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Pneumonia, Aspiration 793

• Retrosternal fat and interindividual variation with handling. Minimal handling is develops a tachypnea or increased effort after
may give the false impression of pleural • Supplemental oxygen should be provided to pleural drainage, alert the attending clinician
important.
VetBooks.ir of animals without pleural effusion. For this • Avoid dorsal recumbence (ventrodorsal view) SUGGESTED READING Diseases and Disorders
effusion on lateral radiographic projections
as soon as possible.
all dyspneic patients.
reason and to determine whether effusion
is unilateral or bilateral, a minimum of
effusions.
two-view thoracic radiographs is indicated. for radiographs in animals with pleural Dempsey SM, et al. A review of the pathophysiol-
ogy, classification, and analysis of canine and
• Supplies for emergency thoracocentesis: feline cavitary effusions. J Am Anim Hosp Assoc
Prevention clippers, skin preparation materials, butterfly 47:1-11, 2011.
Avoid trauma and exposure to anticoagulant needle or needle with an extension set, 3-way AUTHOR: Graham Swinney, BVSc, DVCS, FANZCVS
rodenticides. stopcock, and syringes EDITOR: Megan Grobman, DVM, MS, DACVIM
• Complications of thoracocentesis (e.g., pneu-
Technician Tips mothorax, hemothorax): if patient suddenly
• Animals with large-volume pleural effu-
sions are fragile and susceptible to stress

Pneumonia, Aspiration Client Education
Sheet

BASIC INFORMATION • Pneumothorax • Gastric contents are typically sterile, but acid
• Shock and particulate matter can cause potentially
Definition • Airway obstruction severe damage.
• Infection associated with inhalation of Clinical Presentation ○ Acid causes direct, caustic epithelial injury
oropharyngeal secretions, foodstuffs, other that is followed by inflammation.
foreign material, or gastric contents DISEASE FORMS/SUBTYPES ○ Particulate material may obstruct airways.
• In veterinary medicine, the term is often • Acute or chronic • Infection may follow aspiration of con-
used in reference to aspiration pneumo- • Fulminant or insidious taminated oropharyngeal secretions or as a
nitis, which is chemical injury caused by secondary (opportunistic) complication of
inhalation of gastric contents (most com- HISTORY, CHIEF COMPLAINT respiratory damage.
monly) or other materials (e.g., barium, Clinical signs may be absent or severe; when Severity of injury depends on volume, toxicity,
mineral oil). present, they may include pH, particulates, and pathogen content of
• Anorexia aspirated material. Sequelae may include
Synonym • Collapse • Airway obstruction
Aspiration pneumonitis • Cough • Bronchoconstriction
• Lethargy • Pulmonary hemorrhage
Epidemiology • Respiratory distress • Epithelial necrosis
SPECIES, AGE, SEX • Others that reflect predisposing cause (e.g., • Pulmonary inflammation or edema
Most often male dogs, but dogs (and less often, regurgitation, anesthetic episode)
cats) of either sex and any age DIAGNOSIS
PHYSICAL EXAM FINDINGS
GENETICS, BREED PREDISPOSITION Findings may be absent or severe; when present, Diagnostic Overview
Large breeds of dogs are overrepresented. Irish they may include: Differentiation of aspiration pneumonia from
wolfhound may be predisposed. • Tachypnea bacterial pneumonia or pulmonary edema
• Cough often depends on circumstantial evidence
RISK FACTORS • Inspiratory and expiratory distress such as history of vomiting or regurgitation
• Diseases of • Auscultatory abnormalities (may be localized or involvement of the typical dependant lung
○ Pharynx or larynx (e.g., laryngeal paralysis, if present) lobes.
before and after arytenoid lateralization; ○ Increased or harsh bronchovesicular sounds
extraesophageal reflux) (≈50%) Differential Diagnosis
○ Esophagus (e.g., megaesophagus, severe ○ Decreased bronchovesicular sounds (≈6%) • Infectious pneumonia
esophagitis) ○ Crackles (≈10%) • Cardiogenic or noncardiogenic pulmonary
○ Stomach or intestine (e.g., pyloric or upper ○ Wheezes (≈2%) edema
intestinal obstruction) • Cyanosis (rare) • Neoplastic infiltrates
• Forced enteral administration of drugs or • Fever (<50% are febrile)
foods • Shock (rare) Initial Database
• Impaired protective reflexes (e.g., anesthesia, • Others that reflect predisposing cause • Neurologic exam (p. 1136) reflects underly-
seizure) (e.g., exercise intolerance with myasthenia ing neurologic disease, if present.
gravis–related megaesophagus) • CBC: neutrophilic leukocytosis ± left shift
ASSOCIATED DISORDERS common
• Acute respiratory distress syndrome Etiology and Pathophysiology • Serum biochemical profile and urinalysis:
• Bacterial pneumonia Inhalation of particulates or fluid into the no specific changes
• Hypoxemia larynx and lower respiratory tract triggers • Thoracic radiographs: abnormalities may lag
• Lung lobe abscessation injury. aspiration event by up to 24 hours

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