Stomach Weight-Loss Surgery And Neuropathy

Today's post from journals.lww.com (see link below) addresses a problem that arises out of one of the largest cultural health problems of our age (obesity) and that is neuropathy caused by gastric bypass surgery. Ironically, without the surgery, many seriously obese people will go on to develop neuropathy anyway thanks to diabetes but again for many, surgery is the last option and almost always necessary at that point. Smoking and drinking have always been the habits most associated with health problems and once again, ironically, both can cause nerve damage but obesity is rapidly catching them up. In the best of all possible worlds, people would change their lifestyles and diets and obesity-related problems would disappear but for some, the obesity is so serious that surgery is the only option left to save their lives. Read this article to see how they may be confronted with lifelong nerve damage and its symptoms as a result of the surgery.

NEUROPATHY IS A COMMON COMPLICATION OF BARIATRIC SURGERY  Laino, Charlene Neurology Today:
June 2003 - Volume 3 - Issue 6 - pp 1,13–14

Honolulu, HI — At a time when obesity has reached epidemic proportions in the US, physicians should be aware that neurological complications are common following bariatric surgery to shed potentially deadly excess pounds, according to speakers at a plenary session here at the AAN Annual Meeting.

“Physicians unfamiliar with the complications of the surgery may not recognize these neurological disorders for what they are and therefore may attribute them to something else,” said Joseph R. Berger, MD, Professor and Chair of the Department of Neurology at the University of Kentucky in Lexington.

“This is particularly unfortunate because some of the complications are associated with long-term, even life-long, morbidity, and in some cases, death,” he said. “Yet many respond to simple measures such as thiamine, if administered as quickly as possible.”
 
NEW MAYO STUDY

At the plenary session, Dr. Berger's points were driven home by a new Mayo Clinic study, which found that a constellation of factors – rapid weight loss, postoperative complications, protracted gastrointestinal problems, and poor nutritional support – appear to place morbidly obese patients who undergo gastric bypass surgery at heightened risk of developing neurological ailments, chiefly peripheral neuropathy.

“The most important factor that emerged was probably rapid weight loss, which occurs in most patients who develop peripheral neuropathy following surgery,” said Pariwat Thaisetthawtkul, MD, a neurology fellow at the Mayo Clinic in Rochester, MN. “Rapid weight loss, in turn, may be associated with a high incidence of nausea and vomiting, which would prevent patients from taking nutritional supplements,” he said. “There may be cause and effect.”

Adding to the problem is the fact that fewer than 1 in 5 patients who developed neurological complications even attended a nutritional clinic, compared with 9 in 10 who did not develop neuropathies, Dr. Thaisetthawtkul said.

“The best treatment is probably prevention,” he said. “Gastric bypass surgery patients should attend a nutritional clinic and receive nutritional support.”

NEUROPATHY DEVELOPS

Dr. Thaisetthawtkul drew his conclusions from a retrospective study of 356 morbidly obese adults who underwent gastric bypass surgery for morbid obesity from 1985 to 2001. Sixty-three patients, or 17.7 percent, developed clinically defined symptomatic peripheral neuropathy, he said.

Almost three-fourths of the 63 patients, whose average age was 49, were women. The patients lost an average of 44 kilos, with a mean change in BMI of 16 points.

The median time to reach maximum weight loss was 7.5 months, he said. The median time to the development of peripheral neuropathy after surgery was 24 months.
 
CARPAL TUNNEL: COMMON DIAGNOSIS

The neurological disorders ranged from mononeuropathy to sensory neuropathy, sensory motor neuropathy, and plexopathies, the study showed. Thirty-one of the 63 patients developed a mononeuropathy, with a diagnosis of carpal tunnel syndrome leading the list.

“The clinical pattern was similar to that seen in other patients who develop a median neuropathy at the wrist,” Dr. Thaisetthawtkul said.

Eight patients developed sensory motor neuropathies, with sensory symptoms developing in a symmetrical pattern. “This tended to involve more large fibers, and sensory ataxia was very common,” he said. EMG showed a typical pattern of length-dependent, axonal sensory neuropathy.

Nineteen of the 63 patients developed sensory neuropathy, accompanied by abdominal and thoracic pain, Dr. Thaisetthawtkul said. In contrast to the sensory motor neuropathy, this tended to involve large and small fibers, and sensory ataxia was not common. The EMG showed mild sensory changes.

The other five patients were diagnosed with plexopathy that usually started in a subacute assymetrical pattern in the arms or legs, he said. The onset was usually near the time of surgery and started with pain, followed shortly by weakness. The EMG showed a typical pattern.

PREDICTOR: WEIGHT LOSS RATE

When the patients who developed peripheral neuropathy were compared with those who had no neurological complications, the study showed that the type of operation and the number of procedures had no association with the development of peripheral neuropathy, Dr. Thaisetthawtkul reported.

But when the researchers looked at the rate of weight loss or time to reach maximum weight loss, there was an important link, he said. All the patients who developed peripheral neuropathy reached their lowest weight within one year, with an average time of seven months. In contrast, patients who did not develop peripheral neuropathy did not hit their nadir until up to six years, with a mean time of 18 months.
 
OTHER PREDICTORS

Also, 30 percent of patients who developed peripheral neuropathy had prolonged vomiting and 25 percent had diarrhea for at least three months postoperatively, compared with 6 percent (who had vomiting) and 5 percent (with diarrhea) who did not develop neurological complications.

Nutritional support also emerged as an important predictor of complications, Dr. Thaisetthawtkul said. Only 17 percent of patients with neurological complications attended a nutritional clinic, compared with 90 percent of those who did not.

More patients in the peripheral neuropathy group had a mild nutritional disorder after surgery as defined by an albumin level of less than 3.5: 39 percent versus 12 percent in the group without neuropathy, he said.

Also, significantly more patients in the no-neuropathy group than in the peripheral neuropathy group received B-12 injections (88 percent versus 43 percent), multivitamins (83 percent versus 31 percent), and calcium supplementation (78 percent versus 25 percent), he said.

The peripheral neuropathy group also tended to have more complications that required readmission to surgically correct: 18 percent versus 3 percent in the group with no neurological complications, he said.

Next, the researchers compared the clinical pattern of peripheral neuropathy that developed after gastric bypass surgery to the clinical pattern of peripheral neuropathy after open cholecystectomy in a control group of obese patients, matched by age and gender.

“Polyneuropathy was not seen at all in the cholecystectomy group, and even mononeuropathy was much less frequent than in the gastric bypass patients,” he said.

“Only about 3 percent of patients who underwent open cholecystectomy developed peripheral neuropathy, all of which were mononeuropathies, compared with 17 percent in the gastric bypass arm,” Dr. Thaisetthawtkul said.

HIGH COMPLICATION RATE

“We as physicians must bear in mind the risk of neurological complications following bariatric surgery, which is increasingly performed in the US and other countries,” Dr. Berger said. “Between 1 in 20 and 1 in 10 of these individuals develop neurological complications, many of which require rapid diagnosis and intervention.”

While bariatric surgery can result in lasting weight loss of 50 percent of body weight, the complications exceed those of all other abdominal surgery, Dr. Berger said. The mortality rate is 0.4 percent, with pulmonary embolisms responsible for the majority of deaths. The complication rate is 10 percent, with reoperation not uncommon due to bleeding, abscesses, and wound problems.

Delayed complications are frequently the result of nutritional deficiencies, Dr. Berger said. “Iron, calcium, and potassium are often depleted. It's estimated up to 6 percent of patients develop hypocalcemia unless repleted, 10 to 12 percent develop vitamin B-12 deficiencies, and up to 6 percent develop fat-soluble vitamin deficiencies – each with their attendant neurological complications.”
 
INSUFFICIENT ORAL SUPPLEMENTATION

Many of the neurological complications associated with bariatric surgery can be ascribed to metabolic abnormalities, which, in turn, can often be traced to poor nutritional status, particularly vitamin B1 and vitamin B12 deficiencies, Dr. Berger said.

“But studies show that peripheral neuropathies related to vitamin deficiencies develop even in patients who are given oral vitamin supplementation,” he said. “It is insufficient to simply give oral vitamins to these patients,” Dr. Berger stressed. “Repletion should never be by the oral route alone.”

BARIATRIC SURGERY ON THE RISE

Neurologists will probably be seeing more cases of bariatric surgery-associated neuropathies as the number of obese persons around the world continues to skyrocket, said Joseph R. Berger, MD, Professor and Chair of the Department of Neurology at the University of Kentucky in Lexington.

According to Centers for Disease Control and Prevention data, the prevalence of obesity, defined as a Body Mass Index (BMI) of over 30, doubled from 1976 to 2000.

The numbers are sobering: 33 percent of American adults are obese, 25 percent of children are overweight, and 60 percent of adults are overweight, with the numbers rapidly rising. Overweight is defined as a BMI of over 25.

In one state, 1 in 4 adults is obese, while in 29 states, 20 to 24 percent of adults are, he said. The other 20 states have prevalence rates of 15 to 19 percent.

Groups at highest risk are women, the elderly, those of lower socioeconomic status, and African Americans and Hispanics, Dr. Berger said.

Obesity is responsible for 300,000 deaths annually in the US, he said, and carries a price tag of $100 billion a year.

It is not a problem unique to the US, Dr. Berger added. In the last 10 years, the prevalence of obesity has risen 10 to 40 percent in European nations and among urban populations in undeveloped countries.

From 1990 to 1997, the number of bariatric surgeries performed in the US more than doubled. The operation is typically reserved for those patients with a BMI of over 40 or a BMI of over 35 and two comorbidities related to obesity, he said, with gastric bypass being the most common procedure.

©2003 American Academy of Neurology

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