Vet Path B 250-215 Muscle & Myocardium & Blood Vessels

Front 1

Horse with one hindflank smaller than other

Likely mechanism?

2 possible consequences?

Back 1

Denervation atrophy

Further reduction in mm mass

Reinnervation

Front 2

Starved cow - name the condition

Outline the aetiopathogenesis (mm and fibres affected first?)

Back 2

Atrophy of cachexia

Insuff prot > catabolism of muscle protein > non-postural mm affected first, type 2 (fast) fibres affected first

Front 3

Collapsed cross-bred lamb. Hindlimb muscle on left (compared to normal or partially affected? on right)

Name the condition

Outline the pathogenesis.

Back 3

White muscle D

VitE/Se deficiency > low antiox activity > free radical damage > lipid membrane peroxidation > incr Ca into myofibres > incr ATP used to remove Ca > mito damage, Ca-induced hypercontraction of myofibres > segmental degeneration > mineralisation of contractile proteins

Front 4

Collapsed lamb, affected muscle on left (normal on right).

Describe the typical appearance of muscles affected by WMD

What other tissues are likely to be affected?

Back 4

Pale and flabby or wet, poor development of rigor +/- haemorrhagic streaks

Myocardium
Lamb - left ventricular myocardial necrosis - shown

Front 5

Lamb with twisted limbs

Name the condition

Name a likely aetiological agent

Briefly outline the pathogenesis

Back 5

Arthrogryposis

Akabane virus

virus interferes with nerve development > inadequate foetal mm development > limb immobility > fibrosis of ligaments and contracture of tendons around joints

Front 6

Lamb with arthrogryposis

List 4 potential causes

Back 6

Genetic defect

Teratogenic virus (Akabane)

Teratogenic toxin (plant alkaloid)

Nutritional def in mother (VitA, Mn)

Front 7

WMD

List 4 triggering factors

Back 7

Rapid growth

Unaccustomed exercise

Cold weather

Dietary (eg rancid fish oil)

Front 8

Horse, gluteal muscle post anaesthetic

Provide a likely pathogenesis

Back 8

Horse left on side for too long > ischaemia > coagulation of contractile proteins > inadequate repair dt damage to myofibre & satellite cells > necrosis

???

Front 9

Old cat with paresis in both hindlimbs

Provide a plausible explanation

Back 9

Sorry it's a stretch!

Aortic thromboembolism > saddle embolism at terminal aorta bifurcation > ischaemia and infarction of hindlimb muscles

Front 10

Pale soft wet skeletal muscle from a heavily muscled pig

Name the likely condition

Outline the pathogenesis

Back 10

Porcine stress syndrome

Genetic defect in ryanodine receptor (Ca release channel of SR) > incr Ca in sarcoplasma > decr ATP (used to remove Ca) > switch to anaerobic glycolysis > generate heat & lactic acid > denature muscle proteins

Front 11

Blackened haemorrhagic muscle form an ox that died suddenly

Name the condition

Name the aetiological agent

Back 11

Blackleg

Clostridium chauvoei

Front 12

Blackleg from an ox

Outline the pathogenesis

What other lesions are expected?

Back 12

C. chauvoei spores ingested > dormant in mm > muscle trauma > alkaline pH, low O2 > spores germinate > bacteria grow, toxin produced > muscle necrosis

Malignant oedema (of overlying subcutis and fascia)
Fibrinohaemorrhagic pleuritis
Fibrinohaemorrhagic endocarditis

Front 13

Dog with :"fox head" and inability to open/close jaws but remaining bright and alert

Name this condition

Outline the pathogenesis

Back 13

Chronic stage of masticatory myositis

Auto-antibodies against myosin isotype found in masticatory muscles of adult dogs > CMI attack on muscle > acute: recurrent painful swelling, reluctant to eat > chronic: progressive severe bilat atrophy of masticatory mm

Front 14

Muscles with multiple small cream white foci.

Name the parasites involved

Back 14

Front 15

Name 2 protozoa that commonly cause myositis in domestic animals

Back 15

Toxoplasma gondii

Neospora caninum

(the tachyzoites)

Front 16

What would be your differential diagnostic list if you found multiple small cream white foci randomly scattered throughout the myocardium of an animal at necropsy?

Back 16

Parasites that cause myocarditis
- Taeniid metacestodes
- Sarcocystis spp
- Trichinella spiralis/pseudospiralis
(all > eosiniphilic myocarditis?)

Virus
- encephalomyocarditis virus infection in pigs (pic in slides)
- canine HV, parvovirus

Bacterial abscesses
- Streptococcus spp.

Lymphoma

Fungal granuloma?

Front 17

List 10 possible causes of myocardial necrosis in domestic animals

Back 17

Ischaemia
CNS lesions
Trauma
Stress
Haemorrhagic shock
VitE/ Se deficiency
Toxic cps, eg 1080
Plant toxins eg cardiac glycosides in oleanders
Metabolic disorder eg PSS, Malignant hyperthermia
Renal failure (uraemic endocarditis)
Phaeochromocytoma (incr Ad)

Front 18

Heart from a 2 mo old pig in excellent nutritional condition that died suddenly.

Likely disease?

Other major gross lesions expected?

Back 18

Mulberry heart disease dt VitE deficiency

See here diffuse epicardial haemorrhage.

Other gross lesions could be;

cyanosis of ears and ventral abdomen
petechial haemorrhages
hydropericardium
orbital, palpelbral oedema
pulmonary odema/ congestion
ascites, hydrothorax, congested liver
Anything referable to CHF really!

Front 19

Pig after halothane exposure

Likely condition?

Pathogenesis?

Back 19

Malignant hyperthermia

PSS -like syndrome induced by various drugs
- deficit in SR Ca channels > myofibre hypercontraction > ATP consumption > anaerobic glycolysis > lactic acid, heat > coagulation of contractile proteins

Front 20

Cat opened heart left ventricle

Lesion?

Brief pathogenesis?

Likely sequelae?

Back 20

Left ventricular dilated myopathy

Volume overload (could be mitral valve insufficiency)

Eccentric cardiac hypertrophy if volume overload sustained
- CS referable to LS CHF

Front 21

Opened cat heart at left ventricle

Lesion

Brief pathogenesis

Sequelae

Back 21

Concentric? cardiac hypertrophy

Sustained P overload

CS referable to LS CHF

Front 22

What is a common consequence of cardiomyopathy in cats?

What CS would alert you to this problem?

Back 22

Arterial thromboembolism

Sudden onset hindlimb paresis
No femoral pulse
Cool limbs
Cyanotic nailbeds

Front 23

German Shepherd - mass on right auricle

Likely diagnosis?

Common sequelae?

Back 23

Haemangiosarcoma

Haemopericardium
Metastasis to other organs esp lungs
Predispose to DIC

Front 24

Dog coronary arteriole

Diagnosis

Clinical significance

Back 24

Arteriolosclerosis
(no fatty deposition thus not atherosclerosis)

Rarely of clinical significance, common age related change

Infrequently may cause ischaemia

Front 25

Opened dog thorax

Lesion name

Pathogenesis

Causes

Back 25

Chylothorax

Ruptured thoracic duct

Thoracic trauma
Severe coughing
Neoplasia
Dirofiliariasis
Pleuritis
CHF
Inherited abnormalities of lymphatics