Page 35 - Canine-Diseases

nausea, vomiting, and/or constipation The Keeshond is the most and urination), vomiting, diarrhea, depression, weakness, hyper-
commonly affected breed. excitability, dyspnea (difficulty breathing), tachypnea (rapid
breathing), heart murmur, Tachycardia (rapid heartbeat), abnormal
Hyperpigmentation: Also called ‘hypermelanosis’, is an increase heart beat known as a “gallop rhythm” and palpable enlarged
in coloration within the skin due to increased deposits of melanin thyroid gland.
within the epidermis. Pigment change may be localised or diffuse
and may occur within the basal layer or throughout the epidermis. Hypertrophic osteodystrophy (HOD): Is a bone disease of
Commonly seen in chronic inflammatory and hormonal dermatoses the front limbs in large-breed puppies. The disease has several
and occasionally in neoplastic or developmental disorders. See names including skeletal scurvy, Moller-Barlow’s disease,
Acanthosis nigricans. osteodystrophy II, and metaphyseal osteopathy. Affected puppies
suffer from a non-infectious inflammation of the bony spicules
Hypersensitivity: Hypersensitivity reactions are exaggerated (pointed, mineral structures) in the metaphysis (ends of long
immune reactions to specific allergens. They have been roughly bones) of the long bones. Particularly affected are the metaphyseal
divided into 6 groups based on reaction type, timing, and cell types regions of the long bones distal to the elbow and stifle (i.e., distal
involved. Type I: Immediate or anaphylactic hypersensitivity. radius and ulna and tibia); however, all long-bone metaphysis can
Classically involves a genetic predisposition, exposure to be affected, including the metacarpals, as well as the mandible and
allergen, specific IgE production and mast cell degranulation. maxilla, the costochondral junctions of the ribs, the scapula, and
Onset is within minutes and duration often no longer than 1 hour. even the anterior border of the ilium. These “bony” swellings are
Examples include anaphylaxis, urticaria, drug eruptions, food the result of a fibrous thickening of the periosteum accompanied
hypersensitivity, atopy, flea allergy dermatitis, and angioedema. by periosteal new-bone formation. Most animals experience the
Type II: Cytotoxic hypersensitivity. Involves antibody (IgE or onset of clinical signs between 2 and 7 months of age. Clinical
IgG) binding to specific antigens on body tissues and resulting signs in minimally affected animals usually relate to a slight
in cell destruction. Examples include blood transfusion reactions, limp, with pain exhibited on deep digital palpation of the affected
pemphigus and some drug eruptions. Type III: Immune complex metaphysis. More severely affected animals, however, may
hypersensitivity. Antigen-antibody immune complexes attach to exhibit anorexia, weight loss, fever, and depression accompanied
blood vessel walls and activate complement (an immunological by extremely swollen, warm, and painful long-bone metaphysis,
biochemical cascade), attracting neutrophils which release tissue- with refusal to bear weight on the affected limbs. HOD has
damaging enzymes. Examples include some drug eruptions, been reported to affect the Great Danes, Irish Wolfhounds, Saint
bacterial hypersensitivity and systemic lupus erythematosus. Type Bernards, Borzoi, Boxers, Dalmatians, Irish setters, Weimaraners,
IV: Delayed or cell-mediated hypersensitivity. Classically involves German Shorthaired Pointers, Doberman Pinschers, German
antigen presenting cells (such as Langerhans cells in the skin) Shepherds, Labrador Retrievers, Collies, Greyhounds and Bassett
which process the antigen before presenting it to, and sensitising, Hounds.
T-cells. On further antigen exposure, the sensitised T-cells release
chemical mediators, resulting in tissue damage. The reaction Hyphema: Is the presence of blood within the anterior chamber of
may not be apparent for 24-72 hours. Examples include contact the eye and is a symptom of serious ophthalmic disease. Hyphema
hypersensitivity, flea allergy dermatitis, possibly Malasezzia may be partial or complete. Hyphema is a clinical sign and not a
sensitivity and some drug eruptions. Type V: Late phase reactions. specific disease. The most common causes of hyphema include
Neutrophils and eosinophils infiltrate the tissue initially, followed injury or trauma to the eye or head; severe retinal detachment;
by monocytes. Reactions are mast-cell mediated and may occur 4-8 infection by parasites; bleeding vessels - vasculitis, uveitis, uveal
hours after exposure. Examples include flea allergy dermatitis and neoplasia, and lymphoma; ocular defects such as retinal dysplasia,
atopy. Type VI: Cutaneous basophil hypersensitivity. Mediated by collie eye anomaly, glaucoma etc.; and hypertension.
T-cells or by specific antibodies (IgE or IgG). Tissues are infiltrated
by basophils and large deposits of fibrin occur. Reaction is thought Hypoglycemia: Is defined as a low blood sugar concentration
to occur about 12 hours after exposure and peak after 24-72 hours. which is less than 70 milligrams per deciliter of blood. Symptoms
Possibly important in ectoparasite reactions or hypersensitivities depend on how quickly the blood glucose concentration
to fleas or ticks. Allergic or immune mediated disease may involve decreases, but rarely occur until it falls below 50 mg/dl.
more than one of these hypersensitivity ‘types’. Hypoglycemia is not a disease. It is instead a symptom that
points to an underlying medical condition. Hypoglycemia occurs
Hyperthyroidism: Is a condition that is caused by the thyroid when excessive glucose consumption depletes the reserves of
gland in the neck overproducing thyroxine, a hormone that glucose in the body. Hypoglycemia can be a result of endocrine
controls metabolism. Hyperthyroidism is rarer in dogs than or hepatic disorders, a higher energy requirement for glucose,
hypothyroidism, and it usually results from an aggressive thyroid lack of glucose due to fasting, intestinal parasites, or toxicity.
tumor. Additionally, raw food diets that include an excessive The causes for hypoglycemia in dogs include abnormal growth
amount of thyroid hormones can also cause the condition. These of pancreatic cells, inflammation of the liver, portosystemic
diets often include gullets, head meat, and animal necks, which shunt, cancer in the liver or gastrointestinal system, glycogen-
contain higher levels of thyroid hormones. The most common storage disease, excessive strenuous exercise, overuse of glucose
cause is thyroid carcinoma, a malignant tumor. Signs include in the body during pregnancy, reduced intake of glucose due
excessive weight loss, increased appetite, unkempt appearance, to starvation or malnutrition, delayed time between meals,
poor body condition, polydipsia and polyuria (excessive thirst overdosing of insulin, and toxicity from ingestion of artificial

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