CC: Dyspnea on exertion
ID: 42 yo male with no past medical history presents with dyspnea on exertion and fatigue for 3 weeks. He becomes short of breath with walking ½ block when his baseline was walking miles. He has no chest pain, paroxysmal nocturnal dyspnea, lower extremity edema, cough, or orthopnea. In addition he reports unintentional weight loss of 10 lbs over 3 months, low appetite, and night sweats. Social history is pertinent for drinking six 24 oz beers per day. His exam is notable for conjunctival pallor and hepatosplenomegaly. See the following notable labs:
Overall picture is consistent with ineffective erythropoiesis. The peripheral smear demonstrates macrocytic red blood cells and hypersegmented PMNs, narrowing the diagnosis to folate and/or B12 deficiency. His B12 returned as <100 and Homocysteine/MMA elevated confirming that patient had significant B12 deficiency leading to his pancytopenia. IF-Ab and Parietal Cell Ab were positive which made Pernicious Anemia the most likely cause given lack of other malabsorptive conditions, though patient likely had poor nutrition from his alcohol use complicating the picture.
Morning Report Pearls:
Pancytopenia is a broad differential including infection (EBV, CMV, HIV, Cocci, Histo, TB), rheumatologic conditions (RA, SLE, Sarcoid), drugs, nutritional deficiencies (B12, folate and copper), Zinc toxicity, Lymphomas/Leukemias, Myeloproliferative disorders like MDS and Myelofibrosis, Aplastic Anemia, Liver disease, Alcohol toxicity, Amyloidosis, HLH, Metastatic cancer – see prior Morning Report Post from 5/19/17
Macrocytosis is classically seen in a few of these causes: B12/folate deficiency, MDS, Alcohol toxicity, and Liver disease
Peripheral smear is your friend and can cinch the diagnosis when you see hypersegmented PMNs like in this case of B12 deficiency
Once the diagnosis of B12 deficiency is made, you need to think of causes: malabsorption (due to IBD, celiacs, tropical sprue, gastric bypass), medications (PPI, metformin), pernicious anemia, malnutrition
If patient not responding to B12 supplementation, consider pursuing a diagnosis of MDS with bone marrow biopsy. Indirect bilirubinemia and the elevated LDH should improve within 1-2 weeks following B12 treatment but cell counts can take months to normalize.