To discuss a unique case of acute HIV seroconversion presenting as Stiff Person Syndrome Disorder (SPSD) and emphasizing the need of a clearer diagnostic criteria and treatment modalities of such autoimmune diseases (ADs) in HIV patients for a better prognosis.

The clinical manifestation of HIV seroconversion depends on the underlying pathological process. ADs can rarely emerge during this phase, either through direct effect or indirect immune dysregulation. We present the first case of SPSD occurring during HIV seroconversion.

Case report:

A 22-year-old male with new HIV diagnosis initially presented with muscle spasms and hyperreflexia. Few days later, he developed encephalopathy, autonomic instability, hyperekplexia, and severe myoclonus, leading to rhabdomyolysis and thoracic spinal fractures. CSF studies revealed 17/mm3 lymphocytes, 99.5 mg/dL protein with normal imaging. While the serum autoimmune panel was pending, we started him on Bictegravir, Emtricitabine, Tenofovir, benzodiazepines and Tizanidine. A week later, serum Glutamate decarboxylase-65 antibody(Ab) (0.05 nmol/L) and Glycine receptor alpha1 (GlyRa1) Ab returned positive.  In 8 weeks, he consistently improved in strength and myoclonus, without the need to start immunosuppressive medication.

SPSD commonly presents as stiffness, painful spasms, gait abnormality and hyperexcitability. Diagnostic criteria includes typical clinical symptoms & GAD65(high titers)/ GlyR/ Dipeptidyl Peptidase-like Protein 6 antibody positivity. Misdiagnosis is common, thus emphasizing the importance of avoiding testing without reasonable clinical suspicion. Prognosis depends on case specific symptomatic treatment, immunomodulatory therapy and/or associated comorbidity management, like HIV in our case. It is unclear if the acute seroconversion causing autoimmunity is virally mediated or immune-mediated, or a combination of the two.

The incidence and clinical importance of rare autoimmune disorders like SPSD occurring during HIV seroconversion must be ascertained through additional research to identify pathogenesis, treatment strategies and achieve better prognostic outcomes. While HIV infection does not preclude the use of immunosuppressants, early diagnosis and treatment is essential.