Chapter 13/14 - Environmental/Hereditary Flashcards
What type of necrosis occurs in pressure sores?
Ischaemic necrosis
What is myospherulosis?
An extremely rare granulomatous reaction thought to be due to the interaction of ointments, antibiotics, or endogenous fat with erythrocytes
What are the clinical signs of myospherulosis?
Solitary subcutaneous or dermal nodules, which may or may not have draining tracts.
In myospherulosis, do parent bodies and spherules stain with PAS, GMS or acid-fast stains?
No
What is the pathological mechanism of gangrene?
An occlusion of either arterial or venous blood supply.
Moist gangrene -impairment of lymphatic and venous drainage plus infection
Dry gangrene - arterial blood supply is occluded, but venous and lymphatic drainage remain intact and infection is absent
Gas gangrene/subcutaneous emphysema is associated with which type of infecion?
Clostridial infections
What is a histopathological diagnostic feature of electrical burns?
A fringe of elongated, degenerated cytoplasmic processes that protrude from the lower end of the detached basal epidermal cells into the space separating the epidermis and the dermis. The nuclei of the basal cells and often of the higher-lying keratinocytes appear stretched in the same direction as the fringe of cytoplasmic processes. This gives the image of keratinocytes that are “standing at attention.”
What are the clinical signs of selenium poisoning?
Lameness (typically HL first)
Hoof changes (rings, corrugations, horizontal cracks)
Emaciation
Loss of the long hairs of the mane, tail, and fetlocks
Rough hair coat (breaks easily)
What are the clinical signs of chronic arsenic poisoning?
Gastroenteritis Emaciation Exfoliative dermatitis Dull, dry, rough, easily epilated coat Some horses develop a long hair coat, others alopecia
What are the clinical signs of chronic mercury poisoning?
Nephrosis Lameness Oral ulceration Emaciation Progressive generalised alopecia Depression Anorexia
What are the clinical signs of excessive iodine intake?
Seromucoid nasal discharge Lacrimation Cough Variable appetite Joint pain Severe scaling +/- alopecia - most common over dorsum, head, neck and shoulders
Claviceps purpura infected grain causes which diseae?
Ergotism
Which fungus causes painful, necrotic ulcers in the mouth, nasal region and lips in horses?
Stachybotrys atra (stachybotryotoxicosis)
Which UV spectrum (A, B or C) is associated with photosensitivity reactions?
UVA
Name three drugs that can act as primary photosensitisation agents?
Phenothiazine Thiazides (e.g. diurectics) Promazines Acriflavines Rose bengal Methylene blue Sulfonamides Tetracyclines Coal tar derivatives Furosemide
What are the histopathological features of acute and chronic photosensitisation in horses?
Acute - epidermal and dermal oedema, vaculoated and apoptotic epidermal keratinocytes, intramural and perivascular deposition of eosinophilic amorphous material in superficial dermal blood vessels
Chronic - diffuse necrotising/fibrosing dermatitis and absence of adnexae