GI Infections

GI infection is not one clinical problem. The first decisions are whether the patient is losing effective circulating volume and whether the bowel appears inflamed or structurally threatened. A patient with abrupt vomiting and watery diarrhoea may mainly need oral rehydration and infection-control measures; a patient with bloody stool, fever, severe tenderness, or altered perfusion needs targeted testing and urgent reassessment. The stool pattern provides a useful first classification, but it does not replace examination. Watery stool without blood or high fever is more consistent with toxin-mediated secretion or viral illness. Blood, mucus, fever, tenesmus, or marked abdominal pain suggests mucosal invasion or colitis. Diarrhoea after recent antibiotics or healthcare exposure raises concern for Clostridioides difficile, while prolonged greasy stool, bloating, and weight loss point toward giardiasis. H. pylori is different again: it is a chronic gastric infection associated with ulcer disease and gastric malignancy, not usually an explanation for sudden high-volume diarrhoea. The experienced clinician notices perfusion before counting stools. Orthostatic symptoms, tachycardia, hypotension, confusion, oliguria, dry mucous membranes, and rising creatinine show that fluid loss has become a...