How does adrenal insufficiency affect blood pH?

From the Guidelines

Adrenal insufficiency typically leads to metabolic acidosis, causing blood pH to decrease below the normal range of 7.35-7.45. This occurs because the adrenal glands fail to produce adequate amounts of cortisol and aldosterone. Aldosterone deficiency particularly affects acid-base balance by reducing sodium reabsorption and potassium excretion in the kidneys. This leads to decreased hydrogen ion secretion, resulting in retention of hydrogen ions in the bloodstream and subsequent acidosis. Additionally, cortisol deficiency can contribute to hypoglycemia, which may worsen acidosis through increased production of ketoacids and lactic acid.

Key Points to Consider

• Patients with adrenal insufficiency may present with symptoms including fatigue, weakness, hypotension, and electrolyte abnormalities alongside the acidosis.
• Treatment involves hormone replacement therapy with glucocorticoids (such as hydrocortisone 15-25 mg daily in divided doses) and mineralocorticoids (fludrocortisone 0.05-0.2 mg daily) to restore normal adrenal function and correct the acid-base imbalance, as recommended by guidelines from the Association of Anaesthetists, the Royal College of Physicians, and the Society for Endocrinology UK 1.
• During acute adrenal crisis, higher doses of hydrocortisone (100 mg IV immediately, then 50-100 mg every 6-8 hours) along with fluid resuscitation are necessary to rapidly correct the metabolic derangements, as outlined in the guidelines for the management of glucocorticoids during the peri-operative period for patients with adrenal insufficiency 1.
• It is essential to recognize that prescribed glucocorticoid therapy can cause suppression of the hypothalamo–pituitary–adrenal axis, and patients on such therapy are at risk of adrenal crisis during surgical stress or illness 1.
• The management of patients with adrenal insufficiency requires a pragmatic approach, considering the evidence available, and it is crucial for clinicians to collaborate with the patient’s endocrinologist when planning scheduled surgery or caring for postoperative patients 1.

Management Considerations

• Hydrocortisone 100 mg by intravenous (i.v.) injection should be given at induction of anaesthesia in adult patients with adrenal insufficiency from any cause, followed by a continuous infusion of hydrocortisone at 200 mg.24 h-1, until the patient can take double their usual oral glucocorticoid dose by mouth, as recommended by the guidelines 1.
• For patients with primary adrenal insufficiency, dexamethasone is not adequate as glucocorticoid treatment due to its lack of mineralocorticoid activity 1.
• Children with adrenal insufficiency require special consideration, including frequent blood glucose monitoring and tailored hydrocortisone dosing based on age and body weight, to manage their condition effectively during the peri-operative period 1.

From the Research

Adrenal Insufficiency and Blood pH

• Adrenal insufficiency is a condition characterized by an absolute or relative deficiency of adrenal cortisol production 2.
• The studies provided do not directly address the effect of adrenal insufficiency on blood pH.
• However, it is known that adrenal insufficiency can lead to electrolyte imbalances, such as hyponatremia and hyperkalemia 3, 4, which can affect acid-base balance and potentially lead to changes in blood pH.
• Additionally, adrenal insufficiency can cause metabolic disturbances, including hypoglycemia 4, which can also impact blood pH.
• Further research is needed to fully understand the relationship between adrenal insufficiency and blood pH, as the current evidence does not provide a clear answer to this question.