Category Archives: Dog illnesses and diseases

Autoimmune Disorders

Pemphigus complex the pemphigus complex comprises a group of rare autoimmune diseases described in dogs and cats the diseases are vesiculobullous ulcerative disorders of the skin and often the mucous membranes autoantibody is directed against the epidermal intercellular cement substance and may be demonstrated by direct immunofluorescence testing histologically the pemphigus complex is characterized by acan-tholysis (loss of cohesion between individual epidermal cells) Pemphigus foliaceus the most common of the autoimmune diseases dogs and cats no age, breed or sex predisposition Clinical features often begins on the face, nose and ears as a vesiculobullous or exfoliative pustular dermatitis () footpads are frequently involved with hyperkeratosis mucocutaneous lesions are uncommon Diagnosis history physical examination histological examination: subcorneal acantholysis leading to the development of a cleft. Within the cleft there are neutrophils and eosinophils direct immunofluorescence may reveal intercellular deposition of immunoglobulin throughout the epidermis Differential diagnosis bacterial folliculitis dermatophyte infection seborrhoea systemic lupus erythematosus discoid Read more […]

Hypersensitivity Skin Disorders

Clinical hypersensitivity disorders have been classified by Gel and Coombes. The following description is simplified since in many instances complex interactions occur simultaneously. Type 1 (immediate, anaphylactic) genetically susceptible individuals inhale (absorb percutaneously?) allergens such as pollen and house dust, and produce immunoglobulin E (IgE), which fixes to tissue mast cells and blood basophils the allergen subsequently comes into contact with its specific IgE, leading to the release of vasoactive amines, which cause tissue damage examples are urticaria, angio-oedema, atopy, drug eruption and flea-bite hypersensitivity Type 2 (cytotoxic) IgG or IgM with or without complement binds to complete antigens on body tissues the antigen—antibody reaction causes cell lysis examples are pemphigus, pemphigoid, cold agglutinin disease and dnig eruption Type 3 (immune complex) circulating antigen-antibody complexes fix complement and are deposited in blood vessel walls these complexes attract neutrophils; proteolytic and hydrolytic enzymes released from the neutrophils produce tissue damage examples are systemic lupus erythematosus and bacterial hypersensitivity Type 4 (delayed) incomplete Read more […]

Canine Ovarian Imbalances

poorly understood conditions diagnosis is made on clinical grounds only there are two types Type 1 (hyperoestrogenism) middle-aged to old bitches any breed may be associated with cystic ovaries or ovarian tumours Clinical features bilaterally symmetrical alopecia in the perineal and genital areas, extending anteriorly () the affected area often exhibits a secondary seborrhoea and in chronic cases lichenification enlarged vulva and nipples abnormalities of the oestrus cycle Diagnosis physical examination rule out other differential diagnoses response to treatment Differential diagnosis hypothyroidism hyperadrenocorticism contact dermatitis hormonal hypersensitivity disorders presenting as seborrhoea Treatment ovariohysterectomy symptomatic treatment for seborrhoea allow 3-6 months before assessing the response Type 2 (oestrogen-responsive dermatosis) rare usually seen in bitches spayed before the first oestrus cause is unknown; hypo-oestrogenism has not been demonstrated Clinical features bilaterally symmetrical alopecia in the perineal and genital regions, which spreads to the medial thighs and the ventral abdomen; the dorsum is spared the Read more […]

Panhypopituitarism (Pituitary Dwarfism)

hereditary, thought to be autosomal recessive German shepherd dog and carnelian bear dog are predisposed most dogs have a cyst (Rathke’s cyst) in the pituitary gland signs are principally related to lack of growth hormone, but there are others if the thyroid, adrenal or gonadal releasing hormones are deficient Clinical features pups are normal until approximately 3 months of age, but subsequently fail to grow the puppy coat is retained and no primary hairs develop; hair is easily epilated bilaterally symmetrical alopecia gradually develops during the first year of life although short of stature, affected pups have virtually normal body proportions hyperpigmentation usually develops in the alopecic areas there may be other signs attributable to hypothyroidism or hypoadrenocorticism other abnormalities which may be noted include aggression (fear biting), short mandible, delayed dental eruption, cardiac disorders, megalooesophagus and gonadal abnormalities lifespan is often reduced Diagnosis history physical examination and comparison with litter mates rule out other endocrine disorders biopsy: histopathology is that of a typical endocrinopathy — hyperkeratosis, follicular atrophy Read more […]

Colonic Tumours

The most common tumours of the colon in the dog and cat are polyps, adenocarcinomas and lymphosarcomas, although other types do occur (). Factors which are thought to predispose to colonic and rectal neoplasia include low fibre diets, slow colonic transit times, high levels of bile and fat in the colon, and the presence of longstanding severe colitis (). Polyps are usually benign and occur most frequently in the distal colon or rectum. They tend to be space-occupying causing local obstruction to the passage of faeces. Occasionally they are associated with subsequent development of adenocarcinomas. Lymphosarcoma usually occurs as a diffuse tumour of the colon although focal lesions do occur. They rarely cause obstruction, but thickening of the colonic wall results in interference with motility and absorption. Adenocarcinomas often appear as focal lesions which tend to be proliferative and lead to obstruction of the colon. Ulceration is common as is secondary infection. The consequence of infection and inflammation is fibrous tissue formation and ultimately stricture formation. The commonest site for adenocarcinoma is said to be the distal colon and rectum, with metastasis to the sublumbar lymph nodes (). Clinical Read more […]

Idiopathic Colitis

This lorm of colitis is now considered to be one of the commonest causes of chronic diarrhoea in the dog () and appears to be much less common in the cat. However, there is a report of six cases of lymphocytic-plasmacytic colitis in cats (). It may be better described as a syndrome rather than a specific condition as there are many possible aetiological agents which may be responsible for the changes in the colon. Idiopathic colitis appears to affect any breed of dog and cat with no age or sex predisposition. However, cases appear to be more common in German Shepherd dogs. Rough Collies and Labradors. Unfortunately it is still unusual to determine the cause in the majority of cases of idiopathic colitis, hence the term, but occasionally a specific diagnosis is obtained. In this respect mycotic colitis has been recorded in cats due to Aspergillus spp.. The authors consider that dietary factors may be very important in the aetiology of colitis, because of the response noted to dietary management without drug therapy. Other aetiological agents include Trichuris vulpis infection, Salmonella spp. and Campylobacter spp. Idiopathic colitis may also develop as a sequel to gastroenteritis, secondary to small intestinal Read more […]

Acute Colitis

In a clinical context the difference between acute colitis and chronic colitis is, in many respects, only a difference in the duration of time the condition has been present. As with all forms of colitis, the inflammation leads to disruption of colonic function; namely disruption in the absorption of water and electrolytes. In addition there may be reduced colonic segmented contractions. Acute colitis is relatively common in dogs but is much more unusual in cats. The aetiology is rarely detected although dietary influences may be important. In particular the effects of scavenging and ingestion of abrasive foods such as bone may be important causes. Bacterial infection especially involving Salmonella and Campylobacter spp. should be considered together with heavy infestations of Trichuris vulpis. Clinical diagnosis The onset of clinical signs is usually sudden with profuse watery diarrhoea often containing mucus and occasionally blood. Vomiting may be present as may pyrexia and abdominal pain. Dehydration occurs most frequently when vomiting and diarrhoea are both present, and is unusual with diarrhoea alone. Tenesmus and urgency are often reported by the owner as is nocturnal defaecation. It is important to Read more […]

Hyperadrenocorticism

Also called Cushing’s syndrome, this is principally a problem of the dog. It is extremely rare in the cat. Causes pituitary-dependent — 80% of dogs. Excessive ACTH secretion results in adrenocortical hyperplasia and excess secretion of cortisol. According to Peterson et al. (), most of these cases (80%) are due to microadenomas. Only a few dogs have large pituitary tumours and these are slow-growing and not usually malignant. Very occasionally, neurological signs will develop in these cases some pituitary-dependent cases not associated with tumours may be due to a failure of the negative feedback response by cortisol the remaining 15-20% of naturally occurring cases are caused by unilateral or bilateral adrenal tumours a further significant cause of hyperadrenocorticism is gluco-corticoid abuse (‘iatrogenic hyperadrenocorticism’). The commonest cause of this is the excessive use of injectable repositol glucocorticoids. It is difficult to estimate the number of iatrogenic cases of hyperadrenocorticism occurring, but it is likely that they are of equal importance to naturally occurring cases Clinical features any breed, but particularly toy and miniature poodles, boxers, dachshunds and terrier breeds any Read more […]

Hypothyroidism

the commonest endocrine disorder of the dog the acquired naturally occurring condition has not been documented in the cat although the extremely rare congenital form has been described the metabolically active thyroid hormones are L-thyroxine (T4) and L-3,5,3-triiodothyronine (T3) Aetiology Primary congenital agenesis (rare) non-functional thyroid tumour (rare) lymphocytic thyroiditis; the most important cause (approximately 90%), an autoimmune disorder which results in thyroid destruction idiopathic thyroid necrosis and atrophy may represent the end stage of lymphocytic thyroiditis Secondary Less common than primary1 causes (less than 5%) TSH deficiency leading to inadequate stimulation of the thyroid gland with subsequent reduction in the production of thyroid hormone congenital hypopituitarism (usually in association with GH deficiency) pituitary neoplasia (may present with other signs, e.g. diabetes insipidus) Tertiary thyrotropin-releasing hormone (TRH) deficiency results in deficiency of TSH and reduction in thyroid hormone production due to hypothalamic lesions — extremely rare other equally rare causes of hypothyroidism include: iodine deficiency defects in thyroid Read more […]

Viral Skin Disease

Cowpox uncommon mainly rural cats infection may be from a rodent reservoir — not all affected cats have contact with cattle Clinical features papules, ulcers and particularly scabs develop at the site of cuts or bites, usually the head, neck or limbs these lesions may become generalized to involve the entire body and oral mucous membranes, particularly if there is concurrent debilitating disease, or immunosuppressing viral infections such as feline leukaemia or feline immunodeficiency virus infection, or if glucocorticoids have been administered affected cats may suffer from a transient dullness, but are not usually unwell; in a minority of cases there is dyspnoea, pyrexia, anorexia and depression pruritus is commonly noted Diagnosis history physical examination virus isolation in tissue culture; send scabs and swabs in viral transport medium to the virology laboratory. Biopsy; eosinophilic intracytoplasmic inclusion bodies within keratinocytes serological investigation, e.g. complement fixation, haema-gglutination inhibition or neutralization tests. May be of limited value in immunosuppressed cats and acutely ill cats Differential diagnosis bacterial folliculitis ectoparasites miliary Read more […]