Physiology of Edema and Fluid Dynamics

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Questions and Answers

What condition is characterized by dilated centrilobular sinusoids and pressure atrophy of hepatocytes?

Acute Hepatitis

Fatty Liver Disease

Hepatic Cirrhosis

Chronic Passive Congestion (correct)

Which clinical feature is associated with pulmonary venous congestion?

Peripheral Edema

Jugular Venous Distension

Ascites

Dyspnea (correct)

What is the appearance of a liver affected by right heart failure?

Uniformly enlarged and smooth

Bright red with hemorrhagic spots

Pale and fibrotic

Nutmeg pattern with centrilobular necrosis (correct)

What clinical features are typically observed in patients with deep vein thrombosis (DVT)?

Swelling, pain, and potential venous ulcers Signup and view all the answers

Which organs are typically associated with white infarcts?

Kidney and spleen Signup and view all the answers

What type of venous congestion is associated with constrictive pericarditis?

Hepatic Congestion Signup and view all the answers

What distinguishes red infarcts from white infarcts?

Presence of dual blood supply Signup and view all the answers

Which of the following is NOT a common clinical feature of hepatic congestion?

Severe headaches Signup and view all the answers

What primarily influences the capillary oncotic pressure (πc) that pulls fluid back into the capillary?

Proteins like albumin Signup and view all the answers

What condition can lead to increased hydrostatic pressure causing edema in the body?

Malignant hypertension Signup and view all the answers

Which endocrine disorder is associated with increased sodium retention that may contribute to edema?

Syndrome of inappropriate ADH secretion Signup and view all the answers

What is a potential consequence of decreased oncotic pressure in the blood?

Increased interstitial fluid absorption Signup and view all the answers

What role does the lymphatic system play in preventing edema?

Drains excess interstitial fluid Signup and view all the answers

Which of the following is NOT a cause of edema related to decreased venous drainage?

Kidney failure Signup and view all the answers

Which condition is characterized by excessive leakage of protein from the glomerulus, contributing to decreased oncotic pressure?

Nephrotic syndrome Signup and view all the answers

What can excessive leukocyte activity at the endothelial level generally lead to?

Increased capillary permeability Signup and view all the answers

What is the primary reason that shock can be fatal?

Inadequate tissue perfusion leading to cellular death Signup and view all the answers

Which of the following correctly describes the vasodilation effect in septic shock?

Vasodilation occurs due to inappropriate endothelial damage. Signup and view all the answers

During which stage of shock is the body still able to maintain normal blood pressure but exhibits tachycardia?

Stage I – compensated Signup and view all the answers

What happens during Stage II – decompensated shock?

Tachycardia and hypotension are present. Signup and view all the answers

What critical physiological change occurs as a consequence of high pro-inflammatory cytokine levels?

Adverse impacts leading to tissue dysfunction Signup and view all the answers

What characterizes Stage III – irreversible shock?

Manifestations include hypotension, decreased consciousness, and high tachycardia. Signup and view all the answers

What is anasarca?

Generalized edema in loose connective tissue Signup and view all the answers

Which of the following best describes the movement of leukocytes in septic shock?

Leukocyte migration leads to inflammation and organ dysfunction. Signup and view all the answers

What is a significant risk associated with the failure of compensatory mechanisms in septic shock?

Multiple organ dysfunction syndrome Signup and view all the answers

What distinguishes hyperemia from congestion?

Hyperemia involves arteriolar dilation and increased blood flow Signup and view all the answers

Which condition is associated with hemosiderin deposition?

Chronic passive congestion Signup and view all the answers

What is the primary cause of pulmonary edema?

Damage to alveolar epithelium and capillary endothelium Signup and view all the answers

What can chronic passive congestion in the lungs lead to?

Formation of heart failure cells Signup and view all the answers

What would NOT be a clinical feature of edema?

It is always localized Signup and view all the answers

What color do congested tissues typically appear due to blood stasis?

Dusky reddish-blue Signup and view all the answers

Which of the following best describes the consequence of long-term pulmonary congestion?

Development of fibrosis and cell necrosis Signup and view all the answers

What type of edema results specifically from heart failure?

Pulmonary edema Signup and view all the answers

In the case of hepatic congestion, which feature is typically observed?

Distention of sinusoids with blood Signup and view all the answers

What is the most common cause of ischemic heart disease?

Atherosclerosis of the coronary arteries Signup and view all the answers

Which of the following symptoms is indicative of hypovolemic or cardiogenic shock?

Cool, clammy, cyanotic skin Signup and view all the answers

What pathological process leads to ischemic heart disease through sudden occlusion?

Rupture of an atherosclerotic plaque Signup and view all the answers

Which of the following factors does NOT acutely influence the heart's metabolic demands?

Age of the patient Signup and view all the answers

Which condition describes the inadequate blood supply to the myocardium for its metabolic needs?

Ischemic heart disease Signup and view all the answers

What physiological change occurs due to the progressive narrowing of coronary arteries?

Hypoperfusion of the myocardium Signup and view all the answers

Which of the following best describes the appearance of skin during septic shock?

Warm and flushed Signup and view all the answers

What does Laplace’s law indicate about wall tension in the heart?

It correlates with the energy used by the heart. Signup and view all the answers

What characterizes stable angina compared to unstable angina?

The obstruction remains stable and does not change. Signup and view all the answers

What is a key distinction in the treatment approaches for stable angina compared to unstable angina?

Unstable angina may necessitate more aggressive interventions due to higher risks. Signup and view all the answers

Which treatment is most effective for Prinzmetal angina?

Calcium channel blockers Signup and view all the answers

In which scenario would resting blood flow to the myocardium be significantly affected?

When there is a 90% occlusion. Signup and view all the answers

Which treatment is considered beneficial specifically for myocardial infarction patients with STEMI?

Thrombolytic agents such as alteplase. Signup and view all the answers

What is a common feature associated with acute coronary syndromes?

Symptoms can occur at rest or during activity. Signup and view all the answers

What is the primary purpose of using ASA (acetylsalicylic acid) in the management of ischemic heart disease?

To prevent life-threatening thrombus formation. Signup and view all the answers

Which of the following statements about the management of heart disease is MOST accurate?

Patients with stable angina may not benefit significantly from revascularization. Signup and view all the answers

Which condition primarily leads to ischemic heart disease in most cases?

Coronary atherosclerosis. Signup and view all the answers

What is the main concern that leads to high mortality soon after a myocardial infarction?

Occurrence of cardiac rupture due to necrosis. Signup and view all the answers

Which physiological change can indicate the development of ischemic cardiomyopathy?

Adaptations in cardiac myocyte contraction mechanisms. Signup and view all the answers

What can exacerbate oxygen delivery during episodes of ischemia in heart disease?

Hypertrophy of cardiac muscle. Signup and view all the answers

How do beta blockers primarily contribute to the management of ischemic heart disease?

By decreasing heart rate and myocardial oxygen demand. Signup and view all the answers

What happens when the lumen of a coronary artery is reduced by 80-90%?

Unstable angina symptoms generally occur at rest. Signup and view all the answers

What is the role of nitroglycerin in managing heart conditions?

It acts as a coronary vasodilator to decrease preload. Signup and view all the answers

What differentiates NSTEMI from STEMI in terms of treatment options?

NSTEMI does not typically use clot-busting drugs; instead, other treatments apply. Signup and view all the answers

What differentiates unstable angina from stable angina in terms of symptom patterns?

Unstable angina symptoms are more intense and can occur at rest or with less exertion. Signup and view all the answers

Which of the following treatment strategies is most appropriate for managing stable angina?

Long-term management with beta-blockers and nitrates. Signup and view all the answers

During which condition is sudden cardiac death most commonly associated?

Unstable angina due to worsening coronary ischemia. Signup and view all the answers

Which of the following pharmacologic agents is primarily used in the acute treatment of angina symptoms?

Nitroglycerin. Signup and view all the answers

What is the most appropriate first-line medication for a patient diagnosed with unstable angina?

Anticoagulants. Signup and view all the answers

Which condition is characterized by intermittent chest pain that resolves with rest and often correlates with exertional activities?

Stable angina. Signup and view all the answers

In the management of ischemic heart disease, what is the primary goal of therapy for patients with unstable angina?

Alleviating symptoms and preventing myocardial infarction. Signup and view all the answers

Which clinical feature would most likely suggest the transition from stable angina to unstable angina?

Increasing frequency and duration of pain with lesser exertion. Signup and view all the answers

Study Notes

Venous Side (Right)

Capillary oncotic pressure (πc) pulls fluid back into the capillary from the interstitial space.
Albumin is a key protein that drives πc.
Excess fluid is absorbed by the lymphatic system to prevent tissue swelling (edema).

Edema Causes

Increased hydrostatic pressure:
- Can be caused by generalized global increase in arteriolar blood pressure.
  - Malignant hypertension is an example of extreme blood pressure increases that can overwhelm normal fluid movement.
- Endocrine causes: Hormonal imbalances that affect blood volume and vascular tone.
- Decreased venous drainage can be regional or global, and can increase hydrostatic pressure.
Increased sodium and water retention:
- Sodium retention can occur after dietary increases.
- Kidney pathologies and decreased perfusion to the kidneys can impair sodium elimination.
- Endocrine causes: Syndrome of inappropriate ADH secretion and adrenal cortical pathologies with excess aldosterone.
Reduced lymphatic drainage:
- Cancer that infiltrates lymph nodes, surgeries that resect lymph nodes, infections that cause fibrosis of lymph nodes, and parasitic infestations (filiariasis/elephantiasis).
Decreased oncotic pressure:
- Albumin is the most important plasma protein for blood oncotic pressure.
- Nephrotic syndrome: Excess protein leakage from the glomerulus leads to decreased oncotic pressure. Protein filters from blood, enters the renal tubules, and is excreted in the urine.
- Hepatic failure, protein-losing enteropathies, and malnutrition can also cause decreased oncotic pressure.
Damage to the endothelium or excessive leakiness can lead to edema, often associated with inflammation.
- Pulmonary edema due to damage to alveolar epithelium and capillary endothelium.

Edema Clinical Features

Dependent edema is more noticeable in lower areas of the body, closer to the heart.
Many renal diseases can cause generalized edema.
- Anasarca is a generalized edema that is particularly evident in areas with loosely connected tissue.
- Different from the massive edema of anaphylaxis.
Pulmonary and brain edema are the most severe forms of edema.
- Edema is not just a symptom, but a causative factor in pathophysiology. Unique features of the microvasculature and air spaces (lungs) and inflexible cranial cavity (brain) result in severe consequences.

Hyperemia and Congestion

Hyperemia: Increased blood flow from arteriolar dilation.
- Tissues turn red (erythema) due to engorged vessels with oxygenated blood.
- Example: Blood flow returning to tissue that is warming after being in the cold.
Congestion: Passive process due to reduced outflow of blood from a tissue.
- Systemic (heart failure) or local (venous obstruction).
- Tissues take on a dusky reddish-blue color (cyanosis) due to red cell stasis and accumulation of deoxygenated blood.
- Red blood cells can extravasate, causing hemosiderin deposition.
  - Hemosiderin is a degradation product of hemoglobin found mostly in macrophages.

Chronic Passive Congestion

Long-standing congestion leads to chronic hypoxia.
Cellular degeneration, death, tissue fibrosis, and small foci of hemorrhage can occur.
Macrophages accumulate hemosiderin from phagocytosis of erythrocyte debris.

Congestion in Individual Tissues

Pulmonary congestion:
- Acute: Alveolar capillaries become engorged with blood.
- Chronic: Septa thicken and become fibrotic; alveolar spaces contain hemosiderin-laden macrophages ("heart failure cells").
Hepatic congestion:
- Acute: Hepatocytes degenerate; sinusoids and venules become distended with blood. Hepatocytes near the hepatic artery circulation experience less severe hypoxia and develop fatty change.

Venous Congestion

Pulmonary congestion:
- Causes: Left heart failure, mitral stenosis, and mitral regurgitation.
- Appearance: Engorged pulmonary capillaries and venules, alveolar edema, heart failure cells, brown induration.
- Clinical features: Shortness of breath (dyspnea), wheezing, difficulty breathing while lying flat.
Hepatic congestion:
- Causes: Right heart failure, constrictive pericarditis.
- Appearance: Enlarged liver, centrilobular necrosis, nutmeg liver.
- Clinical features: Right upper abdominal pain, elevated liver enzymes, ascites, peripheral edema, jugular venous distension.
Deep Vein congestion:
- Causes: Blood clot formation (DVT), incompetent valves.
- Appearance: Dilated and tortuous veins, venous ulcers, potential thrombus formation.
- Clinical features: Swelling, pain, tenderness, skin changes.

White vs. Red Infarct

White infarct: Organs with a single blood supply (e.g., kidney, spleen).
Red infarct: Organs with a dual blood supply (e.g., lung, intestine, testis).

Septic Shock

Infections cause widespread inflammation, resulting in dangerously low blood pressure and inadequate blood flow to vital organs.
Fatal due to inadequate tissue perfusion, leading to cellular death, multiple organ dysfunction, systemic inflammatory responses, and failure of compensatory mechanisms.

Septic Shock Pathophysiology

No single diagnostic test, but scoring systems are used to identify high-risk patients.
General characteristics:
- Dysregulated vascular reflexes: Inappropriate vasodilation and potential edema due to endothelium damage.
- Increased pro-inflammatory cytokines: Adverse impacts on tissues like the heart and kidneys.
- Leukocyte movement into organs: Organ dysfunction.
- Activation of coagulation and complement cascades.

Stages of Shock

Stage I (Compensated): Tachycardia, but blood pressure is normal.
Stage II (Decompensated): Body is no longer compensating for reduced tissue flow; tachycardia and hypotension, difficult to reverse.
Stage III (Irreversible): Death likely if not corrected quickly - Difficult to treat; high tachycardia or bradycardia, hypotension, decreased organ function (renal failure, impaired heart function, decreased level of consciousness).

Multi-Organ Dysfunction

Multiple organs fail due to lack of oxygen and blood.
Prognosis is poor.

General Shock Clinical Findings

Hypovolemic and cardiogenic Shock: Hypotension, weak and rapid pulse, tachypnea, cool, clammy, cyanotic skin.
Septic shock: Same as above, but skin may initially be warm and flushed due to peripheral vasodilation.

Ischemic Heart Disease

Inadequate blood supply to the myocardium to meet its metabolic demands.
Most commonly caused by atherosclerosis of the coronary arteries.
Other causes: Aneurysms, autoimmune attacks, coronary vasospasm.
Leading cause of death worldwide.

Pathogenesis of Ischemic Heart Disease

Progressive narrowing of coronary arteries: Leads to hypoperfusion of myocardium and potential heart failure.
Sudden occlusion of a major coronary artery: Atherosclerotic plaque rupture causes acute clot formation, blocking the artery or creating an embolus that blocks blood flow downstream, leading to an infarct.
Exacerbated by increased heart metabolic activity.

Factors Affecting Heart Metabolic Demand

Heart rate: Faster heart rate uses more energy.
Wall tension: Determined by volume and pressure within the heart chambers.
- A dilated heart requires more energy than a normal-sized heart.
- Laplace's Law: 𝝈= 𝑷 ∙𝒓 / 𝒉
Contractility: Influenced by intracellular calcium ions.

Causes of IHD

Coronary atherosclerosis is the most common primary cause
Other factors often exacerbate oxygen delivery or cardiac oxygen consumption

Pathogenesis - Influence of Atherosclerosis

Atherosclerosis is the major cause of ischemic heart disease (IHC), representing 90% of cases
With a 50-75% reduction in lumen size of a large coronary artery, there are usually IHC symptoms during increased activity.
When 80-90% reduction is observed, there are often symptoms at rest.
Often, there is more than one cause for IHC
i.e., hypertension and a hypertrophic heart in combination with atherosclerotic coronary arteries.

General Pathophysiologic Concepts

A healthy person has a substantial coronary flow reserve, and myocardial perfusion can increase to five times resting levels with intense exercise.
Myocardial circulation is mainly controlled by constriction and dilation of small, intramyocardial branches less than 400 μm in diameter.
Reduction in blood pressure distal to the narrowed zone occurs in advanced atherosclerosis of the main epicardial coronary arteries.
Maximal blood flow to the myocardium is not impaired until about 75% of the cross-sectional area of an epicardial coronary artery is compromised by atherosclerosis.
Resting blood flow is not reduced until greater than 90% of the lumen is occluded.

Pathophysiology - Types of IHD Presentation

Stable angina: When there is a plaque or thrombosis causing occlusion, the obstruction is thought to be stable.
Acute coronary syndromes (ACS):
- Unstable angina: Could be a thrombus that forms and breaks down constantly over a plaque. Could be a very significant stable occlusion that limits flow. Other rare conditions, like vasospastic angina, could be the cause.
- **Non-ST elevation myocardial infarction (NSTEMI) **
- ST-elevation myocardial infarction (STEMI)

Pathophysiology - Unstable Angina

Prinzmetal angina (vasospastic or variant angina):
- Technically a type of unstable angina with better prognosis
- Caused by coronary artery spasm
- Occurs early morning; unrelated to exertion
- Usually doesn’t cause infarction
- Responds well to vasodilators (nitroglycerine, calcium channel blockers)
- Typical patient population: younger ( less than 60 years), women.

Adaptations to Chronic Ischemia in the Heart

Hypertrophy and changes to the molecular mechanisms of contraction in cardiac myocytes (more on this later)
Ischemic cardiomyopathy
Development of coronary collateral circulation

Hmmmm…

Intracelular Ca2+

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Description

This quiz covers the mechanisms behind edema, focusing on the venous side and vascular pressures affecting fluid movement. It also explores the role of proteins like albumin in capillary oncotic pressure and various causes of increased fluid retention. Test your understanding of these physiological concepts and their implications for tissue health.