Clinical Review

Lesson of the week: Hypopituitarism after coronary artery bypass grafting▲Commentary: Hypoadrenalism should also be considered in cases of persistent hyponatraemia

BMJ 1998; 316 doi: (Published 28 February 1998) Cite this as: BMJ 1998;316:682

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Lesson of the week: Hypopituitarism after coronary artery bypass grafting▲

  1. J S Davies (, lecturer in medicine,
  2. M F Scanlon, professor of endocrinology
  1. Department of Medicine, University of Wales College of Medicine, Cardiff CF4 4XN
  2. Department of Endocrinology, General Infirmary at Leeds, Leeds LS1 3EX
  1. Correspondence to: Dr Davies
  • Accepted 17 June 1997

Hypopituitarism may develop secondary to pituitary infarction after coronary artery bypass grafting

Pituitary infarction may present in many different ways ranging from the entirely silent to the florid neuro-ophthalmological features of apoplexy.1 It may occur in a normal or an adenomatous pituitary and may be precipitated by haemodynamic changes.1 We present two cases of panhypopituitarism which developed insidiously as a result of pituitary infarction which occurred during coronary artery bypass grafting.

Case 1

A 57 year old man was referred to our endocrine unit because of impotence and reduced libido. Twenty months earlier he had undergone coronary artery bypass grafting. Before surgery he had had normal potency, but erectile dysfunction and reduced libido occurred immediately after. Three months before surgery he had complained of tiredness; his concentration of free thyroxine was 3 pmol/l and thyroid stimulating hormone was 50 mU/l. Primary hypothyroidism was diagnosed. He was treated with thyroxine, which led to clinical improvement and normalisation of thyroid function before surgery.

Coronary artery bypass grafting was performed after investigation of exertional chest pain which occurred after myocardial infarction. It was an uncomplicated procedure; the left internal mammary artery was grafted to the left anterior descending artery and the saphenous vein was grafted to the obtuse marginal artery. Recovery immediately after surgery was uneventful and the patient was discharged on the ninth day after surgery despite plasma concentrations of sodium having fallen from a normal preoperative value to 125 mmol/l (normal range 133 to 144 mmol/l). He was readmitted 1 week later with nausea, weakness, a mild fever of 37.5°C, and severe hyponatraemia (plasma sodium concentration 114 mmol/l) (table 1). Urea and potassium concentrations were normal. The results of a full blood count were normal and blood cultures were negative.

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Table 1

Results of endocrine tests on two patients who developed hyponatraemia after …

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