The array of diagnostic workup for
pyrexia of unknown origin (PUO) generally revolves in searching for
infections, inflammatory/autoimmune, and endocrine etiologies. A differential diagnosis of
fever,
hemolytic anemia, and
thrombocytopenia can have etiologies varying from
infections like
malaria,
dengue, cytomegalovirus, Ebstein barr virus, Parvovirus,
infective endocarditis, to autoimmune disorder (systemic lupus erythromatosis),
vasculitis,
hemolytic uremic syndrome,
thrombotic thrombocytopenic purpura (
TTP),
autoimmune hemolytic anemia/Evan's syndrome, paroxysmal nocturnal hemoglobinuri (PNH), or drugs.
Nutritional deficiencies (especially
vitamin B12 deficiency) as a cause of
fever,
hemolytic anemia, and
thrombocytopenia are very rare and therefore rarely thought of. Severe
vitamin B12 deficiency may cause
fever and if accompanied by concurrent hyper-
homocysteinemia and
hypophosphatemia can sometimes lead to severe
hemolysis mimicking the above-mentioned conditions. We present a case that highlights
vitamin B12 and
vitamin D deficiency as an easily treatable cause of PUO,
hemolytic anemia, and
thrombocytopenia, which should be actively looked for and treated before proceeding with more complicated and expensive investigation or starting empiric treatments.