Page 1224 - Clinical Small Animal Internal Medicine

1162 Section 10 Renal and Genitourinary Disease

Cytology is necessary for a diagnosis and for targeted There are unfortunately very few clinical data or trials in
VetBooks.ir therapy, but caution must be exercised in obtaining sam- veterinary medicine looking at the efficacy of specific
antibiotics and their effectiveness in crossing into the
ples (see Table 124.1). Typical cytology findings include
free and phagocytosed bacteria, intact and degenerate
sepsis, the antibiotic spectrum should be broadened
neutrophils, macrophages, necrotic debris, and hyper- dog prostate and treating prostatitis. In the presence of
plastic epithelial cells with mild anisokaryosis. (beta‐lactam, third‐generation cephalosporin, aminogly-
cosides, imipenem). The blood–prostate barrier is com-
promised in these situations and antibiotics that would
Therapy
not generally penetrate the prostate will do so.
Targeted antibiotic therapy is indicated in both acute and Ciprofloxacin is not indicated in infectious prostatitis
chronic prostatitis and prostatic abscesses. Antibiotics as not only does it have poor oral bioavailability in dogs
must be chosen based on culture and sensitivity results and cats, it also does not penetrate the prostate as well
as well as their ability to penetrate prostatic tissue. The as enrofloxacin. Antibiotic therapy should be continued
ideal antibiotic needs to be lipid soluble and have lower for a minimum of 4–6 weeks, and prostatic culture should
serum protein binding to be able to cross into the prostate be rechecked 3–5 days after discontinuation of antibiot-
(Table 124.2). If higher protein binding is a characteristic ics. Specific treatment for sepsis and peritonitis is detailed
of a particular desired antibiotic, using a higher dosage elsewhere, as is the treatment for acute azotemia.
range is necessary. While awaiting cytology and culture Surgery may be necessary for prostatic abscesses.
results, therapy should be started with enrofloxacin. Medical drainage of abscesses by percutaneous ultra-
sound‐guided aspiration combined with targeted
antibiotic therapy rarely results in the resolution of
abscesses. However, ultrasound‐guided drainage may
facilitate stabilization of a patient if surgery is delayed.
Multiple surgical techniques have been described
including omentalization, marsupialization, placement
of drain tubes, and partial or total prostatectomy, with
omentalization seeming to offer the best results and
fewer complications.
It is always recommended to neuter dogs with prosta-
titis and prostatic abscesses as this can accelerate recov-
ery and also prevent recurrence. Finasteride therapy may
be used in breeding dogs to shrink the prostate but its
efficacy in prostatitis is unknown.

Figure 124.6 Prostatic abscess and prostatitis as seen on Prognosis
ultrasound transverse image plane. Note the mottled appearance
of the prostate surrounding the abscessed region. Source: Image Prognosis is good to guarded in acute prostatitis without
courtesy of Dr Tim Spotswood. abscessation or sepsis. Chronic prostatitis may be more

Table 124.2 Antibiotics used for bacterial prostatitis

Antibiotic Dosage Route Notes
Enrofloxacin 10 mg/kg q24h IV, PO, SC Risk of permanent cartilage damage in large‐breed dogs <18 months;
usually the first‐line drug of choice
Chloramphenicol 50 mg/kg q6–8h PO Dosage listed is at higher end of therapeutic range; monitor CBC for
evidence of bone marrow suppression
Trimethoprim‐ 15 mg/kg q12h IV, PO, SC Potential complications include keratoconjunctivits sicca, acute
sulfamethoxazole hypersensitivity reactions, polyarthropathy, blood dyscrasias, vomiting,
anorexia, hepatopathy and icterus; rarely used as first‐line therapy
Clindamycin 11–20 mg/kg q12h PO, IV, IM, SC Capsules or divided tablets may cause esophagitis; not usually indicated
for prostatitis unless indicated by culture
Erythromycin 10–25 mg/kg q8–12h PO May cause anorexia, vomiting, diarrhea; usually not indicated for
prostatitis unless indicated by culture
CBC, complete blood count; IM, intramuscular; IV, intravenous; PO, by mouth (per os); SC, subcutaneous.