Carcinoid syndrome

Question 1

Define carcinoid syndrome

Answer 1

Constellation of symptoms caused by
systemic release of humoral factors
from carcinoid tumours

Question 2

Explain the aetiology/risk factors of carcinoid syndrome

Answer 2

Carcinoid tumours are slow-growing neuroendocrine tumours. They are mostly derived from serotonin-producing enterochromaffin cells.
They produce secretory products like serotonin, histamine, tachykinins, kallikrein and prostaglandins

75-80% of patients with carcinoid syndrome have
small bowel carcinoids.

NOTE: hormones released into the portal circulation will be metabolised by the liver so symptoms don’t tend to appear until there are hepatic metastases or release into the systemic circulation from bronchial or extensive retroperitoneal tumour.

Question 3

Summarise the epidemiology of carcinoid syndrome

Answer 3

RARE
UK incidence : 1/1,000,000
Asymptomatic carcinoid tumours are more common
10% of patients with MEN-1 have carcinoid tumour

Question 4

Recognise the presenting symptoms of carcinoid syndrome

Answer 4

Paroxysmal FLUSHING
Diarrhoea
Crampy abdominal pain
Wheeze
Sweating
Palpitation

Question 5

Recognise the signs of carcinoid syndrome on physical examination

Answer 5

Facial flushing
Telangiectasia
Wheeze
Right-sided murmurs (tricuspid stenosis/regurgitation or pulmonary stenosis)
Nodular hepatomegaly in cases of metastatic disease

Carcinoid Crisis Signs:
Profound flushing
Bronchospasm
Tachycardia
Fluctuating blood pressure

Question 6

Identify appropriate investigations for carcinoid syndrome

Answer 6

24 hours urine collection - Check 5-HIAA levels (metabolite of serotonin)

Blood
Plasma chromogranin A and B
Fasting gut hormones

CT or MRI Scan
To localise the tumour

Radioisotope Scan - Radiolabelled somatostatin analogue helps localise the tumour

Investigations for MEN-1