Woman’s 4-year mystery illness leads doctors to suspect porphyria

A 19-year-old woman who suffered four years of recurrent seizures and severe abdominal pain with no clear explanation found a possible answer when doctors tested her for acute intermittent porphyria (AIP).

The woman had undergone repeated heart, neurological, and gastrointestinal tests that failed to explain her combination of symptoms. At one point, her seizure-like episodes were attributed to a psychological cause, and she was referred for mental health support.

Another seizure, together with her long history of unexplained abdominal symptoms, prompted doctors to screen her for porphyria. Elevated porphyrin levels in a stool sample raised suspicion of acute porphyria, prompting referral for specialist evaluation and genetic testing.

“This case illustrates the diagnostic complexity of AIP, in which overlapping neurological and psychiatric features can frequently result in misdiagnosis,” doctors wrote in a case report. Stool porphyrin testing may provide useful evidence when other tests are inconclusive, they said.

The study, “A Four-Year Diagnostic Journey to Acute Intermittent Porphyria in a 19-Year-Old Woman: Lessons on Recognizing Neurovisceral Clues,” was published in Cureus.

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Overlapping symptoms, delayed diagnosis

The most common form of acute porphyria, AIP is caused by mutations in the HMBS gene. These mutations disrupt the activity of hydroxymethylbilane synthase (HMBS), an enzyme involved in the production of heme, a molecule that is part of hemoglobin, the protein that carries oxygen in red blood cells.

As a result, porphyrins and other heme precursors, particularly aminolevulinic acid (ALA) and porphobilinogen (PBG), accumulate to toxic levels in the body. Their buildup can trigger sudden neurovisceral attacks, which are marked by severe abdominal pain, seizures, neuropsychiatric symptoms, and problems with involuntary bodily functions.

Because porphyria symptoms span several organ systems and can resemble more common gastrointestinal, neurological, or psychiatric disorders, AIP can be difficult to recognize. Delayed porphyria diagnosis can leave people at risk of serious neurological complications and other long-term health problems.

The two researchers in the U.K. who detailed the woman’s case said her symptoms began with three generalized tonic-clonic seizures within about three hours, each preceded by nausea, heart palpitations, and chest pain. Heart tests found no underlying cardiac problem.

She continued to experience episodes of collapse and involuntary movements over the following years. Several electroencephalograms (EEGs), which measure the brain’s electrical activity, failed to provide definitive evidence of epilepsy. With no clear explanation, the episodes were diagnosed as pseudoseizures, and she was referred for psychological support.

Meanwhile, her recurrent abdominal pain, severe nausea, and vomiting led to multiple hospital admissions and gastrointestinal tests.

Testing ruled out delayed stomach emptying, and she later underwent surgery for suspected appendicitis, tissue analysis of which confirmed was in its early stages.

Within a week of surgery, the woman returned with vomiting, abdominal pain, lethargy, and generalized weakness. Imaging found no intestinal blockage, and she was treated for suspected pelvic inflammatory disease.

Four years after her symptoms began, another seizure brought her to the emergency department. CT and MRI brain scans were normal. This time, her history of recurrent seizure-like episodes together with longstanding unexplained abdominal symptoms prompted doctors to screen for porphyria.

Testing a stool sample showed elevated total porphyrins, providing the key clue that raised suspicion of an acute porphyria and prompted referral to a porphyria specialist.

Urinary ALA and PBG levels, however, were normal, as were porphyrin levels in the blood. The researchers noted that samples were collected between attacks, when ALA and PBG levels may return to normal.

“Normal urinary ALA and PBG levels measured outside an acute attack do not exclude AIP and that these first-line urinary tests are most informative when obtained during a symptomatic episode,” the researchers wrote.

HMBS enzyme activity was also at the low end of normal range. Although this can be seen in latent AIP, the finding alone cannot confirm the disease, the researchers noted. The woman was therefore referred to a porphyria clinic for genetic confirmation and appropriate management.

“This case highlights how the overlapping neurological, psychiatric, and gastrointestinal manifestations of AIP can lead to prolonged misdiagnosis,” the researchers wrote. “Acute porphyria should remain in the differential diagnosis when standard investigations are inconclusive in young women presenting with recurrent neurovisceral symptoms.” They added that “early porphyria screening, including fecal porphyrin analysis, may facilitate earlier diagnosis and enable timely specialist referral.”