Googled the question and it came from another source... This was the answer. I guess knee-jerk response would be going with PMR.
Answer is drug-induced myopathy from steroids:
Steroid myopathy is usually an insidious disease process that causes weakness mainly to the proximal muscles of the upper and lower limbs and to the neck flexors.
In chronic (classic) steroid myopathy, serum levels of creatine kinase typically are within the reference range.
glucocorticoid down-regulation of protein synthesis may lead to decreased levels of these proteins in chronic steroid myopathy.
This patient has a history of temporal arteritis(i.e giant cell arteritis), which is usually treated with high dose oral steroids tapered over a prolonged period of time.Steroid-induced myopathy is the most common cause of drug-induced myopathy and can occur weeks to months after starting steroid therapy.The mechanism of steroid myopathy is thought to be decreased protein synthesis, mitochondrial alteration, increased protein degradation, and electrolyte and carbohydrate metabolism disturbances .
Acute steroid myopathy occurs within 1 week of drug initiation (relatively uncommon) and is cahrachterized by muscle weakness and rhabdomyolysis. The chronic form is more common and has an insidious onset after prolonged steroid use. patient present with proximal muscle weakness (lower extremity before upper ) without significant pain and difficult getting up from a chair , climbing stairs or brushing their hair.
For both acute and chronic forms, the Diagnosis is clinical and no difinitive diagnostic test.
Muscle power imporves after discontinuation of the steroids, but the improvement can take weeks to months.
Choice A Polymyalgia rheumatica can be seen in up to 50% of the patients with temporal arteritis. Patients typically presents with aching and morning stiffness with pain in the shoulder, hip girdle and neck.
The ESR is usually elevated and symptoms usualy improve with steriods.
Choice B Mononeuritis multiplex is usually seen in vasculitis and is caused by nerve damage in two or more nerves in seperate parts of the body.Patient typically presents with peripheral nerve findings ,such as wrist or foot drop.
Choice C Symmetrical poluneuropathy involves more dista; than proximal muscles and is not consistent with the patients presentation.
Choice D Muscle enzymes are elevated
Choice G Myasthenia gravis causes more upper than lower extremity disease and typically occular symptoms.
Additional reference
http://www.ncbi.nlm.nih.gov/pubmed/20471889