INFLAMMATION & REPAIR

Transcription

1 INFLAMMATION & REPAIR Histopath Laboratory 1 Winter 2013 Chelsea Martin Special thanks to Drs. Hanna and Forzan

2 Goals: Examine Tissue and Identify the Organ Describe the lesion, grossly and histologically Formulate a Morphologic Diagnosis Suggest possible etiologies

3 Case 1 5-month-old calf recently purchased with 4 other calves from Nova Scotia. Four days after traveling to the Island the calf was off feed and standing with neck in full extension. Harsh lung sounds were auscultated on both sides of the thorax.

4 Normal lung

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7 GROSS CHANGES Description: The right lung has extensive cranio-ventral areas of consolidation and dark-red discoloration. Much of the overlying pleural surface has large deposits of stringy yellow material (fibrin). The pleural cavity contains abundant cloudy, red-tinged fluid with some strands of fibrin. Pulmonary lobules are firm and dark red on cut section. The interlobular septa are expanded, firm and yellow (due to the presence of fibrin).

8 Subgross image. Note: Pleura, Air spaces Perivascular spaces

9 What is the material overlying the pleural surface and causing thickening of interlobular septae?

10 ** * The material is fibrin [loose * and clumped **] admixed with inflammatory cells.

11 Q: What are these dilated structures* in the interlobular septa? Q: What is their function? * *

12 Q: A: The What structures are these are dilated structures lymphatic in vessels the interlobular filled with septa?* fibrin, Q: neutrophils What is their and function? other debris. A: Their function is to remove the fibrin and suppurative exudate, as well as any other debris to be cleaned up in the lymph nodes. * *

13 Q: What type of necrosis is occurring in the pink (eosinophilic) area? * **

14 A: Liquefactive / caseous necrosis* (complete loss of tissue architecture) and coagulative necrosis **(you can still see the ghost-like outline of the alveoli). * **

15 * ** ** In non-necrotic areas; note bronchiole* and alveoli** filled with debris and inflammatory cells.

16 ** * Alveoli (& airways) are filled with varying mixtures of inflammatory cells* & fibrin**. Most of the inflammatory cells are neutrophils and most of these are degenerate (dying) or necrotic (dead)!

17 * *** ** Higher magnification see the necrotic debris (*) and fibrin (**) within the alveoli, mixed in with the degenerate neutrophils (***). There are also small blue dots (arrow), what can they be?

18 MORPHOLOGIC DIAGNOSIS Organ / anatomic subtype Exudate Distribution Duration Extent BRONCHOPNEUMONIA FIBRINONECROTIZING and SUPPURATIVE LOCALLY EXTENSIVE ACUTE SEVERE Cause / Etiology: Mannheimia haemolytica Etiologic Diagnosis: Mannheimia Bronchopneumonia / Pneumonic Mannheimiosis Name the Disease: Shipping Fever Pneumonia M. Haemolytica has a leukotoxin that binds to the surface of neutrophils and macrophages leading to the formation of pores which are fatal to the cell, resulting in ineffective killing / clearance of pathogen. Abundant fibrin and foci of coagulative necrosis are characteristic!

19 Case 2 uterus submitted from a 6-year-old, female dog. presented with a history of polyuria and polydipsia for 1 week and partial anorexia for last three days. never had puppies. last heat 4 weeks ago.

20 GROSS CHANGES Description: The uterine horns are markedly distended with abundant amounts of darkbrown, turbid, watery fluid (purulent exudate). The adventitial surface (perimetrium) is diffusely red and has distended blood vessels (hyperemia). The endometrium is moderately thickened. Both ovaries have multiple cystic structures and prominent corpora lutea.

21 Tissue: uterus Perimetrium / serosal surface Myometrium Endometrium Lumen

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23 Higher magnification of exudate what is the most numerous cell? Neutrophils

24 Lamina propria What other cells are present? A: Although neutrophils are near the lumen, in the lamina propria the majority are plasma cells

25 Plasma cells Neutrophils

26 Serosal Surface

27 And, these ones? Mostly lymphocytes

28 MORPHOLOGIC DIAGNOSIS? Organ + itis Exudate Distribution Duration Extent (ENDO)METRITIS SUPPURATIVE DIFFUSE SUBACUTE SEVERE Etiologic Diagnosis: Bacterial (Endo)Metritis Name the Disease: Pyometra

29 Pyometra pyometra in the unspayed female dog, particularly those that are not bred, is not uncommon. it is believed to be the result of hormonal abnormalities with secondary bacterial infection of the uterus. the most common bacterium involved is E. coli how does it get there?