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Pyothorax 857

Pyothorax Bonus Material Client Education
Sheet
Online
VetBooks.ir Diseases and Disorders
BASIC INFORMATION
○ Pulmonary or intrathoracic neoplasia
granules) strongly suggest Actinomyces
○ Gastric foreign body migration Macroscopic yellow clumps (sulfur
Definition • Pleuritis (and nonseptic pyothorax) can be (p. 20).
Accumulation of purulent exudate in the pleural associated with canine hepatitis, leptospirosis, ○ Exudate: protein > 3 g/dL, nucleated cell
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space is associated with significant pleural canine distemper, feline infectious peritonitis, count > 7 × 10 /L, often > 30 × 10 /L
inflammation. toxoplasmosis, or feline upper respiratory ○ Degenerate neutrophils predominate, with
tract infection. macrophages and activated mesothelial
Synonyms cells also present; intraleukocytic bacteria
Pleural empyema, thoracic empyema DIAGNOSIS are diagnostic (septic pyothorax).
Epidemiology Diagnostic Overview • Gram stain of fluid: guides initial empirical
antimicrobial therapy
SPECIES, AGE, SEX The diagnosis is suspected based on presenting ○ Oropharyngeal bacteria (e.g., Pasteurella
Dogs and cats: history and physical exam findings. Confirma- spp, Bacteroides spp, Fusobacterium spp)
• Medium and large dog breeds overrepresented tion requires appropriate analysis of pleural common in cats; Escherichia coli in dogs
• Males of both species overrepresented fluid; cytologic exam provides a working clinical (all gram-negative rods)
• Median age of occurrence: 4 years diagnosis, and culture can confirm bacterial ○ Actinomyces (anaerobe) and Nocardia
contribution. (aerobe): important potential pathogens
GENETICS, BREED PREDISPOSITION in dogs from regions where grass awns
Dogs: hunting breeds subject to increased risk Differential Diagnosis are endemic (p. 398); both gram-positive
of inhaled foreign (plant) material • Pulmonary parenchymal disease (e.g., short rods and filaments
pneumonia, edema) • Anaerobic and aerobic bacterial culture and
RISK FACTORS • Pleural effusion susceptibility (C&S):
Cats: higher risk if from multi-cat household ○ Chylothorax ○ For planning long-term antimicrobial
and young. Cat fight wounds and upper ○ Heart failure therapy
respiratory infection are risk factors. Role ○ Hemothorax ○ Dogs: most commonly mixed anaerobes
of feline retrovirus infection not proved. ○ Feline infectious peritonitis and aerobes
No difference in risk for indoor versus ○ Neoplastic effusion ○ Cats: oropharyngeal anaerobes and
outdoor • Diaphragmatic hernia Pasteurella spp, Streptococcus spp, and
• Intrathoracic neoplasia Mycoplasma spp; include specific request
Clinical Presentation for Mycoplasma culture
HISTORY, CHIEF COMPLAINT Initial Database
• Slowly progressive onset of dyspnea, inap- • CBC Advanced or Confirmatory Testing
petence, and weight loss, or ○ Usual: neutrophilic leukocytosis with or CT
• Acute decompensation with dyspnea/ without a left shift • Potentially identify cause of pyothorax.
tachypnea/collapse from pleural effusion ○ Possible: leukopenia, thrombocytopenia • Evaluate mass(es) in thoracic cavity, and
if sepsis determine if resectable
PHYSICAL EXAM FINDINGS • Serum biochemistry profile
• Respiratory: dyspnea (p. 879), tachypnea; ○ Multiple abnormalities (e.g., hepatic and TREATMENT
muffled heart and lung sounds on ausculta- renal parameters, electrolytes, hypoalbu-
tion (unilateral/bilateral), ventral hyporeso- minemia) can occur secondary to sepsis Treatment Overview
nance on thoracic percussion (p. 907). Patient stabilization, pleural drainage (thora-
• Systemic: depression, weight loss, ± pyrexia • Survey thoracic radiographs costomy tubes for pleural lavage), ± surgical
(or hypothermia, especially in cats), ± pale ○ Identify pleural effusion; hold off if animal exploration and debridement of the thoracic
mucous membranes in severe respiratory distress until after cavity, and long-term antimicrobial therapy
• Cats: possibly decreased compressibility of thoracocentesis based on results of microbiologic C&S testing
cranial thorax on palpation ○ After thoracocentesis: to evaluate pleural are the standard of care.
• Sometimes, findings suggest septic shock space, mediastinum, and pulmonary
(e.g., prolonged capillary refill time [p. 907]) parenchyma for potential primary cause Acute General Treatment
of pyothorax • Stabilize respiratory compromise
Etiology and Pathophysiology • Thoracic ultrasound exam ○ Therapeutic (and diagnostic) thoracocen-
• Septic pyothorax (most common): potential ○ Thoracic focused assessment of sonography tesis (p. 1164)
causes of pleural space infection: for trauma (TFAST) can confirm pleural ○ Oxygen administration (p. 1146)
○ Penetrating/migrating plant material fluid for animals in distress (p. 1102). • Correct fluid and electrolyte deficits and
(p. 398) ○ Identify masses, and evaluate their internal address shock if present (p. 907).
○ Inhaled plant material structure. • Antimicrobial therapy: empirical therapy
○ Penetrating injury ○ Identify site of greatest pleural effusion active against aerobic and anaerobic bacteria
Bite, stab, gunshot wounds for centesis (if overall small volume of (combination therapy typical)
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○ Esophageal perforation effusion). ○ Gram stain results (as previously described)
Foreign body ○ Identify foreign material in the pleural ○ Amoxicillin/ampicillin 22 mg/kg IV or
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Spirocerca lupi infection space if possible (may be challenging). PO q 8h if Actinomyces suspected
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○ Hematogenous spread • Pleural fluid evaluation (pp. 1164 and 1343) ○ Trimethoprim-sulfadiazine 15 mg/kg PO
○ Extension from discospondylitis ○ Fluid typically blood tinged; may be q 12h if Nocardia, E. coli, or Pasteurella
○ Pneumonia or lung abscess opaque; often foul odor (anaerobes). suspected
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