Diarrhoea

Carcinoid crisis (peri-procedure) → octreotide cover

Severe malnutrition/failure to thrive; do NOT start a gluten-free diet before testing (false negatives)

Anaphylaxis (IgE); faltering growth

Acute severe flare, obstruction (stricture), abscess/fistula, perforation, toxic dilatation → urgent

Ulcer complications (bleeding/perforation); MEN1 association → screen

Gram-negative sepsis → LPS-driven shock; Sepsis Six + broad-spectrum cover, source control

FALLING FVC (respiratory failure → ventilation), autonomic instability (arrhythmia, BP swings), bulbar weakness

C. difficile with toxic megacolon / severe colitis → surgical review (cross-ref gastroenterology)

C. difficile with toxic megacolon, ileus, shock, or rising lactate/WCC → severe disease, surgical input

Severe dehydration/shock; bloody diarrhoea (dysentery); EHEC O157 → HUS (no antibiotics); enteric fever (typhoid — trave

E. coli O157 → HUS (AKI + haemolysis + thrombocytopenia) — do NOT give antibiotics/antimotility agents

Weight loss/anaemia/blood → not simple lactose intolerance; investigate (coeliac, IBD)

ACUTE SEVERE colitis (Truelove-Witts: ≥6 bloody stools/day + systemic upset) → admit for IV steroids; rescue ciclosporin

Severe dehydration/hypokalaemia → arrhythmia, acute kidney injury

Severe acidaemia with haemodynamic compromise → treat the cause urgently (DKA, sepsis/lactate, toxic alcohols, AKI)

Symptomatic postural hypotension with falls; severe gastroparesis; coexisting cardiac autonomic involvement

NEW change in bowel habit, rectal bleeding, weight loss, anaemia, abdominal/rectal mass, age ≥50 → investigate for color

Intestinal perforation/GI bleeding (third week) → surgical emergency

Thyroid storm (fever, agitation, tachyarrhythmia, delirium, often precipitated by illness/surgery) → emergency

Acute mesenteric ischaemia (pain out of proportion + raised lactate ± AF) → emergency surgery/revascularisation — high m

Red flags → investigate, NOT IBS: rectal bleeding, weight loss, anaemia, nocturnal symptoms, family history of bowel/ova

Rapidly enlarging hard mass + stridor/hoarseness in the elderly → anaplastic — urgent airway/oncology

Perforation (sudden deterioration, free air, peritonitis) → emergency colectomy

2-week-wait referral: age ≥40 with weight loss + abdominal pain; ≥50 with rectal bleeding; ≥60 with iron-deficiency anae

Myasthenic CRISIS — respiratory muscle weakness (monitor FVC), bulbar weakness with aspiration; certain drugs trigger it