Metabolic acidosis

Disease Description (Causes and Symptoms)

• Definition: An acid–base disorder in which blood pH falls below 7.35, caused by loss of blood base (bicarbonate) or excessive accumulation of nonvolatile acids (such as ketone bodies and lactate).
• Main pathophysiology:
  • High anion gap metabolic acidosis: Accumulation of nonvolatile acids due to ketoacidosis (diabetic ketoacidosis), lactic acidosis (severe shock or hypoxia), toxic substances (methanol, ethylene glycol, salicylates), rhabdomyolysis, etc.
  • Normal (non-increased) anion gap: Bicarbonate loss due to gastrointestinal losses (severe diarrhea), impaired renal perfusion, etc.
  • Respiratory compensation: Hyperventilation (Kussmaul respiration)—deep, rapid breathing; in diabetic ketoacidosis, the patient may report a fruity odor
• Main causes: Diabetic ketoacidosis, acute or chronic renal failure, bicarbonate loss due to severe diarrhea, metabolic lactic acidosis (sepsis or hypoperfusion), toxins (methanol, ethylene glycol, salicylates), shock, rhabdomyolysis, etc.
• Main symptoms: Nausea, vomiting, abdominal pain, abdominal cramps, fatigue, malaise, headache, confusion, decreased consciousness, tachycardia, arrhythmia, hyperventilation (deep, rapid breathing), muscle pain, tremors

Treatment

• Treatment principles: Correct the cause → correct fluids and electrolytes → stabilize the acidosis itself
• General treatment
  • Treatment of the underlying disease: For example, in diabetic ketoacidosis (DKA), intravenous fluids (corrected electrolyte solution) + insulin therapy + electrolyte correction (especially potassium)
  • Fluid replacement: Rapid fluid replacement for intravascular volume expansion (such as normal saline)
  • Electrolyte management: Because the risk of hypokalemia is high during treatment, potassium monitoring and replacement are necessary
  • Bicarbonate (NaHCO3) administration: Generally considered when pH is very low (e.g., pH ≤ ~6.9) or in cases of severe hemodynamic instability, life-threatening hyperkalemia, shock due to severe acidosis, or risk due to severe acidosis. It should be used cautiously because overuse may cause fluid overload, hypokalemia, paradoxical intracellular acidosis, etc.
  • Dialysis (hemodialysis/peritoneal dialysis): For severe metabolic acidosis that does not improve with medical treatment, patients with end-stage renal failure, or poisoning with dialyzable toxins (such as ethylene glycol, methanol, or salicylates)
  • Supportive treatment: Oxygen and airway management, intensive care monitoring (repeated ECG, ABG, and electrolyte testing)
• Lifestyle management and precautions
  • Patients with diabetes should manage blood glucose (adhere to diet, medications, and insulin) and prevent infection and dehydration
  • Seek early medical evaluation when extreme diarrhea or vomiting persists
  • Visit the emergency department immediately if exposure to toxic substances is suspected
• Complication management: Inadequate treatment may lead to coma, arrhythmia, or cardiac arrest. Be alert for cardiovascular complications caused by electrolyte imbalances (especially potassium)

Checklist Before an Outpatient Visit (Including Sample Questions)

• Items to bring: List of medications currently being taken (including exact doses), past medical history (kidney disease, diabetes, heart disease, etc.), recent test results (blood glucose, electrolytes, kidney function, and ABG results if available), self-monitored blood glucose records and ketone test results (if available), and a record of when symptoms began and how they progressed
• Items to check in advance at the outpatient visit
  • When the symptoms began and how quickly they progressed (suddenly/gradually)
  • Whether vomiting, diarrhea, or dehydration is present, and changes in urine output (decreased urination)
  • Any recent infection, surgery, trauma, or extreme exercise
  • Medications being taken (diuretics, metformin, salicylates, etc.) and the possibility of toxin exposure
  • Underlying diseases (diabetes, renal failure, liver disease) and recent medication changes
• Sample questions for the outpatient visit (items for the patient to record in advance)
  • "How much have you been eating and drinking over the past few days?"
  • "Have you recently had a fever or symptoms of infection (such as a cough or painful urination)?"
  • "Have you recently ingested any medications or toxic substances (for example, a methanol-containing product)?"

General Sample Questions to Ask the Doctor

• "What do you think is causing this condition?"
• "What will the treatment plan (fluids, medications, and tests) be?"
• "What are the side effects or precautions associated with this medication?"
• "When should I return to the emergency department? What symptoms indicate worsening?"
• "What is the prognosis? What lifestyle changes should I make to prevent recurrence?"

Disease-Specific Sample Questions

• Regarding diabetic ketoacidosis:
  • "What are the target levels for blood glucose and blood ketones? How should I manage myself after discharge (including insulin adjustment)?"
• Regarding renal failure or suspected toxin exposure:
  • "When is dialysis (hemodialysis) necessary? Which test results (such as pH, K, or uremic symptoms) indicate that dialysis is warranted?"
• Regarding bicarbonate use:
  • "What are the criteria for using bicarbonate in my case (such as the pH level), and how can side effects (fluid overload, hypokalemia, etc.) be prevented?"