This is a literature report. A 32-year-old man with recurrent idiopathic pericarditis was admitted with persistent hypotension. Workup revealed elevated ACTH, low DHEA-S, positive ACTH stimulation test and positive 21-hydroxylase antibody consistent with autoimmune Addison disease. Maintenance hydrocortisone, 20 mg in the morning and 5 mg at night, as well as fludrocortisone 0.05 mg daily, were started. He was counselled on the use of emergency dexamethasone injection pens. One month after discharge, he had normal sodium and potassium levels and a renin level of 3.0 ng/mL/h. During a follow-up primary care appointment, the patient was administered routine influenza, diphtheria vaccine toxoid, pertussis vaccine acellular, tetanus vaccine toxoid (TDAP) and Pneumococcal 13-Val Conj Vac (Dipht CRM197 Protein). Six hours after immunisations, the patient developed fever, myalgias, abdominal pain and vomiting that prevented intake of oral steroids. In the emergency department, vital signs revealed fever of 39.5 degree C and hypotension of 88/54, with hyponatraemia and hyperkalaemia. Upon admission to the intensive care unit for adrenal crisis, he received 4 L of normal saline and stress-dose IV hydrocortisone for 24 h. The patient's gastrointestinal symptoms quickly resolved after steroid administration and his sodium and potassium normalised. He was discharged on his home steroid regimen and was instructed to triple his home steroid regimen with any future vaccinations. The patient in this case developed a febrile illness with vomiting after receiving all three vaccinations at once, resulting in adrenal crisis. This case brings into question the optimal method by which we should administer indicated vaccines to patients with adrenal insufficiency. It is unclear if immunisations represent a significant enough physiologic stressor to precipitate adrenal crisis. It is more likely that the magnitude of these stressors varies from patient to patient, and if an immunisation causes the known adrenal crisis precipitants of fever or gastrointestinal symptoms, then these patients should be treated with stress-dose steroids. A prospective study demonstrated that 42% of adrenal insufficiency patients who developed symptoms of impending adrenal crisis did not change their steroid regimens, indicating a need for more extensive patient education Given the known side-effects of immunisations, it is important to counsel patients with adrenal insufficiency on how to use stress-dose steroids after receiving immunisations. Pfizer is a marketing authorization holder of Pneumococcal 13-val conj vac (dipht crm197 protein) in the reporter's country. This may be a duplicate report if another marketing authorization holder of Pneumococcal 13-val conj vac (dipht crm197 protein) has submitted the same report to the regulatory authorities.; Sender's Comments: The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to Regulatory Authorities, Ethics Committees and Investigators as appropriate.