Disturbances of Circulation, Lab 1: Edema and Congestion/Hyperemia. Shannon Martinson, Feb

Transcription

1 Disturbances of Circulation, Lab 1: Edema and Congestion/Hyperemia Shannon Martinson, Feb

2 Case #1 Signalment and History: 6-month old feeder lamb found dead on pasture Necropsy findings: Poor body condition (emaciated) Pale mucous membranes (conjunctiva) Fluctuant, swollen area in submandibular / ventral neck region (not red or painful)

3 Case #1 Description? Pale yellow gelatinous fluid expands the subcutaneous tissue in the submandibular region

4 Case #1 Morphologic Diagnosis? Submandibular subcutaneous edema ( bottle jaw is the common term for this lesion)

5 Case #1 Morphologic Diagnosis? Submandibular subcutaneous edema ( bottle jaw is the common term for this lesion)

6 Case #1 Description? The carcass/organs are pale and clear gelatinous fluid expands the mesentery of the spiral colon

7 Case #1 Hydropericardium What does pallor indicate? It suggests anemia

8 Case #1 Is the edema localized or generalized? Generalized Which of the following processes could this be due to? Plasma colloidal osmotic pressure ** Lymphatic obstruction Blood hydrostatic pressure Vascular permeability

9 Case #1 Possible causes of decreased colloidal pressure Protein losing gastrointestinal disease Protein losing nephropathy

10 Case #1 Description? Numerous slender white and red worms (barber pole appearance) are present in the abomasum

11 Case #1 Description: This lamb had severe anemia and generalized edema: subcutaneous edema (esp in submandibular region = bottle jaw ), hydropericardium and edema of mesenteric connective tissues The abomasum contained abundant brown-black fluid with myriads of Haemonchus type nematodes (red / white barber-pole morphology) Abomasal content was collected and sent to the Parasitology lab: Total worm count = 10,350 Nematodes (~9,000 Haemonchus spp) Morphologic Diagnosis:

12 Case #1 Description: This lamb had severe anemia and generalized edema: subcutaneous edema (esp in submandibular region = bottle jaw ), hydropericardium and edema of mesenteric connective tissues The abomasum contained abundant brown-black fluid with myriads of Haemonchus type nematodes (red / white barber-pole morphology) Abomasal content was collected and sent to the Parasitology lab: Total worm count = 10,350 Nematodes (~9,000 Haemonchus spp) Morphologic Diagnosis: Anemia, generalized subcutaneous edema and hydropericardium, severe Comment: The lesions and parasitology findings are diagnostic for Abomasal haemonchosis At necropsy, counts of 3,000+ Haemonchus contortus in lambs and 9,000+ in adult sheep are usually associated with heavy mortalities.

13 Case #2 Signalment and History: Pregnant dairy cow that was found dead in the morning Necropsy: Lungs were abnormal Twin fetuses were found in the uterus

14 Case #2 Normal lung

15 Case #2 Description? Abundant froth is present in the trachea The lungs are red, wet and heavy and pale gelatinous fluid expands the interlobular septa

16 Case #2 Description? Froth exudes from the airways on section

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18 Case #2 Description? Many of the lymphatics in the pleura are dilated

19 Case #2 Description? Many of the lymphatics in the interlobular septa are dilated

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21 Case #2 Description? There is diffuse congestion of the alveolar capillaries with widespread flooding of alveolar spaces with protein rich fluid

22 Case #2 Description: Many of the lymphatics in the pleura and interlobular septa are dilated. There is prominent diffuse congestion of the alveolar interstitium with patchy to widespread flooding of alveolar spaces with protein rich fluid. Morphologic Dx:

23 Case #2 Description: Many of the lymphatics in the pleura and interlobular septa are dilated. There is prominent diffuse congestion of the alveolar interstitium with patchy to widespread flooding of alveolar spaces with protein rich fluid. Morphologic Dx: Pulmonary congestion and edema, diffuse, acute, severe Give two possible mechanisms for the edema fluid in the alveolar spaces.

24 Case #2 Description: Many of the lymphatics in the pleura and interlobular septa are dilated. There is prominent diffuse congestion of the alveolar interstitium with patchy to widespread flooding of alveolar spaces with protein rich fluid. Morphologic Dx: Pulmonary congestion and edema, diffuse, acute, severe Give two possible mechanisms for the edema fluid in the alveolar spaces. 1. Inflammation of the lung (=pneumonia) Causes hyperemia and inflammatory edema. The edema is due to endothelial contraction/ damage from inflammatory mediators &/or the inciting agent 2. Left-sided heart failure. Left heart failure blood backs up in the pulmonary veins congestion and edema (increased hydrostatic pressure). In more chronic/severe cases of left-sided failure, RBCs escape into the alveolar spaces (via diapedesis) where they will be phagocytosed by alveolar macrophages.

25 Case #3 Signalment and History: An adult silver fox (fur farm) with a 2 week history or respiratory distress. Necropsy: Pale mucous membranes The pleural & abdominal cavities each had ~100 mls of straw-colored fluid The lungs were heavy (~2X normal weight), dark red, and wet The heart was globoid Ross Elliott, Flickr

26 Case #3 Description? The lungs are dark red, wet and heavy Morphologic Diagnosis Pulmonary edema and congestion

27 Case #3 Description? The heart is enlarged and globose, with dilation of the chambers and thinning of the ventricular walls

28 Case #3 Normal lung

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30 Case #3 Description? Edema (clear space) and connective tissue expand the bronchovascular interstitium Lymphatics in this region are dilated

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32 Case #3 Description? The alveolar septa are thickened with excess fibrous tissue and congestion of the blood vessels

33 Case #3 Description? Macrophages are present in the alveolar spaces These cells contain brown-gold cytoplasmic pigment

34 Case #3 Description? Macrophages are present in the alveolar spaces These cells contain brown-gold cytoplasmic pigment

35 Case #3 Description? Pigment within macrophages stains blue with Prussian blue stain (for iron) - the pigment is hemosiderin

36 Case #3 Morphologic Dx: Pulmonary congestion & edema, diffuse, chronic, severe Comment: What tells us that the lesions in this case are chronic? It takes time for the macrophages to produce hemosiderin granules from the phagocytosed erythrocytes There is also thickening of the alveolar septa with fibrous tissue scarring takes weeks What s the mechanism of the pulmonary changes? Decreased venous drainage due to left heart failure congestion Increased hydrostatic pressure due to left heart failure pulmonary edema What s the term used for alveolar macrophages filled with hemosiderin? heart failure cells What was the cause of the heart disease in this fox? Foxes (and cats) can develop dilated cardiomyopathy (injury to cardiac myocytes) due to taurine deficiency in the diet. Often see both right and left heart failure which leads to pulmonary edema (due to left heart failure) and ascites / hydrothorax (due to right heart failure)

37 Case #4 Signalment and History: 1-year-old Ayrshire heifer Necropsy Animal was emaciated Edema present within mesentery and omentum Moderate ascites and marked hydrothorax. Liver was enlarged with rounded edges

38 Case #4 Description? On section, the liver has an enhanced reticular pattern with alternating areas of reddish-brown and pale tan discolouration What is the common term for this appearance: Nutmeg Liver

39 Case #4 Normal liver

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45 Case #4 Description Zone 3 (centrilobular) The sinusoids are dilated and congested There is atrophy and necrosis (loss) of hepatocytes Zone 2 (midzonal) Hepatocytes have lipid vacuoles in the cytoplasm (fatty degeneration) Zone 1 (periportal) Normal hepatocytes

46 Case #4 Morphologic Diagnosis:

47 Case #4 Morphologic Diagnosis: Hepatic congestion, centrilobular, subacute, marked Comment: What would be the likely cause of this lesion? Right-sided heart failure Tricuspid valvular endocarditis Cor pulmonale Cardiomyopathy

48 Questions?