PATHOPHYSIOLOGY all combine

Hypoxia Overview

• Definition: Disturbance of oxidative processes in tissues due to insufficient oxygen intake or utilization.

Importance of Hypoxia

• Common pathological process in various life stages (birth, death).

• Associated with most diseases, leading to metabolic disturbances due to ATP synthesis reduction.

Classification of Hypoxia

By Pathogenesis

1. Exogenous

2. Respiratory

3. Blood pathology-related

4. Circulatory

5. Tissue-related disturbances

6. Hyperbaric

7. Hyperoxic

8. Exertional

9. Mixed

By Severity

• Latent: detected only during exertion.

• Compensated: no tissue hypoxia at rest.

• Decompensated: tissue hypoxia present at rest.

• Uncompensated: severe hypoxia without compensation.

• Terminal: irreversible state.

By Speed and Duration

• Fulminant

• Acute

• Subacute

• Chronic

Types of Hypoxia

Exogenous Hypoxia

• Etiology: Reduced P(O2)

• Conditions: Altitude sickness, work in mines, oxygen supply disruptions.

• Pathogenesis involves hypoxemia and hypocapnia effects on cerebral and cardiac oxygen consumption.

Respiratory Hypoxia

• Caused by impairments in gas exchange, including:

  • Obstructive changes (e.g., lung edema, foreign bodies).

  • Restrictive changes (e.g., pneumonia).

Blood Hypoxia

• Decreased oxygen-carrying capacity due to anemia or hemoglobin inactivation.

• Forms include carboxyhemoglobin and methemoglobin.

Circulatory Hypoxia

• Issues in blood flow (ischemia, shock) affecting oxygen delivery.

Tissue Hypoxia

• Impairs tissue utilization of oxygen leading to metabolic disturbances.

Hyperbaric Hypoxia

• Often due to oxygen therapy under high pressure, affecting ventilation and increasing arterial P(CO2).

Hypoxia of Exertion

• Results from insufficient oxygen supply during high organ function.

Mixed Hypoxia

• Involves synergistic impacts of multiple hypoxic factors.

Impact on Cells and Metabolism

• Cells with high oxygen demand (e.g., brain, heart) are more susceptible.

• Metabolic consequences include increased lactate production and acidosis.

Adaptive Responses to Hypoxia

• Increased breathing rate, red blood cell production.

• Cardiovascular adaptations include increased heart rate and stroke volume.

Pathophysiology and Treatment

• Requires complex intervention strategies including oxygen therapy and correction of underlying causes such as anemia or circulatory issues.