Immune-based non-erosive inflammatory joint disease of the dog. 3. Canine idiopathic polyarthritis

The features of 67 cases of canine idiopathic polyarthritis are described. Idiopathic polyarthritis includes cases of non-infective polysynovitis which cannot be classified into more defined groups. It most often affects young adult dogs, and pyrexia, inappetence and lethargy are exhibited as well as lameness. Radiography usually shows soft tissue changes. Four types are identified according to certain associations; Type I (uncomplicated), Type II (infection elsewhere in the body), Type III (gastro-intestinal disease) and Type IV (neoplastic disease elsewhere in the body). Steroids and/or cytotoxic drugs are used for treatment.     

Type I immune-mediated polyarthritis in dogs: 39 cases (1997-2002)

OBJECTIVE: To determine clinical signs, laboratory findings, relationship to vaccination, and response to treatment for type I immune-mediated polyarthritis (IMPA) in dogs. DESIGN: Retrospective study. ANIMALS: 39 dogs PROCEDURE: Clinical records and radiographic reports from 3 university referral hospitals were reviewed. Clinical signs, laboratory and investigative findings, relationship to vaccination, and response to treatment were evaluated. RESULTS: Clinical signs and initial laboratory and clinical investigative findings were frequently abnormal but were nonspecific and not associated with likelihood of recovery. Time of vaccination was not associated with onset of disease. Chemotherapeutic immunosuppression resulted in complete cure in 56% of dogs. Continuous medication was required in 18% (7/39) of dogs, relapses were treated successfully in 13% (5/39) of dogs, and 15% (6/39) of dogs died or were euthanatized as a result of disease. CONCLUSIONS AND CLINICAL RELEVANCE: The possible involvement of vaccination in type I IMPA was not made clear from this study because of the small population size. Signalment, clinical signs, and results of diagnostic tests other than multiple synovial fluid analyses were generally nonspecific. Most dogs with type I IMPA responded to initial immunosuppressive treatment, but 31% (12/39) of dogs relapsed, required further treatment, or both.     

Polyglucosan body disease in a mixed-breed dog

AIM: To describe the histopathology of a previously unrecorded canine disease and deduce the cause of the lesions. METHODS: Formalin-fixed tissues were processed into paraffin wax and epoxy resin for light and electron microscopy of variously stained sections of liver, brain, heart muscle and kidney. RESULTS: Periodic acid Schiff (PAS) -positive bodies in liver and myocardium were typical of a polyglucosan body disease. Neurons contained coarse granular material that stained similarly to the polyglucosan bodies. CONCLUSION: The nature, distribution and histochemistry of lesions observed are consistent with a putative diagnosis of Glycogen storage disease type IV, an inherited metabolic defect associated with a deficiency of glycogen-branching enzyme not previously reported in dogs.     

Collie eye anomaly in a mixed-breed dog

A 5-year-old, mixed-breed dog was presented for tetraparesis. Neurologic alterations included a decreased menace response in both eyes. Therefore, an ophthalmic examination was requested. The dog was visual, but menace response, dazzle and pupillary light reflexes were reduced bilaterally. Indirect ophthalmoscopy revealed bilateral optic nerve coloboma and severe choroidal hypoplasia. These lesions closely resembled the ophthalmoscopic features of Collie eye anomaly (CEA). In spite of treatment, the dog's condition worsened and the animal was therefore euthanized. Histology of the globes confirmed severe choroidal hypoplasia and optic disc coloboma in both eyes. The dog was diagnosed to have a lymphoma involving the spinal cord. The two entities were considered not related. As only moderate sight impairment was caused by the posterior segment anomalies, it is by chance that these lesions resembling CEA were found in this mixed-breed dog.     

Steroid-responsive meningitis-arteritis in dogs with noninfectious,nonerosive, idiopathic,immune-mediated polyarthritis

Signs related to spinal pain are commonly reported in dogs with noninfectious, nonerosive, idiopathic immune-mediated polyarthritis (IMPA). This study examined the prevalence and etiology of spinal pain in these dogs through a retrospective review of 62 case records of dogs with IMPA. All dogs with IMPA and signs suggestive of spinal pain were described with regard to age, gender, breed, physical stature, location of vertebral pain, rectal temperature, and clinical laboratory findings. The prevalence of spinal pain in these dogs was 29% (18 of 62). Fourteen of the 18 dogs with spinal pain and IMPA were male. Cerebrospinal fluid (CSF) from 11 dogs with signs of spinal pain was analyzed. Five of these (46%) had concurrent steroid-responsive meningitis-arteritis (SRMA). We concluded that SRMA does occur concurrently in some dogs having IMPA. Meningeal involvement may explain the origin of spinal pain observed in some of these dogs.     

Leishmanial polyarthritis in a dog

A dog adopted as a stray in Spain and then brought to Canada 4 years prior to presentation was evaluated for polyarthritis. An electrophoresis showed a marked polyclonal gammopathy and synovial smears contained leishmanial organisms within macrophages.     

Bilateral ectrodactyly and spinal deformation in a mixed-breed dog

A 3-year-old, female mixed-breed dog had malformations of both thoracic limbs and the vertebral column. Radiographs of the forelimbs showed bilateral development of 2 digits and aplasia of 3 carpal bones. Kyphosis, scoliosis, and deformed vertebrae were present in the thoracolumbar vertebral column.     

Thrombopathies causing bleeding in a boxer and mixed-breed dog

Hereditary platelet function disorders are clinically characterized by recurrent surface bleeding and prolonged bleeding time, despite normal platelet count and coagulation tests. The authors describe persistent thrombopathies in two young dogs with increased bleeding tendencies but with normal plasma coagulation times and von Willebrand factor (vWf) concentrations. Buccal mucosal bleeding times were prolonged in both dogs. In aggregation studies, platelets underwent only a shape change or minimal aggregation in response to adenosine diphosphate and collagen. Whole-platelet adenine nucleotide concentrations were normal. Electron microscopic evaluation of fibrinogen and vWf binding to the platelets of case no. 1 demonstrated the presence of glycoprotein IIb/IIIa and Ib receptors. Thus, the intrinsic platelet function defects may be different in these two dogs and may likely represent secretion/signal transduction disorders.     

Ehrlichia canis-related polyarthritis in a dog

Ehrlichia canis-related polyarthritis was diagnosed in a 7-month-old Boxer. The diagnosis was based on intraneutrophilic morulae found in synovial fluid specimens, thrombocytopenia, a positive result for indirect fluorescent antibody testing for E canis, the presence on the dog of the known vector of E canis infection (Rhipicephalus sanguineus), and a favorable response to treatment with tetracycline hydrochloride. The dog has had no recurrence of lameness for 18 months after cessation of treatment.     

Chlamydia-induced septic polyarthritis in a dog

A systemic disease associated with pyrexia, lymphadenopathy, and arthropathy of several joints of the appendicular skeleton in a dog is described. Chlamydia-like organisms were detected on light-microscopic examination of a smear made from joint fluid aspirated from one of the affected joints. A group-specific lipopolysaccharide antigen shared by all Chlamydia spp. was demonstrated by direct fluorescent antibody staining of joint fluid, which also proved positive for chlamydia by means of the relevant polymerase chain reaction test. An indirect fluorescent antibody test on serum was also positive, although the complement fixation test was negative. Attempts to grow the organism from joint aspirates in the yolk sac of embryonating hens' eggs and on appropriate tissue cultures, however, failed. Chlamydia spp. are considered to have played an aetiological role in this case, making it the first substantiated case of naturally-occurring arthropathy in a dog due to chlamydiosis. The origin of the infection could not be traced.     

Progressive polysystemic immune-mediated disease in a dog

A dog with polyarthritis, angular joint deformities, and a high serum antinucleolar antibody titer was treated over a period of 20 months. During the clinical course, leukopenia, thrombocytopenia, Coombs' positive hemolytic anemia, and a pemphigus-type skin disorder developed, all of which responded to immunosuppressive therapy. It is not known whether the polysystemic disease in this dog represents a pleomorphic manifestation of canine systemic lupus erythematosus or multiple autoimmune disorders occurring in the same animal.     

Neuronal vacuolation, myelopathy and laryngeal neuropathy in a mixed-breed dog

A bilateral and symmetrical neuronal vacuolation associated with spinal cord white matter degeneration and laryngeal neuropathy was observed in a 12-week-old male mixed-breed dog with a history of progressive pelvic limbs ataxia. On clinical examination, signs included inspiratory stridor, spinal ataxia, tetraparesis, and proprioceptive deficits more severe in the pelvic limbs. Examination of the larynx showed bilateral laryngeal paralysis and electromyography revealed fibrillation potentials restricted to the intrinsic laryngeal muscles. Clinical and pathological findings resembled the syndrome of neuronal vacuolation and spinocerebellar degeneration described in Rottweiler dogs. This is the first report of a similar disorder in a dog different from Rottweiler.     

Destructive polyarthritis in a dog with leishmaniasis

The clinical history and diagnosis of a dog with leishmaniasis involving both elbow joints and the skin is described. The dog, a female, five-year-old crossbreed, had been imported from Majorca (Balearic Islands, Spain) four years before the diagnosis was made. For two years, the dog had had bilateral forelimb lameness. Physical examination revealed swollen, painful and crepitating elbow joints. Furthermore, an ulcerating dermatitis was found on the concave surface of the left pinna and necrotising margins on both ears. Radiographs of the elbow joints revealed complete destruction of the joint surfaces with dislocation of the radius and the ulna, compatible with severe osteolytic arthritis. The diagnosis of leishmaniasis was confirmed by a direct agglutination test.     

Isotretinoin in the treatment of multiple benign pilomatrixomas in a mixed-breed dog

An 18-month-old cross-breed dog developed multiple skin nodules, which over 8 months had increased in size and number. Biopsy samples were submitted for histopathological examination and revealed multiple benign pilomatrixomas. The dog was treated with 1 mg kg(-1) isotretinoin daily, which led to a stabilization of the size and number of the lesions. Attempts to lower the dosage to an every other day regimen led to an increase in the nodules' size and number. Monthly complete blood count and chemistry tests and Schirmer tear tests were performed to monitor any adverse effects of the retinoid treatment. No adverse effects were noted. To the authors' knowledge, this is the first report of multiple pilomatrixomas arising in a young dog and successfully controlled with oral retinoids.     

Arthroscopic management of septic polyarthritis in a dog

A 4 1/2-month-old male Neapolitan Mastiff was presented with a history of severe non weight-bearing lameness, depression and anorexia, following 6 weeks of intermittent thoracic limb lameness that had deteriorated in the previous 72 hours. Haematogenous septic polyarthritis involving the right elbow joint and left glenohumeral joint was diagnosed, with blood and joint cultures revealing a Pasteurella species. Arthroscopy was utilised to facilitate joint evaluation and effect drainage of both joints. Clinical remission was achieved within 48 hours. Arthroscopy provided a minimally invasive yet thorough joint examination, lavage, and drainage of fibrinopurulent debris, thereby allowing early postoperative mobility and minimal morbidity.     

Suspected immune-mediated megakaryocytic hypoplasia or aplasia in a dog

Megakaryocytic hypoplasia or aplasia causing thrombocytopenia was diagnosed in a 3-year-old Miniature Poodle with scleral hemorrhage, melena, ecchymoses, and blood-loss anemia. Immunosuppressive, cytotoxic, and lithium carbonate therapy resulted in successful correction of the dog's disease. It is important to recognize megakaryocytic hypoplasia or aplasia as the cause of thrombocytopenia, since the response to therapy will be slower when there is stem cell injury.     

Nodular dermatofibrosis and cystic renal disease in three mixed-breed dogs and a Boxer dog

Three mixed-breed dogs and a Boxer dog with nodular dermatofibrosis are described. The three mixed breed dogs had concurrent renal epithelial cysts ( n  = 2) or renal cystadenomas ( n  = 1); these lesions were visualized antemortem on ultrasonographic examination. One of these dogs was a 7-year-old Labrador Retriever-Gordon Setter mixed breed which survived 5 years after diagnosis, and was euthanized for unrelated causes. The Boxer dog had renal cystic adenomatous hyperplasia and renal cystadenocarcinomas which were not visualized on ultrasonographic examination but were diagnosed at necropsy.     

Cyclic hematopoiesis in a mixed-breed dog: case report and brief review

An 8-wk-old, male, mixed-breed puppy was adopted from a rescue organization. From the time of adoption, the puppy suffered episodes of illness affecting various organ systems, which resolved with supportive therapy but relapsed once medical therapy was discontinued. Review of the hematologic data revealed cyclic fluctuations in circulating blood cells. Cyclicity was most prominent in neutrophils, with recurrent severe neutropenia. Neutropenic episodes lasted 5–6 d, with regular cycles of 11–14 d between nadir neutrophil counts. Genetic testing determined that the patient was homozygous mutant for the frameshift mutation in the adaptor protein complex 3 β-subunit (AP3B1) gene, originally identified in gray collies with cyclic hematopoiesis (CH). Pedigree information was not available, but the patient’s features were phenotypically distinct from those of collies. We describe here a case of the AP3B1 mutation in a mixed-breed dog that did not resemble a collie, undescribed previously, to our knowledge. Our findings indicate that the AP3B1 mutation and CH are present within the general canine population and are not restricted to collies.