(258) Severe Hyponatremia After Pneumococcal Vaccine in a Patient With Secondary Adrenal Insufficiency

Introduction: Adrenal Insufficiency (AI) is a condition arising from a deficiency of cortisol. Glucocorticoid therapy is the mainstay of treatment; however, despite compliance, some patients will become steroid deficient. This may cause hypotension, fever, hypoglycemia, and hyponatremia. These patients may also be considered immunosuppressed; therefore vaccinations are of utmost importance.

Description: A 56-year-old woman with Type 2 Diabetes mellitus, hypertension and bilateral adrenalectomy (Maintained on hydrocortisone 10 mg AM and 5 mg PM) was admitted to the ICU with altered mental status, generalized malaise, decreased appetite, fever, non-productive cough, nausea, vomiting, and hypotension. Labs were significant for hypoglycemia and severe hyponatremia. Two days prior, she received the pneumococcal conjugate vaccine (PCV-20) in the morning and became symptomatic by the evening. Before presenting, she had doubled her steroid dosing at home . Blood cultures were obtained; Dextrose, Intravenous Hydrocortisone, isotonic fluids and empiric antibiotics were administered. Infection was ruled out, and the patient was tapered on hydrocortisone after rapid improvement in symptoms.

Discussion: Infection is a major cause of mortality in AI, which can approach 2-3 times that of the general population. Vaccination, therefore, is an important tool but, administration in this group is not straightforward.
Lethargy, Vomiting and diarrhea post PCV-20 vaccination are normally self-limiting. The patient however also had hypoglycemia and hypotension, despite doubling of her steroid maintenance dose. This clinical picture is a result of two separate entities. First is hypovolemia due to GI losses, insensible losses and reduced oral intake. Second is insufficient adrenal hormone replacement.
The Korean Endocrine society expanded its AI sick day rule to cover COVID-19 vaccine side effects, and this principle could have been applied here. These rules allow patients to increase their steroid doses based on symptom severity.
This scenario may have been avoided by either giving a stress dose prior to vaccination or further increasing the sick day dosing at home. Either of these alterations carries risk however, and Endocrine and Immunology input will be invaluable when managing these patients in the future.