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840 Pulmonary Nodules

• Pulmonary angiography: tortuous pulmonary • ARDS and acute severe interstitial lung Recommended Monitoring
arteries indicate PH; perfusion deficits occur disease: consider ventilator if underlying • Clinical parameters: general attitude, exercise
VetBooks.ir • Pulmonary CT much more sensitive to • Right-heart failure due to parasitic pulmonary • Systemic blood pressure
disease and its prognosis justify; extracorporal
tolerance, respiration, severity of ascites
in PTE.
membrane oxygenation if available.
identify/rule out parenchymal disease
• Velocity of TR and pulmonic regurgitation
○ CT-angiography for PTE: less sensitive
(pp. 415 and 418); A. vasorum: recommend
and specific than expected vascular disease–induced PTE: D. immitis PROGNOSIS & OUTCOME
• Pulmonary ventilation/perfusion scintigraphy slow worm kill (i.e., fenbendazole 50 mg/
to rule out PTE (rarely performed) kg PO q 24h for 21 days) Varies with disease/stage:
• Pulmonary wedge pressure: estimate of left • Suspected pulmonary artery vasculitis (D. • Good: parasitic pulmonary vasculature
atrial pressure, systolic and diastolic pulmo- immitis, A. vasorum, E. canis): prednisolone disease with acute PH if patient survives
nary artery pressure; evaluate therapeutic 1 mg/kg q 12h for 1 week, with slow taper acute episode and no progressive vascular
response over 1 month; similar protocol recommended remodeling occurs
• Pulmonary histopathology: not recommended for A. vasorum as for D. immitis (p. 418) • Fair: right-to-left cardiovascular shunts,
to diagnose PH but may be necessary to MMVD, PH secondary to chronic parasitic
identify the underlying disease process Chronic Treatment pulmonary vasculature disease
Because optimal medical treatment for naturally • Poor: advanced PAH (idiopathic or second-
TREATMENT occurring PH in pets is unknown, the following ary), advanced pulmonary fibrosis, ARDS,
are merely treatment considerations: nonparasitic PTE, right-sided heart failure
Treatment Overview • Amlodipine (mild to moderate PH; author’s
Lower PAP in patients with signs of right first choice for PH due to MMVD): 0.05 mg/ PEARLS & CONSIDERATIONS
ventricular failure, improve oxygenation in kg PO q 24h, dose titrated based on response
patients with hypoxemia, and correct/improve while avoiding systemic hypotension Comments
underlying disease. ○ If PH is associated with MMVD, add • PH is rarely a primary process but occurs
an angiotensin-converting enzyme (ACE) secondary to another disease.
Acute General Treatment inhibitor (e.g., enalapril, benazepril). • PTE and right-to-left PDA may be missed
• Oxygen therapy (cage or nasal), as necessary ○ If systemic hypotension occurs before if not considered.
(p. 1146) reduction in PH, change to sildenafil. • Radiographs lack sensitivity to detect even
• Sildenafil 2-3 mg/kg q 8-12h PO to lower • Sildenafil 1-3 mg/kg PO q 8-12h (titrated severe interstitial or vascular pathology.
PAP if clinical signs plausibly due to PH. to effect) is considered by many to be the • Diagnosis of idiopathic PAH is one of
• Pimobendan 0.2-0.3 mg/kg PO q 12h to treatment of choice and is the author’s first exclusion and histologic confirmation.
increase systolic function in CHF due to choice for causes other than MMVD. Can
MMVD improve clinical condition despite only mild Technician Tips
• Careful fluid balance in cases with suspected reduction in PAP. Oxygen should be administered to patients with
increased pulmonary vascular permeability: ○ In pulmonary venous hypertension (e.g., respiratory distress (p. 1146). Owners should
balance of close to zero or negative fluid MMVD, PVOD), decreasing PAP but not be advised about the importance of parasite
balance to avoid additional pulmonary edema systemic arterial pressure can increase prevention in endemic areas.
• Clopidogrel 1-3 mg/kg PO q 24h for pulmonary capillary blood volume and
potential thrombotic pulmonary vascular increase risk of pulmonary edema. Client Education
disease • Specific treatment of underlying mechanism In dogs with cardiac disease, travel to a higher
Specific treatments: or disease in secondary PH altitude (>7000 feet [2200 m]) may aggravate
• PH secondary to congenital cardiovascular PH to a clinically relevant degree.
shunt may be reversible. Patients with newly Possible Complications
developing PH and known PDA and patients • PH: right ventricular failure and systemic SUGGESTED READING
with PDA and moderate to severe PH but arterial hypotension Goldberg AB, et al: Pulmonary hypertension:
still with left-to-right shunting should be • Treatment: systemic arterial hypotension diagnosis, imaging techniques, and novel therapies.
sent for correction as soon as possible. with syncope, prerenal azotemia; potential Cardiovasc Diagn Ther 7:405-417, 2017.
• Cardiogenic pulmonary edema: reduce risk of pulmonary edema with sildenafil in AUTHOR: Tony M. Glaus, Dr.med.vet.habil., DACVIM,
preload with diuretics and left- and right- dogs with MMVD DECVIM
sided afterload with amlodipine (p. 408) EDITOR: Megan Grobman, DVM, MS, DACVIM

Pulmonary Nodules Client Education
Sheet

Epidemiology
BASIC INFORMATION neoplasms have an average reported incidence
SPECIES, AGE, SEX of 5.6/100,000 (dogs) and 2.2/100,000
Definition • Dogs: 9-11 years (cats).
Single or multiple masses of varying sizes occur- • Cats: 11-12 years
ring in the lung parenchyma; usually detected • Females may be at increased risk. RISK FACTORS
radiographically • The prevalence of pulmonary nodules in Exposure to secondhand smoke may be a risk
dogs and cats is not known. Pulmonary factor.

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