WBR1031

Author	PageAuthor::Vendhan Ramanujam
Exam Type	ExamType::USMLE Step 3
Main Category	MainCategory::Community Medical Health Center, MainCategory::Primary Care Office
Sub Category	SubCategory::Musculoskeletal/Rheumatology, SubCategory::Musculoskeletal/Rheumatology
Prompt	[[Prompt::A 49 year old man presents to his primary care physician with complaints of generalized muscle weakness and pain present all throughout the day for the past three days. It started as a vague neck pain before progressing to generalized muscle weakness. He also complains of drooping of his upper eyelids and inability to open his car doors because of hand weakness. Over-the-counter acetaminophen has not been helpful. He denies any history of fever, difficulty in breathing or swallowing and facial muscle weakness. He has a past medical history of gastroesophageal reflux disease and plantar fasciitis that was diagnosed before 1 week for which he is currently taking methylprednisolone. He has a history of smoking 1 pack of cigarette per day for the past 25 years and denies taking alcohol. On examination, his vital signs are blood pressure of 130/85 mm Hg, pulse rate of 80 beats/min, respiratory rate of 15 breaths/min and temperature of 37.2 °C. Bilateral ptosis is noticed and there is pain on palpation of both the upper and lower extremity. Muscle strength is 2 in both the upper and lower extremities. Handgrip is weak, and he has difficulty standing up from sitting position. Sensations are bilaterally normal and symmetrical. Normal deep tendon reflexes are noted. His complete blood count and basic metabolic profile are normal. His other lab tests revealed the following ESR  : 10 mm/hr Creatinine phosphokinase: 890 U/L C-reactive protein  : 14 mg/L A urine dipstick test is positive for hemoglobin. Muscle biopsy and electromyography are not performed. What is the most likely cause for this patient’s complaints?]]
Answer A	AnswerA::Polymyositis
Answer A Explanation	[[AnswerAExp::Incorrect-Polymyositis is an inflammatory myopathy that presents with proximal muscle weakness and elevated serum creatinine kinase and ESR levels. It is confirmed by muscle biopsy.]]
Answer B	AnswerB::Dermatomyositis
Answer B Explanation	[[AnswerBExp::Incorrect-Dermatomyositis is an inflammatory myopathy that presents with proximal muscle weakness and skin lesions. Serum creatinine kinase and ESR levels are elevated. It is confirmed by muscle biopsy.]]
Answer C	AnswerC::Neuromuscular junction disease
Answer C Explanation	[[AnswerCExp::Incorrect-Neuromuscular junction disease usually presents as muscle weakness that is decremental in nature and descends from the face with bilateral ptosis, dysarthria, etc. to the proximal muscles of the limbs while also involving the respiratory muscles.]]
Answer D	AnswerD::Drug induced myopathy
Answer D Explanation	AnswerDExp::'''Correct'''-Acute steroid induced myopathy should be considered in patients who begin to have generalized muscle weakness, elevated serum creatinine kinase levels and myoglobinuria around 1 week after the start of steroid treatment.
Answer E	AnswerE::Polymyalgia rheumatica
Answer E Explanation	[[AnswerEExp::Incorrect-Polymyalgia rheumatica usually presents with stiffness and pain in the shoulder and pelvic girdle. It can be associated with headache as in the case of giant cell arteritis and usually occurs in age group of above 50 years of age.]]
Right Answer	RightAnswer::D
Explanation	[[Explanation::The patient has developed complaints one week after beginning methylprednisolone. Myopathy is a known side effect of glucocorticoid (corticosteroid) therapy since it has a direct catabolic effect on skeletal muscles by affecting the metabolic process that provides amino acids as a substrate for gluconeogenesis. Steroid induced myopathy may either be acute or chronic. Acute presentations are less frequent and usually occur after a week after the onset of treatment. They usually present as generalized muscle weakness rather than proximal muscle weakness. Myalgias and muscle tenderness do not occur. Most patients have high levels of serum creatine kinase, as well as associated myoglobinuria. Muscle biopsy shows focal as well as diffuse necrosis of all types of fiber and some times EMG findings may be abnormal. The main treatment recommendation for steroid induced myopathy is to decrease the dose of steroid or to discontinue the corticosteroid use. Alternate day dosing may also be considered. Educational Objective: Acute steroid induced myopathy should be considered in patients who begin to have generalized muscle weakness, elevated serum creatinine kinase levels and myoglobinuria around 1 week after the start of steroid treatment. Educational Objective: References: ]]
Approved	Approved::Yes
Keyword	WBRKeyword::Drug induced myopathy, WBRKeyword::Steroid induced mypoathy
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