A 45-year-old man comes to the office due to increased irritability and problems at work. The patient, who is usually outgoing and friendly, began to experience significant irritability 2 months ago and has since gotten in trouble at work for inappropriate and rude behavior on several occasions. His performance as a bank loan officer has also suffered and he has made numerous mathematical errors. The patient is in danger of being fired and is very distressed. He has no medical history, but his father experienced a similar change in behavior around the same age and died 15 years later in a nursing home. Temperature is 36.7 C (98.1 F), blood pressure is 125/79 mm Hg, pulse is 74/min, and respirations are 14/min. The patient cannot sit still during the examination and makes repeated involuntary writhing movements that are most prominent in the upper extremities. Deep tendon reflexes are 3+ bilaterally in the upper and lower extremities. He scores 22/30 on the Montreal Cognitive Assessment (normal: ≥26). An MRI is ordered. Which of the following structures shows the most characteristic pattern of atrophy in this patient's disease?

Question

A 45-year-old man comes to the office due to increased irritability and problems at work.  The patient, who is usually outgoing and friendly, began to experience significant irritability 2 months ago and has since gotten in trouble at work for inappropriate and rude behavior on several occasions.  His performance as a bank loan officer has also suffered and he has made numerous mathematical errors.  The patient is in danger of being fired and is very distressed.  He has no medical history, but his father experienced a similar change in behavior around the same age and died 15 years later in a nursing home.  Temperature is 36.7 C (98.1 F), blood pressure is 125/79 mm Hg, pulse is 74/min, and respirations are 14/min.  The patient cannot sit still during the examination and makes repeated involuntary writhing movements that are most prominent in the upper extremities.  Deep tendon reflexes are 3+ bilaterally in the upper and lower extremities.  He scores 22/30 on the Montreal Cognitive Assessment (normal: ≥26).  An MRI is ordered.  Which of the following structures shows the most characteristic pattern of atrophy in this patient's disease?

Quizplus · Accepted Answer

11ec25c8_d5aa_f3ed_bc81_bf46ce0361be_MD0003_00 This patient's behavioral change (eg, increased irritability), cognitive impairment, choreoathetosis (ie, involuntary writhing movements), hyperreflexia, and suggestive family history are consistent with a diagnosis of Huntington disease (HD). HD is an autosomal dominant CAG trinucleotide repeat expansion disease in which an abnormal version of the huntingtin protein causes neurodegeneration. A hallmark neuropathological finding in HD that can be seen on neuroimaging is the preferential atrophy of the caudate nucleus and putamen (ie, neostriatum). Psychiatric manifestations of HD include irritability, depression, apathy, and obsessive-compulsive spectrum symptoms. Cognitive impairment is often present early in the course of HD and primarily affects executive functions (eg, planning, organizing). There is no disease-modifying treatment for HD; treatment is targeted toward symptomatic management. HD most often presents around age 40 with death usually occurring within 10-20 years of symptom onset. The number of trinucleotide repeats may increase across generations (particularly with paternal transmission), leading to an anticipation effect whereby offspring present at earlier and earlier ages. (Choice B) The globus pallidus is the primary output nucleus of the basal ganglia. It does not consistently demonstrate atrophy in HD. (Choice C) The nucleus accumbens is involved in the processing of reward, among other roles, and receives significant dopaminergic inputs. As a result, it may demonstrate atrophy in Parkinson disease but does not consistently show atrophy in HD. (Choice D) Degeneration of the substantia nigra may be seen in Parkinson disease, dementia with Lewy bodies, and multiple system atrophy. (Choice E) Damage to the subthalamic nucleus may result in contralateral hemiballismus (ie, limb flailing). Educational objective: Huntington disease (HD) presents with psychiatric symptoms, cognitive impairment, and chorea. HD is an autosomal dominant CAG trinucleotide repeat expansion disease that is associated with preferential atrophy of the caudate nucleus and putamen. References: Multimodal imaging biomarkers in premanifest and early Huntington's disease: 30-month IMAGE-HD data. (http://www.ncbi.nlm.nih.gov/pubmed/26678864) Surface-based morphometry reveals caudate subnuclear structural damage in patients with premotor Huntington disease. (http://www.ncbi.nlm.nih.gov/pubmed/27730480)

A 45-Year-Old Man Comes to the Office Due to Increased