L8, CVS Pathology PDF

pathology - CVS Cardiomyopathy & myocarditis LECTURE (8) Cardiomyopathy & myocarditis Dr. M. Shalaby pathology - CVS Cardiomyopathy & myocarditis DEFINITION  Group of dis...

pathology - CVS Cardiomyopathy & myocarditis LECTURE (8) Cardiomyopathy & myocarditis Dr. M. Shalaby pathology - CVS Cardiomyopathy & myocarditis DEFINITION  Group of diseases characterized by dysfunction of the myocardium. ① Dilated ② Hypertrophic. TYPES ③ Restrictive. ④ Arrhythmogenic Right ventricular dysplasia.  Manifestations of HF: A. MANIFESTATIONS OF REDUCED CARDIAC OUTPUT: ① Easy fatigability ② Cold extremities ③ Recurrent syncopal attacks ④ Rapid Weak pulse ⑤ Hypotension B. MANIFESTATIONS OF PULMONARY CONGESTION: ① Dyspnea CLINICAL PICTURE ② Orthopnea ③ Cough ④ Pulmonary edema C. MANIFESTATIONS OF SYSTEMIC CONGESTION: ① Congested neck veins ② HSM ③ Malabsorption, anorexia, nausea, vomiting ④ Insomina ⑤ Edema ① Arrythmia. COMPLICATIONS ② Sudden cardiac death in young age. Dr. M. Shalaby pathology - CVS Cardiomyopathy & myocarditis  There is systolic dysfunction. DEFINITION  Damage and wasting of the cardiac myocytes.  Thinning of the myocardium and dilatation of left ventricular cavity. ① Genetic: Muscular dystrophy (Duchenne and Becker) ② Toxins: Alcohol and cocaine CAUSES ③ Infections: Viral as Coxsackie ④ Peripartum: Mostly in 3rd trimester.  The heart assumes a globular shape and there is pronounced ventricular GROSSLY chamber dilatation, diffuse endocardial thickening and atrial enlargement, often with thrombi in the appendages.  Increase in myocyte nuclear size  Myofibrillary loss within myocyte Focal myocyte death  Interstitial fibrosis MICROSCOPICALLY  The myocyte nuclei increase in size  Fibrosis characteristically is interstitial and begins to surround and isolate individual myocytes. DUCHENNE  Mutant Dystrophin  Sarcolemmal membrane tension during contraction → Tears in sarcolemmal membrane & Myocyte loss Dr. M. Shalaby pathology - CVS Cardiomyopathy & myocarditis  Thickening of the ventricular wall.  There is diastolic dysfunction (defective filling). DEFINITION  Obstruction to the blood outflow  Myocyte hypertrophy and dissarray → arrhythmia  Most common cause of sudden cardiac death in young age.  Main gross findings include left ventricular hypertrophy; asymmetric GROSSLY hypertrophy is more common than symmetric  There may also be subaortic mitral valve fibrosis  Hallmarks of histological diagnosis: ① Myocyte hypertrophy. ② Fibrosis. ③ Disarray. MICROSCOPICALLY  Cells are abnormally branched with hyperchromatic and enlarged nuclei  Fibrosis is present interstitially between myocytes, around capillaries in a perivascular pattern or forms scar / replacement tissue after myocyte death. Dr. M. Shalaby pathology - CVS Cardiomyopathy & myocarditis  There is diastolic dysfunction. DEFINITION  Stiffness of the myocardium with resistance to stretch.  Defective filling during diastole.  Infiltration of myocardium by any abnormal substance: ① Amyloid (congo-red positive). ② Sarcoidosis. CAUSES ③ Gaucher disease. ④ Hemochromatosis (Prussian blue).  Fibrosis of myocardium (toxins, irradiation, carcinoid syndrome, Loffler’s syndrome  Ventricular cavity is normal. GROSSLY  Ventricular wall is abnormal, with a rubbery texture.  Thickening of the endocardium may be observed.  Microscopic changes are nonspecific and include myocyte hypertrophy, MICROSCOPICALLY focal or diffuse perimyocytic fibrosis and focal myofiber disarray Dr. M. Shalaby pathology - CVS Cardiomyopathy & myocarditis  The myocardium of RV free wall is replaced by fibrofatty tissue.  RV wall motion is reduced. DEFINITION  Asymmetric motion between RV and LV.  Arrhythmia. Dr. M. Shalaby pathology - CVS Cardiomyopathy & myocarditis DEFINITION  Inflammation of the myocardium with necrosis of cardiac myocyte cells. INFECTIOUS NON-INFECTIOUS ① Viruses.  Organ-specific or systemic ETIOLOGY ② Bacteria. immune-mediated disease, drugs, ③ Fungi. vaccines, toxins ④ Parasites.  Biopsy-proven myocarditis typically demonstrates inflammatory infiltrate PATHOLOGY of myocardium with lymphocytes, neutrophils, eosinophils, giant cells, granulomas, or a mixture. Dr. M. Shalaby