Question

A 52-year-old male presented to the emergency department complaining of muscle pain and weakness for the last two day. He also noticed that his urine is becoming dark (red to brown). The patient has no history of accidents or trauma and no symptoms of anemia. The patient is known to have history of hypertension, Type II diabetes, hypercholesterolemia, and ischemic heart disease. 5-weeks before he came to the emergency he had suffered a myocardial infarction. He was treated in the intensive care unit for two weeks. He recovered well and was discharged with his regular medications except that oral atorvastatin 40 mg/day was added. At that time doctors explained to him that it was becoming more difficult to control his cholesterol levels using dietary measures only, thus they added the new medicine. On examination his muscles were painful to pressure (tenderness). He has no jaundice or abnormal skin coloration. He has no signs of anemia. The blood testing results including blood cell counts, hemoglobin levels, and total bilirubin levels are all normal. Kidney function tests and urine analysis were ordered and the treating doctor is awaiting results. What is the most probable diagnosis in this patient that explain the muscle pain and the dark urine? (one word, 1.5 mark) Which compound in patient’s urine would you expect to be elevated supporting the diagnosis you suggested in question 1? (one word, 1.5 mark) Explain what happened in the patient's body and why did it happen leading to the muscle pain and the dark urine? (30 words, 2.5 marks) What is the doctor rationale behind ordering the kidney function test? (30 words, 2.5 marks) What kidney function tests did you study in biochemistry course that can be used in this situation? (Three words maximum, 2 marks. Note: only the tests I mentioned in the course. Other kidney function tests copied from the internet will be considered wrong.)

Answer 1

1. Rhabdomyolysis

2. Elevation of creatine kinase and myoglobiniria

3. Muscle pain is a fairly common symptom of statins by affecting a protein in the muscle.

The “classic triad” of rhabdomyolysis symptoms are: muscle pain in the shoulders, thighs, or lower back; muscle weakness or trouble moving arms and legs; and dark red or brown urine or decreased urination

4. When muscle breaks down a protein called myoglobin is released into the bloodstream. It is then filtered out of the body by the kidneys. Myoglobin breaks down into substances that can damage kidney cells.

5. Creatinine and urinary proteins are increased