Total protein concentration as a predictor of in neoplastic peritoneal and pleural effusions of dogs

BACKGROUND

The diagnosis of neoplastic cavitary effusions requires the identification of neoplastic cells in effusions, yet the cytologic appearance of neoplastic effusions can be highly variable due to the varied mechanisms of formation. Additional parameters might aid in the interpretation of equivocal cytologic results.

OBJECTIVES

Our goal was to evaluate whether total protein concentrations can be used to support the diagnosis of neoplasia in the peritoneal and pleural effusions of dogs with lower cellularities (≤5000 nucleated cells/μL).

METHODS

Pleural and peritoneal fluid analyses from dogs presented to the University of Illinois Veterinary Teaching Hospital between 2014 and 2019 were evaluated retrospectively. Effusions were categorized as neoplastic or non-neoplastic based on histology or cytology. Non-neoplastic effusions were subcategorized according to mechanism: decreased oncotic pressure, increased hydrostatic pressure, increased vascular permeability, leakage of urine, and leakage of lymph. The TP and blood albumin to fluid TP ratio (Alb_blood :TP_fluid ) were compared among groups.

RESULTS

Twenty-seven neoplastic and 65 non-neoplastic cases were evaluated. TP was higher in the neoplastic group (P = .001) than in the non-neoplastic group. Neoplastic effusions had a lower Alb_blood :TP_fluid than non-neoplastic (P = .001), and effusions with Alb_blood :TP_fluid of ≤0.6 were 5.6 times more likely to be neoplastic (95% CI 1.69-17.36; P = .003).

CONCLUSIONS

Fluid TP concentrations were significantly greater in neoplastic than non-neoplastic effusions; however, given the considerable overlap between groups, the diagnostic utility of this difference is low. A neoplastic etiology might be more likely in cases with an Alb_blood :TP_fluid ≤0.6.

Presumptive tick paralysis in 2 American Miniature horses in the United States

RATIONALE

Tick paralysis has not been reported in horses in North America.

CLINICAL FINDINGS

Two American Miniature horses were examined for progressive weakness and recumbency. Numerous ticks (Dermacentor variabilis) were found on both horses. Horse 1 was recumbent (grade 5/5 gait deficit) on presentation, whereas Horse 2 was standing but ataxic (grade 4/5 gait deficit) and tetraparetic. Both horses had decreased tongue and tail muscle tone, and had normal spinal reflexes. Cerebrospinal fluid cytology was normal. Equine herpesvirus-1 testing was negative.

PERTINENT INTERVENTIONS

Ticks were removed within 24 hours of presentation. Both horses were treated topically with permethrin. Supportive care included fluid therapy, treatment for corneal ulceration, and frequent repositioning during recumbency.

OUTCOME

Within 48 hours of tick removal, both horses were neurologically normal.

CLINICAL RELEVANCE

Ours is the first reported case of presumptive tick paralysis in horses in North America. Although rare, tick paralysis should be considered in horses presented with acute-onset weakness progressing to recumbency.