Clinical Signs in Small Animal Medicine

Michael Schaer D.V.M.

• Publisher: CRC Press
• Year: 2016
• eBook ISBN:
  9781315350332
• Topic: Medicine
• Subtopic: Internal Medicine & Diagnosis

This new edition of the bestselling Clinical Signs in Small Animal Medicine presents 800 all new color photographs of the highest quality, with detailed captions that focus on key pointers to diagnosis and treatment. The book is organised into chapters by body system, each beginning with a list of 'Clinical Pearls'. These amusing and accurate key points will be invaluable when considering conditions or highlighting common concerns. Within each chapter, the superb photographs of real cases are annotated with brief, key information that provides a succinct and useful reminder of lessons learned.

This cat has hypersensitivity of its nasal planum caused by insect bites.

1

Dermatologic disorders

DERMATOLOGY is derived from the Greek term derma, meaning skin, and logos, meaning study or speech, word, or reason. It is an essential discipline for the practitioner because of the high incidence of skin disease that one can encounter daily in practice. These disorders can occur as primary lesions or syndromes or they can be a reflection of some other internal disease process in the body. Adherence to the essentials of obtaining a full history and doing a complete physical examination will be most helpful in determining the cause of the dermatologic disorder. Perhaps the most common group of skin diseases involve hypersensitivity states, but other important conditions might be associated with autoimmune disorders, infectious diseases, neoplasia, nutritional disorders, and various metabolic and endocrine conditions. The diagnostic methodology of skin diseases, after taking a full history and conducting a physical examination, includes general tests such as a complete blood count, serum biochemistry profile, immune or infectious disease serology, skin hypersensitivity testing, and biopsy. The advantages of these tests are that they are readily available to the practitioner and noninvasive for the patient. In many instances the classic appearance of certain lesions will allow for a minimal diagnostic evaluation, thus saving the owner a substantial amount of expense.

1

Dermatologic disorders

A lump is a lump until you stick it.

Don’t look at it, stick it.

Skin turgor is difficult to assess with obesity and cachexia.

Excessive SC fluids cause skin slough.

1.1a, b. Cutaneous vasculitis. The dermatologic lesions on this dog began as distinct multifocal areas of erythema that progressed to eschar and eventual sloughing. These lesions were biopsied and diagnosed as cutaneous vasculitis. This disorder is usually associated with a type III immune reaction. The sensitizing trigger can vary and includes drugs, underlying diseases and infections, and serum sickness; sometimes the cause remains unknown or idiopathic. The lesions can appear as purpura, petechiae, or ulcers. Histologically, white blood cells are seen surrounding the blood vessel walls (leukocytoclastic vasculitis). Treatment entails removing the insulting agent, if possible, and administering immunosuppressive drugs such as prednisone. The vasculitis can involve both superficial and deep small, medium, or large arteries and arterioles.

1.2a–e. Drug-induced vasculitis. This dog developed diffuse superficial ulcerations involving its ears, oral mucosa, periocular skin, nose, and digits. Note the mucocutaneous localization, which would be typical of immune system involvement. The cause was the drug prazosin, which had to be discontinued and replaced by another drug with similar action.

1.3. Atypical mycobacterial infection. Shown is a chronic draining skin wound that had not responded to wound care and antibiotics. This scenario should prompt consideration of atypical mycobacterial infection, which requires special growth media for optimal culture conditions. Diagnosis requires obtaining deep tissue sampling. Once diagnosed these infections require months of continuous treatment and re-evaluation for the possibility of having to alter the antimicrobial treatment because of resistant bacterial strains. Recurrent infection is possible, especially if immunosuppression is present.

1.4a, b. Calcinosis cutis. This dermatologic condition is commonly associated with Cushing’s disease and, more rarely, with other medical disorders. Various forms occur, which can appear as moist inflamed skin lesions or as a dry form that is not inflamed. A yellow colored mineralized deposit in the superficial forms is typical. There is no specific treatment other than treatment of the underlying condition. Most cases will resolve once the hypercortisolism is resolved.

1.5. Heat pad-induced skin burns. Thermal skin injuries can be very extensive, as illustrated in this dog’s lesion. It is usually acquired when prostrate animals are covered with heat emitting devices such as heat pads and hot water bags. The earliest signs are erythema, soon followed by a hardening texture to the skin often accompanied by eschar formation, which e...

Table of contents

• Cover
• Title
• Copyright
• Contents
• Preface
• Abbreviations
• Dedication
• Introduction
• Clinical Pearls
• Chapter 1: Dermatologic disorders
• Chapter 2: Ophthalmologic disorders
• Chapter 3: Infectious diseases
• Chapter 4: Cardiovascular disorders
• Chapter 5: Serum electrolyte disorders
• Chapter 6: Fluid therapy complications
• Chapter 7: Respiratory disorders
• Chapter 8: Hematology and hemostasis disorders
• Chapter 9: Gastrointestinal disorders
• Chapter 10: Liver disorders
• Chapter 11: Immune disorders
• Chapter 12: Endocrine disorders
• Chapter 13: Urogenital disorders
• Chapter 14: Neurologic disorders
• Chapter 15: Neoplastic disorders
• Chapter 16: Toxicologic disorders (including snake bite envenomation)
• Chapter 17: Miscellaneous disorders
• Index