She has progressive unilateral (UL&LL) + jaw tremor, generalized weakness and weight loss for 6 months.
She has no headache, no visual changes, no urinary/stool incontinence, no symptoms of thyrotoxicosis
O/E: She looks well,
She has muscle wasting (temporal & limbs )
Jaw tremor with abnormal voice, action tremor of both right UL & LL.
Muscle power 2/5 of both right UL & LL.
Reflexes can`t be evaluated due to the effect of tremor.
Chest, CVS &Abdomen all are normal.
What is your approach to this patient? DDx? Investigations?