Porphyria Screening Recommended Before Weight Loss Surgery
Researchers describe case of 46-year-old woman diagnosed after acute attack
The case of a woman with variegate porphyria (VP) diagnosed following an acute attack that occurred after weight loss surgery was described in a recent report.
Study authors recommend that people planning weight loss surgery first have a screening for porphyria, since this type of surgery may worsen symptoms.
Her case was described in the study, “Case Report: Variegate porphyria disclosed by post-gastric bypass complications and causing predominant painful sensorimotor axonal peripheral neuropathy,” published in Frontiers in Genetics.
VP is a form of porphyria caused by mutations in the PPOX gene. It’s one of the acute forms of porphyria, which are marked by attacks of symptoms suddenly appearing or worsening.
This report describes the case of a 46-year-old woman who had gastric bypass surgery, a surgical procedure to prevent weight gain and promote weight loss by limiting the amount of food the stomach can hold. The surgery itself was accompanied by severe complications, such as poor wound healing, which required a prolonged hospital stay and additional operations.
Two weeks after being discharged from the hospital following surgery, she had an episode of sudden-onset tetraparesis (muscle weakness in all four limbs) and went to the emergency room. She was referred to a specialist center for testing.
Initial diagnostic tests ruled out numerous infections and vitamin deficiencies, and brain and spinal cord imaging was normal. However, tests found signs of systemic inflammation and impairments in the speed at which electrical signals were being sent by nerves in her limbs.
Subsequent testing showed high levels of certain porphyrin and porphyrin precursors in the woman’s urine, a telltale sign of porphyria, which is caused by these intermediary molecules accumulating to toxic levels.
“Altogether, these findings, in addition to the above-detailed clinical picture, confirmed the diagnosis of VP,” the researchers wrote.
Genetic testing confirmed the patient had a mutation in the PPOX gene. The specific mutation was a deletion of exon 4, meaning a large portion of the gene that contains information to produce a protein was missing.
Learning lessons from this case, we propose a pre-operative cost-effective screening for symptoms highly evocative of porphyria, especially in obese patients intending to opt for or awaiting gastric bypass.
“To the best of our knowledge, this mutation has never been reported before,” the researchers wrote.
The patient was treated with a multidisciplinary neurorehabilitation regime, given a high carbohydrate diet, and she stopped taking all medications that might cause the porphyria to worsen (including fentanyl, an opiate prescribed for pain relief after surgery).
Her condition improved to the point where she was able to be discharged from the hospital, care for her children and perform day-to-day tasks. She still had persistent limb pain and severe fatigue, however.
After her diagnosis, she remarked that she always had unusually fragile skin after exposure to light, though she hadn’t had the blistering that’s common in VP, and she’d frequently had dark-colored urine. Both are common signs of porphyria.
“Detailed and oriented medical history revealed that she had, before undergoing bariatric surgery, symptoms … that could have, if screened for, prompted the search of porphyria,” the researchers wrote, noting doing so might have allowed the woman to be diagnosed before undergoing gastric bypass surgery, which carries many risks for porphyria worsening.
Along with being exposed to medicines that can worsen porphyria, these procedures generally involve calorie restriction and mental and physical stress that can worsen the condition.
“Learning lessons from this case, we propose a pre-operative cost-effective screening for symptoms highly evocative of porphyria, especially in obese patients intending to opt for or awaiting gastric bypass,” the researchers wrote. “Positive screening would prompt appropriate and timely preventive and therapeutic measures, which efficiently reduce short- and long-term adverse outcomes.”