Chapter 13 Granulomatous disease

Question 1

What are hypersensitivity reactions also known as?

Answer 1

Immunopathologic reactions.

Question 2

What is cell-mediated hypersensitivity also referred to as?

Answer 2

Delayed-type hypersensitivity reaction or hypersensitivity type IV reactions.

Question 3

What characterizes a delayed-type hypersensitivity reaction?

Answer 3

Sensitization of T cells leading to a chronic inflammatory response with prominent macrophage activation.

Question 4

What are the possible sources of antigens that trigger cell-mediated immunopathologic reactions?

Answer 4

Environmental, self, microbial, or parasitic antigens.

Question 5

What types of chronic diseases can be caused by microbial antigens?

Answer 5

Mycobacterium tuberculosis and Mycobacterium leprae infections.

Question 6

What are granulomas?

Answer 6

Circumscribed collections of macrophages, epithelioid cells, and multinucleated giant cells, indicating a focal, chronic inflammatory response.

Question 7

What are common clinical manifestations of cell-mediated immunopathologic reactions?

Answer 7

Chronic inflammation, mononuclear cell infiltration, tissue necrosis, fibrosis, and angiogenesis.

Question 8

What types of inflammatory cells can be involved in granulomatous diseases?

Answer 8

Macrophages, lymphocytes, neutrophils, eosinophils, basophils, mast cells, and plasma cells.

Question 9

What are the main steps in the pathogenesis of cell-mediated immunopathologic reactions?

Answer 9

Antigen uptake by APCs, antigen processing and presentation via MHC molecules, T cell sensitization, and chronic inflammation.

Question 10

What roles do Th1 and Th17 cells play in granulomatous inflammation?

Answer 10

Th1 cells activate macrophages leading to granulomatous inflammation, while Th17 cells recruit neutrophils resulting in pyogranulomatous inflammation.

Question 11

What is the diagnostic approach for granulomatous diseases?

Answer 11

History, clinical presentation, and histopathologic evaluation of biopsy specimens.

Question 12

What are some histologic staining techniques used to detect microbial agents in granulomatous diseases?

Answer 12

GMS, PAS, and acid-fast staining.

Question 13

What is the treatment focus for delayed hypersensitivity reactions?

Answer 13

Eliminating the underlying cause, controlling clinical signs, and minimizing complications.

Question 14

What is the role of glucocorticoids in treating granulomatous diseases?

Answer 14

They are used for immunosuppression to control the inflammatory response.

Question 15

What are the side effects of long-term corticosteroid therapy in horses?

Answer 15

Polyuria, polydipsia, laminitis, and secondary infections.

Question 16

What is azathioprine used for in horses?

Answer 16

Immunosuppressive therapy, especially for immune-mediated diseases.

Question 17

What are the characteristics of equine sarcoidosis?

Answer 17

Multifocal skin lesions, granulomatous lesions in internal organs, weight loss, anorexia, icterus, low-grade fever, and peripheral lymphadenopathy.

Question 18

What are common etiologic agents associated with multisystemic granulomatous diseases?

Answer 18

Coccidioides, Mycobacterium avium, Blastomyces spp., and Bacillus Calmette-Guerin.

Question 19

What are the clinical signs of coccidioidomycosis in horses?

Answer 19

Weight loss, intermittent fever, respiratory disease, lameness, abortion, colic, and peritoneal effusion.

Question 20

What is the primary diagnostic method for coccidioidomycosis?

Answer 20

Cytology and culture of tracheobronchial washes, histologic evaluation of tissues, and serology.

Question 21

What are the signs of disseminated mycobacterial infection in horses?

Answer 21

Depression, intermittent fever, weight loss, lymphadenopathy, and chronic diarrhea.

Question 22

What are the common clinical signs of allergic contact dermatitis in horses?

Answer 22

Maculopapular or lichenified skin lesions with varying degrees of pruritis.

Question 23

What is equine collagenolytic granuloma also known as?

Answer 23

Eosinophilic granuloma or nodular necrobiosis.

Question 24

What are the histopathologic features of eosinophilic granuloma?

Answer 24

Eosinophilic granulomatous reaction surrounding areas of degenerated collagen.

Question 25

What are common clinical signs of ulcerative granulomas of the skin?

Answer 25

Single or multiple nodular lesions that erode to ulcerative areas with moderate to severe pruritis and serosanguinous discharge.

Question 26

What are the diagnostic steps for ulcerative granulomas?

Answer 26

Histologic evaluation of biopsies, bacterial and fungal cultures, and special staining techniques.

Question 27

What is the treatment for fungal granulomas and pythiosis?

Answer 27

Combination of surgical resection, anti-fungal drugs, and possibly immunotherapy with autologous vaccine.

Question 28

What are the common etiologic agents of respiratory granulomatous diseases?

Answer 28

Silicosis, coccidioidomycosis, aspergillosis, pneumocystosis, histoplasmosis, cryptococcosis, and idiopathic causes.

Question 29

What are the clinical signs of hypersensitivity pneumonitis in horses?

Answer 29

Exercise intolerance, dyspnea, labored breathing, weight loss, and fever.

Question 30

What is pyogranulomatous bronchopneumonia in foals typically caused by?

Answer 30

Virulent strains of Rhodococcus equi.

Question 31

What are the common clinical signs of Rhodococcus equi infection in foals?

Answer 31

Chronic pneumonia, fever, lethargy, coughing, anorexia, tachypnea, labored breathing, tachycardia, nasal discharge, failure to grow, and weight loss.

Question 32

What is the primary treatment for pyogranulomatous pneumonia associated with Rhodococcus equi?

Answer 32

Antimicrobials, supportive care, and possibly oxygen therapy.

Question 33

What are chronic idiopathic inflammatory bowel diseases in horses?

Answer 33

A group of conditions characterized by immune cell infiltration of the bowel wall, including granulomatous enteritis, MEED, lymphocytic-plasmacytic enterocolitis, and idiopathic eosinophilic enterocolitis.

Question 34

What are the common clinical signs of chronic idiopathic inflammatory bowel diseases in horses?

Answer 34

Recurrent colic, depression, weight loss, hypoproteinemia, and impaired glucose or xylose absorption.

Question 35

What is the proposed etiology of granulomatous enteritis?

Answer 35

Diffuse granulomatous inflammation with epithelioid macrophages and giant cells in the intestinal wall.

Question 36

What is polyneuritis equi?

Answer 36

A progressive dysfunction of the nerves of the cauda equina and cranial nerves in adult horses.

Question 37

What are the clinical signs of polyneuritis equi?

Answer 37

Dysuria, urinary incontinence, tail hyperesthesia followed by hypoesthesia, diminished tail, anal, and perineal tone, hypotonicity and atrophy of muscles, paresis and ataxia of the pelvic limbs, and cranial nerve paralysis.

Question 38

What characterizes the granulomatous inflammation in polyneuritis equi?

Answer 38

Perineural inflammatory infiltrate of T and B lymphocytes, macrophages, giant cells, plasma cells, eosinophils, and neutrophils.

Question 39

What is the management approach for polyneuritis equi?

Answer 39

Supportive care, with possible immunosuppression using systemic corticosteroids and/or azathioprine.

Question 40

What is the role of Th1 and Th17 cells in granulomatous inflammation?

Answer 40

Th1 cells activate macrophages, leading to granulomatous inflammation, while Th17 cells recruit neutrophils, resulting in pyogranulomatous inflammation.

Question 41

What are the typical features of chronic inflammatory response in granulomatous diseases?

Answer 41

Prominent infiltration of mononuclear cells, tissue destruction, fibrosis, and angiogenesis.

Question 42

What are the immunologic mechanisms behind cell-mediated hypersensitivity reactions?

Answer 42

T cells recognize antigen fragments presented by MHC molecules on APCs, leading to T cell sensitization and chronic inflammation.

Question 43

What are the common clinical signs of equine sarcoidosis?

Answer 43

Multifocal skin lesions, granulomatous lesions in internal organs, weight loss, anorexia, icterus, low-grade fever, and peripheral lymphadenopathy.

Question 44

What is the role of glucocorticoids in treating granulomatous diseases?

Answer 44

They suppress the immune response to control inflammation and tissue damage.

Question 45

What are the diagnostic criteria for granulomatous enteritis in horses?

Answer 45

Histopathologic evaluation showing diffuse granulomatous inflammation with epithelioid macrophages and giant cells.

Question 46

What are the potential complications of untreated granulomatous diseases?

Answer 46

Chronic inflammation, tissue necrosis, fibrosis, and potential progression to systemic involvement.