4. Bacteremia and seeding of reticuloendothelial system 5. Sustained fever and systemic symptoms **Mnemonic:** **ROSE** = *S. typhi* classic triad: **R**elative bradycardia, **O**rganomegaly (hepatosplenomegaly), **S**tep-ladder fever, **E**nteric rash (rose spots). ### Diagnostic Confirmation - **Blood culture** (gold standard in first week): Positive in ~80% of untreated cases - **Urine culture** (second–third week): Positive in ~25% of cases - **Stool culture** (third week onward): Becomes positive as bacteremia wanes - **Widal test**: Limited sensitivity/specificity; not recommended for diagnosis alone **Warning:** Do not rely solely on Widal serology for diagnosis—it has poor sensitivity in early disease and high false-positive rates in endemic areas due to prior vaccination or infection. [cite:Harrison 21e Ch 159]
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