TJ

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.