|LETTER TO EDITOR
|Ahead of print publication
Autoimmune encephalitis as a rare complication of autoimmune polyendocrine syndrome type 3
Prashant Gopal, Saranya S Nelabhotla, Pradnya Mukund Diggikar
Department of General Medicine, Dr. D Y Patil Medical College, Hospital and Research Centre, Pune, Maharashtra, India
|Date of Submission||19-Jan-2022|
|Date of Acceptance||17-Apr-2022|
|Date of Web Publication||13-Jul-2022|
Pradnya Mukund Diggikar,
B G Vastu, Flat No 101, Plot No 305, Sector No 28, Pradhikaran, Near Ganganagar Bus Stop, NIGDI, Pune, Maharashtra
Source of Support: None, Conflict of Interest: None
Autoimmune polyendocrine syndromes (APS) are a group of autoimmune disorders characterized by endocrine tissue destruction causing multiple glandular dysfunctions. APS Type-3 presents as autoimmune thyroid disease with one of either diabetes mellitus type 1 (type 3A) or chronic atrophic gastritis or pernicious anemia (type 3B) or vitiligo, alopecia, or myasthenia gravis (type 3C). We describe the case of an 18-year-old female who presented with diabetic ketoacidosis and Graves' thyroiditis and later developed seizures.
A thin built (body mass index – 18.2) female presented with complaints of abdominal pain, 4–5 episodes of vomiting, low-grade fever, and mild breathlessness. Family history revealed that her mother suffered from hypothyroidism. BSL on admission was 412 mg/dl, and urine ketones were 3+. Arterial blood gas analysis showed metabolic acidosis with decompensated respiratory alkalosis [Table 1].
Ketoacidosis was managed with intravenous fluids and insulin infusion. Anti-peroxidase (thyroid peroxidase) antibodies, thyrotropin receptor antibody, and glutamic acid decarboxylase 65 antibodies were positive. Islet cell antibodies and antiparietal cell autoantibodies were negative. Ultrasonography neck revealed a mildly enlarged thyroid with heterogeneous echotexture with increased vascularity suggestive of Graves' thyroiditis. Adrenocorticotropic hormone and cortisol levels were normal. Based on these findings, a diagnosis of APS type 3 was made. The patient was started on beta-blockers and antithyroid medication.
Two days later, the patient developed two episodes of generalized tonic–clonic seizures. Computed tomography brain and magnetic resonance imaging brain (P + C) showed no abnormalities. Electroencephalogram showed nonspecific slowing (generalized slowing of delta range with no delta brush). Cerebrospinal fluid (CSF) routine showed mild lymphocytic pleocytosis and elevated proteins (126 mg/dL). Glucose and Adenosine deaminase (ADA) were normal. CSF cartridge-based nucleic acid amplification test was negative, and the culture showed no growth. CSF viral panel came back negative. Considering the possible association between APS and autoimmune encephalitis, CSF autoimmune panel was sent which came back positive for N-methyl-D-aspartate receptor (NMDA) antibodies. Anti-α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid and anti-γ-aminobutyric acid B antibodies were negative. The patient's paraneoplastic and vasculitis screening came back negative. Systemic lupus erythematosus and Sjögren's screening came back negative.
Autoimmune encephalitis (AE) is characterized by altered mental status, memory impairment, or seizures in the presence of autoantibodies in the blood and CSF. NMDA-R encephalitis is characterized by an initial viral-like prodrome (fever, malaise, headaches, and anorexia), followed by psychiatric symptoms (anxiety, depression, schizophrenia, and psychosis), temporal lobe dysfunction (amnesia and seizures), and finally, severe neurologic deficits (autonomic dysfunction, dystonia/dyskinesia, and profound encephalopathy). The pathophysiology of the disease is not fully understood. It is thought to be caused by autoimmune antithyroid antibodies reacting with neurons, causing widespread central nervous system inflammation.
Treatment options include immunosuppressive drugs and drugs that target antibody-mediated disease pathogenesis. Corticosteroids, such as most other anti-inflammatory drugs, work by reducing inflammation. Other treatments target specific AE pathophysiological stages. These treatments target autoantibodies and other immune mediators (IVIg and PLEX), B-cells and short-lived plasma cells (rituximab), and cytokines associated with autoimmune and inflammatory processes (tocilizumab and low-dose interleukin-2). Antiproliferative drugs (cyclophosphamide, azathioprine, and mycophenolate mofetil) are used in refractory patients or to maintain remission.
The patient was started on antiepileptics and administered two cycles of pulse therapy steroids (1 g/day methylprednisolone for 3 days) and was planned for IVIG/plasmapheresis. Fortunately, she improved with steroid therapy and is asymptomatic on 6 months of follow-up. AE has been reported in patients with APS or Graves' disease. It is an important diagnostic consideration in patients with new-onset altered mental status or seizures. Early detection and treatment of anti-NMDAR encephalitis is crucial for improving outcomes.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initial s will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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