A 59-year-old man with a long history of type 2 diabetes mellitus comes to the physician with complaints of progressive muscle weakness. Six months ago, he experienced clumsiness while holding onto objects or buttoning his shirt. Two weeks ago, he felt weakness in his right foot. Since then he has nearly fallen 3 times. He reports that his speech has become slurred and he also has painful muscle cramps.
His vital signs are normal. Neurologic examination reveals mild-to-moderate dysarthria with a nasal quality. Strength is 4/5 in the proximal right upper extremity and 3/5 distally, with moderate hand muscle atrophy and contracture of the third digit. Strength is 5/5 proximally and 4/5 distally in the right lower extremity. The left arm and leg have normal strength. Both tongue and muscle fasciculations are present. Sensory examination is normal. Reflexes are decreased at the biceps and brachioradialis but are increased at the knees and ankles with bilateral extensor plantar responses.
Which of the following is the most likely diagnosis?

Question

A 59-year-old man with a long history of type 2 diabetes mellitus comes to the physician with complaints of progressive muscle weakness.  Six months ago, he experienced clumsiness while holding onto objects or buttoning his shirt.  Two weeks ago, he felt weakness in his right foot.  Since then he has nearly fallen 3 times.  He reports that his speech has become slurred and he also has painful muscle cramps.
His vital signs are normal.  Neurologic examination reveals mild-to-moderate dysarthria with a nasal quality.  Strength is 4/5 in the proximal right upper extremity and 3/5 distally, with moderate hand muscle atrophy and contracture of the third digit.  Strength is 5/5 proximally and 4/5 distally in the right lower extremity.  The left arm and leg have normal strength.  Both tongue and muscle fasciculations are present.  Sensory examination is normal.  Reflexes are decreased at the biceps and brachioradialis but are increased at the knees and ankles with bilateral extensor plantar responses.
Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

This patient has clinical symptoms most suggestive of amyotrophic lateral sclerosis (ALS). ALS is a progressive neurodegenerative disease that occurs most commonly in men age > 40. Age, family history, and cigarette smoking are the most important risk factors. ALS affects both upper and lower motor neurons with relative sparing of sensory neurons. Microscopically, damage to motor neurons of the anterior horns (lower motor neuron lesion) and demyelination of the corticospinal tracts (upper motor neuron lesion) are seen. upper and lower motor neurons Patients with ALS can present with symptoms of bulbar, cervical, thoracic, or lumbosacral neuronal involvement, depending on the area of involvement. Asymmetric limb weakness (eg, hand weakness and foot drop) is the most common presenting symptom. However, some patients may also have bulbar symptoms such as dysarthria, dysphagia, or, less commonly, respiratory muscle weakness, weight loss, and muscle cramps or atrophy. ALS is diagnosed clinically, but electromyography (EMG), nerve conduction studies, and neuroimaging are necessary to rule out other diseases. Riluzole (glutamate antagonist) is the only drug that is associated with improved clinical outcomes. The median survival time of ALS patients is 5 years, with respiratory failure as the most common cause of death. (Choice B) Patients with diabetic amyotrophy classically present with acute and asymmetric focal proximal lower-extremity pain associated with weakness, autonomic dysfunction (eg, orthostatic hypotension), and unintentional weight loss (usually > 4.5 kg [10 lb]). (Choice C) Guillain-Barré syndrome is associated with symmetric, ascending muscle paralysis and absent deep-tendon reflexes after recent infectious illness. Upper motor neuron signs are not present in Guillain-Barré syndrome. (Choice D) Patients with lacunar strokes usually present with hemiparesis, sensory symptoms, and/or ataxia. Unlike ALS patients, they do not have progressive neurologic symptoms. (Choice E) Multiple sclerosis typically follows a relapsing-remitting course unlike the progressive disease seen in ALS. Similarly, multiple sclerosis patients usually do not have lower motor neuron signs. Educational objective: Amyotrophic lateral sclerosis is a progressive neurodegenerative disease that causes destruction of the upper and lower motor neurons in the brain and spinal cord. Asymmetric limb weakness (eg, hand weakness and foot drop) is the most common presenting symptom. Sensory symptoms are absent. Median survival time is approximately 5 years from the time of diagnosis, and respiratory failure is the most common cause of death. __________ References: Amyotrophic lateral sclerosis. (http://www.ncbi.nlm.nih.gov/pubmed/17574095) The genetics and neuropathology of amyotrophic lateral sclerosis. (http://www.ncbi.nlm.nih.gov/pubmed/22903397) Respiratory therapies for amyotrophic lateral sclerosis: A primer. (http://www.ncbi.nlm.nih.gov/pubmed/22907221)

A 59-Year-Old Man with a Long History of Type 2