Toxic Neutrophils in Cats: Clinical and Clinicopathologic Features, and Disease Prevalence and Outcome—a Retrospective Case Control Study

Abstract

Toxic neutrophils exhibit a variety of nuclear and cytoplasmic abnormalities in Romanowsky-stained blood smears, and are associated with inflammation and infection. The purpose of the retrospective study reported here was to investigate the association of toxic neutrophils with clinicopathologic characteristics, diseases, and prognosis in cats. Cats with toxic neutrophils (n = 150) were compared with negative-control cats (n = 150). Statistical analyses included Fisher exact, independent t-, nonparametric Mann-Whitney, and chi-squared tests. Cats with toxic neutrophils had significantly (P < .05) higher prevalence of fever, icterus, vomiting, diarrhea, depression, dehydration, weakness, and cachexia, as well as leukocytosis, neutrophilia, left shift, neutropenia, anemia, hypokalemia, and hypocalcemia. The prevalence of shock, sepsis, panleukopenia, peritonitis, pneumonia, and upper respiratory tract diseases was significantly higher among these cats, as were infectious (viral and bacterial) and metabolic disorders. Control cats had a significantly higher prevalence of feline asthma, as well as allergic, idiopathic, and vascular disorders. Hospitalization duration and treatment cost were significantly (P < .001) higher in cats with toxic neutrophils. In 53 and 47% of the cats with toxic neutrophils, the leukocyte and neutrophil counts were normal, respectively, whereas in 43%, both abnormalities and left shift were absent, and toxic neutrophils were the only hematologic evidence of inflammation or infection. In conclusion, toxic neutrophils were found to be associated with certain clinicopathologic abnormalities, and when present, may aid in the diagnosis, as well as the assessment of hospitalization duration and cost. The evaluation of blood smears for toxic neutrophils provided useful clinical information.

The feline acute phase reaction

“…A rapid increase in leucocytes is not, therefore, absolutely specific for inflammation. Segev et al (2006) have shown that only about 50% of cats with subacute or chronic inflammation actually had increased number of neutrophils and the degree of neutrophilia was usually higher when inflammation was localised (e.g. in abscesses, pyometra etc.…”

“…Accordingly, a lack of leucocytosis does not necessarily exclude the presence of inflammation. Indeed, the most prevalent finding in cats with inflammation seems to be the presence of toxic neutrophils (Segev et al, 2006).…”

Association of Presence of Band Cells and Toxic Neutrophils with Systemic Inflammatory Response Syndrome and Outcome in Horses with Acute Disease

“…These are defined as a collection of cytoplasmic alterations resulting from accelerated production in the bone marrow, including cytoplasmic basophilia, cytoplasmic vacuolation, D€ ohle bodies, and toxic granulation. 3,7,8 Neutrophil toxic change might be an early indicator of acute systemic illness and has been associated with disease severity, case fatality, hospitalization duration, and cost of treatment in dogs. 7 Similarly, in cats, the detection of toxic neutrophils is associated with disease severity, duration of hospitalization, and treatment cost.…”

“…7 Similarly, in cats, the detection of toxic neutrophils is associated with disease severity, duration of hospitalization, and treatment cost. 8 To our knowledge, no studies have been conducted that have specifically evaluated band neutrophils and toxic change in adult equine emergency admissions and therefore, the value of the microscopic review of peripheral blood smear in adult horses is unknown. Additionally, the microscopic evaluation of the blood smear is frequently underutilized in private veterinary clinics that have in-house hematology analyzers, potentially leading to loss of clinically valuable information.…”

Hematology and Immune-Related Disorders

“…In one study the presence of toxic neutrophils was associated with longer hospitalization. 102 This same study also found that, unlike dogs, toxicity was not associated with increased mortality in cats. Toxic granules represent severe inflammation and, in Birman cats, must be differentiated from the nonpathologic neutrophil granulation anomaly seen in this breed.…”