Carcinoid

Question 1

A 61-year-old male patient is undergoing abdominal surgery for removal of
a carcinoid tumour.

What is a carcinoid tumour?

Answer 1

• A neuroendocrine tumour that arises from enterochromaffin cells.
• Classified according to their location based on the embryonic gut origins:
• Foregut – lungs, bronchus and stomach.
• Midgut – small intestine, appendix and proximal colon.
• Hindgut – distal colon and rectum.
• Hormone secreting tumours; the majority of tumours produce and secrete serotonin. However, the effects of excess hormones do not usually manifest as they are metabolised in the liver prior to entering the circulation.

Question 2

What is carcinoid syndrome?

Answer 2

• Occurs in approximately 25% of patients with a carcinoid tumour.
• In asymptomatic patients, the vasoactive substances produced by the localised gut tumours are metabolised in the liver, so there are no systemic symptoms.
• If the carcinoid tumour metastasises to the liver and rest of the body, the vasoactive substances such as serotonin and histamine enter the bloodstream to produce the stereotypical systemic carcinoid symptoms:
• Flushing.
• Diarrhoea.
• Lacrimation.
• Rhinorrhoea.

Question 3

How would you assess this patient prior to his procedure?

Answer 3

History
* A full and thorough medical history is necessary, focusing on the potential implications of the carcinoid tumour on the patient’s bodily systems.

• The history should also include a routine medical and anaesthetic history with details about regular medications, social history, allergies and airway.
• Disease complications can include:
• Cardiovascular: right-sided cardiac disease.
• Respiratory: wheeze and bronchospasm.
• Gastrointestinal: diarrhoea (leading to dehydration and electrolyte disturbance).
• Skin: flushing.
• General: malnutrition, cachexia.

Examination and investigations:
* These should be directed by findings from the patient history and previous appointments and should include:
- Baseline blood tests including full blood count (anaemia),
electrolytes, liver function tests and clotting.
- Chest X-ray.
- ECG and echo to rule out right-sided cardiac involvement.

Question 4

What are the anaesthetic goals for management of this patient?

Answer 4

• Provide a smooth perioperative course for major abdominal surgery including analgesia.
• Minimise the systemic complications of vasoactive mediator release during tumour handling.
• Avoid the use of anaesthetic agents that may exacerbate carcinoid symptoms or cause a carcinoid crisis e.g. morphine/atracurium causing histamine release.

Question 5

During tumour resection the patient’s blood pressure falls to 64/23 and you notice increased airway pressures.

How do you proceed?

Answer 5

• Initial management is to alert the theatre team, call for senior help and apply 100% oxygen.
• Rapid ABCDE assessment to form a differential diagnosis. Consider the likelihood of a carcinoid crisis and treat early if probable.
• Intravenous bolus of 20 μg octreotide, followed by further boluses titrated to effect. Small doses of phenylephrine or vasopressin can also be considered if resistant to the initial treatment.
• Fluid bolus and close monitoring of cardiac output.
• Consider concomitant effects of potential large blood loss.