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Hematology Interest Group
Case Study

July 4, 2017

Red Blood Cell Inclusions

Case History

A 69-year-old female on vacation from New York was admitted to the ER after friends found her passed out in her hotel room.   The patient stated she felt well until early morning when she awoke with severe nausea, followed by 5-10 episodes of forceful emesis described as either gastric contents or clear fluids and has since become weak and lightheaded.  Other than this current trip, no recent travel.  No history of travel to the tropics.  She denies illness and any recent friends, family, or travel companions.  No recent changes in medication.

Vitals were assessed and confirmed a fever of 99.8F(37.7C). Physical exam reveals a notable rash (petechiae) on lower legs, trace ankle edema, and appears well-nourished.   The patient’s white blood cell (WBC) count is 11.3/μl, hemoglobin is 12.0g/dl, and platelet count is 35,000/μl. The WBC The peripheral blood smear shows ring form inclusions in red blood cells.  The patient is admitted for initiation of treatment.

Constitutional: No history of tick bites

LABORATORY RESULTS

Hematology 

Test

Patient’s Results

Reference Range

Red Blood Cell Count (RBC)

4.26 x106/uL

4.2 – 5.4 x106/uL

Hemoglobin (HgB)

12.0 g/dL

12-16 g/ dL

Hematocrit (Hct)

35.8 %

37-47%

Mean Corpuscular Volume (MCV)

84.0 fl

80-100 fl

Heam Corpuscular Hemoglobin (MCH)

28.2 pg

27-31 pg

Mean Corpuscular Hemoglobin Concentration (MCHC)

33.5 g/dL

32-36 g/dL

Red Cell Distribution Width (RDW)

14.5 %

11.5-14.5 %

Platelets

35 x 103/uL

140-440 x 103/uL

White Blood Cell Count (WBC)

11.3 x103/uL

4.8-10.8 x 103/uL

Chemistry

Test

Patient’s Results

Reference Range

Sodium

136 mmol/L

136 – 145 mmol/L

Potassium

4.0  mmol/L

3.5 – 5.0 mmol/L

Chloride

100  mmol/L

98 - 107 mmol/L

Total CO2

23 mmol/L

22 - 29 mmol/L

Calcium

8.4 mg/dL

8.8 – 10.2 mg/dL

Glucose

94 mg/dL

82- 100 mg/dL

Total Bilirubin

1.7mg/dL

0.1 – 1.3 mg/dL

AST

49 IU/L

<=40 IU/L

ALT

55 IU/L

<= 41 IU/L

Test

Patient’s Results

Reference Range

G6PD

13.4

0.0 -  43.9 U/mL

Immunology

Test

Patient’s Results

Lyme ABs: Bburgdorferi Ratio

0.27

Lyme ABs: Bburgdorferi Abs

Negative

.

Manual Differential

Test

Patient’s Results

Reference Range

Neutrophils

66.0%

6.5 x103/uL

50 – 70%

1.4-6.5 x103/uL

Lymphocytes

17.9%

1.8 x103/uL

20 – 40%

1.2 - 3.4x103/uL

Monocytes

14.7%

1.4 x103/uL

2-9%

0-0.7 x 103/uL

Eosinophils

0.1%

0.0 x103/uL

0-4 %

0-0.5 x 103/uL

Basophils

1.3%

0.1 x103/uL

0-2 %

0-0.2 x 103/uL

RBC Morphology

Parasitic ring forms present in RBC.

Normal

PLT Count and Morphology

Thrombocytopenia

Normal

DxH 800 Interpretation/Flags

According to the hospital laboratory protocol on slide criteria, a blood smear was prepared based on the following:

   Definitive Flag: Thrombocytopenia

Scattergram

Microscopic: Peripheral Blood Smear

Babesia parasites in red blood cells on a wright giemsa stained blood smear at 50x.

   

   

Babesia parasites in red blood cells on a wright giemsa stained blood smear at 100x.

Pathology Review

Pathologist Interpretation : The peripheral blood smear is reviewed as requested. No nucleated red blood cells are seen on scanning. The red cells are normochromic normocytic and normal in number. Numerous erythrocyte intracellular parasite forms are present. There is no significant polychromasia. The leukocytes are normal in number with an absolute monocytosis and unremarkable morphology. No blasts, lymphoma cells, or dysplastic cells are seen. The platelets are markedly decreased in number, and appear unremarkable.

69 year old female with numerous erythrocyte intracytoplasmic parasite forms. Clinical history  favors babesiosis, however, no diagnostic "Maltese cross" forms are identified. Serologic testing and infectious disease consult is recommended.

Parasitemia

Test

Patient’s Results

Reference Range

Parasitemia

2.000 %

0%

Babesia Species by PCR

Test

Patient’s Results

Babesia species by PCR

Detected*

Babesia microti by PCR

Detected*

INTERPRETIVE INFORMATION: Babesia Species by PCR

A negative result does not rule out the presence of PCR inhibitors in the patient specimen or test-specific nucleic acid in concentrations below the level of detection by this test.

Test developed and characteristics determined by ARUP Laboratories.  See Compliance Statement B: aruplab.com/cs

Diagnosis  

The CBC showed that the patient had thrombocytopenia and that 2% of the RBC showed intracellular inclusions favoring babesia. Finally, the Babesia Species by PCR from ARUP Laboratories came back positive, affirming the diagnosis of Babesiosis.  

Babesiosis and thrombocytopenia instructions:  Prescriptions for clindamycin and quinine in addition to Phenergan suppositories.

Discussion

Babesia microti is transmitted by the bite of infected Ixodes scapularis ticks—typically, by the nymph stage of the tick.  Symptoms occur 1-4 weeks following tick bite and are clinically nonspecific. The findings on routine laboratory testing frequently include hemolytic anemia and thrombocytopenia. Additional findings may include elevated levels of liver enzymes, blood urea nitrogen, and creatinine.

In symptomatic patients with acute infection, Babesia parasites typically can be detected by light-microscopic examination of blood smears, although multiple smears may need to be examined. Sometimes it can be difficult to distinguish between Babesia, Plasmodium parasites, or even debris (stain or platelet artifacts).  In these cases, molecular and/or serologic methods can help confirm the diagnosis.

Babesiosis Fact Sheet - CDC

Babesiosis Provider Fact Sheet - CDC

References

  1. https://www.cdc.gov/parasites/babesiosis/biology.html


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CAD877EB-2006-4F93-85D8-20AAD7C7E051.JPG Samantha Dewey, MLS(ASCP)SH

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