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

Shannon Martinson, Feb 2016 http://people.upei.ca/smartinson/

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)

Case #1

Case #1

• Pale yellow gelatinous fluid expands the subcutaneous tissue in the submandibular region

Description?

Case #1

• Submandibular subcutaneous edema (“bottle jaw” is the common term for this lesion)

Morphologic Diagnosis?

Case #1

• Submandibular subcutaneous edema (“bottle jaw” is the common term for this lesion)

Morphologic Diagnosis?

• The carcass/organs are pale and clear gelatinous fluid expands the mesentery of the spiral colon

Description?

Case #1

Case #1

• It suggests anemia

What does pallor indicate?

Hydropericardium

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Is the edema localized or generalized? Which of the following processes could this be due to? ↓Plasma colloidal osmotic

pressure Lymphatic obstruction ↑ Blood hydrostatic pressure ↑Vascular permeability

Generalized

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Possible causes of decreased colloidal pressure

• Protein losing gastrointestinal disease

• Protein losing nephropathy

http://parasites-world.com

http://sciencewatch.com

Case #1

• Numerous slender white and red worms (barber pole appearance) are present in the abomasum

Description?

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:

Case #1

Morphologic Diagnosis:

• Anemia, generalized subcutaneous edema and hydropericardium, severe

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)

Case #1

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.

Signalment and History:

• Pregnant dairy cow that was found dead in the morning

Necropsy:

• Lungs were abnormal

• Twin fetuses were found in the uterus

Case #2

Case #2

Normal lung

Case #2

• Abundant froth is present in the trachea

• The lungs are red, wet and heavy and pale gelatinous fluid expands the interlobular septa

Description?

Case #2

• Froth exudes from the airways on section

Description?

Case #2

Case #2

• Many of the lymphatics in the pleura are dilated

Description?

Case #2

• Many of the lymphatics in the interlobular septa are dilated

Description?

Case #2

Case #2

• There is diffuse congestion of the alveolar capillaries with widespread flooding of alveolar spaces with protein rich fluid

Description?

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:

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.

Give two possible mechanisms for the edema fluid in the alveolar spaces.

Morphologic Dx: Pulmonary congestion and edema, diffuse, acute, severe

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.

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.

Morphologic Dx: Pulmonary congestion and edema, diffuse, acute, severe

Case #2

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

Case #3

Ross Elliott, Flickr

Case #3

• The lungs are dark red, wet and heavy

Description?

• Pulmonary edema and congestion

Morphologic Diagnosis

Case #3

• The heart is enlarged and globose, with dilation of the chambers and thinning of the ventricular walls

Description?

Case #3

Normal lung

Case #3

Case #3

• Edema (clear space) and connective tissue expand the bronchovascular interstitium

• Lymphatics in this region are dilated

Description?

Case #3

Case #3

• The alveolar septa are thickened with excess fibrous tissue and congestion of the blood vessels

Description?

Case #3

• Macrophages are present in the alveolar spaces

• These cells contain brown-gold cytoplasmic pigment

Description?

Case #3

• Macrophages are present in the alveolar spaces

• These cells contain brown-gold cytoplasmic pigment

Description?

Case #3

• Pigment within macrophages stains blue with Prussian blue stain (for iron) - the pigment is hemosiderin

Description?

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)

Morphologic Dx: Pulmonary congestion & edema, diffuse, chronic, severe

Case #3

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

Case #4

Case #4

• On section, the liver has an enhanced reticular pattern with alternating areas of reddish-brown and pale tan discolouration

Description?

What is the common term for this appearance: Nutmeg Liver

Case #4

Normal liver

Case #4

Case #4

Case #4

Case #4

Case #4

Case #4

• The sinusoids are dilated and congested

• There is atrophy and necrosis (loss) of hepatocytes

Zone 3 (centrilobular)

• Hepatocytes have lipid vacuoles in the cytoplasm (fatty degeneration)

Zone 2 (midzonal)

• Normal hepatocytes

Zone 1 (periportal)

Description

Morphologic Diagnosis:

Case #4

Comment:

• What would be the likely cause of this lesion?

• Right-sided heart failure

• Tricuspid valvular endocarditis

• Cor pulmonale

• Cardiomyopathy

Morphologic Diagnosis: Hepatic congestion, centrilobular, subacute, marked

Case #4

Questions?