VIPoma (Verner-Morrison)
VIP-secreting pancreatic neuroendocrine tumour
Overview
A rare vasoactive-intestinal-peptide-secreting pancreatic neuroendocrine tumour causing the WDHA syndrome — Watery Diarrhoea, Hypokalaemia and Achlorhydria (pancreatic cholera). Profuse secretory diarrhoea persists when fasting, with dehydration and electrolyte loss. Diagnosed by a high VIP; treated with somatostatin analogues, fluid/electrolyte replacement and resection.
Recognise
- Profuse WATERY (secretory) diarrhoea that persists on fasting (litres/day) → dehydration
- HYPOKALAEMIA (and metabolic acidosis), ACHLORHYDRIA; flushing; hyperglycaemia/hypercalcaemia
- Markedly raised plasma VIP
Red flags
- Severe dehydration/hypokalaemia → arrhythmia, acute kidney injury
- Distinguish from infective/other secretory diarrhoea (persists on fasting; high VIP)
Differentials & how to tell them apart
Investigations
Plasma VIP (high); stool osmotic gap (secretory); U&Es (low K+), glucose, calcium; localise (CT/MRI, somatostatin scan).
Management
Octreotide + fluid/electrolyte replacement + resection
- 1Confirm secretory diarrhoea persisting on fasting with hypokalaemia and a high VIP; localise. Octreotide controls the diarrhoea; correct fluids/potassium.Gate: Secretory diarrhoea that PERSISTS during fasting (with hypokalaemia/achlorhydria) points to a VIPoma rather than osmotic/infective diarrhoea — check VIP
- 2Resect localised tumour; somatostatin analogue/chemotherapy for metastatic disease; ongoing electrolyte management.
Key points
Litres of watery diarrhoea that don't stop when fasting + low potassium + achlorhydria (WDHA) = VIPoma → high VIP, octreotide. Fasting persistence is the discriminator from osmotic diarrhoea.
Monitor & prognosis
VIP; potassium/fluid balance.
Often metastatic but controllable.
Source: ENETS/UKINETS