Case Report Highlights Hurdles in Identifying Pseudo-TTP

Patients with apparent symptoms of thrombotic thrombocytopenic purpura (TTP) may instead have a deficiency of vitamin B12, although such cases are rare.

In a new case report published in Cureus, investigators highlighted a case of pseudo-TTP. The case was notable because they eventually realized that the patient not only had a vitamin B12 deficiency, but also had a vitamin B1 deficiency.

The study authors said pseudo-TTP has a similar hematological presentation to TTP, but neurological symptoms and renal failure tend to be rare. Most cases of vitamin B12 deficiency–induced pseudo-TTP are the result of pernicious anemia, but in the case at the center of this report, the condition appeared to be nutritional related. However, the patient’s vitamin B1 deficiency also made his case more complicated.

“A confounding factor such as vitamin B1 deficiency complicating the picture can easily be missed, only to realize several weeks later that mentation has continued to decline rather than improve,” the investigators said.

The case involved a man in his 70s who was living independently and had no known medical history. He arrived in the emergency department with confusion, sleepiness, and generalized weakness. The patient had a caregiver who intermittently checked in on him and said the patient reported little appetite in the days leading up to the hospital visit, and experienced nausea, vomiting, and diarrhea.

“TTP was suspected due to the constellation of features, including hemolytic anemia, jaundice, severe thrombocytopenia, mental status changes, acute kidney injury, and diarrhea,” the authors said.

The patient was transferred to another hospital to begin plasmapheresis. In the meantime, additional lab tests were taken, including his vitamin B12 level.

“The labs were sent out to an outside lab, and results were not readily available,” they said. “He was given a dose of 1000 mcg of intramuscular cyanocobalamin, solumedrol (methylprednisolone), fluid boluses, and 3 units of packed red blood cell transfusion.”

The patient’s renal function normalized because of the treatment, but his mental state remained altered. Doctors continued with other tests, including an ADAMTS13 test. On his fourth day in the hospital, the results of that test showed his ADAMTS13 levels were inconsistent with TTP.

“A bone marrow biopsy was already done by this time due to a confusing picture, which showed megaloblastic changes compatible with healing vitamin B12 deficiency (likely from the 1 dose of empiric vitamin B12 injection he received at ER),” the authors wrote.

When the B12 test results came in, they confirmed that the patient had low levels of the vitamin. Plasmapheresis and steroids were discontinued, and instead the patient was placed on parenteral vitamin B12 supplementation. His doctors ordered serum B1 level tests, which also revealed the patient had very low levels. The patient continued B12 and thiamine supplementation, during which time his condition steadily improved.

Once the patient’s mental state allowed him to cooperate with his physicians, he indicated that financial constraints had led to poor nutrition. After discharge, the patient was sent to a skilled nursing facility. Doctors referred him for gastrointestinal evaluation, although the patient opted against endoscopy and colonoscopy.

The investigators said it is critical to identify pseudo-TTP as soon as possible in order to avoid unnecessary plasmapheresis, but they added that since neuropsychiatric symptoms are not typically associated with pseudo-TTP, clinicians should be suspicious of possible concomitant causes.

“Treatment with B12 replacement can resolve hematological abnormalities immediately in nutritionally deficient patients, giving false reassurance about improvement,” they said. “However, irreversible neurological symptoms/damage can occur when concomitant vitamin B1 deficiency is not suspected and treated promptly.’

Reference

Ganipisetti VM, Bollimunta P, Tun NN, et al. Concomitant vitamin B1 and vitamin B12 deficiency mimicking thrombotic thrombocytopenic purpura. Cureus. Published online January 31, 2023. doi:10.7759/cureus.34421