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724.e2 Osteogenesis Imperfecta

Osteogenesis Imperfecta Client Education
Sheet
VetBooks.ir

DIAGNOSIS
quantitative computerized tomography (CT)
BASIC INFORMATION
demonstrated increased bone density after
Definition Diagnostic Overview 4 weekly injections of 1 mg/kg of Pamiron
Osteogenesis imperfecta (OI) is an inherited This rare disorder should be considered when (BCWorld Pharm, Korea).
disorder leading to excessive bone fragility with young pups or kittens develop multiple frac- • Vitamin C 75 mg/kg PO q 24h has been
frequent pathologic fractures beginning early tures with minimal trauma, often on separate attempted in a cat with OI, but the kitten
in life. Rarely reported in cats and dogs, the occasions. Genetic testing is not commercially was euthanized 45 days later due to new
disorder and its variants are well described in available at this time. Because there is no readily fractures.
humans. available specific test, OI is largely a diagnosis
of exclusion after ruling out other causes for Behavior/Exercise
Synonyms multiple or pathologic fractures (see Differential Restrict activity because even minimal trauma
OI, brittle bone disease, fragile bone disease Diagnosis). can precipitate bone fractures.
Epidemiology Differential Diagnosis Possible Complications
SPECIES, AGE, SEX • Trauma, including abuse (repeated, multiple • Pain
Dogs or cats of either sex develop multiple fractures) • Bruising
fractures beginning weeks to months after birth. • Nutritional secondary hyperparathyroidism • Poor growth or weight loss if unable to easily
(p. 697) move toward or eat food
GENETICS, BREED PREDISPOSITION • Renal secondary hyperparathyroidism
• Cats: no reported breed predisposition • Rickets (vitamin D deficiency) and vitamin PROGNOSIS & OUTCOME
• Dogs: beagle (sporadic mutation affecting D–resistant rickets
heterozygote), collie, dachshund (autosomal • Generalized fibrous osteodystrophy Poor
recessive), golden retriever (autosomal • Osteoporosis
dominant), poodle, Norwegian elkhound, PEARLS & CONSIDERATIONS
and Bedlington terrier Initial Database
• CBC: no specific findings Comments
ASSOCIATED DISORDERS • Serum chemistry profile: no biochemical For a young animal presenting with multiple
Respiratory difficulty due to broken ribs may abnormalities detected fractures, consider referral to a veterinary
occur. ○ Use age appropriate reference intervals specialist early in the disease course if the pet’s
○ Calcium and phosphorous are normal for owners wish to continue care.
Clinical Presentation age
DISEASE FORMS/SUBTYPES • Radiographs: multiple fractures in various Prevention
In humans, several distinct clinical subtypes stages of healing, cortices that are less opaque Do not breed affected animals.
are recognized, ranging from mild forms with than expected for age
occasional fractures to severe forms that are Technician Tips
often fatal in utero or shortly after birth. These Advanced or Confirmatory Testing • Extremely gentle handling is necessary, but
subtypes are not recognized in pet animals, but • Parathyroid hormone (PTH) and vitamin D even so, fractures may occur. Use minimal
there are likely more or less severely affected concentrations to rule out other conditions restraint.
dogs and cats. • Genetic testing for specific mutations • Do not place pup or kitten in a top cage, and
(research setting) never leave on exam table or other elevated
HISTORY, CHIEF COMPLAINT • Necropsy demonstrates thin cortical and surface.
Acute lameness and/or pain in a young animal trabecular bone
is often recognized after minimal trauma, such Client Education
as jumping off a chair. Often, a first fracture is TREATMENT This condition is neither curable nor readily
treated in a routine manner, only to be followed amenable to treatment, and euthanasia should
by additional fractures of other bones. Diet history Treatment Overview be considered for humane reasons.
is useful in ruling out other causes of disease. There is no cure for OI, and euthanasia is a
• Lameness reasonable consideration. SUGGESTED READING
• Pain Kamoun-Goldrat AS, et al: Animal models of
• Broken teeth Acute General Treatment osteogenesis imperfect and related syndromes. J
• Analgesia for pain associated with bone Bone Miner Metab 25:211-218, 2007.
PHYSICAL EXAM FINDINGS fractures (e.g., meloxicam 0.1 mg/kg PO
• Fractured long bones loading dose day 1, followed by 0.05 mg/kg ADDITIONAL SUGGESTED
• Rib fractures/pain q 24h)
• Fractured teeth • Stabilize broken bones with splints and/or READINGS
• Translucent or slightly pink color to teeth bandages. Cohn LA, et al: Bone fragility in a kitten: an
• ± Blue tinge to sclera • Crate rest for femur and axial fractures osteogenesis imperfecta-like syndrome. J Am Vet
Med Assoc 197:98-100. 1990.
Etiology and Pathophysiology Chronic Treatment Evason MD, et al: Suspect osteogenesis imperfecta
in a male kitten. Can Vet J 48:296-298. 2007.
Mutations in genes coding for type 1 collagen • Bisphosphonate therapy is used in humans, Haase B, et al: Digging for known genetic muta-
lead to fragile bones that break spontaneously with some improvement in bone density and tions underlying inherited bone and cartilage
or with minimal trauma. Distinct subtypes have reduction in fracture. In a single cat with characteristics and disorders in the dog and cat.
not been recognized in pets. a relatively late diagnosis (1 year of age), Vet Comp Orthop Traumatol 29:269-276. 2016.

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