A 60-year-old man is brought to the office due to a 2-week history of involuntary muscle spasms in his arms, especially when he is startled. Over the past 2 months, the patient has experienced worsening insomnia and confusion and gotten lost in his surroundings. He has no fever, headache, or urinary symptoms. Temperature is 37.1 C (98.8 F), blood pressure is 130/76 mm Hg, and pulse is 82/min. The patient is alert but poorly groomed. Examination is notable for frequent irregular jerks of the upper and lower extremities, increased muscle tone, brisk deep tendon reflexes, and bilateral extensor plantar responses. On cognitive testing, the patient recalls 0 of 3 delayed recall items and is unable to draw a clock. A noncontrast head CT scan is normal. Electroencephalography reveals periodic sharp-wave complexes. Which of the following is the most likely outcome for this patient?

Question

A 60-year-old man is brought to the office due to a 2-week history of involuntary muscle spasms in his arms, especially when he is startled.  Over the past 2 months, the patient has experienced worsening insomnia and confusion and gotten lost in his surroundings.  He has no fever, headache, or urinary symptoms.  Temperature is 37.1 C (98.8 F), blood pressure is 130/76 mm Hg, and pulse is 82/min.  The patient is alert but poorly groomed.  Examination is notable for frequent irregular jerks of the upper and lower extremities, increased muscle tone, brisk deep tendon reflexes, and bilateral extensor plantar responses.  On cognitive testing, the patient recalls 0 of 3 delayed recall items and is unable to draw a clock.  A noncontrast head CT scan is normal.  Electroencephalography reveals periodic sharp-wave complexes.  Which of the following is the most likely outcome for this patient?

Quizplus · Accepted Answer

11ec25c8_d57f_76e0_bc81_45a36ddb46b1_MD0003_00 This patient exhibits sleep disturbances with rapidly progressive dementia, myoclonus (eg, startle-induced involuntary muscle spasm), upper motor neuron signs (eg, extensor plantar reflexes), and periodic sharp-wave complexes (biphasic or triphasic) on an electroencephalogram (EEG). These findings are consistent with Creutzfeldt-Jakob disease (CJD), a fatal transmissible spongiform encephalopathy. CJD is caused by prions, the only known infectious agents that lack nucleic acids (eg, DNA, RNA). Prions are abnormally folded proteins that can induce similar conformational changes in other proteins, which leads to the accumulation of neurotoxic fibrils. This results in noninflammatory spongiform neurodegeneration with widespread loss of neurons throughout the cerebrum and cerebellum. Head CT is often normal, especially early in the disease course. MRI is more sensitive and often shows hyperintensity in the cortex, caudate, and anterior putamen early, with evidence of generalized atrophy and ventricular dilatation becoming more apparent as the disease progresses. CJD is most commonly sporadic, but it can be hereditary, iatrogenic (due to contaminated transplants or surgical instruments), or due to oral consumption of contaminated neural tissue. Although CJD has a long incubation period (estimated mean of 10 years), once symptoms occur, patients experience an inexorable decline (eg, loss of speech, loss of ability for self-care, coma) until death, which occurs less than 12 months after diagnosis. Only supportive treatment is available, which should include symptom-based management, compassionate education, and referral to social services. (Choice B) Severe hypothyroidism can present with rapidly worsening cognitive decline and can be rapidly improved with thyroid hormone supplementation. However, dementia due to hypothyroidism is usually accompanied by fatigue, cold intolerance, and constipation. Upper motor neuron signs, startle-induced myoclonus, and periodic sharp waves on an EEG make CJD much more likely. (Choice C) Symptoms resulting from normal pressure hydrocephalus (NPH) rapidly improve after surgical restoration of cerebrospinal fluid drainage (eg, ventricular shunt). Although NPH can cause significant cognitive impairment and gait disturbance (and in some cases hyperreflexia and spasticity), it also classically causes urinary incontinence and ventricular enlargement on CT scan and would not explain the patient's EEG findings. (Choice D) Although cholinesterase inhibitors can improve mental functioning in Alzheimer disease, frontotemporal dementia, and Lewy body dementia, patients progressively worsen despite therapy. In contrast to CJD, Alzheimer disease has a more gradual onset of cognitive dysfunction (years vs months). In addition, myoclonus, upper motor neuron signs, and EEG periodic sharp waves are more characteristic of CJD. (Choice E) Depression-related cognitive impairment (ie, pseudodementia) refers to cognitive changes associated with major depressive disorder, and these changes often slowly improve with pharmacotherapy. However, this patient does not meet the criteria for major depressive disorder. In addition, myoclonus and upper motor neuron signs make CJD more likely. major depressive disorder Educational objective: Creutzfeldt-Jakob disease is a fatal prion disease that presents with rapidly progressive dementia, myoclonus, mood changes, and sleep disturbances. There is no effective disease-modifying treatment. Patients rapidly decline until death, which occurs less than 12 months after diagnosis. References: Creutzfeldt-Jakob disease. (http://www.ncbi.nlm.nih.gov/pubmed/28028861) Role of the biomarkers for the diagnosis of Creutzfeldt-Jakob disease. (http://www.ncbi.nlm.nih.gov/pubmed/27453757)

A 60-Year-Old Man Is Brought to the Office Due to a 2-Week