neurology
consulted for bilateral cerebellar ataxia
chronic smoker, nondrinker
interior water and electrical works repairman
no family history of gait disturbances / cognitive impairment
PMH: rheumatoid arthritis on isoniazid, leflunomide, methotrexate, P20
insidious onset progressive forgetfulness since 6 months ago, eg forgot about the steps while repairing water pipes and electrical wires, bADL and iADL intact
insidious onset progressive unsteady gait and slurred speech since early 6/2025
admitted twice in 6/2025, documented to be due to arthritis symptoms, patient reported the admissions were mainly for the unsteady gait, joint pain was not a major symptom
unable to work due to the gait symptoms since discharged late 6/2025
intermittent fresh PRB since 2023, CLN 2023 NAD
subjective weight loss, 88kg 4/2025 -> 78kg now, appetite maintained
taken TCM early 7/2025
clinically admitted for unsteady gait / slurred speech / memory problem
no unilateral weakness / numbness / facial asymmetry / diplopia / visual symptoms / dysphagia / sphincter disturbances
no fever / URTI / headache / neck pain / back pain / seizures / OTC meds / illicit drug use
on current dose methotrexate since 2023, adalimumab once 10/2024, isoniazide since 6/2025
no parkinsonism / falls / visual hallucinations / postural dizziness
CTB: no focal lesions / hydrocephalus / cerebellar or pontine atrophy
contrast MRI brain:
– no lesions suggestive of demyelination
– no periaqueductal grey matter / mamillary body lesion
– no midbrain atrophy
– no meningeal enhancement
LP: OP not documented, WCC 15 polymorphs, protein 0.6, glucose not low
VZV -ve, AFB smear -ve, indian ink -ve
TB PCR / cytology TF
CXR: no mass
baseline bloods N except mild normocytic anemia, ALT 120
CRP N, ESR 80
HIV / TP EIA -ve
ANA 640
NMDA / autoimmune encephalitis TF
antiganglioside ab -ve
antiTPO / anti TG TF
TFT N, A1c 6.7
B12 / folate N, thiamine TF
transient lactate ↑, NH3 / CK N
ceruloplasmin not low
urine toxicology -ve
CEA 6.2 (smoker), other tumor markers -ve
paraneoplastic ab -ve
GCS full
neck soft
no ptosis, PEARL, EOM full, saccades normal, no nystagmus / oculopulsion, no facial numbness / weakness, hearing normal, palatal movement symmetrical, dysarthria, no tongue wasting
limbs power full, no pronator drift
no muscle wasting / tremor, tone / reflex normal, no ankle clonus
no sensory level, proprioception normal
bilateral rebound phenomenon, bilateral intention tremor R>L, bilateral heel shin abnormal L>R, no dysdiadochokinesia
gait: mild broad based gait, failed tendem walking, romberg -ve
MOCA 18 (<65yo)
imp:
subacute onset progressive cognitive symptoms / bilateral cerebellar ataxia with constitutional sx
background of RA on immunosuppressants including methotrexate
normal brain MRI, CSF mild pleocytosis / elevated protein
to exclude infective, inflammatory, neoplastic / paraneoplastic, toxic etiologies first
suggest
– PVBS once
– postural BP 013 x2 to look for autonomic dysfunction
– await CSF TB PCR, cytology
– next blood + antiGAD, vitamin E, copper, SPE, HTLV1, ENA, ANCA, ferritin, cryptococcal antigen, lyme disease serology, lead, mercurt
– IP EEG to look for evidence of encephalopathy
– XR Cspine AP lat
– proceed to malignancy screening with contrast PETCT or CT TAP