Sunday, February 7, 2016
Myrna Loy's Necropsy from After Her Death of 8/19/15
The following is the necropsy (autopsy) report of Myrna Loy after her death 8/19/15 of HCM.
The report shows various physical changes and damage to the heart, kidneys, and lungs due to HCM which were somewhat known, and most of which is to be expected with heart disease. The report drills down the damage to the cellular level which may be of interest.
Part of the problem of dealing with congestion was that the damage to the thoracic duct allowed an acidic like fluid to flow from the duct into the lungs. This opaque, milky-white fluid is called chylous or chylothorax. It created pockets in the pleural cavity, pockets where fluid formed and remained and was often difficult to remove. We tried to decrease it by giving Myrna Rutin. Apparently, once chylous appears, the pet is not expected to live for very long due to the damage chylous causes and because its appearance means further left sided heart damage, which means a heart that is failing. Myrna lived eight months after it first appeared in December 2014. When we delivered her body to MSU for the necropsy, the receiving vet was surprised to read that she had lived eight months with the condition and had lived eight months with an almost constant need to have fluid removed from the pleural cavity.
While the report notes signs of hypertension-or high blood pressure-at no time at the end of her life did she have hypertension/high bp noted by a vet or cardiologist. She had an occurrence in 2013 after her heart attack but no further signs once it cleared up.
The report notes mild kidney disease. We worked really hard to see that her kidneys retained as much function as possible. The various vitamins, supplements, potassium, and iron that we gave her improved kidney function and allowed te BUN and creatinine to remain stable. The numbers had increased beginning in September 2014 but remained fairly stable to her death (BUN 35, creatine 2.6.) The report's findings about the state of her kidneys are proof that vitamins, supplements, potassium, and iron are necessary for improving kidney support and that they work.
We were surprised to read that there were no gastro issues noted because she had had many vomiting episodes for the last few weeks of her life after her rear leg thrombosis in May. The vomiting was attributed to a clot and her medicines. I suppose it was just the medicines, not to mention my finger constantly in her mouth, that caused the upset stomach. While she weighed about 10lbs. in late 2014, she did lose a lot of weight suddenly in the last few weeks of her life, especially after being sick almost all of July 2015. But I hand fed her every time she was ill and refusing to eat and she never went for very long without eating enough. (Methods can be found in the blog History tab.) Her weight was still good at about 9.8lbs.
After the initial report, I have listed definitions for various phrases used in the report.
Report processed at Michigan State University Veterinary College Diagnostic Center for Population and Animal Health
Rcvd Date: 8/19/2015 11:23:00 AM
Gender: Female, MYRNA LOY, Feline, 6 years, Domestic Shorthair Cat
Received Date/Time: 8/19/2015 12:31:00 PM
Verified Date/Time: 8/20/2015 5:51:05 AM
REPORT OF LABORATORY EXAMINATION
Necropsy Preliminary Report
A 6 year old spayed DSH died on 8/19/15. The cat had a history of clotting secondary to heart disease. Owner is concerned about gastric and renal disease.
A 4.45 kg (9lbs. 8 oz approx) female spayed cat is necropsied on 8/19/15. Autolysis is mild. There are adequate visceral fat stores and the body condition score is 6/9. The eyes are mildly sunken into the orbits, and mucous membranes are pale pink. The thoracic cavity and pericardial sac respectively contain 15-20 ml of red, clear, slightly opaque fluid, and 5 ml of dark red clear fluid. The parietal surfaces of the pericardial sac and pleura are multifocally and loosely adhered to the thoracic wall by numerous fibrinous adhesions. The edges of the cranioventral lung lobes are collapsed and plumb colored. All lung lobes float in formalin. The heart is enlarged weighing 20.1 g (0.45% of total body weight), and the right ventricular free wall and left ventricular free wall respectively measure 0.1 cm (RVF) and 0.8 cm (LVF). The left atrioventricular valvular leaflets contain numerous, 0.2-0.3 mm in diameter, tan, firm, smooth nodules. Lining the endocardial surface of the left ventricle are ~10, thin, white-pink, string-like bands of connective tissue (moderator bands) bridging the ventricular septum and the left ventricular free wall. The liver has slightly round edges and a prominent reticulated pattern. The cortex of both kidneys is slightly granular. There are no additional remarkable gross lesions.
Left ventricular concentric hypertrophy
Left atrioventricular endocardiosis
Excessive moderator bands
Liver: Mild hepatomegaly and centrilobular congestion
Pericardial sac: Pericardial effusion
Lung: locally extensive atelectasis and mild fibrinous pleuritis
The heart was overall large and the left ventricle was markedly thickened, consistent with hypertrophic cardiomyopathy which is a condition in which the muscle of the heart thickens (especially on the left side) and compromises the contractility and blood-pumping efficiency of the heart. Left sided heart failure often presents clinically with a thoracic/pleural effusion, as seen in this case; however, the slight milky consistency suggest a chylous/lymph component which can occur if there is damage to the thoracic duct. In addition, the large liver and centrilobular congestion are common changes seen in right sided heart failure. There was also evidence of endocardiosis of the mitral valve, and excessive moderator bands, but the significance of these changes in relation to the enlarged heart is unknown. Endocardiosis is a common age related degenerative of the valvular leaflets. If severe, these lesions can cause leaky valves and eventually heart failure, but the changes were mild in this case. Excessive moderator bands have been observed in normal cats and in cats with hypertrophic cardiomyopathy, but the significance is unknown.
Representative sections of brain, eye, heart, lung, liver, spleen, kidney, adrenal gland, thyroid gland with parathyroid gland, bone marrow, stomach, esophagus, and intestine are examined. Within the heart there are severe coalescing regions of myofiber disarray, multifocal myofiber degeneration, and fibrosis. Disarrayed myofibers interweave and are separated by increased loose fibrillar eosinophilic interstitial fibrosis. Multifocal degenerative foci have variable myofiber size and staining with flocculent and hypereosinophilic sarcoplasm and loss of cross striations. There is moderate medial thickening of small caliber vessels in the heart, and kidney. In the kidney, there is mild to moderate, multifocal, segmental, membranous glomerulonephritis and tubular proteinosis. In addition, there is mild multifocal interstitial infiltrates of lymphocytes, plasma cells, fewer neutrophils, and mild fibrosis. Hepatic (liver) sinusoids have mild congestion, which is most prominent around central veins. Within the lung there is severe atelectasis and mild diffuse pulmonary edema characterized by small quantities of pale proteinaceous material and low numbers of macrophages in alveolar spaces. There are no additional remarkable findings.
Heart: Severe myofiber disarray, degeneration, and fibrosis
Lung: Atelectasis, mild edema, and alveolar histiocytosis
Liver: Mild centrilobular congestion
Heart and kidney: Moderate arteriosclerosis
Kidney: Mild to moderate, membranous glomerulonephritis and tubular proteinosis; Mild multifocal lymphoplasmacytic interstitial nephritis and fibrosis
Severe hypertrophic cardiomyopathy with bicavitary effusion and hypertension
Hypertrophic cardiomyopathy is the most common form of heart disease in cats, and although the disease appears inherited in some breeds (i.e., Maine Coon), the exact pathogenesis is unknown. In this case, diminished cardiac function most likely resulted in fluid accumulation in the thoracic cavity, lung, and pericardial sac. There was also evidence of renal disease and thickening of small vessels which are likely attributed to hypertension secondary to heart disease. Although there was a concern of fibrin thrombi and gastric hemorrhage, these changes were not evident during gross or histologic examination. No further testing is currently pending.
Definitions of Words Found in the Necropsy
Severe coalescing (to come together to form a whole) regions of myofiber (myofiber is a multinucleated single muscle cell) in disarray.
"Myofiber disarray" defines a nonparallel arrangement of cardiac myocytes (muscle cells of the heart). The presence of a sufficient quantity of myocardial fibers showing this change is considered to be a specific histological feature of hypertrophic cardiomyopathy.
Multifocal (multiple foci) myofiber-A cylindrical, multinucleate cell composed of numerous myofibrils that contracts when stimulated.
Fibrosis-thickening and scarring
Fibrillar-Any of various threadlike fibers or filaments that are constituent parts of a cell or larger structure. Fibrils make up the contractile part of striated muscle fiber in the body.
Hypereosinophilic- It occurs when an individual's blood has very high numbers of eosinophils.
Eosinophilic -Eosinophils are a type of white blood cell. They help fight off infections and play a role in your body's immune response. They can also build up and cause inflammation...when the body produces too many eosinophils, they can cause chronic inflammation resulting in tissue damage.
Sarcoplasm is the cytoplasm of a myocyte (muscle fiber). The sarcoplasm of a muscle fiber is comparable to the cytoplasm of other cells, but it contains unusually large amounts of glycosomes (granules of stored glycogen) and significant amounts of myoglobin, an oxygen binding protein. The calcium concentration in sarcoplasma is also a special element of the muscular fiber by means of which the contractions take place and regulate.
It contains mostly myofibrils (which are composed of sarcomeres), but its contents are otherwise comparable to those of the cytoplasm of other cells. It has a Golgi apparatus, near the nucleus, mitochondria just on the inside of the cytoplasmic membrane or sarcolemma, as well as a smooth endoplasmic reticulum organized in an extensive network.
Lymphocytes-a form of small leukocyte (white blood cell) with a single round nucleus, occurring especially in the lymphatic system.
Plasma cells, are white blood cells that secrete large volumes of antibodies. They are transported by the blood plasma and the lymphatic system.
Neutrophil granulocytes (also known as neutrophils or occasionally neutrocytes) are the most abundant type of granulocytes and the most abundant (40% to 75%) type of white blood cells in most mammals. They form an essential part of the innate immune system.
Neutropenia-is an abnormally low count of neutrophils, a type of white blood cell that helps fight off infections. The lower your neutrophil count, the more vulnerable you are to infectious diseases.
Proteinaceous material-relating to, resembling, or being protein
Macrophages-type of white blood cell that engulfs and digests cellular debris, foreign substances, microbes, cancer cells, and anything else that does not have the types of proteins specific to the surface of healthy body cells
Arteriosclerosis-thickening, hardening and loss of elasticity of the walls of the arteries. This process gradually restricts the blood flow.
Hyptertension- Blood pressure is determined both by the amount of blood your heart pumps and the amount of resistance to blood flow in your arteries. The more blood your heart pumps and the narrower your arteries, the higher your blood pressure.
Multifocally-Having to do with two or more foci or arising from two or more places.
Fibrinous adhesions-an adhesion that consists of fine threads of fibrin r from an exudate of plasma or lymph, or an extravasation of
Cranioventral is an anatomical description of a direction and means directed "upwards" (cranial) and "to the front" (ventral).
Autolysis- In biology, autolysis, more commonly known as self-digestion, refers to the destruction of a cell through the action of its own enzymes.
Thoracic cavity - The thoracic cavity (or chest cavity) is the chamber of the body of vertebrates that is protected by the thoracic wall (rib cage and associated skin, muscle, and fascia).
The outer layer of the pericardium which is a conical sac of fibrous tissue that surrounds the heart and the roots of the great blood vessels.
Pericardial sac-The pericardium (from the Greek περί, "around" and κάρδιον, "heart") is a double-walled sac containing the heart and the roots of the great vessels. The pericardial sac has two layers, a serous layer and a fibrous layer. It encloses the pericardial cavity which contains pericardial fluid.
Chylothoracic-Chylothorax is a relatively rare condition in the cat in which lymphatic fluid or chyle accumulates in the pleural cavity. It results from lymph formed in the digestive system called chyle accumulating in the pleural cavity due to either disruption or obstruction of the thoracic duct.
Atrioventricular- Pertaining to the atria (the upper chambers of the heart) and the ventricles (the lower chambers of the heart).
Mitral valve (not to be confused with the congenital bicuspid aortic valve) and the tricuspid valve are known collectively as the atrioventricular valves because they lie between the atria and the ventricles of the heart and control the flow of blood.
Endocardial surface of the left ventricle-endocardium is the innermost layer of tissue that lines the chambers of the heart.
Ventricular septum -The interventricular septum (IVS) is the stout wall separating the lower chambers (the ventricles) of the heart from one another. The ventricular septum is directed obliquely backward to the right, and curved with the convexity toward the right ventricle; its margins correspond with the anterior and posterior longitudinal sulci (coronary groove which contains the trunks of the nutrient vessels of the heart, and is deficient in front, where it is crossed by the root of the pulmonary trunk. On the posterior surface of the heart, the coronary sulcus contains the coronary sinus.)
Excessive moderator bands-
The moderator band is a muscular band of heart tissue found in the right ventricle of the heart...frequently extends from the base of the anterior papillary muscle to the ventricular septum. While normal, if excessive, they impair heart function.
Left ventricular concentric hypertrophy-Left ventricular hypertrophy is enlargement and thickening (hypertrophy) of the walls of your heart's main pumping chamber (left ventricle).
Left atrioventricular endocardiosis-Mitral valve disease is a serious heart condition caused by the abnormal function of the valve that separates the upper and lower chamber of the left side of the heart.
Endocardiosis is a valvular insufficiency. The most commonly affected site is the mitral valve. The condition results in slowly developing heart failure as the valves become swollen and shortened/misshapen, so the heart cannot pump blood effectively from the left ventricle to the circulation.
Leaky valves-The valves consist of flaps that open to let blood flow in one direction as it moves through the chambers of the heart. Then the valves close to keep blood from flowing backwards into the chamber it just left. Each valve typically has three flaps, except for the mitral valve, which has two. means that just after the heart squeezes and pumps blood forward, some blood will leak backward through the valve. Leaking through the valve is also called valve regurgitation.
Pleura-each of a pair of serous membranes lining the thorax and enveloping the lungs in humans and other mammals.
Pleural cavity is the thin fluid-filled space between the two pulmonary pleurae (visceral and parietal) of each lung.
Pulmonary pleurae are the two pleurae of the invaginated sac surrounding each lung and attaching to the thoracic cavity. The visceral pleura is the delicate serous membrane that covers the surface of each lung and dips into the fissures between the lobes. The parietal pleura is the outer membrane which is attached to the inner surface of the thoracic cavity. It also separates the pleural cavity from the mediastinum. The parietal pleura is innervated by the intercostal nerves and the phrenic nerve.
Lung lobes- parts of the lung.
Fibrinous pleuritis-fibroid tissue, damage in the pleural cavity.
Pulonary edema-excess fluid in the lungs.
Atelectasis-a complete or partial collapse of a lung or lobe of a lung. Atelectasis can make breathing difficult and lower oxygen particularly if lung disease is already present. It is a condition where the alveoli are deflated down to little or no volume.
Interstitial fibrosis -group of lung diseases affecting the interstitium (the tissue and space around the air sacs of the lungs)
Alveolar histiocytosis-Histiocytosis is a general name for a group of disorders or "syndromes" that involve an abnormal increase in the number of immune cells that are called .
About Liver disease and heart failure -Damage done to a liver is due to right sided heart failure.
Congestive hepatopathy of the liver-also known as nutmeg liver and chronic passive congestion of the liver, is liver dysfunction due to venous congestion, usually due to congestive heart failure. The gross pathological appearance of a liver affected by chronic passive congestion is "speckled" like a grated nutmeg kernel; the dark spots represent the dilated and congested hepatic venules and small hepatic veins.
(Liver) sinusoids -A sinusoid is a small blood vessel that is a type of capillary similar to a fenestrated endothelium.
Kidneys have a somewhat granular outer section (the cortex), containing the glomeruli and convoluted tubules, and a smooth, somewhat striated inner section (the medulla), containing the loops of Henle and the collecting tubules.
Granular- A granular surface of the kidney may be present in both benign and malignant hypertension and is indicative of atrophy and fibrosis of the cortex due to the destruction of the small blood vessels. The degree of the granulation depends on the duration of the hypertension.
Glomerulonephritis -acute inflammation of the kidney of tiny filters in your kidneys (glomeruli). Glomeruli remove excess fluid, electrolytes and waste from your bloodstream and pass them into your urine.
Tubular proteinosis. -the accumulation of excess protein in the tissues. These proteins are normally filtered by the glomerulus and are almost completely reabsorbed in the proximal tubule. Diseases that interfere with proximal tubular function, such as tubulointerstitial nephritis, reduce reabsorption of these proteins and lead to tubular proteinuria. High concentrations of protein cause frothy or sudsy urine.