Ask a Neurologist and Get an Answer ASAP
Has he had an LP (lumbar puncture)?
I would suggest you ask his doctors to check his CSF (cerebrospinal fluid). This is an important element in ruling out certain infectious causes. For example, progressive adult onset sporadic ataxias may sometimes be caused by chronic infections of the central nervous system. The most common infections related to progressive sporadic ataxia are neurosyphilis, Whipple's disease, Lyme disease and HIV.
Another possible line of investigation would be immune-mediated ataxias. These are neurological conditions related to auto-immune disorders. Immune-mediated ataxias include: gluten ataxia, ataxia associated with antibodies against the glutamic acid decarboxylase (anti-GAD), steroid-responsive encephalopathy associated with autoimmune thyroiditis and paraneoplastic cerebellar degeneration.
Alcohol or other toxic exposures may also cause or exacerbate a pre-existing ataxia. The main substances causing toxic ataxia are: lithium, phenytoin, amiodarone, toluene and some chemotherapy’s (5-fluorouracil and cytosine arabinoside). There are also descriptions of ataxia induced by mercury or bismuth subsalicylate exposure. Other drugs may rarely cause cerebellar symptoms: carbamazepine, valproic acid, cyclosporine, isoniazid, metronidazole, nitrofurantoin, procainamide and even statins. When toxic ataxia is suspected, these substances should be immediately discontinued. Clinical outcome is variable after drug cessation: patients may have significant improvement or only stabilization of symptoms.