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The underlying cause determines the prognosis of lactic acidosis. In sepsis, elevated lactate levels correlate with mortality. The mortality of lactic acidosis in people taking metformin was previously reported to be 50%, but in more recent reports this was closer to 25%.
Direct removal of lactate from the body (e.g. with hemofiltration) is difficult, with limited evidence for benefit. In type A lactic acidosis, treatment consists of effective management of the underlying cause, and limited evidence supports the use of sodium bicarbonate solutions to improve the pH (which is associated with increased carbon dioxide generation and may reduce the calcium levels).
In type B lactic acidosis produced by medication, withdrawal of the medication may be necessary to resolve the lactic acidosis.
Lactic acidosis in the context of mitochondrial disorders (type B3) may be treated with a ketogenic diet and possibly with dichloroacetate (DCA), although this may be complicated by peripheral neuropathy and has a weak evidence base.
A pH under 7.1 is an emergency, due to the risk of cardiac arrhythmias, and may warrant treatment with intravenous bicarbonate. Bicarbonate is given at 50-100 mmol at a time under scrupulous monitoring of the arterial blood gas readings. This intervention, however, has some serious complications in lactic acidosis, and in those cases, should be used with great care.
If the acidosis is particularly severe and/or intoxication may be present, consultation with the nephrology team is considered useful, as dialysis may clear both the intoxication and the acidosis.
Causes of increased anion gap include:
- Lactic acidosis
- Ketoacidosis
- Chronic renal failure (accumulation of sulfates, phosphates, urea)
- Intoxication:
- Organic acids, salicylates, ethanol, methanol, formaldehyde, ethylene glycol, paraldehyde, isoniazid
- Sulfates, metformin
- Massive rhabdomyolysis
A mnemonic can also be used - MUDPILES
- M-Methanol
- U-Uremia (chronic kidney failure)
- D-Diabetic ketoacidosis
- P-Paraldehyde
- I-Infection, Iron, Isoniazid, Inborn errors of metabolism
- L-Lactic acidosis
- E-Ethylene glycol (Note: Ethanol is sometimes included in this mnemonic, as well, although the acidosis caused by ethanol is actually primarily due to the increased production of lactic acid found in such intoxication.)
- S-Salicylates
Causes include:
The newest mnemonic was proposed in "The Lancet" reflecting current causes of anion gap metabolic acidosis:
- G — glycols (ethylene glycol & propylene glycol)
- O — oxoproline, a metabolite of paracetamol
- L — L-lactate, the chemical responsible for lactic acidosis
- D — D-lactate
- M — methanol
- A — aspirin
- R — renal failure
- K — ketoacidosis, ketones generated from starvation, alcohol, and diabetic ketoacidosis
The mnemonic MUDPILES is commonly used to remember the causes of increased anion gap metabolic acidosis.
- M — Methanol
- U — Uremia (chronic kidney failure)
- D — Diabetic ketoacidosis
- P — Paracetamol, Propylene glycol (used as an inactive stabilizer in many medications; historically, the "P" also stood for Paraldehyde, though this substance is not commonly used today)
- I — Infection, Iron, Isoniazid (which can cause lactic acidosis in overdose), Inborn errors of metabolism (an especially important consideration in pediatric patients)
- L — Lactic acidosis
- E — Ethylene glycol (Note: Ethanol is sometimes included in this mnemonic as well, although the acidosis caused by ethanol is actually primarily due to the increased production of lactic acid found in such intoxication.)
- S — Salicylates
Another frequently used mnemonic is KARMEL.
- K — Ketoacidosis
- A — aspirin
- R — Renal failure
- M — Methanol
- E — Ethylene glycol
- L — Lactic acidosis
Another frequently used mnemonic is KULT.
- K — Ketoacidosis (DKA, AKA)
- U — Uremia
- L — Lactic acidosis
- T — Toxins (Ethylene glycol, methanol, as well as drugs, such as aspirin, Metformin)
The preferred mnemonic of D. Robert Dufour, the chief of the Pathology and Laboratory Medicine Service, Veterans Affairs Medical Center, is DUMPSALE, which omits the I of MUDPILES as the proposed values of *I* are exceedingly rare in clinical practice.
- D — Diabetic ketoacidosis
- U — Uremia
- M — Methanol
- P — Paraldehyde
- S — Salicylates
- A — Alcoholic ketoacidosis
- L — Lactic acidosis
- E — Ethylene Glycol
The mnemonic for the [rare, in comparison] toxins is ACE GIFTs: Aspirin, Cyanide, Ethanolic ketosis, Glycols [ ethylene and propylene ], Isoniazid, Ferrous iron, Toluene. Most of these cause a lactic acidosis.
In the United States, hyperkalemia is induced by lethal injection in capital punishment cases. Potassium chloride is the last of the three drugs administered and actually causes death. Injecting potassium chloride into the heart muscle disrupts the signal that causes the heart to beat. This same amount of potassium chloride would do no harm if taken orally and not injected directly into the blood.
Sodium zirconium cyclosilicate (ZS-9) is an investigational selective oral sorbent that binds potassium in the gastrointestinal tract in exchange for sodium and hydrogen ions.
When acidosis is present on blood tests, the first step in determining the cause is determining the anion gap. If the anion gap is high (>12 mEq/L), there are several potential causes.
High anion gap metabolic acidosis is a form of metabolic acidosis characterized by a high anion gap (a medical value based on the concentrations of ions in a patient's serum). An anion gap is usually considered to be high if it is over 12 mEq/L.
High anion gap metabolic acidosis is caused generally by acid produced by the body. More rarely, high anion gap metabolic acidosis may be caused by ingesting methanol or overdosing on aspirin. The Delta Ratio is a formula that can be used to assess elevated anion gap metabolic acidosis and to evaluate whether mixed acid base disorder (metabolic acidosis) is present.
The list of agents that cause high anion gap metabolic acidosis is similar to but broader than the list of agents that cause a serum osmolal gap.
In the fetus, the normal range differs based on which umbilical vessel is sampled (umbilical vein pH is normally 7.25 to 7.45; umbilical artery pH is normally 7.20 to 7.38). In the fetus, the lungs are not used for ventilation. Instead, the placenta performs ventilatory functions (gas exchange). Fetal respiratory acidemia is defined as an umbilical vessel pH of less than 7.20 and an umbilical artery PCO of 66 or higher or umbilical vein PCO of 50 or higher.
Treatment consists of oral bicarbonate supplementation. However, this will increase urinary bicarbonate wasting and may well promote a bicarbonate . The amount of bicarbonate given may have to be very large to stay ahead of the urinary losses. Correction with oral bicarbonate may exacerbate urinary potassium losses and precipitate hypokalemia. As with dRTA, reversal of the chronic acidosis should reverse bone demineralization.
Thiazide diuretics can also be used as treatment by making use of contraction alkalosis caused by them.
Treatment of uncompensated metabolic acidosis is focused upon correcting the underlying problem. When metabolic acidosis is severe and can no longer be compensated for adequately by the lungs, neutralizing the acidosis with infusions of bicarbonate may be required.
In general, the cause of a hyperchloremic metabolic acidosis is a "loss of base", either a gastrointestinal loss or a renal loss.
- Gastrointestinal loss of bicarbonate ()
- Severe diarrhea (vomiting will tend to cause hypochloraemic alkalosis)
- Pancreatic fistula with loss of bicarbonate rich pancreatic fluid
- Nasojejunal tube losses in the context of small bowel obstruction and loss of alkaline proximal small bowel secretions
- Chronic laxative abuse
- Renal causes
- Proximal renal tubular acidosis with failure of resorption
- Distal renal tubular acidosis with failure of secretion
- Long-term use of a carbonic anhydrase inhibitor such as acetazolamide
- Other causes
- Ingestion of ammonium chloride, hydrochloric acid, or other acidifying salts
- The treatment and recovery phases of diabetic ketoacidosis
- Volume resuscitation with 0.9% normal saline provides a chloride load, so that infusing more than 3-4L can cause acidosis
- Hyperalimentation ("i.e.", total parenteral nutrition)
Hyperchloremic acidosis is a form of metabolic acidosis associated with a normal anion gap, a decrease in plasma bicarbonate concentration, and an increase in plasma chloride concentration (see anion gap for a fuller explanation). Although plasma anion gap is normal, this condition is often associated with an "increased" urine anion gap, due to the kidney's inability to secrete ammonia.
The primary treatment goal is prevention of hypoglycemia and the secondary metabolic derangements by frequent feedings of foods high in glucose or starch (which is readily digested to glucose). To compensate for the inability of the liver to provide sugar, the total amount of dietary carbohydrate should approximate the 24-hour glucose production rate. The diet should contain approximately 65–70% carbohydrate, 10–15% protein, and 20–25% fat. At least a third of the carbohydrates should be supplied through the night, so that a young child goes no more than 3–4 hours without carbohydrate intake
In the last 30 years, two methods have been used to achieve this goal in young children: (1) continuous nocturnal gastric infusion of glucose or starch; and (2) night-time feedings of uncooked cornstarch. An elemental formula, glucose polymer, and/or cornstarch can be infused continuously through the night at a rate supplying 0.5–0.6 g/kg/h of glucose for an infant, or 0.3–0.4 for an older child. This method requires a nasogastric or gastrostomy tube and pump. Sudden death from hypoglycemia has occurred due to malfunction or disconnection, and periodic cornstarch feedings are now preferred to continuous infusion.
Cornstarch is an inexpensive way to provide gradually digested glucose. One tablespoon contains nearly 9 g carbohydrate (36 calories). Although it is safer, less expensive, and requires no equipment, this method does require that parents arise every 3–4 hours to administer the cornstarch. A typical requirement for a young child is 1.6 g/kg every 4 hours.
Long-term management should eliminate hypoglycemic symptoms and maintain normal growth. Treatment should achieve normal glucose, lactic acid, and electrolyte levels, and only mild elevations of uric acid and triglycerides.
The most significant acute problem in childhood is a vulnerability to episodes of metabolic acidosis precipitated by minor illnesses. If a vomiting illness persists longer than 2–4 hours, the child should be seen and assessed for dehydration, acidosis, and hypoglycemia. If these are developing, intravenous fluids should be provided at a rate above maintenance. For mild acidosis, an effective fluid is 10% dextrose in ½ normal saline with 20 mEq/l KCl, but if acidosis is severe, 75–100 mEq/l and 20 mEq/l of K acetate can be substituted for the NaCl and KCl.
Low temperature is a commonly reported trigger of acute gout: an example would be a day spent standing in cold water, followed by an attack of gout the next morning. This is believed to be due to temperature-dependent precipitation of uric acid crystals in tissues at below normal temperature. Thus, one aim of prevention is to keep the hands and feet warm, and soaking in hot water may be therapeutic.
Respiratory alkalosis is caused by hyperventilation, resulting in a loss of carbon dioxide. Compensatory mechanisms for this would include increased dissociation of the carbonic acid buffering intermediate into hydrogen ions, and the related excretion of bicarbonate, both of which lower blood pH. Hyperventilation-induced alkalosis can be seen in several deadly central nervous system diseases such as strokes or Rett syndrome.
Metabolic alkalosis can be caused by repeated vomiting, resulting in a loss of hydrochloric acid in the stomach contents. Severe dehydration, and the consumption of alkali are other causes. It can also be caused by administration of diuretics and endocrine disorders such as Cushing's syndrome. Compensatory mechanism for metabolic alkalosis involve slowed breathing by the lungs to increase serum carbon dioxide, a condition leaning toward respiratory acidosis. As respiratory acidosis often accompanies the compensation for metabolic alkalosis, and vice versa, a delicate balance is created between these two conditions.
Metabolic alkalosis is usually accompanied by low blood potassium concentration, causing, e.g., muscular weakness, muscle pain, and muscle cramps (from disturbed function of the skeletal muscles), and muscle spasms (from disturbed function of smooth muscles).
It may also cause low blood calcium concentration. As the blood pH increases, blood transport proteins, such as albumin, become more ionized into anions. This causes the free calcium present in blood to bind more strongly with albumin. If severe, it may cause tetany.
This is relatively straightforward. It involves correction of the acidemia with oral sodium bicarbonate, sodium citrate or potassium citrate. This will correct the acidemia and reverse bone demineralisation. Hypokalemia and urinary stone formation and nephrocalcinosis can be treated with potassium citrate tablets which not only replace potassium but also inhibit calcium excretion and thus do not exacerbate stone disease as sodium bicarbonate or citrate may do.
Increased levels predispose for gout and, if very high, kidney failure. The metabolic syndrome often presents with hyperuricemia. Prognosis is good with regular consumption of Allopurinol.
People with gout, and by inference hyperuricemia, are significantly less likely to develop Parkinson's disease, unless they also require diuretics.
The main causes of hypokalemic acidosis are systemic disorders that can be divided into:
- Carbonic anhydrase inhibitors such as acetazolamide
- Dialysis, in the post-treatment
- Diarrhea
- Renal tubular acidosis
- Treated DKA with insulin therapy
- VIPoma
Familial disorders
- Cystinosis
- Galactosemia
- Glycogen storage disease (type I)
- Hereditary fructose intolerance
- Lowe syndrome
- Tyrosinemia
- Wilson's disease
Acquired disorders
- Amyloidosis
- Multiple myeloma
- Paroxysmal nocturnal hemoglobinuria
- Toxins, such as HAART, ifosfamide, lead, and cadmium
Hypokalemic acidosis is a normal anion gap metabolic acidosis that has various direct and associated symptoms. Symptoms are associated with hypokalemia instead of hyperkalemia.
The goal for treatment of GSD type 0 is to avoid hypoglycemia. This is accomplished by avoiding fasting by eating every 3-4 hours during the day. At night, uncooked corn starch can be given because it is a complex glucose polymer. This will be acted on slowly by pancreatic amylase and glucose will be absorbed over a 6 hour period.
Glycogen-storage disease type 0 is most commonly diagnosed during infancy and early childhood.