Infectious Disease

Diagnoses from the

Hematology

LaboratoryCHARLOTTE STEWART, MT (ASCP)

APRIL 5, 2019

Why should we think about infectious

diseases on peripheral smears? On

body fluids?

What we find may not have been in the clinical

differential diagnosis

What we find IS in their differential diagnosis, but

other confirmatory test take days to come back

Case #1

12 year old female with 3 day history of headache,

lethargy, and fever (up to 103ºF)

In the past 12 hours, developed nausea and vomiting

CT scan of head: no abnormal findings

CBC: Mild leukocytosis with normocytic anemia

Gram stain

Case #2

30 year old male

Presents feeling tired with muscle aches, joint

pain and headache

Recent camping trip

1.99

8.7

25

40

Morulae

Seen with Ehrlichia or Anaplasma species

Depending on the species, will affect either the

neutrophils or monocytes

Ehrlichia chafeensis (monocytes) and ewingii(neutrophils)

Lone star tick

Anaplasma (neutrophils)

Ixodes tick

Tick borne illness

Ticks are prevalent in Arkansas

Mild winter – predicted bad tick season

55 year old man presents to his PCP

2-3 week complaint of feeling tired, nauseous and has a low grade

fever

Case #3

Babesia microti

Parasite transmitted by the Ixodes tick

Separate Missouri strain

Usually mild illness unless the patient is asplenic

Treatment:

Atovaquone plus azithromycin is used to treat most cases

and is usually taken for 7 to 10 days

Clindamycin plus quinine is used in more severe cases

Case #4

2 brothers were adopted from Africa

Check up with their new pediatrician

Plasmodium falciparum

This is the one the clinicians want to rule out

Multiplies rapidly

Can cause severe anemia

Can clog small vessels

Mechanism of cerebral malaria, which can be fatal

The banana-shaped gametocyte is classic

Quick antigen test

Follow up with PCR testing

Plasmodium vivax

Most importantly, it’s not P. falciparum

Probably the most prevalent human malarial

parasite

Has dormant liver stages (as does P. ovale)

which can activate and invade the blood

months to years after the initial mosquito bite

Case #5

4 year old female

Seen in GI clinic for follow up

Patient has a G-tube and mom noticed that her

daughter has been a little tired

Mimics

Mimics are much more common than

actual infectious organisms

Overlying platelets

Giant platelets

Nucleated RBCs

Stain precipitate

Our front line

Questions

Acknowledgements to Dr. Rebecca Levy