Metabolic Acidosis Causes and Symptoms

Study Notes

Metabolic Acidosis

Caused by excess H+ in ECF, exchanged with K+ in cells
Renal excretion of hydrogen ions occurs if possible
Causes:
- Lactic acidosis (e.g., due to metformin)
- Ketoacidosis (e.g., due to diabetes, ethanol)
- Renal failure
Symptoms:
- Ventricular arrhythmias and reduced cardiac contractility
- Pulmonary edema and/or systemic hypotension
- Chronic metabolic acidosis leads to musculoskeletal problems
Treatment:
- Identify and treat the underlying cause (e.g., lactic acidosis, ketoacidosis)
- In renal failure, NaHCO3 is indicated to regenerate HCO3-

Metabolic Alkalosis

Caused by increased arterial pH due to a primary increase in HCO3- concentration
Compensation:
- Increase in PaCO2 through deep breathing (hypoventilation)
Causes:
- Processes that elevate serum HCO3- concentration (e.g., gastric or renal loss of acids)
- Processes that impair renal HCO3- excretion (e.g., hypovolemia, hypokalemia, mineralocorticoid excess)
Symptoms:
- Rarely due to alkalemia; usually related to volume depletion or hypokalemia
- Hypoventilation can cause hypoxemia
Treatment:
- Identify and treat the underlying cause
- Discontinue diuretics, nasogastric suction, and corticosteroids if possible
- Treat fluid deficits with IV normal saline

Respiratory Acidosis and Alkalosis

Respiratory acidosis:
- Caused by respiratory insufficiency, resulting in increased arterial CO2 concentration
- Compensation: increase in serum HCO3-
Respiratory alkalosis:
- Caused by hyperventilation, resulting in decreased arterial CO2 concentration
- Compensation: decrease in serum HCO3-

Acid-Base Derangements

Therapeutic approach:
1. Identify and treat the underlying cause
2. Normalize the pH: supportive treatment of pH and electrolytes is often needed
3. Continuous cardiovascular and hemodynamic monitoring is required

Respiratory Acidosis

Caused by primary increase in arterial PaCO2 (hypercapnia)
Compensation: rise in HCO3- concentration
Causes:
- Adult Respiratory Distress Syndrome
- Pulmonary edema
- Respiratory failure
Symptoms:
- Breathlessness and restlessness
- Skin warmed and flushed due to vasodilation caused by excess CO2
- Tremors, convulsions, coma
Treatment:
- Maintain oxygenation and improve alveolar ventilation if possible
- Naloxone for opiate-induced hypoventilation
- Bronchodilator therapy for acute bronchospasm

Respiratory Alkalosis

Caused by primary decrease in arterial PaCO2 (hyperventilation)
Compensation: fall in HCO3- concentration
Causes:
- Anxiety
- Hypoxemia, anemia
- Pulmonary embolism
Symptoms:
- Increased irritability of the central and peripheral nervous systems
Treatment:
- Treat the underlying cause
- Breathe into a paper bag

Description

This quiz covers the causes and symptoms of metabolic acidosis, including lactic acidosis, ketoacidosis, and renal failure. Learn how metabolic acidosis affects the body and its potential complications.