Polyarteritis Nodosa in a Cat with Involvement of the Central and Peripheral Nervous Systems

An 18-month-old neutered male domestic shorthair cat was referred with a history of pyrexia, polyuria and polydypsia, and transient episodes of bilateral hindlimb paralysis. Cardiac evaluation revealed severe systemic hypertension and severe concentric hypertrophy of the left ventricle. One month later the cat had a new episode of hindlimb paralysis with recurrent seizures, and died in status epilepticus. At necropsy examination, the coronary arteries, arcuate renal arteries and common iliac arteries showed marked thickening with nodules segmentally located along the vessels and consequent narrowing of the lumina. Histologically, acute and chronic inflammatory infiltration of the vascular walls was associated with necrosis of the muscular layer. Lesions were consistent with polyarteritis nodosa and involved the small, medium and large arteries of the heart, kidneys, small and large intestine, mesentery, liver and thyroid. Multifocal meningeal vasculitis associated with focal infarction of the frontal lobe and necrotizing vascular polyneuropathy were detected. Involvement of the central and peripheral nervous systems in polyarteritis nodosa is a novel finding in cats.

Hemorrhage in the central canal of the cervical spinal cord in a coonhound diagnosed with canine juvenile polyarteritis (steroid responsive meningitis-arteritis)

Patchy meningeal and parenchymal contrast enhancement of the spinal cord with multifocal central canal dilations was noted in a computed tomography myelogram of the cervical spine of a 6-month-old intact female coonhound with a confirmed diagnosis of canine juvenile polyarteritis and associated hemorrhage within the central canal.

High Incidence of Polyarteritis Nodosa in the Brains of Culled Sows

A total of 307 brains of purebred sows obtained from an abattoir were retrospectively examined. These sows were culled with reasons of reproductive failure, urogenital infections, or locomotor problems. The most common macroscopic lesions were cavitations or lacunae in the basal nuclei (9.1%, 28/307) and coarse and thickened leptomeninges with marked vessels (3.9%, 12/307). The most frequent microscopic lesion was polyarteritis nodosa (21.2%, 65/307), which was found in all 40 brains with the above-mentioned gross lesions and in all 25 brains with microscopic cerebral infarcts or cavitations. The affected arteries of polyarteritis nodosa were distributed primarily in the cerebral leptomeninges, basal nuclei, and internal and external capsules. Histopathologically, a characteristic change of the affected arteries was transmural fibrinoid necrosis with severe infiltration of mixed inflammatory cells; narrowing or occlusion of the lumen. The inflammatory cells were chiefly composed of lymphocytes, macrophages, and plasma cells, with a few eosinophils and occasional multinucleated giant cells. Polyarteritis nodosa was found at a high percentage in the brains from culled sows. It may result in cerebral ischemia, infarcts, and hemorrhage, and possibly play a role in the necessity for culling due to locomotor problems.

Idiopathic canine polyarteritis in control beagle dogs from toxicity studies

It is sometimes difficult to assess the relevance of polyarteritis with treatment-related lesions in dog toxicity studies, as number of dogs used in a toxicity study is small and the lesions are similar to those seen in spontaneous diseases. This report is intended to establish a general profile of idiopathic canine polyarteritis in beagle dogs. Data from a total of 40 dog studies including 4-, 13- or 52- weeks studies conducted between 1990 and 2003 at Huntingdon Life Sciences, UK, were collected and analysed. There was no death by this disease and also no prominent clinical signs related to this disease. Histologically, males tended to develop polyarteritis more frequently than in females and epididymis is the most probable tissues, followed by thymus and heart. Dogs in two studies showed higher incidences of these lesions, whereas animals in the other studies did not exhibited, suggesting that genetic predilection plays an important role in this disease.

Polyarteritis nodosa in a cynomolgus macaque (Macaca fascicularis)

Polyarteritis nodosa (PAN) is an idiopathic necrotizing vasculitis affecting small- to medium-sized arteries. The disease is well recognized in humans, and PAN-like syndromes have been described in a number of other species. This report describes a case of PAN in a 6-year-old male cynomolgus macaque. The animal had necrotizing arteritis affecting vessels in the kidney, small intestine, colon, heart, spleen, mesentery, urinary bladder, and pancreas. The lesions were segmental in distribution and of varying severity and stage of development. A transmural mixed inflammatory cell infiltrate was present, often accompanied by fibrinoid necrosis of the tunica media and loss of the internal elastic lamina. Immunohistochemical staining showed that many of the infiltrating cells were T lymphocytes and histiocytes, suggesting a cell-mediated component to the pathogenesis.

Intradural vasculitis and hemorrhage in full sibling Welsh springer spaniels

Two, full sibling, Welsh springer spaniel presented at 8 and 18 mo of age with rapidly progressive ataxia, recumbency, and pyrexia. The spinal cord contained extensive subdural hemorrhage and, in 1 dog, suppurative and necrotizing arteritis in the dura. The findings suggest a familial form of canine juvenile polyarteritis syndrome.

Differentiating spontaneous from drug-induced vascular injury in the dog

When vascular injury is observed in dogs used in preclinical toxicology studies, careful evaluation of the lesions is warranted, especially when differentiating drug-induced vascular changes from spontaneous findings, such as idiopathic canine polyarteritis. The clinical signs as well as the nature and distribution of lesions can often be distinguishing, as is the case with vasoactive drugs, including vasodilators and/or positive inotropes (hydralazine, minoxidil, endothelin receptor antagonists, and phosphodiesterase III inhibitors). For most types of vasodilator-induced vascular injury, the lesion is often restricted to coronary arteries, whereas in idiopathic canine polyarteritis, arterial lesions not only involve coronary arteries, but also medium to small arteries of other organs. In addition, the nature of the changes in vessels yields important clues. Medial and adventitial hemorrhage is generally associated with vasodilator-induced arterial lesion, whereas hemorrhage is generally absent in idiopathic polyarteritis. Although idiopathic canine polyarteritis can generally be differentiated from vasoactive-induced vascular injury in dogs, there are increasing incidences of this type of polyarteritis in dogs receiving any 1 of a number of unrelated classes of compounds, suggestive of an exacerbation of the spontaneous disease. Therefore, in order to differentiate drug-induced injury from idiopathic canine polyarteritis, it is critical that examination of the vascular pathology be conducted with good understanding of clinical, pharmacological, and mechanistic data associated with the drug.

Restriction fragment length polymorphism of the T-cell receptor beta-chain gene in dogs

Since T-cells and the T-cell receptor (TCR) play a pivotal role in the response of the immune system, they are a target for pathogenesis studies in immune mediated diseases and have been used to generate markers for T-cell dependent diseases in humans and dogs. TCR rearrangement is generated at the genomic DNA level and can be analyzed by Southern blotting techniques. In the present study this method to detect rearrangement of the TCR beta chain in the dog was critically examined. To search for restriction fragment length differences due to either inherited polymorphism or in diseases with suspected superantigen influence (X-linked severe combined immune deficiency and canine juvenile polyarteritis syndrome) 13 dog families of three different breeds were examined. In addition primary spleen cell cultures, stimulated with either phytohemagglutinin A (PHA) or staphylococcus enterotoxin A (SEA) and B (SEB) were studied. The germline digest pattern of the enzymes Pst I, Sst I, Bgl II, Eco RI and Eco RV were identical in all dogs examined with the exception of one dog with canine juvenile polyarteritis syndrome. In this dog an additional band was found in the Bgl II and Eco RV digestion suggestive of specific TCR rearrangement. Bam HI digestion revealed restriction fragment length polymorphisms (RFLPs) showing Mendelian inheritance. After digestion of the genomic DNA extracted from PHA, SEA or SEB stimulated spleen cells and Southern blot analysis, no differences in fragment patterns between the unstimulated cells and the stimulated cells could be detected. An important point to consider before a specific pattern variation between dogs is classified to be a marker for a specific disease or is used in pathogenesis studies, is the possibility of an inherited RFLP, especially after Bam HI digestion. In such studies the combined examination of the parents and the offspring must be recommended.

Pathologic features of naturally occurring juvenile polyarteritis in beagle dogs

Eighteen young Beagle dogs (eight males and 10 females), ages 6-40 months, with canine juvenile polyarteritis syndrome (CJPS), a naturally occurring vasculitis and perivasculitis of unknown etiology, were necropsied, and their tissues were examined by histopathologic and histochemical methods. The condition is characterized by recurring episodes of an acute onset of fever (> 40 C) and neck pain that persist for 3-7 days. The major histopathologic alterations were a systemic vasculitis and perivasculitis. During the febrile, painful period of CJPS, the vascular lesions ranged from a histiocytic-lymphocytic periarterial infiltration to transmural arterial inflammation with concomitant fibrinoid necrosis and vascular thrombosis. Massive periarterial accumulations of inflammatory cells were common and often extended into adjacent tissues. The small- to medium-sized muscular arteries of the heart, cranial mediastinum, and cervical spinal meninges were consistently involved. Vasculitis occasionally occurred in other organ systems. The vascular lesions in dogs examined during clinically normal periods consisted of intimal and medial fibrosis, ruptured elastic laminae, and mild perivasculitis; these lesions were probably related to previous episodes of vasculitis. Eight dogs that had experienced repeated acute episodes also developed splenic, hepatic, and renal amyloidosis. The clinical signs, laboratory abnormalities, and the vascular lesions suggest that the condition may be immune-system mediated. CJPS may serve as a naturally occurring animal model of human immune-system-mediated vasculitides such as polyarteritis nodosa, infantile polyarteritis, and Kawasaki disease.

Systemic necrotizing vasculitis in nine young beagles

A systemic necrotizing vasculitis of unknown etiopathogenesis may be termed juvenile polyarteritis syndrome (JPS). The syndrome has been recognized primarily in young Beagles used for toxicologic studies. We studied 9 young Beagles with JPS. Affected dogs had fever (40 to 41.5 C), anorexia, and signs of pain in the cervical area. They had a characteristic hunched stance, and were unwilling to move. Laboratory abnormalities in all dogs included nonregenerative anemia, hypoalbuminemia, and leukocytosis characterized by a mature neutrophilia. Analysis of CSF revealed a moderate to severe neutrophilic pleocytosis and a mildly high protein concentration in most dogs. Signs of disease resolved rapidly with high doses (2.2 mg/kg of body weight, PO) of prednisone. If untreated, clinical signs and laboratory abnormalities had a remitting and relapsing course in most dogs. Findings at necropsy included necrotizing arteritis with fibrinoid necrosis, periarteritis, thrombosis, and intimal proliferation that most frequently affected small- to medium-sized vessels in the cervical spinal cord, mediastinum, and heart. An immune-mediated pathogenesis for this disease is suspected.

Canine leishmaniasis associated with systemic vasculitis in two dogs

Two cases of canine leishmaniasis associated with systemic necrotizing vasculitis are described. The main macroscopic lesions were haemorrhagic in type; histopathological changes confirmed a vascular lesion affecting small arteries of several organs (skin, intestinal tract, kidney, urinary bladder, mesenteric lymph nodes, adrenal gland, myocardium, lung, eye and choroid plexus). The presence of the parasite was confirmed with a specific immunocytochemical stain. The possibility of an immunological aetiology of the vasculitis and its classification is discussed.

An idiopathic febrile necrotizing arteritis syndrome in the dog: beagle pain syndrome

The clinical, laboratory, and pathologic features of a syndrome in dogs characterized by intermittent pain, fever, neutrophilia, and necrotizing arteritis are described to alert others involved in toxicity testing to the existence of this disorder. It is considered that this idiopathic syndrome is a latent condition, the expression of which can be precipitated in predisposed dogs by experimental treatment, and thus, its occurrence could complicate interpretation of toxicity studies. We have observed the disorder in 14 beagle dogs. The syndrome is rare and most cases for study were supplied by the breeder. Typical clinical signs observed included evidence of pain when the mouth was opened, grunting when lifted, and standing with an arched back and lowered head. Appetite was usually reduced. Body temperature was elevated (e.g., 104-106 degrees F). There was progressive, bilateral atrophy of temporal and cervical musculature. Such signs have been observed to persist unremittingly or, more commonly, with periods of expression and remission. Neutrophilic leukocytosis and thrombocytosis were present. Hemoglobin and hematocrit were usually slightly decreased. Serum total protein was usually normal but albumin was reduced and alpha-2 globulins were markedly increased. Rheumatoid factor was elevated in several dogs. Arteritis was observed histologically and was characterized by necrosis, intimal proliferation, neutrophil and mononuclear cell infiltration in the media and periarterial tissues, and hemorrhage. Amyloidosis was observed in several dogs. The cause of this disorder is unknown. Knowledge of the distinct features of this syndrome should obviate complication of interpretation of results in toxicity studies and hopefully will lead to studies of this syndrome to provide an understanding of its etiopathogenesis.

Polyarteritis nodosa and rheumatic heart disease in a dog

A 12-year-old spayed Corgi-type dog developed an acute febrile illness about 2 weeks after excision of a subcutaneous arteriovenous fistula. The dog was moribund after 1 week of illness and was euthanatized. Necropsy disclosed uncommon lesions comparable to those of polyarteritis nodosa and rheumatic heart disease of human beings. The pathogenesis of the arterial and cardiac lesions was not established, but was consistent with that of an immune-mediated mechanism.

Sequential study of vasculitis in MRL mice

The frequency, age of onset and organ distribution of spontaneously occurring vasculitis was examined in a sequential study with 170 MRL mice of both substrains. Necrotizing vasculitis was seen in 55.8% of MRL/Mp-lpr/lpr mice studied, beginning at the age of 3 months. The kidney and urinary bladder were most frequently involved. In MRL/Mp- +/+ mice necrotizing vasculitis was much less frequently present (7.6%), beginning at the age of 18 months, and was seen only in the kidney, stomach and testes. In both substrains mononuclear infiltration of pulmonary vessel walls preceded the occurrence of necrotizing arteritis in other organs. The immunofluorescence study revealed the presence of immune complex components (immunoglobulin G, C3, murine leukaemia virus antigen gp71) in the vessel walls of the renal arteries of six out of 36 lpr/lpr mice with necrotizing arteritis.

Periarteritis in a beagle colony

Primary periarteritis, an uncommon necrotizing vasculitis in the dog, was found to affect, almost exclusively, the major branches of the coronary arteries in a number of young beagle dogs. The arteritis was mainly distributed in the proximal segment of the right coronary artery. Immunocytochemical studies failed to identify immunoglobulin deposits in the lesions and the cause of the arteritis remains unknown. It is important to be aware of this spontaneous condition and its regional distribution since certain cardiovascular drugs may also produce necrotizing arteritis at similar sites.

[Polyarteritis nodosa]

With reference to sixteen cases of polyarteritis nodosa (seven dogs, two cats, two goats, three pigs, two cattle), current views regarding classification, aetiology and pathogenesis of this disease are discussed. Polyartertis nodosa is not a disease entity, but rather a symptom that may be associated with various forms of disease and may vary in pathogenesis. The clinical picture depends upon the localisation of the vasculitis. Toxic agents and various viruses may be directly responsible for the vascular lesions. In addition, genetic, autoimmune and allergic factors may be implicated. The immunological pathogenesis is illustrated with reference to the serum sickness model.

Immune-mediated disorders of cats

Immune-mediated disorders in cats share many clinical and pathologic similarities with their counterparts in other species. Cats, however, are unique among domestic animals owing to the involvement of feline leukemia virus. In addition, a number of other infectious organisms can produce immune-mediated sequelae--that is, FIP virus, FeSFV, and H. felis. Therefore, the diagnostic and therapeutic aims in the management of feline immune-mediated disorders must take into account the probability of a primary or underlying disease process.

Polyarteritis nodosa in a sow

A case of polyarteritis nodosa in a sow is described. Microscopic lesions of the disease were observed in the kidneys, heart, gastrointestinal tract, meninges, lungs and liver. Pathology records at 2 veterinary schools were reviewed; in one the disease was diagnosed mainly in female pigs.

Ocular encephalitozoonosis (nosematosis) in blue foxes. Polyarteritis nodosa and cataract

In young blue foxes an association has previously been established between the protozoon Encephalitozoon (Nosema) cuniculi and generalized arterial lesions of the polyarteritis nodosa type. The same vascular changes are found in the posterior ciliary arteries and their intraocular branches of these foxes. Most of the eyes which are thus affected, have a severe cataract. The parasite can easily be demonstrated both in the arteries and the lenses. It is thought that the Encephalitozoon is the cause of the vascular lesions and the cataract, and that possibly an autoimmune reaction is involved.

Polyarteritis nodosa associated with nosematosis in blue foxes

The patho-morphological lesions in fox nosematosis (encephalitozoonosis) were studied in a material comprising 150 young blue foxes from 23 different farms. Disseminated nosematosis in blue fox pups was regularly accompanied by severe vasculitis, affecting medium-sized and small arteries in various organs. The acute damage has the form of a necrotizing angiitis, with mural necrosis and sometimes resultant thrombosis. The causative organism Nosema cuniculi, is frequently present in the freshly affected arterial walls, either in endothelial or in medial smooth muscle cells. Older lesions include nodular fibrous thickening of the arterial walls, and intimal proliferation, sometimes with luminal obliteration. The conclusion is drawn that the arterial lesions are morphologically equivalent to classical polyarteritis nodosa.

[Polyarteritis nodosa: general aspects and occurrence in domestic animals, particularly in association with nosematosis in blue foxex (author's transl)]

A survey of polyarteritis nodosa in domestic animals is presented, including a description of the patho-morphological lesions and a discussion on the causal factors. This vascular disease occurs in domestic animals in association with both viral infections (infectious plasmacytosis in mink), bacterial infections (erysipelas in swine), and protozoan infections (nosematosis in blue foxes). The conclusion is drawn that the observations in domestic animals support the view that immunological disturbances are involved as pathogenetic mechanisms. Nosematosis is dealt with in more detail; the infecting agent (fig. 1), Nosema cuniculi (Encephalitozoon cuniculi), is a widespread mamalian parasite, which causes cerebral and renal lesions in blue foxes of the same type as in animals of other species. In addition, the vascular system throughout the body is affected, resulting in patho-morphological alterations corresponding to classical polyarteritis nodosa (Fig. 2). In the early stages of involvement, masses of parasitic organisms are regularly found within the walls of affected arteries (Fig. 3). This disease is frequently lethal, and always accompanied by elevated values of gamma globulins. Both the hypergammaglobulinemia and the tissue lesions, seem at times, at least in part, to be reversible.

[Pathogenesis of aleutian mink disease. VII. Chronic hepatitis with bile duct proliferation]

Aleutian disease is a chronic persistent viral infection of mink characterized by hypergammaglobulinema, generalized plasmacytosis, sclerosing glomerulonephritis, polyarteritis, and plasma cell hepatitis with bile duct proliferation. The development of hepatic lesions was studied both light- and electron-microscopically in mink experimentally infected with Aleutian disease virus. Fifteen normal and 99 mink experimentally infected with Aleutian disease virus were used. Experimental mink were killed in intervals from 3 weeks to 23 months after infection, and liver sections were processed for both light- and electron-microscopic studies. Experimentally infected mink developed portal and intralobular lymphocytic and plasmacytic infiltrates in the liver 3 weeks after infection. Four to five weeks after infection there was evidence of early bile duct proliferation that began as an outgrowth of the portal bile ducts. Three to five months after infection a marked bile duct proliferation was present in some of the portal triads and adjacent liver lobules; but there was no tendency of these lesions to progress into biliary cirrhosis. Ultrastructural characteristics of proliferating bile duct cells were marked deformation, formation of multiple cell layers, reduction in the number of microvilli and desmosomes, and infiltration of the epithelial cells by lymphoid cells and plasmacytes. The hepatic lesions either develop by direct virus stimulation or by the deposition of virus-antibody complexes.