Pathology - Term 7

What are the factors the pathogenesis of myocardial ischemia depend on?

What are the causes of myocardial ischemia?

1. Vascular spasm - Prinzmetal angina

2. Moderate vascular occlusion - anemia, hypoxemia, shock, myocardial hypertrophy

3. Myocardial vessel inflammation - vasculitis

4. Coronary emboli from vegetations

5. Coronary artherosclerosis and thrombosis

State factors contributing to coronary atheromas.

1. Hypertension

2. Diabetes mellitus

3. Cigarette smoking

4. Genetic/familial factors

5. Increased LDL cholesterol

What is the treatment for acute coronary syndrome?

1. Anti ischemic medication

2. Anti thrombotic drugs

3. Anti platelet drugs

4. Statins

5. Coronary revascularization

What are the anti ischemic medications given in acute coronary syndrome?

1. Nitrates - IV and sublingual

2. Beta blockers

3. Calcium channel blockers - usually avoided but can be given if EF is normal - dihydropyridine

What are the antiplatelet drugs prescribed in acute coronary syndrome?

1. Aspirin

2. P2Y12 inhibitors

   clopidogrel

   ticagrelor

   prasugrel

What are the anti thrombotic drugs prescribed in acute coronary syndrome?

1. Heparin

   LMW

   Unfractionated

2. Fondaparinux

3. Bivalirudin

Define heart failure

The condition in which the heart is unable to pump at a rate sufficient to meet the metabolic requirements of peripheral tissues despite normal venous return or can only do so at an elevated filling pressure

State reasons for acutely developed heart failure

Hemodynamic stresses such as

1. Fluid overload

2. Acute valvular dysfunction

3. Acute MI

State reasons for insidiously developed heart failure

due to the cumulative effects of chronic overload:

1. Hypertension

2. Ischemic heart disease/MI

3. Valvular disease

Name the compensatory mechanisms in heart failure

1. Frank Starling mechanism

2. Activation of the neurohumoral systems

3. Myocardial structural changes

Describe the effect of the Frank Starling mechanism as a compensatory mechanism in heart failure

Increased end diastolic filling volumes dilate the heart

This causes increased stretching of the cardiac myofibers and increased functional cross bridge formation within the sarcomere

These lengthened fibers contract with more force generating an increased cardiac output

If the dilated ventricle is able to maintain cardiac output, it is called compensated heart failure

However this comes at the expense of increased wall tension and increased oxygen demand of already comprised myocardium.

Eventually the failing muscle is no longer able to propel sufficient blood to meet the needs of the body and the body developed decompensated heart failure

Describe the role of activation of neurohumoral systems as a compensatory mechanism in heart failure

N

Define dilated cardiomyopathy

Dilatation and impaired contraction of left or both ventricles, usually with concomitant hypertrophy

Define hypertrophic cardiomyopathy

Left or right ventricular hypertrophy, often asymmetrical, that usually involves the interventricular septum, defective diastolic filling due to a poorly compliant myocardium and in one third of cases - intermittent ventricular outflow obstruction

Define restrictive cardiomyopathy

Restricted filling and reduced size of either or both ventricles with normal or near normal systolic function

Define what an atheroma is.

Patchy intimal thickening of arterial wall due to

1. Deposition of lipids

2. Proliferation of smooth muscle cells

3. Formation of fibrous tissue

that impinge on the vascular lumen and can rupture to cause sudden occlusion.

State constitutional/non modifiable risk factors of atherosclerosis

1. Age - old age

2. Gender - pre menopausal women relatively protected against it than same age men. Different post menopause, incidence might exceed that of men

3. Familial history -

Identify and describe the stage of lobar pneumonia shown

Congestion (1-2 days)

Macroscopy - red, heavy, boggy

Microscopy - numerous bacteria present

Vascular engorgement

Intralveolar fluid with few neutrophils

Identify the stage of lobar pneumonia shown and describe it.

Red hepatization (2-4 days)

Macroscopy - Red, firm, airless, heavy and liver like consistency

Pleura contains fibrinous or fibrinopurulent exudate

Microscopy - massive exudate in alveoli

Intra alveolar fluid contains neutrophils, red cells and fibrin

Identify the stage of lobar pneumonia shown and describe it.

Grey hepatization (4-8 days)

Macroscopy - color change to grey.

Heavy, airless and firm with liver like consistency

Persistence of fibrinopurulent exudate in pleura

Microscopy - vascular congestion is less

Disintegration of RBC

Massive exudate in alveoli - intra alveolar fluid with neutrophils and fibrin

Describe the microscopy of bronchopneumonia

Neutrophil rich exudate filling the bronchi, bronchioles and adjacent alveolar spaces

alevolar exudate consisting mainly of neutrophils

Surrounding alveolar walls have congested capillaries (dilated and filled with RBCs)

Describe the Macroscopy of bronchopneumonia

Lesion are

Slightly elevated

Dry

Granular

Grey red to yellow

Poorly demarcated

Describe the Macroscopy of acute atypical pneumonia

Affected areas are

Red blue

Congested

Sub crepitany

Describe the microscopy of acute atypical pneumonia

Inflammatory reaction lafgerly confined to walls of alveoli

Septa are widened and edematous

Contains a mononuclear inflammatory infiltrate

Alveolar spaces are free of cellular exudate

In severe cases - full blown diffuse alveolar damage with hyaline membranes

Describe microscopy of severe cases of acute atypical pneumonia

Full blown diffuse alveolar damage with hyaline membranes

Name the local complications of pneumonia

Pleural effusion

Empyema

Organizing pneumonia

Lung abscess

Name the general complications of pneumonia

Respiratory failure

Sepsis

MOF

Define consolidation

Solidification of the lung due to replacement of air by exudate in the alveoli

State the possible fungal causes of penumonia

1. Aspergillus spp.

2. Pneumocystis jirovecii

3. Cryptococcus neoformans

4. Coccidioides immitis

State the extrapulmonary features of community acquired pneumonia

Arthalgia, myalgia and malaise - Legionella, mycoplasma

Headache - legionella

Abdominal pain, vomitting and diarrhea

Hepatitis - legionella

Labial herpes simplex reactivation - pneumococcal pneumonia

Erythema multiforme, nodosum - Mycoplasma

Myocarditis and pericarditis - Mycoplasma

Identify the labelled

A - pus cell

B - squamous epithelial cell

Cut surface of lung showing two abscesses

Several abscesses with irregular, rough surfaced walls within areas of tan consolidation in a lung

Abscess with air fluid level

Tuberculous enteritis

Basilar meningitis seen with tuberculous meningitis. Thickening of meninges over pons is visible

Microscopy of tuberculous granuloma

A - Langhans giant cell

B - caseous necrosis

C - epithelial macrophages

D - lymphocytes

Tuberculous granuloma

Ghon complex

Ghon complex

miliary TB

Miliary tuberculosis of spleen

Pulmonary hamartoma

• Commonest benign tumor

• Firm

• Discrete

• Often have calcifications

• Most are small <2cm

Consists mainly of

• Mature cartilage admixed with

• Fat

• Fibrous tissue

• Blood vessels

Name and define what is shown

Lung abscess

Characterized as a localized collection of pus or necrotic tissue within the lung parenchyma resulting in a cavity

Define asthma

A chronic airway inflammatory diseases defined by a history of respiratory symptoms such as wheezing, SOB, chest tightness and cough that vary over time and in intensity with variable expiratory airflow limitation

What are the 3 characteristics of asthma?

1. Airflow limitation

2. Airway hyper responsiveness

3. Inflammation of bronchi and bronchioles

What does airway hyper responsiveness mean?

Tendency of the airway to narrow in response to various stimuli

What are the types of asthma?

1. Atopic (Extrinsic)

2. Non-atopic (Intrinsic)

3. Drug induced

4. Occupational