A 54-year-old woman presents to your office complaining of difficulty walking. She describes severe weakness and occasional pain in her thigh muscles. She has stumbled and fallen several times over the last week. Her past medical history is significant for hypertension treated with hydrochlorothiazide and metoprolol. She consumes two to three cans of beer on weekends. Her younger brother died of a neurological disease when he was 20 years old. Her mother suffers from hypertension and diabetes mellitus. Her heart rate is 90/min and blood pressure is 170/100 mmHg. Chest examination is within normal limits. A bruit is heard over the left carotid artery. Neurologic examination reveals hyporeflexia and decreased strength in all muscle groups. Her ESR is 12 mm/hr. ECG shows flat and broad T waves with occasional premature ventricular contractions. Which of the following is the most likely cause of this patient's current complaints?

Question

A 54-year-old woman presents to your office complaining of difficulty walking.  She describes severe weakness and occasional pain in her thigh muscles.  She has stumbled and fallen several times over the last week.  Her past medical history is significant for hypertension treated with hydrochlorothiazide and metoprolol.  She consumes two to three cans of beer on weekends.  Her younger brother died of a neurological disease when he was 20 years old.  Her mother suffers from hypertension and diabetes mellitus. Her heart rate is 90/min and blood pressure is 170/100 mmHg.  Chest examination is within normal limits.  A bruit is heard over the left carotid artery.  Neurologic examination reveals hyporeflexia and decreased strength in all muscle groups.  Her ESR is 12 mm/hr. ECG shows flat and broad T waves with occasional premature ventricular contractions.  Which of the following is the most likely cause of this patient's current complaints?

Quizplus · Accepted Answer

This woman has weakness due to hypokalemia. Symptoms of hypokalemia depend on the severity of the imbalance, but can include weakness, fatigue, and muscle cramps. Flaccid paralysis, hyporeflexia, tetany, rhabdomyolysis, and arrhythmias may occur with severe hypokalemia (serum concentration <2.5 mEq/L). An ECG will show broad flat T waves, U waves, ST depression, and premature ventricular beats. Atrial fibrillation, torsades de pointes, and ventricular fibrillation can occur. This woman is taking a potassium-wasting diuretic, which is the most likely cause of her hypokalemia. Other common causes include diarrhea, vomiting, anorexia, and hyperaldosteronism. This patient's symptoms should resolve with potassium supplementation. (Choice A) Stroke does not cause muscle pain and usually has focal findings. The presentation for an ischemic stroke will depend on the location of the lesion. (Choices B and C) The hallmarks of an epidural hematoma are headache, confusion, somnolence, and focal neural deficits that develop within hours of a trauma. Subdural hematomas present similarly to epidural hematomas but the onset is typically more delayed. (Choice D) Lumbar spinal stenosis presents with back pain radiating to the buttocks and thighs that interferes with walking and lumbar extension. Lumbar flexion will often improve the symptoms. (Choice E) Multiple sclerosis (MS) is a common demyelinating disease. Symptoms are separated by time and space (i.e., episodic) and most commonly include numbness, weakness, spastic paraparesis, paresthesias, gait abnormalities, and vision difficulties. (Choice F) Amyotrophic lateral sclerosis (ALS) is a degenerative motor neuron disease that affects both upper and lower motor neurons. Sensation is preserved and cognition is rarely affected. Symptoms include weakness and difficulty chewing, swallowing, coughing, and breathing. Patients develop hyperreflexia, spasticity, and fasciculations. It is usually fatal within 5 years. (Choice G) The patient in this vignette does not have other symptoms of hyperthyroidism. (Choice H) Inflammatory myopathies often present with muscle weakness and may have associated muscle pain or a skin rash. ESR and creatine kinase will be elevated. (Choice I) Neuromuscular junction disorders include myasthenia gravis and the Lambert-Eaton myasthenic syndrome. These both have insidious onset and present with proximal muscle weakness. Ptosis and diplopia may be present as well. Educational Objective: Hypokalemia is a common electrolyte abnormality that causes weakness, fatigue, and muscle cramps. When severe, it can lead to paralysis and arrhythmia. The ECG may show U waves, flat and broad T waves, and premature ventricular beats.

A 54-Year-Old Woman Presents to Your Office Complaining of Difficulty