Case Description—A 7-year-old domestic shorthair cat with a 2-month history of decreased appetite and weight loss was examined because of paraparesis of 1 week's duration that had progressed to paraplegia 3 days earlier.
Clinical Findings—Neurologic examination revealed normo- to hyperreflexia and absence of deep pain sensation in the hind limbs and thoracolumbar spinal hyperesthesia. Neuro-anatomically, the lesion was located within the T3 through L3 spinal cord segments. Biochemical analysis and cytologic examination of CSF revealed no abnormalities. Radiography revealed narrowing of the T11-12 intervertebral disk space and intervertebral foramen suggestive of intervertebral disk disease. Myelography revealed an extradural mass centered at the T12-13 intervertebral disk space with extension over the dorsal surfaces of T11-13 and L1 vertebral bodies.
Treatment and Outcome—A right-sided hemilaminectomy was performed over the T11-12, T12-13, and T13-L1 intervertebral disk spaces, and a space-occupying mass was revealed. Aerobic bacterial culture of samples of the mass yielded growth of a yeast organism after a 10-day incubation period; histologically, Histoplasma capsulatum was identified. Treatment with itraconazole was initiated. Nineteen days after surgery, superficial pain sensation and voluntary motor function were evident in both hind limbs. After approximately 3.5 months, the cat was ambulatory with sling assistance and had regained some ability to urinate voluntarily.
Clinical Relevance—In cats with myelopathies that have no overt evidence of fungal dissemination, differential diagnoses should include CNS histoplasmosis. Although prognosis associated with fungal infections of the CNS is generally guarded, treatment is warranted and may have a positive outcome.
A 9-year-old spayed female Golden Retriever developed a mass on the right mandible. At the time that the owner noticed the mass, it was not associated with signs of pain, and the dog was eating and drinking without difficulty. Although the mass did not change considerably over the next 4 months, the dog was examined by a veterinarian and 2 needle biopsy specimens were obtained for histologic evaluation. The histopathologic diagnosis was inconclusive. The dog was then referred to the University of Minnesota Veterinary Medical Center to undergo computed tomography of the head and for possible excision of the
Objective—To determine the clinical, radiographic,
ultrasonographic, and arthroscopic findings associated
with tenosynovitis of the carpal synovial sheath
induced by exostoses that originate from the caudal
surface of the physeal scar of the distal radius and
determine the results of surgical removal of those
exostoses in horses.
Procedure—Medical records of horses with effusion
in the carpal synovial sheath and lameness evaluated
from 1999 to 2003 were examined.
Results—All horses had a history of intermittent mild
to moderate effusion of the carpal synovial sheath
and lameness of 1 forelimb. Results of regional perineural
and intrathecal anesthesia of the carpal synovial
sheath confirmed that the lameness originated
in the carpal synovial sheath. Radiography revealed
exostoses originating from the caudal cortex of the
distal radius at the level of the closed physis.
Arthroscopy was performed for confirmation and
removal of exostoses that penetrated the carpal synovial
sheath and impinged on the deep digital flexor
tendon. All horses returned to previous athletic activity.
One horse had a recurrence of clinical signs 12
months after surgery, which resolved with medical
Conclusions and Clinical Relevance—Tenosynovitis
of the carpal synovial sheath and lameness were
caused by impingement of exostoses of the caudal
radius on the lining and contents of the carpal synovial
sheath. Although the clinical signs and surgical treatment
were similar to that caused by osteochondromas,
these exostoses developed at the level of the
closed physis of the distal radius and were not radiographically
or histologically similar to osteochondromas.
(J Am Vet Med Assoc 2004;224:264–270)
A 634-g (1.4-lb) 14-month-old castrated male ferret was evaluated because of lethargy, decreased appetite, and a 2-cm-diameter nodular mass in the inguinal area. The ferret was anesthetized via IM administration of buprenorphine hydrochloride and inhalation of isoflurane and oxygen, and a punch biopsy specimen of the mass was obtained. Sections of the biopsy specimen were stained with H&E or Gram stain for bacteria. The results of the histologic examination were indicative of pyogranulomatous steatitis; a few intralesional cocci were present in the mass tissue. Clarithromycin was administered orally twice daily to the ferret, and the mass decreased in size
To describe the radiographic appearance of benign bone infarcts and bone infarcts associated with neoplasia in dogs and determine the utility of radiography in differentiating benign and malignancy-associated bone infarcts.
49 dogs with benign (n = 33) or malignancy-associated (16) infarcts involving the appendicular skeleton.
A retrospective cohort study was performed by searching a referral osteopathology database for cases involving dogs with a histologic diagnosis of bone infarction. Case radiographs were anonymized and reviewed by 2 board-certified veterinary radiologists blinded to the histologic classification. Radiographic features commonly used to differentiate aggressive from nonaggressive osseous lesions were recorded, and reviewers classified each case as likely benign infarct, likely malignancy-associated infarct, or undistinguishable.
Only 16 (48%) of the benign infarcts and 6 (38%) of the malignancy-associated infarcts were correctly classified by both reviewers. Medullary lysis pattern and periosteal proliferation pattern were significantly associated with histologic classification. Although all 16 (100%) malignancy-associated lesions had aggressive medullary lysis, 23 of the 33 (70%) benign lesions also did. Eight of the 16 (50%) malignancy-associated infarcts had aggressive periosteal proliferation, compared with 7 of the 33 (21%) benign infarcts.
CONCLUSIONS AND CLINICAL RELEVANCE
Results suggested that radiography was not particularly helpful in distinguishing benign from malignancy-associated bone infarcts in dogs.
The carcass of a 14-month-old 18.5-kg female capybara (Hydrochoerus hydrochaeris) with a history of hind limb lameness for several days prior to sudden death was presented for necropsy. The capybara was born and raised at a privately owned petting zoo that housed a small herd of capybaras along with several other exotic species, including Patagonian maras, emus, and alpacas. The owner reported feeding the capybaras a diet of pelleted horse feed, a commercial macropod food, dog food, corn on the cob, lettuce, timothy hay, Bermuda grass, and various fruits and vegetables. The owner also reported that this
A 28-year-old Quarter Horse gelding was evaluated at the Texas A&M University Veterinary Medical Teaching Hospital because of an episode of colic of 1 day's duration. The horse had a history of trauma; 1 week previously, the horse was reported to have pulled back on the crossties and injured its neck.
On initial evaluation, the horse had a high heart rate (60 beats/min) and high respiratory rate (42 breaths/min). The horse's rectal temperature was within reference limits. The horse held its neck in an extended and horizontal position and was reluctant to move its head in any direction. The
A 5-year-old 6.15-kg (13.53-lb) castrated male red-dilution domestic shorthair cat was evaluated because of a nonhealing proliferative wound on the right ear of 5 months' duration. The lesion began as a small cut, presumably due to self-trauma, but increased in size over time with repeated injury. Aside from the lesion on the ear, the cat was otherwise healthy and negative for FeLV antigen and anti-FIV antibody. The cat's vaccination status was current; it was maintained on a parasite prevention regimen but was not receiving any additional medications. The cat had been adopted 1 year prior from a local animal
Objective—To compare macrostructural and microstructural features of proximal sesamoid bones (PSBs) from horses with and without PSB midbody fracture to gain insight into the pathogenesis of PSB fracture.
Sample Population—PSBs from 16 Thoroughbred racehorses (8 with and 8 without a PSB midbody fracture).
Procedures—Parasagittal sections of fractured and contralateral intact PSBs from horses with a PSB fracture and an intact PSB from age- and sex-matched control horses without a PSB fracture were evaluated for visual, radiographic, microradiographic, histologic, and his-tomorphometric differences in bone porosity, vascular channels, heme pigment, trabecular anisotropy, and pathological findings.
Results—Fractured PSBs and their contralateral intact PSBs had more compacted trabecular bone than did control PSBs. Focal repair or remodeling was evident in the palmar aspect of many fractured and contralateral intact PSBs. Fracture coincided with microstructural features and propagated from the flexor to the articular surface.
Conclusions and Clinical Relevance—Fractured PSBs had adapted to high loading but had focal evidence of excessive remodeling and porosity that likely predisposed the horses to complete fracture and catastrophic injury. Detection of focal injury before complete fracture provides an opportunity for prevention of catastrophic injury. Development of diagnostic imaging methods to assess porosity of PSBs may help to identify at-risk horses and allow for modifications of training and racing schedules to reduce the incidence of PSB fracture in Thoroughbred racehorses.