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Pituitary disease

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Pituitary disease
Photo by Robina Weermeijer / Unsplash

Here is our run-through of the key points you need to know about pituitary disease as an anaesthetist. This is not a comprehensive article about the organ nor its function - there's loads of those around - this is a brief highlight of what you as the anaesthetic trainee need to know for your patients and your exams.

Enjoy, and let us know if you think we've missed something!

Take home messages

  • The pituitary  regulates all of the other endocrine glands in the body
  • The patient usually presents with either symptoms of mass effect, or endocrine disturbances
  • Patients with pituitary disease are of concern to the anaesthetist, as they can have difficult airways and endocrine dysregulation requiring perioperative management

Anatomy

  • Divided into anterior and posterior lobes
  • 0.5 - 1g in size
  • Sits next to cranial nerves 3, 4, 5 and 6
  • Sits below third ventricle and hypothalamus, as well as optic chiasm
  • It lies outside the blood brain barrier

Presentation

  • Patients usually present with symptoms either of mass effect from a pituitary mass, or with endocrine symptoms from hyper or hypo function of the gland
  • Endocrine presentations include: acromegaly, Cushing's disease, Panhypopituitarism and hyperprolactinaemia
  • Mass effect symptoms can vary but classically described is a visual field defect producing bitemporal hemianopia

Concerns for the anaesthetist

Acromegaly

  • Airway obstruction, macroglossia, sleep apnoea
  • Cardiovascular instability, cardiomyopathy, hypertension
  • Respiratory failure, kyphosis, myopathy and hypoventilation
  • Diabetes
  • Difficult cannulation

Cushing's disease

  • Obstructive sleep apnoea
  • Difficult intubation - buffalo hump, truncal obesity
  • Post op hypoventilation - proximal muscle weakness
  • Hypertension - avoid cocaine as nasal mucosal vasoconstrictor - use co-phenylcaine instead
  • Increased VTE risk
  • Difficult cannulation, thin skin liable to damage
  • Difficult positioning, joint pain, osteoporosis
  • Thick neck makes CVC insertion difficult
  • Increased risk of infection
  • Corneal abrasion (exophthalmos)
  • Glucose control
  • Gastric ulcers - avoid NSAIDs where possible

Hypothyroidism

  • Highly sensitive to anaesthetic agents
  • Slow recovery
  • Reduced hypercapnoeic and hypoxic drive
  • Hypothermia
  • Risk of heart failure

Diabetes insipidus

  • Lack of anti-diuretic hormone (posterior pituitary)
  • Treat with ddAVP (desmopressin)
  • Risk of hypernatraemia and dehydration

Surgery

  • Trans-sphenoidal
  • Oral intubation - fibreoptic if needed
  • Oropharynx packed with wet gauze to absorb blood and stabilise tube
  • Antibiotics and hydrocortisone at induction
  • Nasal bone and sphenoid are deliberately broken, which is highly stimulating - remifentanil and alfentanil may be helpful
  • NSAIDs are controversial as they may be linked to post-op bleeding
  • Lots of anti-emetic cover is needed

What are the complications of trans-sphenoidal surgery?

  • CSF leak
  • Meningitis
  • Panhypopituitarism
  • Stroke
  • Bleeding
  • Venous air embolism is surprisingly uncommon 

Post operative concerns

  • CPAP is contraindicated (tension pneumocephalus)
  • Risk of airway obstruction
  • Neurological observations on HDU/ITU
  • Hormone and steroid replacement

What is pituitary apoplexy?

  • Acute haemorrhagic infarction, usually of the anterior pituitary
  • Can happen after debulking of tumour
  • Treatment is with emergency decompression and then supportive treatment with hormone and steroid replacement

Some useful tweets

References and Further Reading

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