pathology 10 - granulomatous disease

Question 0

granulomatous diseases?

Answer 0

characterised by granulomatous inflammation

Question 1

granulomatous is?

Answer 1

chronic (long duration) inflammation.

Question 2

granulmoatous inflammation is?

Answer 2

macrophages predominate it!!!!!

Question 3

what causes a granulomatous disease?

Answer 3

usually caused by irritants or agents that persist and are not easily degraded by macrophages.

Question 4

what do macrophages look like and what is their role?

Answer 4

they are large, mononuclear wbc’s, they phagocytose debris and pathogens and present antigens to other immune cells.

Question 5

what is the difference between a granulomatous disease and granulation tissue?

Answer 5

granulation tissue is simply to do with wound healing as is protruding tissue as a wound heals. it has no nerves and is very vascular. granulomatous diseases are that which have macrophages predominating the inflammatory response.

Question 6

There are 3 ways to classify granulomatous diseases, what are they?

Answer 6

1. with/without granulomas
2. by the cells that are present
3. aetiology - what caused it?

Question 7

with /without a granuloma is one way to classify, how? what is a granuloma? if no granuloma then what would it look like?

Answer 7

not all granulomatous diseases can cause granulomas
a granuloma is a focally discrete, closely packed, aggregate of macrophages surrounded by lymphocytes and plasma cells and a rim of fibroblasts. - it may or may not have a central necrotic area.

it may also be mineralised? if no gramuloma then it may just be thickened and inflammed.

Question 8

how would you classify according to the cells present?

Answer 8

1. granulomatous disease - macrophages and giant cell and lymphocytes. (mainly macro)
2. eosinophillic granulomatous disease - macrophages plus eosinophils. common in a cat or horse. eg. feline eosinophillic granuloma complex.
3. pyogranulomas - macrophages plus neutrophils. eg. wooden tongue. or actinomyces bovis (lumpy jaw in bone)

Question 9

what do equine eosinophils look like?

Answer 9

they are very pink and many granules are seen.

Question 10

how would you classify granulomatous disease by the aetiology?

Answer 10

could be bacteria, parasite, fungi, foreign material.

Question 11

what are the characteristics of a bacterial granulomatous disease?
what normally happens to bacteria?

Answer 11

they have the ability to survive within macrophages. eg. mycobacteria, salmonella. plus they may have resistance to antibiotics because of this. (cell wall features) normally bacteria are phagocytosed by macrphages and the vesicles they are in will then fuse to a lysosome to form a phagolysosome and this is excreted by exocytosis.

Question 12

what stain do you use for bacteria within a cell?

Answer 12

Zeihl neelsen stain shows them up red.

Question 13

what are the characteristis of a parasitic granulomatous disease?

Answer 13

eg. lungworm. eg. muellerius cappilaris (sheep) - grey lesions on dorsal surface of lung - may see larvae within the parenchyma.
or dictyocaulus viviparus (cattle)

Question 14

what are the characteristics of a fungal granulomatous disease?

Answer 14

eg. aspergillus spp.

they are opportunistic eg. if immunocompromised. -viral infection of the gut. antibiotics work.

Question 15

name two viruses that cause granulomatous disease?

Answer 15

1. feline coronavirus causes FIPV - LIVES IN MACROPHAGES.

2. porcine circovirus (causes PMWS)

Question 16

Explain FIPV? what would you see on PM? closely related to? which all cats have. what mutates?

Answer 16

FELINE INFECTIOUS PERITONITIC VIRUS. caused by feline coronavirus. lives in them macrophages. pathology is as a result of the vasculitis. wet and dry forms. very closely related to FECV - feline enteric coronavirus (harmless) 3c gene mutates in so,e cats and virus becomes FIPV. infected macrophages accumulate around small vessels and cause vasculitis - deposits immune complexes.

see fluid in abdomen (ascites) and yellow dots of fibrin due to the vasculitis.

clinical signs are wet: fever inappentence, weight loss, abdominal distention, dyspnea - effusion of thorax.

dry: eyes and CNS. kidney liver and lymph nodes.

Question 17

PMWS.? what is it? caused by?

Answer 17

porcine cirvovirus -2 causes PCVAD (porcine circovirus associated diseases. eg. PMWS (post weaning multisystemic wasting syndrome.

weight loss, jaundice, hard to breath, lymph nodes, inflamm in lungs, liver and kidneys (lymphangitis)

Question 18

how does foreign material cause a granulomatous disease?

Answer 18

difficult for macrophages to break down. eg. dust hair sperm - aspiration pneumonia - swabs left inside.

Question 19

feline eosinohillic granuloma complex? 3 diseases?

Answer 19

• feline eosinophillic granuloma (skin, pads, alopecia)
• eosinophillic plaque - pruritic, lymphocytes
• indolent ulcer - upper lip. adjactent to philtrum - mast cells too.

Question 20

mycobacteria cause? what happens? 4 types?

Answer 20

intracellular survival allows them to cause granulomas - specialised cell wall - survive in granulomas.
granulomas form to wall off the disease.

M.BOVIS - TB in cattle, human
M.TUBERCULOSIS - TB in human
m.leprae - leprosy in cat
m.a.paratuberculosis - johnes /paratb. chronic enteritis. wieght loss and diarrhoea in cattle sheep etc.

Question 21

what happens in johnes. what is it caused by? sheep have two types?

Answer 21

thickened and corrugated small intestine. sometimes sheep mucosa is yellow. terminal ileum often affected. swollen lymphatics. enlarged mesenteric lymph nodes.

2 types in sheep:

• multibacillary - macrophages/giant cells, acid fast bacteria - stain with ZN .
• paubacillary - lymphocytes/plasma cells. few bacteria so may get false negatives from faeces test. stunted thick villi and cells.

cattle rarely have paucibacillary form.

Question 22

what do you see with m.bovis?

Answer 22

tb in cattles. classic granulomas in resp tract/lungs/systemic. signs can be very subtle. tested for regularly in UK. badgers spread?