Pancytopenia

Today we discussed a a fascinating case of newly identified pancytopenia. By definition this means that all three cell lines (RBC, WBC and platelets) are decreased, however given the fact that the clinical approach is similar to bicytopenia (only two cell lines down), the distinction is not clinically relevant.

Overall, cytopenia is a common problem encountered in medicine. Many of our patient have multiple medical illnesses which impact the blood counts in various ways. The patient we enountered today was unique in that he was previously well, suggesting a unifying diagnosis for his pancytopenia. Presenting complaints can vary, but are usually related to the impact of each impaired cell line, anemia causing weakness/fatigue/SOB, leukopenia allowing infectious illness and thrombocytopenia causing bleeding. A study by Guyathri et al. looked at >100 patients with pancytopenia and found weakness/fatigue to be the most common complaint (100%), dyspnea (40%), fever (38%), and organomegaly (30%) followed distantly by bleeding (3%).

The DDx is huge, but consists of:

Drugs: cytotoxic chemotherapy, antibiotics (chloramphenical), NSAIDS, anti-thyroid Rx (PTU/methimazole), antibiotics etc.

Infection: Viral (parvovirus, hepatitis A/B/C, HIV, EBV/CMV), bacterial (TB, sepsis, leptospirosis)

Malignancy: Infiltration (leukemia, NHL, MDS), fibrosis (Hodgkins)

Inflammatory: SLE (57% have anemia, 47% neutropenia, 25% thrombocytopenia)

Deficiencies: copper, B12, folate

Sequestration

Pregnancy

Congenital: Fanconi's anemia, Schwacmann-Diamond, HLH

A prospective study found megaloblastic anemia to be the most common cause of pancytopenia in presenting cases (~74%).

Now that you have your differential, you order your tests accordingly and await the bone marrow results. Our patients presentation is most consistent with AML given the acuity and severity of illness. things to look for on the blood film would be signs of DIC (schistocytes/thrombocytopenia), blast cells with Auer rods (suggestive of AML).

We spoke briefly about the categorization of AML which is as follows:

1. AML secondary to medications (usually chemo)
2. AML with recurrent genetic abnormalities
3. AML with myelodysplastic features
4. AML not otherwise specified

This breakdown has prognistic importance. The large majorty >80%, end up being not otherwise specified. The classification for AML not otherwise specified consists of categories M0-M7, but this is mainly for research purposes and is not based on disease prognosis.