Obesity Surgery Linked to Atypical Encephalopathy

March  12, 2007 — Bariatric surgery appears to increase the risk for
atypical  Wernicke encephalopathy, a serious neurologic condition caused
by  thiamine deficiency that is typically associated with alcoholism.

In  the first study to characterize the syndrome in this patient group,
researchers at Wake Forest University School of Medicine in  
Winston-Salem, North Carolina, conducted a systematic literature review
in an attempt to describe the clinical features, risk factors,  
radiographic findings, and prognosis of Wernicke encephalopathy.

"What  we found in our paper, which is clinically useful, is that this  
syndrome is most commonly reported in young women who present with  
vomiting 1 to 3 months — although it can range from 2 weeks to 18 months
 — following obesity surgery," principal investigator Sonal Singh, MD,
told Medscape.

The paper is published in the March 13 issue of Neurology.

Is Incidence Rising?
Growing  rates of obesity in the United States and other developed
countries,  coupled with the increasing popularity of obesity surgery,
could result  in an increased incidence of this syndrome.

"I think this is  definitely an emerging problem that neurologists are
going to be  confronted with more frequently. Most neurologists have
some awareness  of this syndrome, but many may not be fully aware of the
heterogeneity  of it following obesity surgery," said Dr. Singh.

Dr. Singh added  that he became interested in studying the syndrome in
this particular  patient group because he observed an increased number
of cases in  clinical practice.

The scientific literature for all reported  cases of the syndrome
occurring after obesity surgery was reviewed, and  investigators found a
total of 32 reported cases, 27 of which were in  women.

Wernicke encephalopathy was reported after vertical  banded
gastroplasty, Roux-en-Y gastric bypass, elective gastric  partitioning,
and gastric plication.

Patients ranged in aged from  23 to 55 years. Of the total group, 12
were aged 21 to 30 years, 14  were aged 31 to 40 years, 5 were aged 41
to 50 years, and 1 patient was  older than 50 years.

Diagnostic Challenges

Because of its  atypical presentation, diagnosing Wernicke
encephalopathy in bariatric  surgery patients poses a number of
challenges, said Dr. Singh.

For  instance, in addition to the typical triad of symptoms — confusion,
 ataxia, and nystagmus — that characterize Wernicke encephalopathy,
many  patients also presented with myriad atypical symptoms, including
hearing  loss, convulsions, peripheral neuropathy, and Korsakoff
psychosis.

In addition, said Dr. Singh, the study showed magnetic resonance screening findings were not helpful in all cases.

"MRI  [magnetic resonance imaging] is usually used to confirm a
diagnosis of  Wernicke [encephalopathy] in alcoholics, but in this
patient group we  found that in many cases MRI results were normal,"
said Dr. Singh.

Furthermore,  he said, blood levels of thiamine were also inconsistent.
"Blood levels  [of thiamine] were low in a few cases but normal in
others," he said.  This finding, added Dr. Singh, suggests there are
other,  as-yet-unidentified, multiple nutritional factors at play.

"Gastric  bypass may interfere with thiamine absorption but also with
other  vitamin absorptions. We are postulating that it may not only be
thiamine  deficiency but that it could be a mechanism of some other
unexplained  vitamin deficiency or some inflammatory injury to the brain
that is  causing these atypical features. This is something that needs
to be  explored in further studies," he said.

There was also wide  variability with respect to timing of onset, which
ranged from 2 weeks  to 18 months. "We really don't have a plausible
explanation for this  variation — 1 to 3 months makes sense, but the
fact that it can occur so  long after surgery is something we can't
explain and requires further  study," he said.

High Index of Suspicion

Currently, said  Dr. Singh, there is no standardized pre- or
postoperative protocol aimed  at preventing Wernicke encephalopathy; it
is left up to the individual  providers to determine treatment.

Although some research suggests  preoperative thiamine supplementation
provides effective prophylaxis,  more research is required to confirm
that this is the case.

The  good news is that if caught in the early stages, the syndrome is
very  responsive to thiamine treatment given intravenously or by
injection.  The study showed that 13 of the 32 patients made a full
recovery; others  had some residual neurological deficits.

In the meantime, said  Dr. Singh, clinicians should have a high index of
suspicion for Wernicke  encephalopathy in patients who present with any
type of neurological  symptoms after bariatric surgery.

"It is important that doctors  and patients are aware that the outcome
is wholly dependent on early  diagnosis. Patients should be advised to
immediately report any  neurological symptoms," he said.

In the meantime, a prospective  long-term study to determine the
incidence of the syndrome is needed to  help guide preventive, as well
as treatment, protocols.

Neurology. 2007;68:807–811.

Source: http://www.medscape.com/viewarticle/553480?src=mp

Related Topics:
Barash - Handbook of Clinical Anesthesia Free Download
Oxford Handbook of Anaesthesia Free Download
Pocket Anesthesia (Pocket Notebook Series) Free Download
Clinical Anesthesia Procedures of the Massachusetts General Hospital Free Download
Monitoring in Anesthesia and perioperative care Free Download
Anesthetic Pharmacology Basic Principles and Practice Free Download
Foundations of Anesthesia: Basic Sciences for Clinical Practice Free Download

ENJOY