Differential diagnosis, investigations and treatment
Subacute progressive extremities weakness with painless visual loss strongly suggests inflammatory and demyelinating disorders such as neuromyelitis optica spectrum disorder (NMOSD) or multiple sclerosis (MS), as well as autoimmune and paraneoplastic syndromes like systemic lupus erythematosus (SLE), sarcoidosis, or paraneoplastic neurological disorders. Other considerations include vascular causes (e.g., Susac syndrome, ischemic optic neuropathy), infectious etiologies (e.g., neurosyphilis, HIV), metabolic and toxic causes (e.g., vitamin B12 deficiency, methanol toxicity), and mitochondrial disorders (e.g., mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes, MELAS) Investigations included MRI of the brain and spine with contrast to evaluate for demyelination, CSF analysis for oligoclonal bands and inflammatory markers, serological tests for aquaporin-4 (AQP4) and myelin oligodendrocyte glycoprotein (MOG) antibodies and autoimmune panels (ANA, dsDNA, ACE, paraneoplastic antibodies)
Cerebrospinal fluid analysis revealed significantly elevated protein and decreased glucose levels, no white blood cells, positive oligoclonal bands, mild elevation in lactate dehydrogenase, and negative CSF cultures for various pathogens. Serum ACE levels were within normal limits, ESR levels were not elevated, ANA, dsDNA were negative and screening tests for HIV, syphilis, tuberculosis, and Coccidioides were negative. Anti- AQP4 and anti-MOG antibodies were also negative.
MRI Brain with and without contrast [Figure 1,2] showed leptomeningeal enhancements within the intraorbital portion of the right optic nerve, in the left hypothalamic region, along the left superior cerebellar hemisphere, along the surface of the cervicomedullary junction, and along the anterior surface of the pons, without evidence of abnormal enhancement in the brain parenchyma. MRI C-T-L spine with and without contrast [Figure 3,4] revealed multifocal nodular leptomeningeal enhancements along the surface of the cervical cord, thoracic cord, and along the cauda equina nerve roots, with suspected intramedullary enhancement associated with leptomeningeal enhancing lesions at the C6, C7, T1, T4, T7-8, T11, and T12 levels.
The patient was treated with 5 days of IVIG at 0.4 g/kg/day due to a diagnosis of possible neurosarcoidosis, but his clinical status remained unchanged after treatment. He was discharged to a rehabilitation facility.