Vitamin B Deficiency Can Mimic TTP, Case Report Warns

Pseudo-thrombotic microangiopathy (pseudo-TMA) is relatively easy to treat, but it is also easy to mistake for a much more serious condition, thrombotic thrombocytopenic purpura (TTP).

In a new report in Cureus, investigators explained a case in which a patient with vitamin B12 deficiency received a diagnosis of pseudo-TMA. They said the case offers important insights about how to avoid a burdensome misdiagnosis.

Only about 2.5% of people with vitamin B12 deficiency have pseudo-TMA, wrote the case report’s authors. Patients with a severe deficiency can present with anemia, thrombocytopenia, and schistocytosis, she said.

Those are similar symptoms to those exhibited by patients with primary TMA, a category that includes TTP, Shiga toxin–mediated hemolytic uremic syndrome (HUS), drug-induced TMA, and complement-mediated TMA, the authors noted.

Although pseudo-TMA can look like TTP, their treatment and implications are very different, the study’s authors said.

“It is essential to distinguish pseudo-thrombotic microangiopathy from TTP and HUS to avoid expensive treatments like plasmapheresis, which has a spectrum of adverse effects, including electrolyte abnormalities, coagulation factor abnormalities, allergic reactions, and problems with fluid overload,” they wrote.

The patient that is the subject of their report was a 69-year-old man with a history of gastroesophageal reflux disease who sought care a week after developing a rash in his inguinal area, along with fatigue and a 10-pound weight loss over the previous few months.

Initial cardiovascular, respiratory, neurologic, and abdominal exams turned up nothing out of the ordinary, the authors said.

Doctors decided to admit him to the hospital after his initial lab workup showed a hemoglobin drop from 14 to 7.5 g/dL, a mean corpuscular volume (MCV) of 124, and a vitamin B12 level below 50. He underwent a fecal occult blood test, which the investigators said was negative. The patient had previously been prescribed cephalexin and topical ketoconazole for his rash, they noted.

The next day, labs showed a lactate dehydrogenase level of 824 U/L, the study investigators said.

“A complete blood count revealed thrombocytopenia of 109 and 1+ schistocytes,” the authors said. “His total bilirubin was 2.1, and indirect bilirubin was 1.6; folate and thyroid-stimulating hormone were normal.”

The patient received 2 units of blood transfusions and vitamin B12 injections of 1000 mcg/d. After consulting with hematology, the investigators put him on high-dose prednisone out of concern about possible drug-induced hemolytic anemia. When his direct antiglobulin test was negative, he was tapered off steroids.

“On follow-up with hematology after a month, it was found that his haptoglobin was less than 15,” the authors said. “His repeat bloodwork showed normalization of all his lab values, including hemoglobin, MCV, bilirubin, and lactate dehydrogenase.”

They said it is important to differentiate pseudo-TMA from actual TMA, in large part because the former is simple to treat and the latter requires emergency care.

They added that clinicians should also be more cautious when treating patients who have specific risk factors for vitamin B12 deficiency.

“For instance, patients who are vegetarians or others with malabsorption tendencies, such as bariatric surgery patients,” they wrote.

Reference

Sathi T, Luhadia K, Yashi K, et al. Pseudo-thrombotic thrombocytopenic purpura due to severe vitamin B12 deficiency: a case report. Cureus. Published online June 10, 2023. doi:10.7759/cureus.40212