A 15-year-old boy is brought to the office by his parents due to worsening articulation and gait instability. His parents say that his speech has been increasingly difficult to understand over the last 2 months, but he has had no difficulty with comprehension. The patient has also had progressive gait instability over the last month. He is falling more frequently and had to quit his basketball team. He has no chronic medical problems or allergies. The patient takes no medications and does not use alcohol or illicit drugs. Blood pressure is 120/70 mm Hg and pulse is 80/min. Musculoskeletal examination shows scoliosis. Neurologic examination reveals dysarthria and a wide-based, unstable gait. There are absent deep tendon reflexes of the bilateral lower extremities. MRI of the brain and spinal cord shows marked atrophy of the medulla and dorsal columns of the spinal cord. This patient is at greatest risk of mortality from which of the following conditions?

Question

A 15-year-old boy is brought to the office by his parents due to worsening articulation and gait instability.  His parents say that his speech has been increasingly difficult to understand over the last 2 months, but he has had no difficulty with comprehension.  The patient has also had progressive gait instability over the last month.  He is falling more frequently and had to quit his basketball team.  He has no chronic medical problems or allergies.  The patient takes no medications and does not use alcohol or illicit drugs.  Blood pressure is 120/70 mm Hg and pulse is 80/min.  Musculoskeletal examination shows scoliosis.  Neurologic examination reveals dysarthria and a wide-based, unstable gait.  There are absent deep tendon reflexes of the bilateral lower extremities.  MRI of the brain and spinal cord shows marked atrophy of the medulla and dorsal columns of the spinal cord.  This patient is at greatest risk of mortality from which of the following conditions?

Quizplus · Accepted Answer

11ec25c8_d6e2_d6de_bc81_cdc0ac2a8884_MD0003_00 Friedreich ataxia (FA) classically presents as progressive gait ataxia and dysarthria in adolescents or young adults. FA is an autosomal recessive disorder caused by a trinucleotide repeat (GAA) expansion that results in a loss-of-function mutation in the frataxin gene. Neurologic manifestations (eg, ataxia, dysarthria, loss of vibration/position sense) result from degeneration of the spinal tracts (ie, spinocerebellar tracts, posterior columns). Other clinical features include hypertrophic cardiomyopathy, diabetes mellitus, and skeletal deformities (eg, scoliosis). Friedreich ataxia (FA) Treatment typically involves multidisciplinary supportive care and monitoring for complications; there is no specific disease-modifying therapy. After disease onset, survival rarely exceeds 20 years. The most common cause of death is cardiac dysfunction related to cardiomyopathy, typically a fatal arrhythmia or congestive heart failure. (Choice B) Diabetes mellitus develops in a minority of patients with FA but is a rare cause of death. (Choice C) Ataxia-telangiectasia is an autosomal recessive disorder that presents with immunodeficiency, progressive cerebellar ataxia, and ocular and cutaneous telangiectasias. Patients with ataxia-telangiectasia have deficits in DNA repair that increase the risk of malignancy. FA does not predispose to cancer. (Choice D) Guillain-Barré syndrome (GBS) is an immune-mediated polyneuropathy that classically presents as ascending paralysis and can progress to respiratory failure, but the overall risk of mortality is relatively low. GBS is associated with absent reflexes, but it typically follows an infection, is not commonly associated with dysarthria, and would not cause abnormal medullary or dorsal column findings on MRI. Although patients with FA can have aspiration pneumonia and respiratory complications due to bulbar weakness, mortality is most commonly due to cardiac dysfunction. (Choice E) Status epilepticus can result in mortality from cerebral anoxia, aspiration, and respiratory failure. Patients with FA do not have an increased risk of seizures. Educational objective: Friedreich ataxia is a neurodegenerative disorder that classically presents in adolescence with progressive ataxia and dysarthria. The most common cause of death is cardiac dysfunction (eg, arrhythmia, congestive heart failure) due to hypertrophic cardiomyopathy. References: Mortality in Friedreich ataxia. (http://www.ncbi.nlm.nih.gov/pubmed/21652007) Clinical neurogenetics: Friedreich ataxia. (http://www.ncbi.nlm.nih.gov/pubmed/24176426)

A 15-Year-Old Boy Is Brought to the Office by His