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Cardiovascular System Overview

Rheumatic Heart Diseases

  • Definition of Rheumatic Fever

    • An immune-mediated inflammatory acute febrile illness following a pharyngeal infection (e.g., acute tonsillitis, scarlet fever) caused by beta-hemolytic group A streptococcus.

Post-Streptococcal Glomerulonephritis

  • Definition

    • A complication due to autoantibody enhancement by nephritogenic strains of group A streptococcal bacteria. Does not combine with the M protein antigen.

Common Sites Affected in Rheumatic Fever

  • Affected Endocardium Sites

    1. Lines of contact between valve cusps when closed

    2. Chordae tendineae

  • Clinical Complications

    • Fibrous union leads to stenosis, while thickened chordae cause valve incompetence (regurgitation). Repeated attacks can result in chronic heart failure.

Incidence of Cardiac Valve Involvement in RF Patients

  • Common Involvement Patterns

    • Mitral valve alone

    • Mitral and aortic valves simultaneously

    • Mitral, aortic, and tricuspid valves together

    • Rare: Aortic valve alone and very rare for tricuspid valve alone.

Morphology of Aschoff Bodies

  • Macroscopic

    • Scattered pale foci

  • Microscopic

    • Granulomatous lesions with eosinophilic hyaline fibrinous material encircled by lymphocytes, macrophages, and giant cells.

  • Clinical Importance

    • Pathognomonic for rheumatic myocarditis; they dissipate after the acute phase.

Heart Failure Types in Rheumatic Myocarditis

  • Type of Heart Failure

    • Acute heart failure

  • Explanation

    • Resulting from loss of myocardial function, leading to left ventricular dilation.

Heart Failure in Rheumatic Pericarditis

  • Type of Heart Failure

    • Acute heart failure

  • Explanation

    • Caused by serofibrinous effusion interfering with heart movement.

Other Body Parts Affected by Rheumatic Fever

  • Clinical Examples

    • Joints: Migratory polyarthritis with redness and swelling

    • Skin: Erythema marginatum, subcutaneous nodules

    • CNS: Mild encephalitis, Sydenham’s chorea (involuntary movements)

Important Serological Tests for RF

  • Tests

    1. Antistreptolysin O (ASO) antibodies: Long half-life can cause false positives; should be <250 IU

    2. DNAseB antibodies: May yield false negatives, not all Streptococcus A strains are positive.

Major and Minor Criteria for Clinical Diagnosis of RF

  • Major Criteria

    • Migratory polyarthritis

    • Myocarditis/pericarditis causing acute HF

    • Subcutaneous nodules

    • Erythema marginatum

    • Sydenham’s chorea

  • Minor Criteria

    • Fever (38.2–38.9 °C)

    • Arthralgia

    • Leukocytosis

    • Heart block on ECG

    • History of prior rheumatic fever

Atherosclerosis

  • Definition

    • Abnormal buildup of yellow plaques within the intima of arteries, consisting of fatty substances, cholesterol, cellular waste, leading to thickened and stiffened arterial walls.

Complications of Atherosclerosis

  • Stenosis causing impaired blood flow:

    • Angina (coronary)

    • Chronic ischemia (lower legs)

    • Ischemic bowel disease (mesenteric arteries)

  • Plaque rupture leading to thrombosis:

    • Myocardial infarction (coronary)

    • Stroke (middle cerebral artery)

  • Vessel weakening resulting in aneurysms (e.g., abdominal aorta).

Morphological Stages of Atheroma

  1. Yellow Fatty Streaks: Lipid-laden macrophages forming macular yellow lesions.

  2. Young Atheromatous Plaque: Lipid accumulation, smooth muscle cell proliferation, fibrous cap formation.

  3. Mature Atheroma: Thick fibrous cap, lower rupture risk but causes lumen narrowing.

Risk Factors for Atherosclerosis

  • Age, Hyperlipidemia, Gender, Hypertension, Diabetes Mellitus, Genetic predisposition, Cigarette smoking, Stress, Obesity, Lack of exercise, Oral contraceptive use.

Definition and Complications of Aneurysm

  • Definition

    • Localized vascular dilatation due to vessel wall stretching.

  • Possible Complications

    • Rupture leading to massive bleeding

    • Mural thrombus leading to thrombotic embolism.

Types of Aneurysms

  1. Atheromatous

  2. Syphilitic

  3. Infective

  4. Cerebral (e.g., berry)

  5. Cardiac

  6. Capillary (e.g., diabetic retinopathy)

Benign Vascular Tumors

  1. Hemangioma

  2. Glomangioma

  3. Multiple angiomatosis syndrome

Malignant Vascular Tumors

  1. Hemangioendothelioma

  2. Hemangiopericytoma

  3. Angiosarcoma

  4. Kaposi's sarcoma

Pulmonary Edema

  • Definition

    • Abnormal fluid accumulation in interstitium and alveoli of the lungs.

  • Clinical Classes

    • Cardiogenic and Non-Cardiogenic pulmonary edema.

  • Mechanism Classifications

    • Hydrostatic pressure edema

    • Permeability edema with/without diffuse alveolar damage (DAD)

    • Mixed pulmonary edema.

Causes of Pulmonary Edema

  • Hydrostatic Pressure PE

    • Left heart failure, Volume overload.

  • Permeability PE with DAD

    • ARDS due to toxins, inflammatory mediators, infectious processes.

  • Permeability PE without DAD

    • “Crack-lung”, High-altitude PE, Cytokine administration.

  • Mixed PE Causes

    • Severe neurologic injury, Abrupt lung re-expansion, Lung transplant.

  • Cardiogenic PE Causes

    • Left ventricular dysfunction, Valvular dysfunction, Rhythm disorders.

Paroxysmal Nocturnal Dyspnea in PE

  • Sudden breathlessness at night, relieved by sitting, due to increased pulmonary venous pressure when supine.

Orthopnea in PE

  • Breathlessness while lying flat, worsened pulmonary edema, similar to PND.

Crackles on Auscultation in PE

  • Fluid in alveoli and interstitial spaces causes crackles during air passage.

Ischemic Heart Disease Classification

  • Angina Pectoris, Myocardial Infarction, Chronic Ischemia with CHF, Sudden Death.

  • Definition of Angina Pectoris

    • Intermittent chest pain from reversible myocardial ischemia, characterized by severe pressing pain lasting 15 secs to 15 mins.

  • Stable Angina: Caused by fixed atherosclerotic obstruction, induced by oxygen demand increases, relieved by rest/nitroglycerin.

  • Variant Angina (Prinzmetal): Occurs at rest due to artery spasm, not related to exertion.

  • Unstable Angina: Severe chest pain at rest due to plaque disruption, potential for MI.

Incidence of Thrombotic Occlusion in IHD by Artery

  • Arteries

  • LAD: Anterior left ventricle (40-50%)

  • RCA: Posterior left ventricle (30-40%)

  • LCX: Lateral left ventricle (15-20%).

Factors Affecting Severity of Regional MI

  • Coronary occlusion characteristics, Duration, Blood size, Metabolic needs, Collateral flow, Myocardial response.

Typical Presentation of MI

  • Severe retrosternal pain, possible nausea, dyspnea, diaphoresis, weakness.

  • Silent MI: No symptoms, common in diabetes, elderly.

Acute Complications of MI

  • Sudden death, Arrhythmias, Cardiogenic shock, Ventricular aneurysm, Cardiac rupture.

Chronic MI Complications

  • CHF, Recurrent arrhythmias, Chronic ischemic heart disease.

Sub-Endocardium Zone MI

  • Severe ischemia in inner myocardium, often from partial occlusion or global hypoperfusion.

Important Investigations for MI Diagnosis

  • ECG: Q waves and ST changes

  • Serum Biomarkers: Troponins, CK-MB.

Heart Failure Definition

  • HF is the heart's inability to meet blood flow demands, resulting from low output or exceeding body's supply.

Pathological Types of Heart Failure

  • Low Output HF (congestive)

  • High Output HF.

Renin System and Congestion in Congestive HF

  • Decreased renal perfusion activates Renin-Angiotensin system, leading to fluid retention and pressure increase.

Cardiac Changes Secondary to Increased Afterload Pressure

  • LVH develops initially, leading to ventricular dilation, reduced compliance, and diastolic dysfunction over time.

Left Ventricular Ejection Fraction (LVEF)

  • The percentage of blood ejected during systole; indicative of systolic function, reduced in systolic HF.

Causes of Left and Right Systolic Congestive HF

  • Left: MI, Myocarditis, Dilated cardiomyopathy, Hypertension.

  • Right: Pulmonary hypertension, PE, Myocardial infarction.

Causes of Diastolic Congestive HF

  • Left: Pericardial diseases, Hypertrophy, Restrictive cardiomyopathies.

  • Right: Tricuspid stenosis.

Tachypnea, Palpitation, and Gallop Rhythm in HF

  • Tachypnea: Increased breathing from low cardiac output.

  • Palpitations: Awareness of abnormal heartbeats from compensatory tachycardia.

  • Gallop Rhythm: Third heart sound due to rapid filling from increased atrial pressure.

Clinical Features of Right-Side Congestive HF

  • Jugular venous distension, Hepatomegaly, Lower limb edema, Ascites.

Causes of High Output HF

  • Severe anemia, Uncontrolled thyrotoxicosis, Beriberi (Vitamin B1 deficiency), Arteriovenous fistula.

Investigating Methods of HF

  • Chest X-ray: Detects cardiomegaly, pulmonary congestion.

  • ECG: Identifies MIs and arrhythmias.

  • Echocardiography: Determines type, etiology, LVEF.

  • Blood Tests: Evaluates cardiac enzymes and other dysfunctions.

Cardiomyopathies

  • Definition

    • Heterogeneous myocardial dysfunctions, often with genetic bases.

  • Main Classifications:

    • Dilated Cardiomyopathy (Most common), Hypertrophic Cardiomyopathy, Restrictive Cardiomyopathy (Least common).

Pathological Effect of Dilated Cardiomyopathy (DCM)

  • Thin, stretched heart walls lead to systolic failure.

Problems Related to DCM

  • Mural thrombi, Secondary mitral regurgitation, Arrhythmias.

Etiology of DCM

  • Idiopathic, Genetic mutations, Viral myocarditis, Alcohol abuse, Medications, Pregnancy.

Morphological Changes in Hypertrophic Cardiomyopathy (HCM)

  • Massive hypertrophy of LV and interventricular septum, thick-walled, hypercontracting heart.

Problematic Issues Related to HCM

  • Mitral regurgitation (asymmetric hypertrophy), Functional aortic stenosis (subaortic hypertrophy).

Microscopic Features of HCM

  • Hypertrophied myocytes with interstitial fibrosis.

Pathogenesis of HCM

  • Autosomal dominant disorder caused by mutations in sarcomere protein genes leading to hypercontractility and hypertrophy.

Syncope and Sudden Death in Athletes with HCM

  • Syncope: Reduced output due to obstruction.

  • Sudden Death: Caused by ventricular arrhythmias.

Morphological Changes in Restrictive Cardiomyopathy

  • Ventricular wall rigidity disrupts diastolic filling, potentially affecting systolic function.

Etiology of Restrictive Cardiomyopathy

  • Infiltrative and systemic diseases (e.g., amyloidosis, hemochromatosis).

Infective Endocarditis (IE) Overview

  • Etiology

    • Commonly caused by gram-positive bacteria, particularly Streptococcus viridans, and occurs after transient bacteremia.

  • Predisposing Factors

    • Rheumatic valvular diseases, congenital lesions, prosthetic valves, immunosuppression, poor dental hygiene.

Pathological Changes in IE

  • Causes friable vegetations on valves, leading to necrosis, scarring, and potential embolization.

Differences Between Acute and Sub-Acute IE

  • Acute IE: Fast, severe course, high mortality (>50%). Caused by virulent bacteria.

  • Sub-Acute IE: Longer, less severe, caused by less virulent bacteria.

Microscopic Features of IE Vegetations

  • Composed of fibrin, platelets, microorganisms; underlying valves show necrosis.

Hematuria and Other Symptoms in IE

  • Hematuria: Renal infarcts or glomerulonephritis due to embolization.

  • Petechiae and Splinter Hemorrhages: Embolic phenomena from angitis causing skin and mucosal lesions.

Main Complications of IE

  • Acute heart failure, organ embolization, renal failure, chronic heart failure.

Myocarditis Causes

  • Viral, bacterial, parasitic infections, and non-infectious causes (e.g., rheumatic fever).

Gross and Microscopic Changes in Myocarditis

  • Flabby heart, four-chamber dilatation, patchy hemorrhage, interstitial infiltrates depending on the infective agent.

Local and Systemic Causes of Pericarditis

  • Local: MI, Surgery, Trauma, Radiation.

  • Systemic: Uremia, autoimmune diseases, infections.

Types of Acute and Chronic Pericarditis

  • Acute Types: Serous, fibrinous, purulent, hemorrhagic.

  • Chronic Types: Adhesive, constrictive, caseous.

Inflammatory Vascular Disorders

  • Local Complications: Thrombosis, rupture, aneurysm formation, chronic ischemia.

Infectious Vasculitis Examples

  • Localized arteritis, infected emboli, meningococcal vasculitis, syphilitic arteritis.

Thrombophlebitis and Phlebothrombosis

  • Thrombophlebitis: Inflammation with thrombosis.

  • Phlebothrombosis: Thrombosis without inflammation, migrans indicates cancer.

Immune-Mediated Vasculitis Examples

  • Polyarteritis nodosa, cranial arteritis, Buerger’s disease, Kawasaki disease.

Upper Respiratory Tract Disorders

  • Rhinitis: Inflammation of nasal mucosa, types include acute and chronic variants.

Acute Catarrhal Rhinitis

  • Caused by viral infections, predisposed by cold; secondary bacterial infections possible.

Chronic Non-specific Rhinitis Causes

  • Nasal obstruction due to various factors, chronic sinusitis, occupational exposure.

Rhinoscleroma

  • Granulomatous inflammation caused by Klebsiella; complications include nasal obstruction and infections.

Types of Sinusitis

  • Acute and chronic types; inflammation of sinus mucosa.

Nasal Polyps and Fungal Sinusitis Types

  • Edematous mucosal projections, fungal types can be invasive or noninvasive.

Epistaxis Causes

  • Nosebleeds caused by trauma and various local factors.

Tumors in Nose and Sinuses

  • Benign: Papillomas, angioma, osteoma

  • Malignant: Carcinomas, sarcomas.

Acute Tonsillitis Overview

  • Causes: Viral (common), bacterial; prevalent in ages 5-15.

Types of Acute Tonsillitis

  • Forms include catarrhal, follicular, and membranous.

Complications of Acute Tonsillitis

  • May lead to peritonsillar abscess, infections spreading, and systemic effects.

Chronic Non-Specific Tonsillitis Features

  • Hyperplasia of lymphoid tissues, chronic inflammation, and potential late-stage fibrosis.

Diphtheria Overview

  • Caused by Corynebacterium, leading to pseudomembranous inflammation and severe complications.

Nasopharyngeal Carcinoma

  • Linked to EBV, dietary factors, characterized by diverse clinical features.

Chronic Nonspecific Laryngitis and Singer's Nodes

  • Results from voice strain; nodes develop on vocal cords due to chronic stress.

Carcinoma of the Larynx

  • Subtypes include supraglottis, glottis, subglottis; early detection is crucial for prognosis.

Pneumonia Overview

  • Definition: Infectious inflammation of lung tissue causing pus- or liquid-filled air sacs.

Pneumonia Classifications

  • Based on anatomical site, causative agent, clinical course, and transmission route.

Complications of Pneumonia

  • Include abscess formation, pleural effusion, ARDS, respiratory failure.

Morphology of Bronchopneumonia

  • Patchy consolidation in lung lobes, often bilateral, with elevated lesions.

Lobar Pneumonia Characteristics

  • Involves entire lobes; primarily caused by Streptococcus pneumoniae.

Etiology of Atypical Pneumonia

  • Caused by intracellular organisms like Mycoplasma; morphological changes differ from typical pneumonia.

SARS Overview

  • Caused by a coronavirus, leading to pulmonary damage and ARDS.

Aspiration Pneumonia Definition

  • Results from inhalation of contaminated material leading to inflammation and infection.

Lung Abscess Definition

  • Suppurative necrosis in lung tissue with potential for formation through various mechanisms.

Chronic Pneumonias Examples

  • Histoplasmosis, blastomycosis, coccidiomycosis.

Bronchial Asthma Definition

  • Chronic inflammatory airway disorder characterized by episodic dyspnea and cough, often with reversible obstruction.

Main Mechanisms of Asthma

  • Include airway hyper-responsiveness, bronchospasm, smooth muscle hypertrophy, and excessive mucus secretion.

Classification of Asthma

  • Atopic: IgE driven, more common in children; Non-allergic: In adults, triggered by external factors.

Inflammatory Cells in Asthma

  • Mast cells, eosinophils, lymphocytes, and other immune cells contribute to airway inflammation.

Status Asthmaticus Definition

  • Severe asthma attack unresponsive to treatment, requiring intensive intervention.

Sputum Cytology in Asthma Diagnosis

  • Reveals eosinophils, Curschmann's spirals, and Charcot-Leyden crystals indicative of inflammatory activity.

Emphysema Definition

  • Permanent airway dilatation due to lung tissue damage, resulting in fewer but larger air pockets.

Classification of Emphysema

  • Centri-acinar: Associated with smoking, Pan-acinar: Linked to alpha-1 antitrypsin deficiency, Distal: Near pleura but less obstructive.

Complications of Emphysema

  • Include respiratory failure and pneumothorax among others.

Pathogenesis of Emphysema

  • Imbalance of protease-antiprotease activity leading to alveolar damage.

Morphological Features of Emphysema

  • Hyper-distended lungs with visible enlarged air spaces; damaged alveolar structures.

Chronic Bronchitis Definition

  • Persistent bronchial inflammation indicated by a chronic productive cough.

Pathogenesis of Chronic Bronchitis

  • Caused by inhalation of irritants leading to mucus hypersecretion and secondary infections.

Morphological Features of Chronic Bronchitis

  • Edematous membranes, mucous casts; chronic inflammatory cell infiltration.

Bronchiectasis Definition

  • Long-term abnormal airway dilation due to chronic inflammation and mucus accumulation.

Causes of Bronchiectasis

  • Result from necrotizing infections, bronchial obstructions, or hereditary conditions like cystic fibrosis.

Pulmonary Embolism Types

  • Includes saddle embolus, occlusions in major pulmonary arteries, and multiple small emboli.

Saddle Embolus Definition

  • Large thrombus at the bifurcation, causing severe chest pain, dyspnea, and rapid death risk.

Multiple Small Pulmonary Emboli Details

  • Can lead to acute or chronic respiratory issues or pulmonary arterial hypertension.

Inflammatory Disorders of Pulmonary Vessels

  • Includes Goodpasture’s syndrome and Wegener’s granulomatosis, both involve severe vascular inflammation.

Cor Pulmonale Definition

  • Right heart failure stemming from pulmonary hypertension, leading to structural and functional heart changes.

Pulmonary Hypertension Classification

  • Pre-capillary, Capillary, Post-capillary, each with distinct causes.

Types of Pleural Effusion

  • Hydrothorax: Due to pressure changes, Hemothorax: Blood leakage, Chylothorax: Lymph fluid accumulation, Inflammatory Effusion: Infection-related.

Empyema Definition

  • Collection of pus in thoracic cavity due to infection.

Pneumothorax Definition

  • Presence of air in pleural space; can be traumatic or spontaneous.

Mesothelioma Definition

  • Rare malignant tumor linked with asbestos exposure; aggressive with poor prognosis.