Title : Dreams, diabetes, and dysautonomia: Steroid-Responsive Encephalopathy Associated with Autoimmune Thyroiditis (SREAT) heralding a multifocal autoimmune syndrome
Abstract:
Background: Steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT), historically termed Hashimoto’s encephalopathy, is a clinically heterogenous syndrome characterized by subacute neuropsychiatric manifestations, elevated thyroid autoantibodies, and a characteristic response to corticosteroids in the absence of an alternative explanation. its overlap with other organ-specific autoimmune disorders is increasingly recognized; however, presentations integrating latent autoimmune diabetes in adults (LADA), REM-sleep-behavior-disorder-like parasomnia, small-fiber/autonomic neuropathy remain sparsely characterized.
Case presentation: A 52-year-old man with newly diagnosed GAD65-positive LADA (HbA1c 13.6%, transitioned from oral hypoglycemics to insulin) developed a subacute multidomain neurologic illness over four months. The syndrome evolved from a migratory pruritic rash with regional dysesthetic burning to ascending bilateral lower-extremity neuropathic pain (“like stepping on rocks”), a wide-based ataxic gait requiring a a walker, and nocturnal complex dream-enactment behaviors with motor automatisms (chewing, undressing, reaching, thrashing), occasional myoclonic jerks, and post-prandial orthostatic intolerance. Examination disclosed global areflexia, truncal instability, dysmetria and hyponatremia (Na 123 mmol/L).
Investigations: CSF demonstrated elevated protein (137 mg/dL) and 5 CSF-restricted oligoclonal bands without pleocytosis. serology revealed markedly elevated anti-TPO and anti-thyroglobulin antibodies and low-titer GAD65 (0.18 nmol/L); a comprehensive autoimmune/paraneoplastic encephalitis panel (NMDA-R, LGI1, CASPR2, CAGA-BR, AMPA-R, DPPZ, IgLON5, GFAP, AGNA-1, ANNA-1/2/3. amphiphysin, CRMP5, mGluR1, septin-7, PDE10A, TRIM46) was otherwise negative. RT-QuIC and prion markers were negative. Brain and neuraxis MRI showed only an incidental retrocerebellar arachnoid cyst without cortical ribboning or inflammatory lesions. Serial EEGs captured the automatisms without ictal correlate. Polysomnography demonstrated complex dream-enactment behaviors with poorly differentiated REM. EMG/NCS revealed only mild bilateral L5-S1 radiculopathy without large-fiber polyneuropathy. Oncologic screening (CT chest/abdomen/pelvis, testicular ultrasound, FNA of an incidentally identified thyroid nodule with cervical adenopathy) was unrevealing.
Management and Outcome: A diagnosis of probable SREAT was rendered. IVIG (2g/Kg over 5 days) produced modest gains; subsequent high-dose prednisone (60 mg daily) yielded a marked sustained response with resolution of parasomnia, restoration of gait, and substantial attenuation of neuropathic pain, allowing clonazepam discontinuation. A four-month corticosteroid taper was completed without relapse. Persistent exertion-triggered acral burning pain with vasomotor flushing, dependent edema and dystrophic nails persisted, but post-prandial dizziness, diaphoresis and constipation improved. Currently evaluating for small fiber and/or autoimmune neuropathy with pending punch skin biopsy for intraepidermal nerve fiber density.
Discussion and Conclusion: This case illustrates SREAT as a protean, clinically actionable diagnosis that may serve as the sentinel manifestation of a broader polyautoimmune phenotype: here intersecting LADA, autoimmune thyroiditis, RBD-like parasomnia, and a suspected small-fiber/autonomic neuropathy. Recognition of this overlap is critical as timely immunotherapy reverses central manifestation, whereas residual peripheral and autonomic features may demand independent immunomodulatory consideration. This case underscores the diagnostic yield of integrating CSF profiling, multimodal neurophysiology, board autoantibody surveillance, and longitudinal phenotyping in patients with apparently disparate neuroendocrine syndromes, and supports a low threshold for empiric corticosteroids when the clinical and immunologic gestalt is suggestive, even in the absence of a defining surface-antigen antibody.
