What are the clinical manifestations of acute metabolic acidosis?

From the Guidelines

Acute metabolic acidosis typically manifests with rapid, deep breathing (Kussmaul respirations), headache, nausea, vomiting, fatigue, and confusion, as evident in the most recent study 1. The clinical manifestations of acute metabolic acidosis can vary depending on the underlying cause, but common symptoms include:

• Rapid, deep breathing (Kussmaul respirations)
• Headache
• Nausea
• Vomiting
• Fatigue
• Confusion
• Abdominal pain
• Decreased appetite
• Cardiac arrhythmias and hypotension in severe cases As acidosis worsens, mental status changes can progress from lethargy to somnolence and eventually coma. Physical examination may reveal tachycardia and warm, flushed skin in early stages, followed by cold, clammy skin and hypotension as acidosis becomes more severe. Laboratory findings include a low arterial pH (below 7.35), decreased serum bicarbonate (below 22 mEq/L), and a normal or low partial pressure of carbon dioxide (PaCO2), reflecting respiratory compensation, as seen in studies such as 2 and 3. The anion gap may be normal or elevated depending on the underlying cause. These manifestations occur because excess hydrogen ions affect multiple organ systems, particularly the cardiovascular, respiratory, and central nervous systems. The body attempts to compensate by increasing ventilation to eliminate carbon dioxide and by buffering hydrogen ions, but when these mechanisms are overwhelmed, clinical symptoms appear and worsen proportionally to the severity of the acidosis, as discussed in 4. It is essential to identify and treat the underlying cause of metabolic acidosis to prevent further complications and improve patient outcomes.

From the FDA Drug Label

Sodium Bicarbonate Injection, USP is indicated in the treatment of metabolic acidosis which may occur in severe renal disease, uncontrolled diabetes, circulatory insufficiency due to shock or severe dehydration, extracorporeal circulation of blood, cardiac arrest and severe primary lactic acidosis Intravenous sodium bicarbonate therapy increases plasma bicarbonate, buffers excess hydrogen ion concentration, raises blood pH and reverses the clinical manifestations of acidosis

The clinical manifestations of acute metabolic acidosis are not explicitly stated in the provided drug labels. However, the labels do mention that sodium bicarbonate therapy reverses the clinical manifestations of acidosis [5][6].

• The labels provide indications for the use of sodium bicarbonate in various conditions that may lead to metabolic acidosis, such as: + Severe renal disease + Uncontrolled diabetes + Circulatory insufficiency due to shock or severe dehydration + Cardiac arrest + Severe primary lactic acidosis However, the labels do not provide a direct description of the clinical manifestations of acute metabolic acidosis.

From the Research

Clinical Manifestations of Acute Metabolic Acidosis

The clinical manifestations of acute metabolic acidosis can be severe and life-threatening. Some of the key manifestations include:

• Depressive effects on cardiovascular function 7
• Facilitation of cardiac arrhythmias 7
• Stimulation of inflammation 7
• Suppression of the immune response 7
• Adverse effects on cellular function, including a fall in extracellular and intracellular pH 7

Causes of Acute Metabolic Acidosis

Acute metabolic acidosis can occur due to various causes, including:

• Lactic acidosis, which can evolve from various conditions with or without systemic hypoxia 8, 9
• Ketoacidosis, such as diabetic ketoacidosis 9, 10, 11
• Renal failure 9, 7, 11
• Intoxication with substances like ethylene glycol, methanol, salicylate, and others 9
• Gastrointestinal bicarbonate loss 9
• Renal tubular acidosis 9
• Drugs-induced hyperkalemia 9
• Administration of acids 9
• Unbalanced electrolyte solutions, which can induce hyperchloremic metabolic acidosis 8

Treatment and Management

The treatment of acute metabolic acidosis is often controversial, and the effectiveness of sodium bicarbonate therapy is still debated 8, 9, 7, 10. Some studies suggest that sodium bicarbonate may improve kidney-related endpoints in critically ill patients 8, while others have found no benefit in terms of morbidity and mortality 9, 7, 10. A structured approach to assessment and management, including prompt resuscitation and specific causal treatment, can lead to positive outcomes in patients with extreme metabolic acidosis 11.