Page 1895 - Cote clinical veterinary advisor dogs and cats 4th

950 Subinvolution of Placental Sites

activity. Sudden death typically occurs during gradient < 50 mm Hg and when follow-up This phenomenon is potentially caused by
visit shows no progression of SAS
or shortly after strenuous exercise. However, • Severe SAS: guarded a relatively smaller outflow tract/aorta in that
VetBooks.ir quality of life. ○ Depending on studies, median survival • Differentiation between SAS and the normal
breed, predisposing them to increased ejec-
this recommendation must be weighed against
tion velocity and development of murmurs.
time is 19-61 months when untreated.
Drug Interactions
challenging and requires a combination
• Concurrent use of antacids can alter the ○ Medical management is associated with state in the most mildly affected dogs is
a median survival of 4.5 years.
bioavailability of atenolol. ○ Most dogs with pressure gradients of physical exam, echocardiography (left
• Calcium channel blockers may cause hypo- > 125-130 mm Hg develop serious ventricular thickening, left atrial enlargement,
tension and bradycardia when administered complications or die suddenly in the first steep aortoseptal angle, and aortic insuffi-
together with atenolol. 3 years of life. ciency suggest SAS) and regular follow-up
• Effects of theophylline can be blocked by exams (progression of these abnormalities
beta-blocking agents such as propranolol. PEARLS & CONSIDERATIONS and of Doppler-derived pressure gradient
suggest SAS).
Possible Complications Comments
• Ventricular arrhythmias/ventricular tachy- • SAS is a problematic disease; it is difficult to Prevention
cardia diagnose mildly affected dogs, and there is • Screening of breeding dogs for SAS
• Exertional syncope or sudden death no definitive cure for severely affected dogs, • Genetic testing may become available in the
• Left-sided heart failure which remain at risk of sudden death even near future.
• Aortic valve endocarditis: antibiotics may after surgical intervention.
be indicated during periods of anticipated • The combination of a ≥ grade IV/VI ejection Technician Tips
bacteremia (dental procedures, surgery, left-sided heart murmur that radiates crani- Avoid stress and intense activity in dogs with
wounds, other concurrent bacterial disease). ally to the thoracic inlet and over the carotid severe SAS dogs because of risk of syncope or
arteries along with a weak femoral pulse in sudden death.
Recommended Monitoring a large-breed puppy is highly suggestive of
• Control ventricular arrhythmias when present severe SAS. Client Education
(p. 1033). Ambulatory ECG is recommended • The severity of ventricular arrhythmias • In cases of severe SAS, avoid prolonged or
if syncope is noted and for monitoring detected by extended (24-hour) ambulatory vigorous exercise.
efficacy of antiarrhythmic treatment (p. ECG recordings correlates with the severity • Contact breeders to notify them of SAS cases;
1120). of disease. do not breed SAS dogs.
• SAS can progress during puppyhood, and • Because of the progressive nature of SAS
a cardiac evaluation should be done at full during growth, the lesion/heart murmur may SUGGESTED READING
maturity to stage the severity of disease. be clinically silent in very young puppies Beijerink NJ, et al: Aortic stenosis. In Ettinger SJ, et
but becomes increasingly prominent at 2-3 al, editors: Textbook of veterinary internal medicine,
PROGNOSIS & OUTCOME months of age. ed 8, St. Louis, 2017, Elsevier, pp 1234-1240.
• Breeding dogs affected by mild SAS may
• Mild to moderate SAS: good generate severely affected offspring. AUTHOR: Marie-Claude Bélanger, DVM, MSc,
DACVIM
○ Normal quality of life and longevity, • Overtly healthy boxer dogs may have EDITOR: Meg M. Sleeper, VMD, DACVIM
especially for dogs with peak pressure systolic murmurs without obvious SAS.

Subinvolution of Placental Sites Bonus Material Client Education
Sheet
Online

Clinical Presentation
BASIC INFORMATION • Any age but more prevalent after the first
parturition, especially in bitches < 3 years HISTORY, CHIEF COMPLAINT
Definition old • History of recent whelping or abortion
Persistent bright red, bloody vulvar discharge is • Litter size has no effect. • Hemorrhagic vulvar discharge is persistent
usually observed in young primiparous bitches even after pups are weaned.
with failure of or delayed uterine involution GENETICS, BREED PREDISPOSITION • Bitch is otherwise in good health.
beyond 12 weeks after whelping. These dogs are No breed predisposition
not systemically ill unless the retained placental PHYSICAL EXAM FINDINGS
remnants become infected or there is severe RISK FACTORS • Bright red discharge rather than normal
uterine bleeding (metrorrhagia). Low parity (especially after the first pregnancy) brown lochia
• Slight pallor of mucous membranes if
Synonyms ASSOCIATED DISORDERS discharge is copious
Postpartum metrorrhagia, postpartum placen- • Anemia (rarely hemorrhage is so severe that • Abdominal palpation may reveal discrete
titis, SIPS it requires a hysterectomy) uterine swellings of various sizes.
• Postpartum metritis (secondary to infected • Physical exam generally reveals an otherwise
Epidemiology placental remnants) healthy animal.
SPECIES, AGE, SEX • Uterine rupture can occur as a result of SIPS
• Incidence in dogs (histopathologic evaluation (rare). Etiology and Pathophysiology
of postpartum uteruses): 8%-21% • Normally, expulsion of the fetal membranes
○ Does not occur in cats and lochia occurs immediately postpartum,

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