Autoimmune Adrenalitis Following mRNA Covid- 19 Immunization; This is a literature report.  A 45-year-old female patient received bnt162b2 (BNT162B2), as dose 2, single (Batch/Lot number: unknown) for covid-19 immunisation. The patient's relevant medical history included: "Hashimoto thyroiditis" (unspecified if ongoing); "celiac disease" (unspecified if ongoing). The patient's concomitant medications were not reported. Vaccination history included: Covid-19 vaccine (DOSE 1, MANUFACTURER UNKNOWN), for Covid-19 immunisation. The clinical course is as follows: The patient presented after a syncopal episode that resulted in a motor vehicle accident. The patient had symptoms of fatigue, nausea, and anorexia for three weeks following the second dose of the Pfizer- BioNTech COVID-19 Vaccine. Initial laboratory tests revealed hyponatremia with serum sodium (Na) of 123mEq/L that worsened to 111mEq/L after receiving the normal saline infusion. Serum potassium was 3.4mEq/l, thyroid stimulating hormone level was 6.350mIU/l, free thyroxine level was 1.1 ng/dl and glucose were 85mg/dl. The PCR test for COVID-19 was negative. Vitals were unremarkable except for a low blood pressure of 90/60. On physical examination, the patient was alert and communicative and there was no hyperpigmentation of the skin. The patient denied personal and family history of adrenal insufficiency. She denied prior use of any steroid medications. Her prior outpatient serum Na levels were normal (138-140 mEq/L). The patient was admitted to the ICU for severe hyponatremia, where she was treated with fluid restriction and hypertonic saline. However, she remained hypotensive, and serum sodium failed to improve above 118mEq/l. Serum cortisol at 8: 00 am and 10:00 am were 4.5 and 5.8 mcg/dl, respectively. She was started on stress doses of hydrocortisone 100 mg intravenous (IV) followed by hydrocortisone 50 mg IV every 8 hours and serum Na improved to 130mEq/l. Steroids were tapered gradually to physiological doses. The levothyroxine dose was also increased from the home dose of 75mcg to 88 mcg daily due to the elevated TSH. Hormonal workup showed aldosterone of 0.3ng/dl, plasma renin activity of 20, and adrenocorticotropic hormone (ACTH) levels of >1250pg/ml. Gonadotropins, insulin-like growth factor-1, and prolactin were within normal limits. Cosyntropin stimulation test after holding steroids for 24 hours was abnormal, with pre-cosyntropin cortisol level 7.0mcg/dl, and the 60-minute postcosyntropin cortisol level 7.1mcg/dl. The diagnosis of autoimmune adrenalitis was confirmed with a positive 21-hydroxylase antibody test. The patient had an uneventful recovery and was discharged on oral hydrocortisone.  No follow-up attempts are possible. No further information is expected.; Sender's Comments: Based on the available information, the known product safety profile and implied temporal association, a causal relationship between the reported events and suspect product cannot be excluded. 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.