A pain in the arms

Dr Catalano: In October 2011, a 73-year-old shoemaker was admitted to the chest pain unit of a provincial hospital for atypical chest pain that arose a few hours earlier. He had a history of ischemic heart disease, and had an acute myocardial infarction at the age of 65, and had a subsequent coronary artery bypass graft. He also had peripheral edema and with bilateral upper limb functional weakness and progressively more severe myalgia. These other symptoms had arisen about 2 weeks prior, and with growing intensity. Blood tests excluded an acute coronary syndrome (troponin negative), but showed the presence of an elevated serum creatinine phosphokinase (CPK). During hospitalization in the chest pain unit, the patient also underwent an echocardiographic examination, which showed the presence of moderate heart disease. A few days later, the patient was transferred to our unit because of worsening bilateral edema and myalgia of the upper limbs. There was no family history of muscular disorders, but only hypertension and diabetes mellitus (DM). He reported that at the age of 53 years, a monoclonal gammopathy had been diagnosed, and 1 year later arterial hypertension. He had been under treatment for several years with betablockers, acetyl salicylic acid, antihypertensives, nitrates, proton pump inhibitors as well as simvastatin (20 mg/day), but had never shown clinical or biochemical findings of muscle toxicity. On visual examination, the patient was afebrile but the arms, especially the forearms, were red and swollen with diffuse bilateral hard edema and marked weakness. The blood pressure was 120/80 mmHg, heart rate 80 beats/min., and no other physical signs were present. Dr Cecere: We carried out blood tests that were normal except for a CPK 2504 U/L (nv: 21–232), lactic dehydrogenase (LDH) 305 U/L (vn: 100–190), creatine kinase MB (CK-MB) 5.1 U/L (nv up to 3.6), myoglobin 707 ng/ml (vn: 16–96), erythrocyte sedimentation rate 33 mm/h (vn: 1–10), fibrinogen 745 mg/dl (170–410), serum glutamic oxaloacetic transaminase 210 U/L (vn: 15–37), serum glutamic pyruvic transaminase 84 U/L (nv 12–78), hemoglobin 11.3 g/dl (nv 12–15). Urinalysis showed moderate hemoglobin concentration with no sign of red blood cells on microscopic examination. This was hypothesized to be due to the presence of myoglobinuria.