Pathology Flashcards

Question

Morphology of atherosclerosis

Answer 1

1. **Fatty streaks and dots**: precursor lesions of atheromatous plaque -Gross: lesions flat / slightly elevated & yellow, form of small multiple dots or elongated beaded streaks -Microscopically: foam cells, lipid containing elongated smooth muscle cells, lymphoid cells, lipid, collagen, proteoglycans 2. **Gelatinous lesions**: precursor lesions of atheromatous plaque, round or oval, circumscibed grey elevations 3. **Atheromatous plaques** -Gross: white to yellowish white lesions -Microscopically: **cholesterol cleft**, fibrin, necrotic debris & lipid laden **foam cells** in deeper central core 4. **Complicated plaques**: - **Calcification**: common in aorta & coronaries, calcium saltes are deposited around the necrotic area - **Ulceration**: layers covering the soft material of an atheroma may ulcerate as a result of haemodynamic forces or mechanical trauma. Results in discharge of emboli - **Thrombosis**: ulcerated plaques & the endothelial damage are vulnerable areas for foramtion of superimposed thrombi - **Haemorrhage**: intimal haemorrhage occur (1) blood in vascular lumen through an ulcerated plaque (2) rupture of thin walled capillaries that vascularise the atheroma from adventitial vasa vasorum - **Aneurysmal dilatation**: advanced lesions may be associated with secondar changes in media & adventitia

Answer 2

**Acute or chronic form of cardiac disability arising from imbalance between the myocardial supply and demand for oxygenated blood. ** - Group of closely related syndromes all due to myocardial ischaemia - 90% cases - Atherosclerotic Coronary Artery Disease (CAD) - **Risk factors are same as Atherosclerosis** - **90% of IHD patients have atherosclerosis**

Answer 3

**Coronary Atherosclerosis** * One or more than one branches may have atherosclerosis: **Anterior descending left coronary is the most common branch**, **Right coronary**, least is **Circumflex branch** to get affected by atherosclerosis * 75% or more blockage of coronary lumen usually causes chronic myocardial ischaemia. * Mostly the severe blockage is about 3-4 cm away from opening (coronary ostia) and near bifurcation of coronary. * Fixed atherosclerotic plaque in coronary are eccenteric and buldges in lumen of coronary **Superadded changes in atherosclerosis of coronary** * **Acute changes in plaque**: **Haemorrhage** in plaque, **Fissuring** in plaque and **Ulceration** of plaque leading to thrombosis & embolism of debris of plaque or thrombus. Such acute changes occurs due to spasm of coronary, tachycardia, haemorrhage inside plaque and hypercholesterolemia. * **Coronary thrombosis**: thrombus develops on ulcerated atherpmatous plaque, lipid content of plaque is thrombogenic, and small fragment of thrombus may get dislodged and embolised and block blood supply * **Local platelet aggregation and coronary spasm**: Sometimes local aggregation of platelets on plaque may form like thrombus and block coronary. And platelets releases vasospasmodic mediators cause spasm of coronary. **Non-atherosclerotic causes** * **Vasospasm** (without atherosclerosis) * **Stenosis of coronary ostia** (extension of syphilitic aortitis) * **Arteritis** (rheumatic vasculitis, polyarteritis nodosa) * **Embolism** (embolus from anywhere in body) * **Thrombotic diseases** (shock, polycythemia vera, sickle cell anaemia, thrombotic thrombocytopenia purpura) * **Trauma** (penetrating injury) * **Aneurysm** (dissecting aneurysm of aorta) * **Compression** (primary / secondary tumor)

Answer 4

Functional: - ischemic muscle ceases to contract within a few minutes. Necrosis is inhibited if flow is restored within 20-40mins Biochemical: - oxygen tension falls, mitochrondrial respiration declines - ceases - fatty fuels cannot be used - anaerobic glycolysis - increased concentration of lactic acid - limited glycogen stores - reduced intracellular ATP - concentrations reach zero in 40-60 mins - creatinine phosphate concentration - zero in 15mins. Myosin ATPase inhibited - cessation of contraction

Answer 5

1. **Angina pectoris** 2. **Myocadial infarction** 3. **Chronic ischaemic heart disease & heart failure** 4. **Sudden cardiac death**

Answer 6

**It is clinical syndrome of ischemic heart disease resulting from transient myocardial ischemia** Angina is caused by - paroxysmal and recurrent pain in the substernal or precardial region of chest aggravated by increased in demand of heart and relieved by decreased work load of heart - constricting, chocking, squeezing, knifelike feeling - transient - 15 sec to 15 mins - **No cardiac muscle cell death** - falls short of infarction

Answer 7

1. **Stable** (typical) angina -most common form -reduction of coronary perfusion due to chronic stenosing atherosclerosis -seen at times of increased demand -attack comes after physical or emotional stress and strain -relieved by rest, **nitroglycerin**, or other vasodilators -ECG shows **ST segment depression** -no elevation of enzymes (no myocardial damage) 2. **Prinzmetal** or variant angina -caused by pain at rest -cause: **not known may be due to sudden vasospams due to coronary atherosclerosis** -ECG: **ST segment elevation** -respond to **nitroglycerin** 3. **Unstable** or cresendo angina -pattern of pain that is progressive with increasing frequency -most serious pattern -precipitated by less effort -often occurs at **rest** -tends to be long duration -induced by disruption of atherosclerotic plaques, with superficial thrombosis, embolisation and vasospasm -pre infarction angina -ECG: **non ST segment elevation**

Answer 8

**Infarction of myocardial muscle due to ischemia due coronary artery diseases** Acute coronary syndromes 1. myocardial infarction 2. unstable angina 3. sudden cardiac death

Answer 9

1. DM 2. Hypertension 3. Dyslipidemia (familial hypercholesterolemia) 4. Smoking 5. Obesity 6. Lack of adequate exercise 7. Stress & strain 8. Family history

Answer 10

**Myocardial ischaemia** * **diminished blood supply** due to blockage or shock, **increased myocardial demand** in exercise, **hypertrophy of cardiac muscles without increase in blood supply** * due to **reduced or inadequate blood supply** by blocked coronary. Oxygen tension in myocardium falls which causes disturbances in electrical, mechanical, and biochemical functions of myocardium, ventricular contractility is affected in ischemia area leading to disturbance in myocardial pumping action * When ischaemia is transient it usually cause **angina pectoris** * but when it remain for longer time it causes myocardial necrosis and scarring with or without clinical picture **Platelets** - rupture of plaque exposes subendocardial collagen and platelets are attached to damaged area and get activated cause aggregation and mass which leads to thrombosis or embolism. **Plaque** - acute rupture of plaque and haemorrhage usually cause acute MI **Non atherosclerotic cause** - block the blood supply in vasospasm, stenosis, arteritis, embolism, vegetative endocarditis, trauma, compression **Unexplained**

Answer 11

* Left ventricle more affected > than right ventricle * Left atrium is relatively protected due to oxygenated blood supply from left atrium * Blockage of coronary decides the region of heart involve * **Left anterior descending artery** * **Right coronary artery** * **Left circumflex artery**

Pathology Flashcards

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