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766 Pattern Alopecia, Canine

• Iatrogenic: surgical hemorrhage, occlusion
device embolization into the aorta or a
VetBooks.ir arteriotomy site
pulmonary artery branch, hematoma at

* D A * PROGNOSIS & OUTCOME
• Types 1-3A: 90%-98% successful correction
P with experienced interventionalist/surgeon.
After correction, most will live a normal life
span.
• Type 3B: 98% initially successful if heart
failure and arrhythmia are controlled pre-
operatively and can live for years but life
span is usually shortened
A B • Type 4: may live for years if erythrocytosis
is controlled
PATENT DUCTUS ARTERIOSUS Aortic injection angiograms in a dog with PDA before (A) and after (B)
PDA occlusion with a canine ductal occluder by a catheter-based (minimally invasive) approach. A, An injection PEARLS & CONSIDERATIONS
of contrast through a catheter in the aorta (arrow) opacifies the aorta (A), PDA (D), and pulmonary arteries
(P), demonstrating patency of the ductus. A measuring catheter (asterisks) is placed in the esophagus for scale Prevention
(1-cm markers). B, The ductal occluder (arrow) has been deployed, and an aortic injection demonstrates absence Avoid breeding affected animals.
of flow through the PDA. (Image courtesy Dr. Etienne Côté, copyright 2013.)
Technician Tips
PDA closure confers an important survival
benefit for affected animals, with similar results
whether the procedure is performed with a
Chronic Treatment Possible Complications thoracotomy or minimally invasive approach.
Type 4: • Uncontrolled (type 1-3): refractory CHF,
• Sildenafil 1-2 mg/kg q 8h may reduce severity refractory arrhythmias SUGGESTED READING
of pulmonary hypertension and therefore • Uncontrolled (type 4): complications caused Buchanan JW: Patent ductus arteriosus: morphology,
right-to-left shunting (pp. 838 and 1274). by hyperviscosity (p. 509) pathogenesis, types and treatment. J Vet Cardiol
• Hydroxyurea to suppress erythrocytosis at the • Pulmonary artery dissection may be a rare 3:7-16, 2001.
bone marrow level 25-30 mg/kg PO every complication of uncorrected PDA in dogs. AUTHOR: James W. Buchanan, DVM, M Med Sci,
other day; titrated downward as needed based Closure of the duct appears to improve DACVIM
on resulting hematocrit outcome. EDITOR: Meg M. Sleeper, VMD, DACVIM

Pattern Alopecia, Canine

BASIC INFORMATION • Alopecia and melanoderma of Yorkshire • CPA, pinnal type: progressive alopecia of
terriers is breed specific. the convex aspect of the ear pinnae, starting
Definition around 6 months of age. Alopecia of the
Canine pattern alopecia (CPA) is a relatively Clinical Presentation bridge of the nose also can occur.
common, likely heritable, noninflammatory DISEASE FORMS/SUBTYPES • Alopecia and melanoderma of Yorkshire
alopecic disorder of specific breeds. It encom- • The two main forms of CPA are the ventral terriers: alopecia and hyperpigmentation
passes several distinct syndromes. type, the most common syndrome, and the of the convex aspect of the ear pinnae and
pinnal type. the bridge of the nose
Synonyms • Alopecia and melanoderma of Yorkshire
CPA, canine pattern baldness terriers is clinically very similar to CPA, Etiology and Pathophysiology
pinnal type, and it is most likely the same CPA may be an overshoot reaction to artificial
Epidemiology disorder. selection pressure favoring the fine, delicate
SPECIES, AGE, SEX coat sought by breeders. Over past decades,
• Dogs of either sex and of any reproductive HISTORY, CHIEF COMPLAINT smooth-hair dachshund breeders have been able
status Dogs born with a normal hair coat are presented to markedly decrease the incidence of CPA,
• Early onset (usually < 1 year of age) for evaluation of a gradual thinning of the coat ventral type, by selective breeding, but as a
in specific body areas. result, dogs generally have a coarser haircoat.
GENETICS, BREED PREDISPOSITION
• CPA, ventral type, is seen in dogs with fine, PHYSICAL EXAM FINDINGS DIAGNOSIS
short coats such as dachshunds, Chihuahuas, • CPA, ventral type: progressive alopecia
miniature pinschers, whippets, greyhounds, developing along the ventral neck, thorax, Diagnostic Overview
Boston terriers, and boxers. abdomen, caudomedial aspect of thighs, The diagnosis is based on history, dermatologic
• CPA, pinnal type, is seen mainly in perineum, and postauricular regions (base exam, and exclusion of endocrinopathies and
dachshunds. of the ear pinnae) inflammatory diseases such as alopecia areata.

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