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