What are the key clinical features of carcinoid syndrome that I should look for in patients with suspected neuroendocrine tumours?

Key clinical features of carcinoid syndrome in patients with suspected neuroendocrine tumours include:

• Flushing of the skin, often episodic and involving the face and upper chest.
• Diarrhoea, which may be frequent and watery.
• Wheezing or bronchospasm, resembling asthma symptoms.
• Abdominal cramping and pain.
• Right-sided heart valve lesions leading to symptoms of heart failure in advanced cases.

These features arise due to secretion of serotonin and other vasoactive substances by the neuroendocrine tumour. Identification of these symptoms in primary care should prompt consideration of neuroendocrine tumours and referral for further investigation.