Page 1027 - Cote clinical veterinary advisor dogs and cats 4th

Hypertrophic Osteodystrophy 507

• Echocardiogram: q 3-12 months, depending studies but varies greatly. Cats surviving the despite a normal genotype due to an unidenti-
on severity of HCM; monitor left atrial first month after ATE and then placed on fied mutation.
VetBooks.ir or ATE. Monitor LVH to assess possible (median, 443 days; recurrence rate, 43%) Technician Tips Diseases and Disorders
clopidogrel had longer time to recurrent ATE
size as risk factor for development of CHF
progression of disease or assess potential
than cats treated with aspirin (median, 192
• Cats with HCM and CHF tend to be very
antihypertrophic therapeutic effects.
mize stress. For thoracocentesis, cats may be
clinical trial.
• If systemic hypertension or hyperthyroid- days; recurrence rate, 75%) in the FATCAT fragile and require careful handling to mini-
ism is present, a recheck echocardiogram maintained in a comfortable sternal position
3-4 months after cat is normotensive or PEARLS & CONSIDERATIONS with minimal but effective restraint; mild
euthyroid; should show regression of LVH. sedation with butorphanol and midazolam
If hypertrophy is still present, the cat has Comments may be considered.
concurrent HCM, or there is incomplete • Wide range of severity and progression of • Blood pressure measurement should be
control of the systemic disorder. HCM in individual cats, which explains the performed before other diagnostic tests,
• Systemic blood pressure and serum thyroxine large number of cats with this disease that with minimal but effective restraint/stress.
q 6-12 months (adult HCM cats). Systemic live a normal life. • Review with the owner techniques for admin-
hypertension and hyperthyroidism can • In a multicenter, prospective, randomized, istering oral medications because many cats
worsen LVH but in a reversible way (see and blinded study, neither ACE inhibitors, with heart failure are on multidrug therapy. If
above). atenolol, nor diltiazem were shown to clopidogrel is prescribed, discuss with owner
• If arrhythmia: recheck ECG to assess emer- improve survival over furosemide alone that clopidogrel is bitter, and provide tips
gence of new arrhythmia +/− response to for cats with severe HCM and CHF or for administering it, such as placing in a gel
antiarrhythmic therapy. ATE. cap or pill pocket, and avoiding crushing or
• Pimobendan appears to benefit many cats putting in liquid.
PROGNOSIS & OUTCOME with refractory CHF but can worsen left
ventricular outflow tract obstruction (if SAM Client Education
• Fair to good prognosis for cats with mild is present) and cause hypotension. • In cats with CHF, teaching clients to monitor
nonprogressive HCM. Cats with HCM and • Avoid long-acting glucocorticoid injections; resting respiratory rate (RRR) and respiratory
no clinical signs have a median survival time avoid large volumes of SQ fluids (>100 mL) effort is helpful. Owner should contact the
of 3 to > 5 years. in cats with subclinical HCM. doctor when rates are consistently > 30-35
• Outcome for 647 occult HCM cats over 5 • Anesthetic considerations: avoid high fluid breaths/min. Technicians can review client-
years: 17% (3.4%/yr) developed CHF; 8.5% rates (e.g., 5 mL/kg/h for low rate) and drugs monitored RRR logs when calling back for
(1.7%/yr) developed ATE; all-cause cardiac that cause tachycardia. Consider induction updates or during recheck exams.
mortality was 22% (4.4%/yr). with midazolam and propofol, Alfaxan, or • Advise about risk of sudden death and ATE.
• Young male cats and Ragdoll cats with etomidate; maintenance with isoflurane It is difficult to prevent ATE when severe
significant LVH often progress more rapidly underlying cardiac disease is present.
and die from their disease (often by 4 years Prevention
of age). Genetic screening tests are available for Maine SUGGESTED READING
• Severe HCM and CHF: poor long-term coon cats and Ragdolls. Breeding programs Hogan DF, editor: The feline heart. J Vet Cardiol
prognosis; median survival of 3 months, should be aimed at eliminating genetically 17(suppl 1):1760-2734, 2015.
although survival times vary greatly, with affected cats. Echocardiograms are necessary
over 2 years in some cats. to screen potential breeding candidates in all AUTHOR: Kristin A. MacDonald, DVM, PhD, DACVIM
• Severe HCM and ATE: poor prognosis; breeds, including Maine coon cats and Ragdoll EDITOR: Meg M. Sleeper, VMD, DACVIM
median survival time of 2 months in early cats because some of these cats may have HCM

Hypertrophic Osteodystrophy Client Education
Sheet

BASIC INFORMATION GENETICS, BREED PREDISPOSITION HISTORY, CHIEF COMPLAINT
• Large and giant breeds • Acute onset of swelling of the distal ante-
Definition • Great Danes predisposed brachial and/or distal tibial metaphyseal
A disease of the long bones of rapidly growing • Reported in litters of Weimaraner puppies regions (generally bilateral)
dogs, causing disruption of metaphyseal trabecu- • Peracute refusal to stand, anorexia, signs of
lae, often accompanied by systemic inflammation RISK FACTORS pain, or
Rapid rate of growth; association with recent • Low-grade lameness of short duration
Synonyms vaccination suggested in some
HOD, metaphyseal osteopathy, Barlow’s disease, Clinical Presentation PHYSICAL EXAM FINDINGS
canine skeletal scurvy, idiopathic osteodystro- • Fever: temperature often ≥ 104°F (≥ 40°C)
phy, Moeller-Barlow disease, osteodystrophy DISEASE FORMS/SUBTYPES • Metaphyses (most commonly of distal radius,
types I and II • Lameness ± systemic disease ulna, and tibia) swollen, hot, painful on
• Some Weimaraners: vaccine-associated onset palpation
Epidemiology • Rarely, severe systemic disease with secondary • Peracute cases can show lethargy, dehydra-
SPECIES, AGE, SEX sepsis tion, and severe pain.
• Dogs 2-8 months old; males > females
• Occasionally reported in kittens

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