Find information on thousands of medical conditions and prescription drugs.

Metabolic acidosis

In medicine, metabolic acidosis is a state in which the blood pH is low (under 7.35) due to increased production of H+ by the body or the inability of the body to form bicarbonate (HCO3-) in the kidney. Its causes are diverse, and its consequences can be serious, including coma and death. Together with respiratory acidosis, it is one of the two general types of acidosis. more...

Home
Diseases
A
B
C
D
E
F
G
H
I
J
K
L
M
Mac Ardle disease
Macroglobulinemia
Macular degeneration
Mad cow disease
Maghazaji syndrome
Mal de debarquement
Malaria
Malignant hyperthermia
Mallory-Weiss syndrome
Malouf syndrome
Mannosidosis
Marburg fever
Marfan syndrome
MASA syndrome
Mast cell disease
Mastigophobia
Mastocytosis
Mastoiditis
MAT deficiency
Maturity onset diabetes...
McArdle disease
McCune-Albright syndrome
Measles
Mediterranean fever
Megaloblastic anemia
MELAS
Meleda Disease
Melioidosis
Melkersson-Rosenthal...
Melophobia
Meniere's disease
Meningioma
Meningitis
Mental retardation
Mercury (element)
Mesothelioma
Metabolic acidosis
Metabolic disorder
Metachondromatosis
Methylmalonic acidemia
Microcephaly
Microphobia
Microphthalmia
Microscopic polyangiitis
Microsporidiosis
Microtia, meatal atresia...
Migraine
Miller-Dieker syndrome
Mitochondrial Diseases
Mitochondrial...
Mitral valve prolapse
Mobius syndrome
MODY syndrome
Moebius syndrome
Molluscum contagiosum
MOMO syndrome
Mondini Dysplasia
Mondor's disease
Monoclonal gammopathy of...
Morquio syndrome
Motor neuron disease
Motorphobia
Moyamoya disease
MPO deficiency
MR
Mucopolysaccharidosis
Mucopolysaccharidosis...
Mullerian agenesis
Multiple chemical...
Multiple endocrine...
Multiple hereditary...
Multiple myeloma
Multiple organ failure
Multiple sclerosis
Multiple system atrophy
Mumps
Muscular dystrophy
Myalgic encephalomyelitis
Myasthenia gravis
Mycetoma
Mycophobia
Mycosis fungoides
Myelitis
Myelodysplasia
Myelodysplastic syndromes
Myelofibrosis
Myeloperoxidase deficiency
Myoadenylate deaminase...
Myocarditis
Myoclonus
Myoglobinuria
Myopathy
Myopia
Myositis
Myositis ossificans
Myxedema
Myxozoa
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
Medicines

Signs and symptoms

Symptoms are aspecific, and diagnosis can be difficult unless the patient presents with clear indications for arterial blood gas sampling. Symptoms may include chest pain, palpitations, headache, altered mental status, decreased visual acuity, nausea, vomiting, abdominal pain, altered appetite (either anorexia or excessive eating) and weight loss (longer term), muscle weakness and bone pains. A slightly specific finding is when the patient reports rapid breathing, not due to shortness of breath but an unmotivated drive to hyperventilate. Kussmaul respiration is rare, but may indicate ketoacidosis.

Exteme acidosis leads to neurological and cardiac complications:

  • Neurological: lethargy, stupor, coma, seizures.
  • Cardiac: arrhythmias (ventricular tachycardia), decreased response to epinephrine; both lead to hypotension (low blood pressure).

Physical examination occasionally reveals signs of disease, but is otherwise normal. Cranial nerve abnormalitites are reported in ethylene glycol poisoning, and retinal oedema can be a sign of methanol (methyl alcohol) intoxication. Longstanding chronic metabolic acidosis leads to osteoporosis and can cause fractures.

Diagnosis

Arterial blood gas sampling is essential for the diagnosis. The pH is low (under 7.35) and the bicarbonate levels are decreased (<12 mmol/l). In respiratory acidosis (low blood pH due to decreased clearance of carbon dioxide by the lungs), the bicarbonate is elevated, due to increased conversion from H2CO3. An ECG can be useful to anticipate cardiac complications.

Other tests that are relevant in this context are electrolytes (including chloride), glucose, renal function and a full blood count. Urinalysis can reveal acidity (salicylate poisoning) or alkalinity (renal tubular acidosis type I). In addition, it can show ketones in ketoacidosis.

To distinguish between the main types of metabolic acidosis, a clinical tool called the anion gap is considered very useful. It is calculated by subtracting the chloride and bicarbonate levels from the sodium plus potassium levels.

Anion gap = ( + ) - ( + )

As sodium and potassium are the main extracellular cations, and chloride and bicarbonate are the main anions, the result should reflect the remaining anions. Normally, this concentration is about 8-16 mmol/l. An elevated anion gap (i.e. > 16 mmol/l) can indicate particular types of metabolic acidosis, particularly certain poisons, lactate acidosis and ketoacidosis.

As the differential diagnosis is narrowed down, certain other tests may be necessary, including toxicological screening and imaging of the kidneys.

Read more at Wikipedia.org


[List your site here Free!]


Metabolic acidosis
From Gale Encyclopedia of Medicine, 4/6/01 by Altha Roberts Edgren

Definition

Metabolic acidosis is a pH imbalance in which the body has accumulated too much acid and does not have enough bicarbonate to effectively neutralize the effects of the acid.

Description

Metabolic acidosis, as a disruption of the body's acid/base balance, can be a mild symptom brought on by a lack of insulin, a starvation diet, or a gastrointestinal disorder like vomiting and diarrhea. Metabolic acidosis can indicate a more serious problem with a major organ like the liver, heart, or kidneys. It can also be one of the first signs of drug overdose or poisoning.

Causes & symptoms

Metabolic acidosis occurs when the body has more acid than base in it. Chemists use the term "pH" to describe how acidic or basic a substance is. Based on a scale of 14, a pH of 7.0 is neutral. A pH below 7.0 is an acid; the lower the number, the stronger the acid. A pH above 7.0 is a base; the higher the number, the stronger the base. Blood pH is slightly basic (alkaline), with a normal range of 7.36-7.44.

Acid is a natural by-product of the breakdown of fats and other processes in the body; however, in some conditions, the body does not have enough bicarbonate, an acid neutralizer, to balance the acids produced. This can occur when the body uses fats for energy instead of carbohydrates. Conditions where metabolic acidosis can occur include chronic alcoholism, malnutrition, and diabetic ketoacidosis. Consuming a diet low in carbohydrates and high in fats can also produce metabolic acidosis. The disorder may also be a symptom of another condition like kidney failure, liver failure, or severe diarrhea. The build up of lactic acid in the blood due to such conditions as heart failure, shock, or cancer, induces metabolic acidosis. Some poisonings and overdoses (aspirin, methanol, or ethylene glycol) also produce symptoms of metabolic acidosis.

In mild cases of metabolic acidosis, symptoms include headache, lack of energy, and sleepiness. Breathing may become fast and shallow. Nausea, vomiting, diarrhea, dehydration, and loss of appetite are also associated with metabolic acidosis. Diabetic patients with symptoms of metabolic acidosis may also have breath that smells fruity. The patient may lose consciousness or become disoriented. Severe cases can produce coma and death.

Diagnosis

Metabolic acidosis is suspected based on symptoms, but is usually confirmed by laboratory tests on blood and urine samples. Blood pH below 7.35 confirms the condition. Levels of other blood components, including potassium, glucose, ketones, or lactic acid, may also be above normal ranges. The level of bicarbonate in the blood will be low, usually less than 22 mEq/L. Urine pH may fall below 4.5 in metabolic acidosis.

Treatment

Treatment focuses first on correcting the acid imbalance. Usually, sodium bicarbonate and fluids will be injected into the blood through a vein. An intravenous line may be started to administer fluids and allow for the quick injection of other drugs that may be needed. If the patient is diabetic, insulin may be administered. Drugs to regulate blood pressure or heart rate, to prevent seizures, or to control nausea and vomiting might be given. Vital signs like pulse, respiration, blood pressure, and body temperature will be monitored. The underlying cause of the metabolic acidosis must also be diagnosed and corrected.

Prognosis

If the metabolic acidosis is recognized and treated promptly, the patient may have no long-term complications, however, the underlying condition that caused the acidosis needs to be corrected or managed. Severe metabolic acidosis that is left untreated will lead to coma and death.

Prevention

Diabetic patients need to routinely test their urine for sugar and acetone, strictly follow their appropriate diet, and take any medications or insulin to prevent metabolic acidosis. Patients receiving tube feedings or intravenous feedings must be monitored to prevent dehydration or the accumulation of ketones or lactic acid.

Key Terms

Diabetic ketoacidosis
A condition caused by low insulin levels where the amount of sugar and ketones in the blood is high.
pH
A measurement of the acidity or alkalinity of a solution based on the amount of hydrogen ions available. Based on a scale of 14, a pH of 7.0 is neutral. A pH below 7.0 is an acid; the lower the number, the stronger the acid. A pH above 7.0 is a base; the higher the number, the stronger the base. Blood pH is slightly alkaline (basic) with a normal range of 7.36-7.44.

Further Reading

For Your Information

    Books

  • "Acid-Base Disturbances." In Cecil Textbook of Medicine. 20th ed. Philadelphia: W.B. Saunders Company, 1996.
  • DuBose, Thomas D., Jr. "Acidosis and Alkalosis." In Harrison's Principles of Internal Medicine. 14th ed. New York: McGraw-Hill, 1998.
  • "Fluid, Electrolyte, and Acid-Base Disorders." In Family Medicine Principles and Practices. 5th ed. New York: Springer-Verlag, 1998.
  • "Fluid & Electrolyte Disorders." In Current Medical Diagnosis & Treatment 1998. 37th ed. Stamford, CT: Appleton & Lange, 1998.

Gale Encyclopedia of Medicine. Gale Research, 1999.

Return to Metabolic acidosis
Home Contact Resources Exchange Links ebay