A 35-year-old male is found dead in his apartment 48 hours after being last seen alive. On external examination, the body shows a greenish discoloration starting from the right lower abdomen, which has spread to involve the entire abdomen and lower chest. The skin appears blistered in areas. Which of the following post-mortem changes is BEST described by these findings?

Explanation

## Post-Mortem Changes: Putrefaction **Key Point:** The clinical presentation describes **putrefaction**, the decomposition of body tissues by bacterial action, which is the most advanced post-mortem change visible at 48 hours in normal environmental conditions. ### Characteristic Features of Putrefaction: - **Greenish discoloration**: Begins over the right lower abdomen (caecal region) where bacterial flora is highest; caused by hydrogen sulfide reacting with haemoglobin to form sulphaemoglobin - **Spread pattern**: Progresses centrifugally (outward) from the abdomen to involve the chest and extremities - **Blistering (post-mortem blistering)**: Caused by gas accumulation beneath the epidermis; appears as fluid-filled vesicles - **Timeline**: Becomes visible within 24–48 hours under normal tropical/temperate conditions; accelerated by heat, humidity, and obesity ### Why Putrefaction Occurs: Bacterial proliferation in the intestinal tract (especially anaerobes like *Clostridium* and *Bacillus*) produces gases (H₂S, NH₃, CH₄) and pigments that discolour tissues and cause bloating. **Clinical Pearl:** The **right lower abdomen** is the classic site of first appearance because the caecum harbours the densest bacterial flora. **High-Yield:** Putrefaction is temperature-dependent; it progresses 8× faster at 37°C than at 4°C.