Modified drug plan aids tuberculosis patient with acute porphyria
Switch made after woman developed severe symptoms with standard antibiotics
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A young woman with tuberculosis and previously undiagnosed acute intermittent porphyria developed severe symptoms after starting standard antibiotics but improved with hemin and a modified regimen using medications considered safer for porphyria, according to a case report.
Tuberculosis is an infection caused by the bacterium Mycobacterium tuberculosis.
The woman’s case was described in the report, “Navigating tuberculosis therapy in acute intermittent porphyria: A case report and narrative review,” which was published in Therapeutic Advances in Infectious Diseases.
Woman’s condition worsened with antibiotics
Treating tuberculosis in someone with acute intermittent porphyria, a genetic disease that affects how the body produces heme, a substance needed for the oxygen-carrying hemoglobin protein in red blood cells, can be difficult. Some of the standard antibiotics can trigger a sudden episode of severe symptoms, called an acute neurovisceral crisis. However, “evidence to guide management is limited,” the researchers wrote.
In their report, they described the case of a 26-year-old woman in Colombia who had tuberculosis affecting the peritoneum, the thin lining around the abdominal organs. She had experienced repeated episodes of abdominal pain, nausea, and vomiting since adolescence, but previous medical evaluations had not found the cause. She was eventually found to have an abnormal buildup of fluid in the abdomen.
Doctors performed a laparoscopy, a procedure in which a small camera is inserted into the abdomen. They found many small nodules on the abdominal lining and reproductive organs. A tissue sample showed granulomatous inflammation, a pattern of inflammation commonly associated with tuberculosis. A molecular test that detects the genetic material of bacteria was positive for Mycobacterium tuberculosis, confirming infection.
The woman also had a seizure, an episode of abnormal electrical activity in the brain, along with a fast heart rate and high blood pressure. Because tuberculosis can sometimes spread to the brain and spinal cord, doctors started treatment with a combination of the antibiotics isoniazid, rifampicin, pyrazinamide, and ethambutol. Moxifloxacin and linezolid were also prescribed because they can cross into the brain.
Within 24 hours, however, her condition worsened. She developed severe abdominal pain, weakness in her arms and legs, and extremely low blood sodium, which can cause seizures. Doctors initially considered syndrome of inappropriate antidiuretic hormone secretion, in which the body retains too much water and dilutes the sodium in the blood. However, brain scans were normal.
Woman eventually diagnosed with acute intermittent porphyria
Further questioning revealed that she had previously experienced abdominal attacks accompanied by hallucinations and other psychological or neurological symptoms. Examination revealed reduced muscle tone, absent reflexes, and mild eyelid drooping. Nerve testing showed an axonal sensorimotor polyneuropathy, meaning damage to nerves that carry movement and sensation.
These findings led doctors to suspect porphyria. Urine showed very high levels of porphobilinogen and delta-aminolevulinic acid, two substances that build up when the heme production pathway is disrupted. About one year later, genetic testing found a disease-causing mutation in the HMBS gene, confirming the diagnosis of acute intermittent porphyria. Her father had the same genetic mutation but no symptoms.
The immediate treatment for the acute neurovisceral crisis included a concentrated dextrose solution, which provides glucose (sugar) and reduces the body’s production of substances needed to build heme. She then received three courses of hemin, a heme derivative that helps suppress excessive activity in the heme-production pathway.
Because treatment for tuberculosis could worsen porphyria, doctors stopped all original antituberculous antibiotics. They then created a modified regimen using moxifloxacin, linezolid, and ethambutol, which were considered less likely to trigger porphyric symptoms. Isoniazid was later cautiously added because the bacteria were susceptible to it.
his case shows how important it is to balance effective tuberculosis treatment against the risk of triggering porphyria.
However, treatment remained complicated by side effects and repeated porphyria-related problems. About four months after the initial presentation, she developed signs of damage to the liver. Isoniazid was considered responsible, so all antibiotics were temporarily stopped. After the liver tests returned to normal, ethambutol, moxifloxacin, and linezolid were restarted.
Moxifloxacin was later changed to levofloxacin because she had difficulty tolerating it. Isoniazid was eventually tried again at a low dose of 100 mg per day and gradually increased to 300 mg under supervision. She required another course of hemin because of worsening nerve pain despite receiving pregabalin, a painkiller.
By about eight months, she had damage to nerves and reduced vision that was attributed to the cumulative toxicity of the antibiotics. A repeat laparoscopy found no signs of active tuberculosis. Because the risks of continuing treatment were considered high relative to the evidence of residual infection, antibiotics were discontinued. The woman recovered, became independent in daily activities, and had no evidence of tuberculosis returning during one year of follow-up.
“This case shows how important it is to balance effective tuberculosis treatment against the risk of triggering porphyria,” the researchers wrote. “Because there is very little published evidence and no agreed guidelines for this rare combination, we offer practical, experience-based suggestions to help doctors manage it.”
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