Carcinoid syndrome

Question 1

outline a typical presentation of carcinoid syndrome?

Answer 1

Facial flushing, right-sided murmurs, crampy pain, palp,D, bronchospasm, nodular hepatomegaly in mets, 5-HIAA (5-hydroxyindole acetic acid) levels high in 24hr urine , chromogranin A levels in blood

Question 2

define carcinoid syndrome?

Answer 2

Constellation of symptoms (esp liver mets) caused by systemic release of humoral factors from carcinoid tumours (slow-growing type of neuroendocrine tumours)

Question 3

explain the aetiology of carcinoid syndrome?

Answer 3

Carcinoid tumours are slow-growing neuroendocrine tumours

mostly derived from serotonin-producing enterochromaffin cells (ileum)

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 tumours

Question 4

give a risk factor for carcinoid syndrome?

Answer 4

genetic multiple endocrine neoplasia type 1 (MEN-1) syndrome

Question 5

outline the epdemiology of carcinoid syndrome?

Answer 5

RARE

UK incidence : 1/1,000,000

Asymptomatic carcinoid tumours are more common

10% of patients with MEN-1 have carcinoid tumours

Question 6

what are the presenting symptoms of carcnoid syndrome?

Answer 6

Paroxysmal FLUSHING

Diarrhoea

Crampy abdominal pain

Wheeze – due to bronchospasm

Sweating

Palpitations

Question 7

what are the signs of carcinoid syndrome on physical examination?

Answer 7

Facial flushing

Telangiectasia

Wheeze

Right-sided murmurs (tricuspid stenosis/regurgitation or pulmonary stenosis)

Nodular hepatomegaly in cases of metastatic disease

Question 8

what are the features of a carcinoid crisis?

Answer 8

Profound flushing

Bronchospasm

Tachycardia

Fluctuating blood pressure

Question 9

what are the appropriate investigations for carcinoid syndrome?

Answer 9

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

Blood

• Plasma chromogranin A and B – elevated
• Neuron spec enolase (NSE)
• Substance P
• Gastrin (Fasting gut hormones)
• Elevated Cr if dehydrated from diarrhoea
• LFTs-> variable, changes include aminotransferase elevation depending on site of tumour

CT or MRI Scan or PET scan-> To localise the tumour

Radioisotope Scan

• Radiolabelled somatostatin analogue helps localise the tumou