Lack of skin symptoms for woman leads to variegate porphyria ‘blind spot’
VP undiagnosed for 3 years in diabetes patient despite abdominal pain
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A 71-year-old woman in China with type 2 diabetes experienced three years of unexplained abdominal pain and psychiatric symptoms until she was ultimately also diagnosed with variegate porphyria (VP), a type of the rare genetic disorder that’s usually marked by severe pain around the abdomen.
Because her symptoms did not involve the hallmark skin lesions typically seen in VP, the woman became trapped in what researchers described as a likely “diagnostic blind spot,” according to a new report describing her case. Her symptoms were viewed as likely complications of diabetes, the researchers noted.
Noting that VP “is a rare metabolic disorder,” the team wrote that “its diagnosis is challenging when [skin-related] features are absent and symptoms overlap with common conditions,” such as diabetes.
As such, “this case underscores the importance of considering VP in the differential diagnosis of unexplained neurovisceral symptoms, even in the absence of skin lesions, particularly among patients with diabetes,” the researchers wrote.
The study, “A type 2 diabetes patient with three years of persistent abdominal pain: the culprit was variegate porphyria — a case report,” was published in the journal Frontiers in Endocrinology.
Porphyria refers to a group of genetic disorders in which the body cannot properly produce heme, the iron-containing molecule in red blood cells that carries oxygen throughout the body.
A type of porphyria, VP is caused by mutations in the PPOX gene that reduce the production of an enzyme involved in this process. As a result, intermediate heme-making molecules — known as porphyrins and their precursors, including porphobilinogen (PBG) — build up to toxic levels, driving disease symptoms.
Woman had lived with diabetes for 30 years
People with VP may develop sensitivity to sunlight, leading to fragile skin and blistering, and may experience so-called neurovisceral attacks. These attacks, which can last days to weeks, often involve abdominal pain along with nausea, vomiting, and constipation. Psychiatric symptoms, such as depression and anxiety, and nerve-related problems, including muscle weakness, may also occur.
Some of these symptoms can resemble those of diabetic neuropathy, a type of nerve damage caused by prolonged high blood sugar in people with diabetes. Diabetic neuropathy can lead to pain and numbness in the legs, feet, and hands, as well as muscle weakness and digestive problems.
Here, a team from Quzhou KeCheng People’s Hospital described the case of a woman whose VP symptoms, occurring in the absence of typical skin lesions, were initially attributed to complications of her long-standing diabetes. This led to a delayed diagnosis — one finally made three years later.
According to the researchers, the woman had lived with type 2 diabetes for 30 years. She began experiencing diffuse abdominal discomfort and bloating about three years before the new diagnois, along with insomnia.
She was initially diagnosed with an anxiety disorder and treated with medications, but her abdominal symptoms persisted and recurred, leading to multiple hospitalizations, the team noted.
Eight years earlier, she had also developed numbness in her limbs and occasional foot spasms, which were attributed to diabetic neuropathy. During her most recent hospital admission, the woman continued to report persistent abdominal pain and distension, along with muscle weakness and worsening psychiatric symptoms, including anxiety, depressed mood, occasional feelings of impending doom, and poor sleep.
Extensive testing, including blood tests, imaging scans, and endoscopic examinations, did not identify a clear cause. Given the woman’s abdominal discomfort and fatigue, combined with psychiatric symptoms, doctors began to suspect porphyria.
Because specialized biochemical testing to measure PBG in the urine was unavailable, a screening test was performed. The test showed that her urine changed color after exposure to sunlight, raising further suspicion. Genetic analysis then identified a disease-causing mutation in the PPOX gene, confirming a diagnosis of VP.
Abdominal pain eased within days of treatment for VP
Because the woman’s abdominal pain was mild and not accompanied by nausea, vomiting, or significant neurological complications, and her laboratory findings were unremarkable, the episode was classified as a mild acute attack.
Standard hemin therapy was not available, so treatment instead focused on supportive care, according to the researchers. The woman was given intravenous, or into-the-vein, glucose (sugar), which helps reduce the production of toxic heme precursors.
Her abdominal pain lessened within one to two days, and her psychiatric symptoms, including anxiety and insomnia, gradually eased over the following days.
Given her underlying diabetes, her blood sugar levels were maintained at slightly higher levels during hospitalization to avoid low-calorie states that can trigger porphyria attacks, the team noted. She was also treated with medications considered safe for porphyria to help manage anxiety, depression, and sleep disturbances.
During follow-up, she was advised to maintain adequate caloric intake and avoid fasting. At three- and six-month follow-up visits, she reported fewer episodes of abdominal pain and lessened psychiatric symptoms.
The researchers noted that the overlap between diabetic complications and VP symptoms, particularly in the absence of skin signs, likely delayed her diagnosis. The team theorized that reduced carbohydrate intake, common in diabetes management, may have triggered attacks.
“This case illustrates the diagnostic challenge of VP in an elderly patient with long-standing type 2 diabetes mellitus,” the researchers wrote. According to the team, this porphyria should be considered in patients with unexplained abdominal and neuropsychiatric symptoms, even when typical skin signs are absent.
The researchers emphasized that early recognition and appropriate management, even with supportive treatments such as glucose therapy, can lead to favorable outcomes.
“This case … demonstrates that mild attacks can be managed with tailored supportive care,” the team concluded.
