A 55-year-old man comes to the office due to difficulty chewing food over the past 2 months. The patient initially experienced coughing while drinking liquids and has recently had difficulty ingesting solid foods. In addition, several people have told him they have difficulty understanding his speech. Review of systems is positive for a 5-kg (11-lb) weight loss over the past 3 months. The patient smoked a pack of cigarettes daily for 35 years. Temperature is 37 C (98.6 F), blood pressure is 120/70 mm Hg, pulse is 78/min, and respirations are 14/min. BMI is 24 kg/m². On examination, there is pooling of secretions in the oral cavity. Involuntary muscle twitching is noted over the chin, tongue, and upper and lower limbs. Power is 4/5 in both upper extremities. Deep tendon reflexes are 3+ throughout. Bilateral Babinski is present. Mental and sensory examinations are normal. Which of the following is most likely present in this patient?

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11ec25c8_d56b_7999_bc81_c3911e1ad2b3_MD0003_00 This patient with bulbar symptoms (eg, dysphagia, dysarthria), muscle wasting and fasciculations, and hyperreflexia with positive Babinski has amyotrophic lateral sclerosis (ALS). ALS is a progressive disease that results from degeneration of upper motor neurons (UMNs) (eg, motor nuclei in the precentral gyrus and their projections in the corticospinal tract and corticobulbar tract) and lower motor neurons (LMNs) (eg, cranial nerves, spinal nerves). Because any motor neuron can be involved, the initial presentation may vary widely but typically includes weakness in multiple muscle groups, with both LMN (eg, muscle atrophy, fasciculations) and UMN (eg, increased muscle tone, hyperreflexia, upgoing Babinski) signs. In 20% of patients, cranial nerves (eg, hypoglossal, ambiguus, motor trigeminal) are affected first, which results in bulbar symptoms (eg, coughing or choking when eating, weight loss); these patients have a worse prognosis. (Choices A and B) Disorders of the neuromuscular junction include myasthenia gravis, which results from antibodies against postsynaptic acetylcholine receptors, and Lambert-Eaton myasthenic syndrome, which results from antibodies against presynaptic Ca channels and is associated with malignancy (eg, weight loss, smoking history). These disorders can present with asymmetric muscle weakness, including of the bulbar muscles. However, symptoms are typically fluctuating, and, because they affect the neuromuscular junction, UMN signs would not be present. (Choice C) Brainstem compression can result in bulbar symptoms and UMN signs in the extremities. However, compression would typically also affect other cranial nerves (eg, III, V, VII, XI) and would likely also affect the respiratory drive (due to medullary compression). LMN signs such as fasciculations are not common with brainstem compression. (Choice E) Inflammatory myopathies (eg, polymyositis) cause widespread muscle weakness. However, because they affect the musculature (rather than motor) neurons, hyporeflexia may occur but UMN signs (eg, hyperreflexia, abnormal Babinski) would be unexpected. Educational objective: Amyotrophic lateral sclerosis leads to degeneration of the upper motor neurons (eg, motor nuclei in the precentral gyrus and their projections in the corticospinal and corticobulbar tracts) and lower motor neurons (eg, cranial nerves, spinal nerves). Because any motor neuron can be involved, patients may have a variety of symptoms, including bulbar muscle weakness. Examination shows both upper motor neuron and lower motor neuron signs.

A 55-Year-Old Man Comes to the Office Due to Difficulty