Abdominal Pain, Confusion May Indicate Acute Attack
Complaints of abdominal pain with no apparent cause during physical examination, accompanied by neuropsychiatric symptoms such as confusion and agitation, may be indicative of an acute porphyria attack, according to a recent case report.
The study highlighted the importance of promptly performing urine screening tests and starting treatment as soon as possible following a positive test result.
Authors also noted that a diagnosis of acute porphyria should remain a possibility even in people from countries like China, where the incidence of the disease is thought to be lower.
The 28-year-old Chinese woman went to the hospital after experiencing generalized tonic-clonic seizures — those caused by abnormal electrical activity in the entire brain — at home. She had been discharged from the hospital the previous day after experiencing bouts of abdominal pain and receiving treatment for acute cystitis (sudden bladder inflammation).
Apart from having an acute appendicitis at the age of 16, her clinical history was unremarkable for chronic illnesses.
When readmitted to the hospital, her heart rate was elevated (112 beats per minute) and she had high blood pressure. She was agitated, despite having received multiple into-the-vein doses of two anti-anxiety medicines.
She was intubated and admitted to the ICU for a suspected amphetamine overdose following a rapid urine analysis. Amphetamine is a stimulant of the central nervous system (brain and spinal cord) that causes high blood pressure and tachycardia (unusually fast heart rate).
Later, however, further analysis found no traces of amphetamine and the initial findings were deemed a false positive.
A urine analysis performed afterward revealed signs of syndrome of inappropriate antidiuretic hormone secretion (SIADH), a condition that arises when the body produces excessive amounts of antidiuretic hormones — those that help the kidneys regulate the amount of water lost in the urine.
Specifically, her urine showed alterations in the levels of sodium and osmolality, which is a parameter that reflects the amount of dissolved substances in the urine.
She was infused with a solution to correct sodium levels, which became normalized on her third day in the ICU. However, she remained confused, was unable to consistently obey instructions, and was sometimes agitated despite the use of sedatives.
The patient was fed for two days by a tube inserted through her nose directly into the stomach, after which she became calmer and she was weaned from the sedatives. After a week, she was extubated and left the ICU.
However, as soon as the sedatives were reduced, she started experiencing abdominal pain once again. A physical examination, however, was unable to determine a cause for her pain. Various tests for infectious diseases also came back negative.
Her unexplained abdominal pain, along with SIADH, and neuropsychiatric symptoms led physicians to suspect acute porphyria.
They ordered a urine screening test, which came back positive for porphobilinogen and coproporphyrin, two heme precursors whose levels tend to be higher than normal in porphyria patients. Blood tests failed to detect porphyrins. Of note, heme is a molecule that plays a key role in oxygen transport. In porphyria, disruptions in heme production result in the buildup of porphyrins and other heme precursors in the body.
These lab test results led physicians to diagnose the patient with an acute porphyria attack. Despite no immediate family history suggestive of acute porphyria, an extensive family background check revealed the patient had an uncle who also experienced unexplained recurrent bouts of abdominal pain since a very young age.
Also, the clinical history of the patient revealed she consumed slimming products and was undergoing a caloric restriction diet for the past months.
She was instructed to follow a high-carbohydrate diet and prescribed to receive into-the-vein dextrose, a type of sugar. Her sodium levels were closely monitored.
Within a few days, her abdominal pain resolved, and her behavior returned to normal.
Physicians argued that intermittent fasting and a low caloric diet might have acted as triggers for her attack. She refused a genetic test to confirm the diagnosis and determine the specific type of acute porphyria.
She was discharged in overall good health after two weeks of hospitalization with recommendations to avoid long periods of time without ingesting food, as well as alcohol, smoking, and certain medications that might trigger porphyrinogen buildup.
In her outpatient visits, her sodium levels remained normal and she reported no recurrence of abdominal pain or neuropsychiatric symptoms.
Overall, “this case report aims to convey the message that acute porphyria should be suspected in patients presenting with unexplained abdominal pain in the presence of associated features of neuropsychiatric manifestation, irrespective of the ethnicity,” the researchers wrote.
“This is important as early and accurate diagnosis has been shown to reduce the case-fatality rate of acute porphyria,” they wrote.
Most cases of acute porphyria have been described in European studies, but increasingly research, including this case report, suggest that in China acute porphyria cases may be more frequent than anticipated previously.