Chapter 8. Inflammatory Diseases
A 74-year-old man with no known history has had progressive dysphagia and cognitive decline over the past 8 weeks. He is brought to the emergency department (ED) with acute psychosis after he assaulted his family members and accused them of poisoning him. On examination, his blood pressure is 196/85, heart rate is 120 bpm, respiratory rate is 26 breaths/min, and pulse oximetry of 94%. Limited neurologic examination reveals symmetric/reactive pupils bilaterally, incomprehensible speech, prominent dysarthria, increased tone in all 4 extremities but relatively symmetric strength, brisk reflexes, and upgoing plantar reflex bilaterally.
During the evaluation, the patient also exhibits frequent involuntarily jerking of his extremities, which is exaggerated when he is startled. A magnetic resonance imaging (MRI) scan is obtained, and diffusion-weighted imaging (DWI) sequence reveals the findings shown in the figure below. Despite extensive lab workup, toxicology, and several lumbar punctures including analysis for cerebrospinal fluid (CSF) 14-3-3 protein, no conclusive diagnosis is found. Unfortunately the patient’s symptoms continue to progress and he dies 6 weeks later. What is the most likely diagnosis in this patient?
MRI brain, sequential axial diffusion weighted images.
A. Intravascular central nervous system (CNS) lymphoma
B. Anti-Hu encephalomyelitis
C. Hashimoto encephalopathy
D. Creutzfeldt-Jacob disease
D. This patient presents with rapidly progressive neurobehavioral symptoms, a hallmark of Creutzfeldt-Jacob disease (CJD). Rapidly progressive mental deterioration and “startle myoclonus” as exhibited in this patient are 2 cardinal clinical features in CJD. In addition, the MRI reveals restricted cortical diffusion, which, although not specific, is classical for CJD in conjunction with the current clinical picture. CSF 14-3-3 is an adjunctive lab test but is neither specific nor sensitive, with numerous false-positive CSF 14-3-3 results reported in other neurologic disorders. A recent assay (RT-QuIC) has been proposed as a sensitive diagnostic test in CJD, with sensitivity and specificity of 85% to 87% and 99% to 100%, respectively. Unfortunately, there is no treatment for CJD, which is uniformly fatal but with a varied course of weeks to months.
Choice B is incorrect. Paraneoplastic CNS disorder is an umbrella term for various autoimmune neurologic disorders. Anti-Hu is one of many of the known paraneoplastic orders, which is often multifocal affecting the temporal lobes, brainstem, cerebellum, dorsal roots and autonomic system. See Table 8-1. It is most often found in conjunction with small-cell lung carcinoma. However, even in its most aggressive form, survival is typically months to years. Choice C is incorrect since Hashimoto encephalopathy generally has a more favorable prognosis, and symptoms progress very slowly. Choice A is incorrect as intravascular lymphoma should not present with myoclonus; in addition, ...