Test 2: lab 3 Flashcards
Heart from a 10-year-old golden retriever dog that presented for acute lethargy and collapse. On physical examination, the dog had pale mucous membranes and muffled heart sounds.
Description:
Morphologic diagnosis:
SALTD
DSSCLL
An approximately 3 cm x 2 cm X 1 cm region of the right auricle is effaced by an infiltrative, firm, dark red mass.
Right atrial hemangiosarcoma
Right atrial hemangiosarcoma
What are potential sequelae if this mass ruptures?
Rupture of right atrial hemangiosarcoma → bleeding into the pericardial cavity (hemopericardium) → rapidly increased pressure within pericardial cavity → compression of the heart with decreased cardiac filling (cardiac tamponade) → cardiogenic shock (can be fatal)
What are other common sites for hemangiosarcoma
in dogs
Spleen, liver, and skin are other common sites. German Shepherds, Golden Retrievers, Portuguese Water Dogs and Labrador Retrievers are over-represented.
Name some other neoplasms primary to the heart (or heart base)?
Chemodectoma (aortic body/carotid body tumors), lymphosarcoma, rhabdomyosarcoma.
cat heart
This heart weighs 24 grams. Normal weight of a feline heart is approximately 14-18 grams.
Description:
Morphologic diagnosis:
The heart is severely enlarged with diffuse thickening of the left ventricular wall.
Severe cardiomegaly with diffuse left ventricular hypertrophy
Name the most likely type of cardiomyopathy IF this were a PRIMARY disease of the cat heart:
Hypertrophic cardiomyopathy (HCM)
What is the typical age and sex of cats with HCM and which breeds are predisposed
HCM is the most common primary myocardial disease in cats. The typical patient is a young adult to middle-aged male. Maine coon, and ragdoll, Persian, Bengal breeds are over-represented.
Name the most likely disease if cardiomegaly is SECONDARY disease of the heart. What other organ would you expect to have pathologic changes?
Thyrotoxic cardiomegaly secondary to feline hyperthyroidism. An associated lesion would be adenomatous hyperplasia of one or both thyroid glands.
DOG HEART
Description:
Name the type of cardiomyopathy this represents:
The left ventricle is severely dilated, and the ventricular wall is thin.
Dilated cardiomyopathy (DCM)
What are potential causes of the dilated cardiomyopathy in a dog?
DCM can be primary (heritable) in several breeds of dog, including Doberman pinschers, Boxers and Great Danes. This particular case came from a dog who was fed a grain-free diet; some formulations of grain-free diets particularly including various types of peas, lentils, or potatoes have been linked to the development of DCM in dogs. Studies on this are still ongoing.
A variant of this type of cardiomyopathy is found in boxers and English bulldogs. What is the name of that specific cardiomyopathy, and what are the gross changes to the heart with that disease?
Arrhythmogenic right ventricular cardiomyopathy. The typical gross changes include replacement of the myocytes of the right ventricle by adipose or fibroadipose tissue. The right ventricle is dilated in about 1/3 of Boxers with this disease. Patients may die suddenly of an arrhythmia.
Dog with a history of exercise intolerance, cough, and heart murmur.
Description (hint: there are two lesions to describe):
Morphologic diagnoses:
The margins of the mitral valve leaflets are multifocally thickened and distorted by several 1-3 mm diameter, smooth, firm, glistening, pale tan nodules. Within the left atrium superior to the mitral valve, two approximately 1.5 cm linear regions of the endocardium and subendocardial tissue are roughened, irregularly raised, and white.
- Severe multifocal chronic mitral valvular endocardiosis.
- Moderate multifocal chronic subendocardial fibrosis (jet lesions).
What is the relationship between valves and jet lesions?
Valvular endocardiosis → improper closure of valve leaflets → abnormal jets of blood regurgitating into the atrium → chronic mechanical irritation of the atrial surface → focal fibrosis and inflammation of the atrial endocardium and subendocardial tissue (jet lesion)
What do the nodules on the valve leaflets consist of?
chronic mitral valvular endocardiosis
The nodules are myxomatous degenerative lesions consisting of proliferations of loose, fibroblastic tissue with deposition of mucopolysaccharides. Inflammation is NOT a feature.
pig
Description:
Morphologic diagnosis:
The valve leaflets are severely thickened and effaced by multiple coalescing 0.2-1.8 cm diameter, friable, tan to red, rough masses.
Severe multifocal to coalescing subacute vegetative endocarditis
What do the proliferations on the valve leaflets with vegetative endocarditis
consist of?
The proliferative lesions on the valve consist of abundant fibrin, bacteria, and neutrophils, with granulation tissue and fibrosis developing with chronicity.
Pathogenesis of vegetative endocarditis
Persistent bacteremia (many potential causes) → adhesion of the bacteria to the valve at the site of minor endocardial damage (usually at the lines of valve apposition) → proliferation of bacteria with further endothelial damage and inflammation → growth of septic thrombus on valve (vegetative valvular endocarditis)
What lesions might you see in other organs with vegetative endocarditis
As pieces of the thrombi break off, they can form thromboemboli and potentially carry bacteria (septic thromboemboli). From the left side of the heart, the thromboemboli can lead to infarcts and localized inflammation in the kidneys, brain, and other organs. From the right side of the heart, the thromboemboli can lodge in the pulmonary arteries of the lungs. The mitral (left AV) valve is the most common site of vegetative valvular endocarditis in most species, so renal infarcts are a common associated finding.
sheep
Description
Morphologic diagnosis:
Approximately 60% of the epicardial (visceral pericardial) surface is covered by strands and mats of pale tan to yellow material (fibrin).
Severe diffuse acute fibrinous pericarditis
Possible routes of infection and possible etiologic agents that causes acute fibrinous pericarditis
Routes of infection include hematogenous spread of bacteria, direct penetration into the pericardial sac, or local extension from the myocardium or other adjacent structures. Common bacterial agents include Haemophilus parasuis, Pasteurella, E. coli, Streptococcus, or Salmonella.
If the disease progresses to a chronic stage, how will heart function be affected?
With time, the fibrin may be replaced by collagenous tissue (fibrosis). If severe enough, the fibrosis can constrict the heart and cause a decrease in cardiac filling/output, resulting in congestive heart failure.
Similar but more suppurative lesions can be seen in cows with traumatic reticulopericarditis (hardware disease). Outline the pathogenesis of traumatic reticulopericarditis:
Cow ingests a metallic foreign body → foreign body penetrates wall of reticulum → perforation of diaphragm and pericardium → inoculation of pericardium and pericardial cavity with bacteria from the reticulum → fibrinosuppurative pericarditis
Description
Name the condition:
A short, narrow band of fibrous tissue passes between the pulmonary artery and the aorta, which in this animal is descending to the right rather than the left. As the ligamentum crosses over the esophagus, it compresses it. The esophagus proximal to the partial obstruction is dilated.
Persistent right aortic arch
What is the name of the band of tissue crossing and compressing the esophagus?
What clinical effects could this condition cause?
Ligamentum arteriosum, the remnant of the ductus arteriosus which was patent in the fetus.
Megaesophagus can lead to regurgitation and aspiration pneumonia.
