Table 1

Differential diagnosis and investigations

Differential diagnosisInvestigationResults and conclusion
StrokeHistory, T2W and DWI/ADC MRIInsidious onset of symptom, sudden vascular event unlikely, 4-month time needed to full establishment of the syndrome. Upper motor, reflex and sensory examinations normal. No focal lesions
Space occupying lesion of brain and spineT2W MRINo mass lesions. Minimal cerebral atrophy. No cerebellar atrophy. No evidence of intracranial hypertension or middle shift
Multiple sclerosisT2W MRINo paraesthesia or sensory abnormalities. No evidence of demyelination disseminated in time/space on MRI fails to satisfy MacDonald’s criteria
Multiple system atrophyHistory, T2W MRIAutonomic features at presentation were absent and a pure cerebellar syndrome is not common such as in our patient. The absence of typical MRI features such as ‘hot cross bun sign’
Paraneoplastic syndromeHistory, FDG-PET, onconeural antibodiesNo clinical pointer to malignancy. FDG-PET was not available. Onconeural antibodies were negative
Inherited spinocerebellar ataxiaHistory, SCA6 genetic testingThere were no signs of dysarthria, peripheral neuropathy, spasticity, areflexia, vegetative symptoms or fasciculations. SCA6 Genetic testing was unavailable
A toxic or metabolic cerebellar syndromeHistory, biochemistryUnlikely without alcohol or recreational drugs consumption, exposure to chemicals or radiation, or medication history (eg, lithium, phenytoin). Absent ophthalmoplegia is seen in thiamine deficiency or areflexia and proprioception loss in vitamin E deficiency. Serum vitamin B12, folate levels and haemoglobin were normal
Creutzfeldt-Jacob diseaseHistoryNo additional features such as rapidly progressive dementia, psychiatric disturbance, myoclonus and sensory symptoms
Hashimoto’s encephalopathyHistory, GAD-Abs, anti-thyroid antibodiesSteroid-responsive encephalopathy with autoimmune thyroiditis that could not be confirmed by elevation of anti-TPO or anti-thyroid microsomal antibody and/or anti-thyroglobulin. No additional features such as seizures, myoclonus or tremor, chorea, dystonia and psychosis. When ataxia is the only manifestation, it can easily be missed or mistaken for degenerative ataxia, however GAD-Abs were positive
Autoimmune cerebellar syndromeHistory, GAD-AbsClinical manifestations were typical of the disease and were associated with nystagmus, hypothyroidism and diabetes. GAD-Abs were strongly positive in serum. Consent for lumbar puncture was not obtained
  • DWI/ADC MRI, diffusion-weighted imaging/ apparent diffusion coefficient magnetic resonance imaging; FDG-PET, fluorodeoxyglucose-positron emission tomography; GAD-Abs, glutamic acid decarboxylase autoantibody; SCA6, spinocerebellar ataxia type 6; T2W MRI, T2-weighted magnetic resonance imaging.