Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (294 page)

Suggested Reading

Sheinberg P, Young N. How I treat acquired aplastic anemia.
Blood.
2012;120:1185−1196.

PANCYTOPENIA

   Definition

Pancytopenia is a disorder in which all three blood lines, red cells, white cells, and platelets, are reduced. It is not a disease entity, but a triad of findings that may result from a number of disease processes, most of which involve the bone marrow. Occasionally early on, only two of the three blood lines may be decreased:
bycytopenia.
Eventually, all three lineages become affected.

   Etiology

Pancytopenia may be the result of a congenital anomaly, neoplasia, or autoimmunity or may be iatrogenic (Figure
9-1
). The following mechanisms may account for pancytopenia:

   Decreased production of hematopoietic cells by the bone marrow resulting in a hypocellular marrow;

   Ineffective hematopoiesis with a cellular (or even hypercellular) marrow;

   Infiltration of the bone marrow by extraneous elements;

   Systemic conditions.

A
bone marrow aspirate and biopsy
are mandatory in most cases without a clear etiology. Deciding the bone marrow cellularity may at times be difficult, because of imprecise quantitation of cellularity or sample error due to unequal distribution of bone marrow tissue. In some cases, biopsies from multiple sites may be necessary. Moreover, hypocellular marrow due to aplastic anemia may evolve over time into a hypercellular marrow. This happens for instance when acute leukemia or PNH develops.

A thorough history and physical examination
also play a prominent role in establishing the etiology of pancytopenia, with important clues, such as a history of any drug or toxin exposure or splenomegaly, directing the clinician to possible etiologic causes.

When to suspect pancytopenia
:

   Finding a persistent decrease in all three hematopoietic lines on a routine CBC

   Clinical symptoms suggestive of anemia, bleeding, or prolonged fever

   Repeated infections

Tests recommended
:

   CBC with differential.

   Chemistry, immunology, or infectious investigations as suggested by systemic manifestations.

   Flow cytometry to rule out paroxysmal nocturnal hemoglobinuria (PNH) or hematologic malignancies.