AN UNUSUAL CAUSE OF ENCEPHALOPATHY: STEROID RESPONSIVE ENCEPHALOPATHY ASSOCIATED WITH AUTOIMMUNE THYROIDITIS (SREAT)

Abstract

SESSION TITLE: Critical Care 4 SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/09/2018 01:15 PM - 02:15 PM INTRODUCTION: SREAT is an autoimmune disease associated with anti-thyroid antibodies. Its features mimic the fatal Creutzfeldt-Jacob disease (CJD), but SREAT responds to steroids. We present a case of SREAT to increase physician awareness of an important fully reversible disease. CASE PRESENTATION: An 84-year-old woman with hypothyroidism was brought to our hospital due to decreased responsiveness for 1 day. Examination: BP: 75/42 mmHg, heart rate: 38 bpm, temperature: 33.8 ºC, minimal response to sternal rub, no focal neurological abnormalities. Chest X-ray: Small right pleural effusion. CT head: Chronic microvascular changes. ECG: Sinus bradycardia. Laboratory evaluation: WBC: 2.2 K/CUMM, mild hyponatremia and acute kidney injury. After initial resuscitation, we started IV fluids, high dose levothyroxine, antibiotics and hydrocortisone for myxedema coma and pneumonia. TSH and free thyroxine were normal, making myxedema coma unlikely and levothyroxine was discontinued. Encephalopathy did not improve and seizures developed. SREAT was considered due to rapid onset encephalopathy, seizures and prior hypothyroidism. Thyroid peroxidase antibody level was 1,021 IU/mL (normal < 4 IU/mL). EEG: Moderate diffuse slowing and triphasic waves. CSF: Normal protein and cell count. IV methylprednisolone 1 g/day was started, and on day 3, she became alert, oriented and started conversing. Subsequently, she developed uremic encephalopathy requiring hemodialysis due to worsening acute tubular necrosis (ATN), recurrent sepsis, and upper gastrointestinal bleed and expired despite aggressive ICU care. DISCUSSION: SREAT presents with acute/subacute encephalopathy consistently. Myoclonus, seizures, stroke like or psychiatric manifestations are associated features. Due to reversibility of SREAT, antithyroid antibodies should be ordered in acute encephalopathy syndromes associated with neuropsychiatric manifestations. Diagnosis is based on clinical features, high titer antithyroid antibodies and response to steroids. Most patients with SREAT have generalized slowing in EEG, but focal temporal or frontal slowing, triphasic waves and periodic sharp waves may be seen. 60% develop seizures. MRI is normal in 50%, but generalized cerebral atrophy, restricted diffusion, and increased T2 and flair white matter signal may be seen. Patients may be euthyroid, have subclinical or overt hypothyroidism, or rarely hyperthyroidism. CSF shows elevated protein in 85% of cases. 98% of patients with SREAT respond well to high dose steroids. CONCLUSIONS: SREAT is important to consider in unexplained encephalopathy, due to its excellent response to steroids. Though high dose steroids have excellent efficacy in SREAT, steroids are associated with adverse events such as GI bleed and sepsis. ATN in ICU patients has a mortality of > 60%, and high dose steroids increases risk of uremic bleeding. Early institution of hemodialysis may improve ATN outcome. Reference #1: Laurent, Charlotte, et al. “Steroid-Responsive Encephalopathy Associated with Autoimmune Thyroiditis (SREAT): Characteristics, Treatment and Outcome in 251 Cases from the Literature.” Autoimmunity Reviews, vol. 15, no. 12, Dec. 2016, pp. 1129–33. CrossRef, https://doi.org/10.1016/j.autrev.2016.09.008. Reference #2: Lee, Susan W., et al. “Steroid Responsive Encephalopathy Associated with Autoimmune Thyroiditis (SREAT) or Hashimoto’s Encephalopathy: A Case and Review.” Psychosomatics, vol. 52, no. 2, Apr. 2011, pp. 99–108. PubMed, https://doi.org/10.1016/j.psym.2010.12.010. Reference #3: Annals of Long-Term Care: Clinical Care and Aging. 2015;23(9):25-27. DISCLOSURES: No relevant relationships by Camelia Arsene, source=Web Response No relevant relationships by Maxwell Cretcher, source=Web Response no disclosure on file for E.M. Malitha Hettiarachchi; No relevant relationships by Katherine Kelley, source=Web Response No relevant relationships by Aditya Kotecha, source=Web Response No relevant relationships by Parker Latshaw, source=Web Response no disclosure on file for Sidrah Najam; no disclosure on file for Udorji Ogochukwu; no disclosure on file for Christina Rose