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Anemia, Nonregenerative, and Pure Red Cell Aplasia 63

○ RBC transfusion is an essential therapy • Pit bull dogs should be screened by serology • If the development of IMHA was associated
in severe IMHA cases. and PCR for Babesia gibsoni as soon as with a recent vaccination, discretion should
VetBooks.ir • In dogs, mild primary IMHA may Technician Tips SUGGESTED READINGS Diseases and Disorders
○ Antithrombotic therapy is important for
be used for future vaccinations.
hemolysis is recognized (p. 105).
the prevention of thromboembolism.
respond to immunosuppression with only
a glucocorticoid. Thromboembolism can develop unexpect- Swann JW, et al: Systemic review of evidence relating
edly (often during recovery from the initial
to the treatment of immune-mediated hemolytic
• Adjunctive immunosuppressive medica- crisis), and signs of respiratory effort, collapse, anemia in dogs. J Vet Intern Med 27:1-9, 2013.
tions may improve immunosuppression or abdominal distention warrant prompt AUTHOR: John M. Thomason, DVM, MS, DACVIM
and allow for an accelerated reduction in evaluation. EDITOR: Jonathan E. Fogle, DVM, PhD, DACVIM
glucocorticoids to minimize side effects
but could increase the risk of secondary Client Education
infections. • Clearly describe the side effects associated
• Non–immune-mediated hemolytic anemia with high-dose glucocorticoid therapy.
may present with signs similar to IMHA, • After immunosuppressive therapy is stopped,
including hemolysis, icterus, and regenerative monitor the patient’s PCV for early signs of
anemia. (p. 59). relapse.

Anemia, Nonregenerative, and Pure Red Cell Aplasia Client Education
Sheet

BASIC INFORMATION PHYSICAL EXAM FINDINGS PRCA and is indicated when a persistent
Pale mucous membranes, tachycardia, tachy- nonregenerative anemia exists without an
Definition pnea, systolic heart murmur, weakness. Perform identifiable underlying cause.
A decrease in red blood cell (RBC) mass, hema- rectal exam to check for melena.
tocrit (HCT), or hemoglobin lacking an appropri- Differential Diagnosis
ate compensatory, regenerative response (absence Etiology and Pathophysiology Acute hemorrhage or erythrocyte destruction
of reticulocytosis). Pure red cell aplasia (PRCA) • Nonregenerative anemia with insufficient time for reticulocytosis (3-5
is a type of nonregenerative anemia that is associ- ○ Delay in regeneration: insufficient time days)
ated with marked depletion or absence of erythroid to stimulate regeneration (2-5 days)
precursor cells in the bone marrow, without ○ Anemia of chronic disease: several mecha- Initial Database
affecting leukocyte and platelet precursor cells. nisms: infections (FeLV, FIV, ehrlichiosis, • CBC: severity of anemia, changes in eryth-
Anaplasma, parvovirus), nonseptic inflam- rocyte indices
Epidemiology mation, neoplasia, chronic liver disease, ○ PRCA, dogs and cats: marked normocytic,
SPECIES, AGE, SEX hypoadrenocorticism, hypothyroidism normochromic anemia. Leukocyte and
• Nonregenerative anemia ○ Bone marrow disorders: immune-mediated platelet counts are within normal limits
○ Dogs and cats of any age or either sex (immune-mediated hemolytic anemia or slightly above reference intervals.
○ Depends on underlying cause [IMHA], PRCA), FeLV, neoplasia (leu- • Reticulocyte count: corrected count: < 1%,
• PRCA kemia, lymphoma, myelophthisis), absolute count: < 60,000/mcL
○ Dogs: middle-aged, both sexes (females myelofibrosis, myelodysplastic syndrome, ○ PRCA, dogs and cats: corrected count:
may be overrepresented) aplastic anemia; often part of bicytopenia commonly ≤ 0.1%, absolute count: com-
○ Cats: young (<3 years old), both sexes or pancytopenia. monly ≤ 10,000/mcL
○ Lack of factors needed for effective • Blood smear: abnormal cell morphology,
GENETICS, BREED PREDISPOSITION erythropoiesis or hemoglobin synthesis: basophilic stippling (lead poisoning),
Congenital cobalamin deficiency: giant schnau- deficiencies in erythropoietin (CKD), iron spherocytosis (IMHA)
zer, border collie, Shar-pei, beagle, Australian (often due to gastrointestinal [GI] bleed- ○ PRCA, dogs and cats: no consistent
shepherd ing), folate, cobalamin abnormalities (occasional spherocytes or
○ Drug-induced dyscrasia: chemotherapeutic microcytes)
RISK FACTORS agents, estrogenic compounds • Serum biochemistry and urinalysis: detect
• Nonregenerative anemia: chronic kidney • PRCA underlying disorders (e.g., CKD)
disease (CKD), cobalamin deficiency disor- ○ Primary: immune-mediated ○ Normal total serum proteins and bilirubin
ders, many chronic systemic or inflammatory ○ Secondary: parvovirus (dogs), FeLV posi- (pp. 57 and 59)
illnesses tive (cats) ○ Nonregenerative anemia and PRCA: no
• PRCA: cats: feline leukemia virus (FeLV; consistent abnormalities
p. 329) and feline immunodeficiency virus DIAGNOSIS • Cats: FeLV and FIV serologic testing; ± FeLV
(FIV; p. 325) positive PCR
Diagnostic Overview
CONTAGION AND ZOONOSIS Anemia confirmed with a complete blood count Advanced or Confirmatory Testing
Feline retroviral infection (CBC) or packed cell volume (PCV), but a • Diagnostic tests to identify primary or
diagnosis of a nonregenerative anemia requires underlying systemic disorders as clinically
Clinical Presentation a corrected or absolute reticulocyte count. indicated (e.g., thoracic radiographs, abdomi-
HISTORY, CHIEF COMPLAINT Diagnostic investigation of systemic, underlying nal ultrasound) before performing bone
Signs develop over weeks to months and can causes of anemia should be initiated before marrow aspirate/ biopsy
include lethargy, weakness, exercise intolerance, performing a bone marrow aspirate/biopsy. A • Bone marrow aspirate or core biopsy (p.
collapse, and tachypnea. bone marrow aspirate is necessary to diagnose 1068): cellularity, myeloid-to-erythroid

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