FRCA Notes

Adrenocortical Disease

The curriculum asks for knowledge of 'endocrine abnormalities of significance to anaesthesia e.g. Cushing’s, Addison’s'.

This topic ties in with the perioperative management of patients with adrenal insufficiency, which has been the subject of a CRQ in the past.

Resources

  • The adrenal cortex is responsible for the production of the adrenocortical hormones; cortisol, aldosterone and sex hormones
  • Disease of the adrenal cortex can impair or augment steroidogenesis, leading to various clinical states which can impact on surgery and anaesthesia

Perioperative management of the patient with adrenocortical disease


  • Addison's disease is characterised by a deficiency of both mineralocorticoid and glucocorticoid adrenal hormones i.e. hypoadrenalism

Aetiology

  • The commonest cause is 'tertiary' hypoadrenalism, owing to exogenous steroid therapy suppressing the adrenal glands ability to secrete adrenocortical hormones

  • Secondary hypoadrenalism is more common than primary hypoadrenalism
  • It describes an issue 'upstream' of the adrenal glands affecting the HPA axis:
    • Pituitary disease e.g. post-resection, Sheehan's syndrome, SAH, trauma
    • Hypothalamic disease

  • Primary hypoadrenalism is less common:
    • Autoimmune destruction of the adrenal gland
    • TB
    • Post-surgical resection
    • Haemorrhagic e.g. Waterhouse-Friderichsen syndrome
    • CAH
    • Suppression by drugs e.g. etomidate, ketoconazole

Clinical features

Mineralocorticoid deficiency Glucocorticoid deficiency
Loss of sodium and water; dehydration Weight loss
(Postural) hypotension Muscle weakness
Hyperkalaemia Nausea
Hyponatraemia Hypoglycaemia
Metabolic acidosis ↓ stress response
Arrhythmia (2° ↓K+)
Impaired myocardial contractility

Diagnosis and management

  • Diagnosis may include evidence of reduced random/baseline cortisol levels and short synacthen testing

  • Management
    • Steroid replacement via hydrocortisone and fludrocortisone (50-100μg/day)
    • Treatment of underlying causes

  • Physiological stress may cause an Addisonian crisis; refractory hypotension, hypoglycaemia, abdominal pain and reduced conscious level
  • Requires HDU care with aggressive steroid replacement, fluid replacement and glucose correction

Anaesthetic considerations

  • Ensure correction of dehydration/volume deficit, hypoglycaemia, hyperkalaemia, hyponatraemia and other metabolic disturbance
  • Q4H monitoring of glucose and potassium
  • Appropriate steroid therapy

Aetiology

  • Primary hyperaldosteronism i.e. Conn's syndrome - due to adrenal adenoma, hyperplasia or carcinoma
  • Secondary hyperaldosteronism i.e. chronic oedematous states characterised by elevated renin production e.g. cardiac failure, liver failure

Clinical features & management

  • Hypertension, which is often refractory to treatment
  • End-organ damage from hypertension e.g. cardiomyopathy, cerebrovascular disease, CKD
  • Salt and water retention
  • Hypokalaemia
  • Hypomagnesaemia
  • Metabolic alkalosis
  • Management is with spironolactone i.e. aldosterone antagonism
  • Surgical removal of the adrenal adenomas, or glands, may be necessary

Anaesthetic considerations

  • Correction of electrolyte and metabolic disturbance
  • Ensure hypertension controlled
  • Continue spironolactone, as discontinuation risks hypertension and hypokalaemia
  • If patient is undergoing bilateral adrenalectomy will need post-operative corticosteroid replacement

Aetiology

  • Cushing's syndrome describes an excess of glucocorticoid, due to:
    • Cushing's disease i.e. pituitary adenoma causing excess ACTH secretion
    • Adrenal adenomas
    • Excessive exogenous steroid therapy

Clinical features

  • Centripetal obesity, buffalo hump, moon face, muscle wasting and striae
  • Multiple other sequelae of chronic glucocorticoid excess:
    • OSA
    • Glucose intolerance ± diabetes
    • Hypertension and associated end-organ damage e.g. LVH, LV systolic/diastolic dysfunction, pulmonary hypertension ± RV failure
    • Hypokalaemia (as cortisol has weak mineralocorticoid activity) and associated metabolic alkalosis
    • GORD
    • Osteoporosis

Management

  • Identifying and removing the underlying cause e.g. pituitary surgery
  • Metyrapone is a drug which inhibits cortisol synthesis which can be used as an inpatient to aid diagnosis and management

Anaesthetic considerations

  • Pre-operative
    • Ensure adequate BP control
    • Assessment of end-organ damage including LV dysfunction, renal dysfunction and IHD e.g. U&E, 12-lead ECG, TTE
    • Screen for OSA
    • Screen for diabetes ± manage appropriately
    • PPI for reflux

  • Intra-operative
    • Careful positioning, BP cuff and tourniquet use as patients often have fragile skin
    • Anticipate difficult airway due to obesity and OSA
    • Sensitive to NMBA due to a blend of existing muscle weakness, hypokalaemia and circulating catecholamines
    • May need perioperative steroid replacement if being rendered into a panhypopituitary state