Homozygous sickle cell disease in a 28 year old female

Marsha C. Kinney, MD
Vanderbilt University Hospital
Nashville, Tennesee, USA

Clinical Data This patient was a 28 year old female with a longstanding history of sickle cell anemia. She has suffered multiple episodes of vaso-occlusive crises, requiring hospitalization. Having received multiple transfusions during her lifetime, this patient has been treated with iron-chelating agents for iron overload.

Laboratory Data Laboratory results showed a WBC of 17.03 x 10³/L Hgb level of 7.0 g/dL, Hct of 20.9%, RDW of 19.4%, and a Reticulocyte count of 22%. In addition to a positive Sickledex test for Hb S, a quantitative hemoglobin evaluation (HPLC) revealed 92.6% Hb S, 4.8% Hb F and 2.6% Hb A.

Morphology The manual differential revealed 5 NRBC's /100 RBCs, Howell Jolly bodies, 2+ sickle cells, 1+ target cells, 3+ poikilocytosis, and 2+ polychromasia. No abnormal white blood cells were present on the peripheral smear (Figure 1). The automated ADVIA 120 WBC differential was confirmed by a reference manual method.

Table 1. Laboratory Data: CBC and Manual and Automated Differential

CBC Count
WBC (x 10³ /L)	17.03
RBC (x10⁶ /L)	2.25
Hgb (g/dL)	7.0
Platelets (x 10³ /L)	408
RDW (%)	19.4
HDW (g/dL)	4.83
% Hyper	11.2

Differential	ADVIA 120	Manual
Neutrophils (%)	52.1	51
Lymphocytes (%)	36.0	41
Monocytes (%)	4.8	5
Eosinophils (%)	4.9	2
Atypical Lymphocytes/LUCs (%)	2.0	1
LI	2.07
NRBC		5

ADVIA 120 Flagging
NRBC flag	++
MACRO flag	+
HYPER flag	++
HC VAR flag	+++
ANISO flag	++

ADVIA 120 Pattern Significance

ADVIA 120 pattern was consistent with sickle cell anemia, demonstrating the presence of 11.2% of hyperchromic (dense) cells and supported by significant RBC morphology flagging (Table 1). Diffuse pattern of red blood cells on the RBC cytogram, presence of hyperchromic cells on V/HC cytogram, and increased percentage of reticulocytes are indicative of sickle cell anemia (Figure 2).

Discussion

Homozygous sickle cell disease (Hb SS) is an inherited disorder that causes chronic hemolytic anemia and frequent occurrences of painful vaso-occlusive crises. Vaso-occulsion, obstruction of the microcirculation by adherence of sickle cells to endothelial cells, can cause complications in virtually every organ in the body and result in multiorgan failure (1,2). Since our patient experienced a vaso-occulsive crisis only once or twice a year, she was successfully managed in our outpatient hematology clinic.

REFERENCES

1. Wang, Winfred C. and Lukens, John N.: Sickle Cell Anemias and Other Sickling Syndromes. Chapter 51 in: Wintrobe's CLINICAL HEMATOLOGY, 10th Edition. Edited by Lee, G. Richard, Ferster, John, Lukens, John, Paraskeuas, Frixus, Greer, John P., and Rogers, George M. Baltimore, Williams & Wilkins, 1999.

2. Embury, Stephen H. and Vichinsky, Elliott P.: Chapter 30 in: HEMATOLOGY: Basic Principles and Practice, 3rd Edition. Edited by Hoffman, Ronald, Benz, Edward J. Jr., Shattil, Sanford J., Furie, Bruce, Cohen, Harvey J., Silberstein, and Leslie, McGlave Philip. Philadelphia, Churchill Livingstone, 2000.

Legend to Figures

Figure 1. Peripheral blood smear stained with Wright stain reveals presence of dense cells and significant poikilocytosis (?)

Figure 2. ADVIA 120 results

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