Seizure Increase Not Seen Following Gastric Bypass

BALTIMORE – No notable increases in new-onset seizure disorder or exacerbations of a pre-existing seizure disorder were seen following gastric bypass surgery in a retrospective case series of more than 1,500 patients from the Mayo Clinic.

Reports of new-onset or exacerbated seizure disorders following Roux-en-Y surgery are often posted on epilepsy patient-oriented Web sites such as epilepsy.com, along with reports of other neurologic complications such as Wernicke-Korsakoff syndrome, polyradiculoneuropathy, myelopathy, and optic neuropathy. However, few previous studies have examined a potential connection between gastric bypass and epilepsy, Dr. Richard S. Clemmons and Gregory D. Cascino said in a poster at the annual meeting of the American Epilepsy Society.

A diagnosis of epilepsy pre-existed prior to Roux-en-Y surgery in 12 of 1,542 patients who were operated on at the Mayo Clinic between September 1997 and September 2007. Those patients were selected from a larger group of 1,776 patients because they had more than 1 year of follow-up, had undergone surgery for morbid obesity, and were aged 18 years or older. Despite evidence that gastric bypass surgery might result in decreased absorption of drugs with high proximal absorption or low pH (Am. J. Health Syst. Pharm. 2006;63:1852-7), 8 of these 12 patients had no decrease in drug levels, based on patient report or on serum testing before and after surgery. One patient who did have a low drug level was suspected of poor compliance. None of the 12 had exacerbations of their seizures.

"Based on the limited data here, there was not a decrease in serum drug levels for valproic acid, carbamazepine, or levetiracetam. ... Even patients with significant seizure risk factors did not manifest an exacerbation of seizures," noted Dr. Clemmons and Dr. Cascino, both of whom were affiliated with the division of epilepsy in the department of neurology at the Mayo Clinic, Rochester, Minn., at the time of the study. Dr. Clemmons is currently in private practice in Denver.

Only 5 of the 1,542 patients developed new-onset epilepsy following surgery. Of those, only 3 (1.9% of the total cohort) could be considered to have unprovoked epilepsy. One of the other two patients had a history of meningoencephalitis and had just a single seizure 2 years after surgery that was possibly associated with hypoglycemia. The other one had a seizure in the setting of a stroke 3 months after surgery. None of the five developed intractable epilepsy.

About three-fourths of the patients in the study were female. Their charts were examined for evidence of seizure exacerbation post surgery, defined as an increase in seizure frequency above preoperative baseline where another cause was not identified. Patient questionnaires were used to supplement where data were lacking.

"Based on the reviewed data, there is no clear exacerbation of preexisting seizure disorder following gastric bypass ... Most patients with seizure disorder do well following Roux-en-Y," they concluded.

Dr. Clemmons, who presented the poster at the meeting, stated that he had no financial disclosures.

BALTIMORE – No notable increases in new-onset seizure disorder or exacerbations of a pre-existing seizure disorder were seen following gastric bypass surgery in a retrospective case series of more than 1,500 patients from the Mayo Clinic.

Reports of new-onset or exacerbated seizure disorders following Roux-en-Y surgery are often posted on epilepsy patient-oriented Web sites such as epilepsy.com, along with reports of other neurologic complications such as Wernicke-Korsakoff syndrome, polyradiculoneuropathy, myelopathy, and optic neuropathy. However, few previous studies have examined a potential connection between gastric bypass and epilepsy, Dr. Richard S. Clemmons and Gregory D. Cascino said in a poster at the annual meeting of the American Epilepsy Society.

A diagnosis of epilepsy pre-existed prior to Roux-en-Y surgery in 12 of 1,542 patients who were operated on at the Mayo Clinic between September 1997 and September 2007. Those patients were selected from a larger group of 1,776 patients because they had more than 1 year of follow-up, had undergone surgery for morbid obesity, and were aged 18 years or older. Despite evidence that gastric bypass surgery might result in decreased absorption of drugs with high proximal absorption or low pH (Am. J. Health Syst. Pharm. 2006;63:1852-7), 8 of these 12 patients had no decrease in drug levels, based on patient report or on serum testing before and after surgery. One patient who did have a low drug level was suspected of poor compliance. None of the 12 had exacerbations of their seizures.

"Based on the limited data here, there was not a decrease in serum drug levels for valproic acid, carbamazepine, or levetiracetam. ... Even patients with significant seizure risk factors did not manifest an exacerbation of seizures," noted Dr. Clemmons and Dr. Cascino, both of whom were affiliated with the division of epilepsy in the department of neurology at the Mayo Clinic, Rochester, Minn., at the time of the study. Dr. Clemmons is currently in private practice in Denver.

Only 5 of the 1,542 patients developed new-onset epilepsy following surgery. Of those, only 3 (1.9% of the total cohort) could be considered to have unprovoked epilepsy. One of the other two patients had a history of meningoencephalitis and had just a single seizure 2 years after surgery that was possibly associated with hypoglycemia. The other one had a seizure in the setting of a stroke 3 months after surgery. None of the five developed intractable epilepsy.

About three-fourths of the patients in the study were female. Their charts were examined for evidence of seizure exacerbation post surgery, defined as an increase in seizure frequency above preoperative baseline where another cause was not identified. Patient questionnaires were used to supplement where data were lacking.

"Based on the reviewed data, there is no clear exacerbation of preexisting seizure disorder following gastric bypass ... Most patients with seizure disorder do well following Roux-en-Y," they concluded.

Dr. Clemmons, who presented the poster at the meeting, stated that he had no financial disclosures.

BALTIMORE – No notable increases in new-onset seizure disorder or exacerbations of a pre-existing seizure disorder were seen following gastric bypass surgery in a retrospective case series of more than 1,500 patients from the Mayo Clinic.

Reports of new-onset or exacerbated seizure disorders following Roux-en-Y surgery are often posted on epilepsy patient-oriented Web sites such as epilepsy.com, along with reports of other neurologic complications such as Wernicke-Korsakoff syndrome, polyradiculoneuropathy, myelopathy, and optic neuropathy. However, few previous studies have examined a potential connection between gastric bypass and epilepsy, Dr. Richard S. Clemmons and Gregory D. Cascino said in a poster at the annual meeting of the American Epilepsy Society.

A diagnosis of epilepsy pre-existed prior to Roux-en-Y surgery in 12 of 1,542 patients who were operated on at the Mayo Clinic between September 1997 and September 2007. Those patients were selected from a larger group of 1,776 patients because they had more than 1 year of follow-up, had undergone surgery for morbid obesity, and were aged 18 years or older. Despite evidence that gastric bypass surgery might result in decreased absorption of drugs with high proximal absorption or low pH (Am. J. Health Syst. Pharm. 2006;63:1852-7), 8 of these 12 patients had no decrease in drug levels, based on patient report or on serum testing before and after surgery. One patient who did have a low drug level was suspected of poor compliance. None of the 12 had exacerbations of their seizures.

"Based on the limited data here, there was not a decrease in serum drug levels for valproic acid, carbamazepine, or levetiracetam. ... Even patients with significant seizure risk factors did not manifest an exacerbation of seizures," noted Dr. Clemmons and Dr. Cascino, both of whom were affiliated with the division of epilepsy in the department of neurology at the Mayo Clinic, Rochester, Minn., at the time of the study. Dr. Clemmons is currently in private practice in Denver.

Only 5 of the 1,542 patients developed new-onset epilepsy following surgery. Of those, only 3 (1.9% of the total cohort) could be considered to have unprovoked epilepsy. One of the other two patients had a history of meningoencephalitis and had just a single seizure 2 years after surgery that was possibly associated with hypoglycemia. The other one had a seizure in the setting of a stroke 3 months after surgery. None of the five developed intractable epilepsy.

About three-fourths of the patients in the study were female. Their charts were examined for evidence of seizure exacerbation post surgery, defined as an increase in seizure frequency above preoperative baseline where another cause was not identified. Patient questionnaires were used to supplement where data were lacking.

"Based on the reviewed data, there is no clear exacerbation of preexisting seizure disorder following gastric bypass ... Most patients with seizure disorder do well following Roux-en-Y," they concluded.

Dr. Clemmons, who presented the poster at the meeting, stated that he had no financial disclosures.