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A 33 year old woman is brought to the emergency department with a history of recent confusion and frequent falls in the past week. She underwent bariatric surgery two months ago for morbid obesity. Blood pressure is 170/100. Temperature in normal. Your examination shows difficulty with recent memory, impaired tandem gait, saccadic pursuit in all gaze directions, and the abnormalities shown in this video.
What is the likely cause of these abnormalities?
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Correct!
You are looking at gaze-evoked horizontal jerk nystagmus on side gaze and upbeat nystagmus on upgaze. This form of nystagmus is a common feature of
Wernicke encephalopathy (WE), a deficiency of thiamine (vitamin B1), which is a co-factor in many metabolic pathways critical to central nervous system
function.
The classic clinical triad of WE consists of a confusional state, ataxia, and ophthalmoplegia, but only a minority of patients display all three components. Nystagmus is actually more common than ophthalmoplegia (which, in WE, usually means reduced conjugate gaze or abduction deficits). So look for nystagmus, even when no other neurologic manifestations are present.
In the past, the common setting for WE was alcohol binge drinking. But with the growth of bariatric surgery, it is seen in those patients, especially if they are not adherent to vitamin supplementation regimens. (This patient had not been taking the supplements because she could not afford them. Other patients fail to absorb them because they are vomiting.)
The manifestations of WE usually develop from 4 to 8 weeks after surgery. Treatment is prompt administration of thiamine 500 mg intravenously three times a day for 3 days, followed by thiamine 250 mg intravenously or intramuscularly once daily for 5 days to prevent permanent amnestic dementia (Korsakoff syndrome). The ophthalmic manifestations often resolve within days of treatment, but ataxia and cognitive impairment often endure.
The neuropathology of WE consists of capillary proliferation, microhemorrhages, and neuronal and glial loss. It is prominent in the thalamus, mammillary bodies, and periventricular regions of the brainstem, including the sixth nerve nuclei. In this patient, T2 and FLAIR MRI sequences showed high signal in the dorsomedial thalamus
These MRI abnormalities are specific for WE, but a negative MRI occurs in at least 50% of cases. Blood tests (whole blood thiamine, erythrocyte
transketolase, and thiamine pyrophosphate levels), which should be drawn before administering thiamine, can help confirm the diagnosis, but may also be
normal. So, whenever you see this kind of nystagmus after bariatric surgery or with a history of binge drinking, the presumptive diagnosis is WE!
The other answer choices here are reasonable, but less apt. Infectious (and non-infectious inflammatory) meningoencephalitis is always an important consideration, eliciting further prompt evaluation with imaging, lumbar puncture, and other studies. Hypertensive encephalopathy typically causes homonymous visual field loss, cognitive impairment, and seizures, and discloses high T2/FLAIR MRI signal in the posterior cerebral hemispheres (“posterior reversible encephalopathy syndrome,” or PRES
it does not typically cause nystagmus. Osmotic demyelination syndrome (formerly called “central pontine myelinolysis”) occurs after rapid correction of
hyponatremia usually following heavy alcohol intake. The increase in extracellular sodium results in rapid escape of intracellular water and cellular
dysfunction, most often affecting the pons. Patients present with impaired consciousness and quadriparesis. MRI should show symmetrical high T2/FLAIR
sign in the central pons
and sometimes in the lateral geniculate bodies.
The classic clinical triad of WE consists of a confusional state, ataxia, and ophthalmoplegia, but only a minority of patients display all three components. Nystagmus is actually more common than ophthalmoplegia (which, in WE, usually means reduced conjugate gaze or abduction deficits). So look for nystagmus, even when no other neurologic manifestations are present.
In the past, the common setting for WE was alcohol binge drinking. But with the growth of bariatric surgery, it is seen in those patients, especially if they are not adherent to vitamin supplementation regimens. (This patient had not been taking the supplements because she could not afford them. Other patients fail to absorb them because they are vomiting.)
The manifestations of WE usually develop from 4 to 8 weeks after surgery. Treatment is prompt administration of thiamine 500 mg intravenously three times a day for 3 days, followed by thiamine 250 mg intravenously or intramuscularly once daily for 5 days to prevent permanent amnestic dementia (Korsakoff syndrome). The ophthalmic manifestations often resolve within days of treatment, but ataxia and cognitive impairment often endure.
The neuropathology of WE consists of capillary proliferation, microhemorrhages, and neuronal and glial loss. It is prominent in the thalamus, mammillary bodies, and periventricular regions of the brainstem, including the sixth nerve nuclei. In this patient, T2 and FLAIR MRI sequences showed high signal in the dorsomedial thalamus
The other answer choices here are reasonable, but less apt. Infectious (and non-infectious inflammatory) meningoencephalitis is always an important consideration, eliciting further prompt evaluation with imaging, lumbar puncture, and other studies. Hypertensive encephalopathy typically causes homonymous visual field loss, cognitive impairment, and seizures, and discloses high T2/FLAIR MRI signal in the posterior cerebral hemispheres (“posterior reversible encephalopathy syndrome,” or PRES
Incorrect