Case Description
A 17-year-old male with history of intestinal resection secondary to
gastroschisis at birth was referred to the emergency room for shortness
of breath, fatigue, and lightheadedness for a week. His history was
significant for celiac disease, iron and B12 deficiency with symptomatic
anemia in the past, requiring transfusions. It had been at least a year
since he had taken his last supplements and he had not adhered to a
gluten-free diet. He denied constitutional symptoms, fevers, bleeding,
or recurrent illnesses. His physical examination was significant for
weight below the third percentile, pallor, mildly icteric sclerae and
hepatosplenomegaly. He was alert and oriented with no noticeable
neurological deficits.
His complete blood count (CBC) was significant for pancytopenia with a
WBC: 2.42 x 10^3/uL, Hb: 5.9 g/dL, MCV: 95.4 fL, Plt: 111 x
10^3/uL and a reticulocytopenia of 0.6%. Review of his peripheral
smear was significant for anisocytosis, microcytosis, poikilocytosis and
schistocytes. Routine chemistries were suggestive of hemolysis with an
elevated LDH of >50 000 U/L, an unconjugated
hyperbilirubinemia of 3.7 mg/dL and an undetectable haptoglobin. His
synthetic liver function was unremarkable with normal coagulation
studies despite a notable transaminitis. A liver ultrasound showed
diffuse echogenicity with likely fatty infiltration but no evidence of
portal hypertension. He had a negative direct coombs, iron studies were
unremarkable and a B12 <109 pg/mL. His renal function was also
unremarkable. He was transfused two units of packed red blood cells,
which allowed for stabilization of his hemoglobin and he was started on
oral iron and B12 supplementation.
The differential included a pancytopenia secondary to B12 deficiency
with a superimposed hemolytic process as well as concern for a malignant
bone marrow infiltrative process given his pancytopenia and
hepatomegaly. Paroxysmal nocturnal hemogobinuria testing was negative. A
bone marrow biopsy and aspirate displayed no changes consistent with
myelodysplasia or malignancy. There was evidence of erythroid
hyperplasia and megaloblastic maturation along with hypersegmented
neutrophils consistent with his B12 deficiency as shown in Fig. 1. His
liver biopsy showed non-alcoholic steatohepatitis attributed to his
uncontrolled celiac disease and the decision was made to convert his
oral B12 to an intramuscular formulation.
Repeat B12 and LDH were 525 pg/mL and 503 U/L respectively showing
resolution of his symptoms. Despite not being included in the initial
differential, a hemolytic anemia in the presence of a progressive
thrombocytopenia warrants the consideration of a TMA. However, given the
resolution of his symptoms with B12 supplementation the diagnosis of
pseudo-TMA secondary to B12 deficiency was made.