Case of pregnancy-related AIP highlights challenges in diagnosis

Woman misdiagnosed with several conditions before AIP was confirmed

Andrea Lobo, PhD avatar

by Andrea Lobo, PhD |

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A 33-year-old pregnant woman experiencing severe abdominal pain shortly before delivery and showing worsening neurological symptoms thereafter was misdiagnosed with several conditions before an acute intermittent porphyria (AIP) diagnosis was confirmed, according to a case report from Saudi Arabia.

“[Neurologic] porphyria is an easily missed entity due to its lack of typical clinical presentation. Therefore, misdiagnoses or late diagnoses are common and ultimately delay the management and lead to [poor health] and mortality,” the researchers wrote.

The case study, “Acute Intermittent Porphyria Labeled Initially As Guillain-Barre Syndrome: Challenging Diagnosis,” was published in the journal Cureus.

Porphyria encompasses a group of genetic diseases caused by a deficiency in one of several enzymes needed for making heme. Heme is a component of iron-containing proteins, including hemoglobin, which carries oxygen in red blood cells.

AIP is caused by mutations in the HMBS gene, which provides instructions to produce an enzyme that is involved in the first steps of heme production. These mutations ultimately lead to the accumulation of heme precursors called porphyrins to toxic levels in the body’s tissues.

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A woman sitting on a bed holds her abdomen in pain.

Givlaari successfully treats acute attacks in woman with AIP, 36

AIP patients typically experience recurrent abdominal pain and neurological symptoms, most commonly affecting the peripheral nerves, or those outside the brain and spinal cord.

Also, women are more likely to develop the disease, “especially during periods with alterations in the level of sex hormones such as ovulation, menstruation, and pregnancy,” the researchers wrote.

Now, researchers in Saudi Arabia described the case of a 33-year-old pregnant woman with AIP whose diagnostic process was challenged by her non-disease-specific symptoms.

The woman, who had ovarian problems, had undergone several rounds of in vitro fertilization until she became pregnant with triplets. At 23 weeks of gestation, she developed severe abdominal pain and was admitted to the hospital where she was treated for a urinary tract infection.

Pain worsens after birth of triplets

One week later, the babies were born prematurely, and a week after discharge she returned to the hospital due to abdominal pain worsening.

The woman underwent a procedure for suspected retention of pregnancy tissues, after which she developed a fever and vision problems, and had a seizure.

She received anti-seizure medication and standard treatment for suspected meningitis, an inflammation — most commonly caused by infection — of the membranes surrounding the brain and the spinal cord.

A week later, the woman was transferred to the researchers’ tertiary care center for further examination. Given that no signs of infection were found in the fluid that surrounds the brain and spinal cord, treatment for meningitis was stopped.

A brain imaging scan showed signs consistent with posterior reversible encephalopathy syndrome — a condition characterized by seizures, altered mental status, vision loss, and swelling in certain parts of the brain — to which she received supportive treatment.

However, she still complained of abdominal and leg pain, visual and hearing hallucinations, and severe insomnia. She was believed to have postpartum psychosis, a serious mental illness that can develop soon after giving birth. Despite being treated with an antipsychotic, she was not getting better.

Meanwhile, lab tests revealed she had low blood sodium levels that kept worsening despite treatment, requiring admission to the intensive care unit (ICU). Her sodium levels normalized, but she complained of generalized pain, fatigue, and weakness, with further examination revealing moderate muscle weakness.

She had a sodium level relapse that required a second ICU admission, during which she presented severe confusion, progressive weakness in both arms and legs, poor tendon reflexes, and facial paralysis.

She also showed signs of breathing impairments, despite maintaining normal blood oxygen levels. She later was in a critical condition, requiring breathing support through intubation.

Based on her clinical condition, physicians suspected Guillain-Barré syndrome, a rare disease where the immune system wrongly produces self-reactive antibodies that attack the peripheral nerves, leading to muscle weakness and paralysis.

She was therefore treated with a plasma exchange, a blood-cleaning procedure aimed to remove self-reactive antibodies from her blood.

However, her clinical history also suggested the presence of porphyria, and a blood and urine sample were sent out for analysis. Results three weeks later showed high levels of porphyrins and porphobilinogen, a type of porphyrin that builds up in AIP, confirming the diagnosis.

She started treatment with intravenous (into-the-vein) Panhematin (hematin), a molecule that ultimately suppresses porphyrin formation.

At the last evaluation, she showed minimal neurological improvement and still required ventilatory support. The patient’s enrollment in an extensive rehabilitation program was being planned.

“In retrospect, acute porphyria attacks should be taken into consideration in patients with persistent unexplained [treatment-resistant] abdominal pain and peripheral neuropathies,” the researchers concluded.