An Unusual Presentation Of Painless Myocardial Infarction To The Emergency Department

摘要

Myocardial Infarction presenting without chest pain is not uncommon in the Emergency Department. We present a case of painless myocardial ischemia in a patient with a complex background of chronic pain whose perception of pain was possibly altered by the use of high doses of opioid analgesics. The significance of early diagnosis of silent ischemia and the pit falls for physicians working in the emergency department are discussed. The importance of simple tests like an electrocardiogram in the overall assessment of patients presenting with a blurred history is also highlighted. Case Report A 65 year old man presented to the emergency department early in the morning with severe pain in his neck, left arm and left leg. He had an intricate orthopaedic background and had previously attended the department on multiple occasions for pain relief. He had been suffering from continuous severe pain after a road traffic accident 3 years ago in which he sustained a left femoral neck and L3 and L4 vertebral fractures. A year ago he had undergone C5, C6 & C7 laminectomy for spinal stenosis. For the past 3 months his symptoms of cervical stenosis had worsened. He was now complaining of paresthesia in both his hands and legs with hypertonicity in the left arm. Recent surgery for a peri-prosthetic fracture had left him with a very painful left hip. He was taking large doses of non opioid analgesics and was currently on 240 mgs of modified release oral morphine in divided doses. This was supplemented by 10 mgs of oral morphine sulphate for breakthrough pain. Before presenting, he had taken 300 mg oral morphine in the last 24 hours; however the intensity of pain had failed to settle. On close questioning, he mentioned that during his physiotherapy session in the morning, he had experienced palpitations. This had continued on and off through out the day, and the worst episode was in the evening which lasted approximately one hour. There were no other associated symptoms and he denied any chest pain. He had neither past history nor any risk factors for developing ischemic heart disease. Cardiovascular examination was completely normal. During his routine workup, an electrocardiogram was done which surprisingly showed ST elevations in the inferior leads (Fig 1). His troponin I was found to be 4.86 μg /dl and creatinine kinase was 556 iU/ L. Other blood tests including lipid profile were normal and he had a normal chest X-ray. A diagnosis of painless myocardial infarction was made and he was transferred to coronary care unit for further management. A coronary angiogram showed that he had significant occlusion of the right coronary artery, which was successfully treated with percutaneous balloon angioplasty and stent placement. He remains symptom free on cardiovascular follow up.