Renal Tubular Acidosis
What is it?
Renal tubular acidosis (RTA) is a disorder in
which too much acid builds up in the blood because
the kidney tubules aren’t functioning properly.
The build up of acid in the blood is called
metabolic acidosis.
Who gets it?
RTA is more common in people with certain
diseases, such as autoimmune diseases, and people
with chronic kidney conditions. Some types are
more common in women and young people.
What causes it?
The kidneys normally remove substances such as
acid from the blood and excrete them through the
urine. There are three types of renal tubular
acidosis, called Types 1, 2, and 4 (there is no
Type 3). Type 1 may be hereditary or can be
triggered by an autoimmune disease (such as
lupus), certain drugs, chronic kidney obstruction,
or kidney transplant. Type 2 is usually caused by
a hereditary disease, such as hereditary fructose
intolerance, Lowe’s syndrome, Wilson’s disease, or
Fanconi’s syndrome; heavy metal poisoning; kidney
transplant; vitamin D deficiency; and certain
drugs. Type 4 is the only type that is not
hereditary, but is caused by autoimmune disease,
diabetes mellitis, urinary tract obstruction, or
sickle cell disease.
What are the symptoms?
The symptoms of RTA depend upon the type. Type
1 causes mild dehydration, fragile bones/bone
pain, kidney stones, and kidney failure. Blood
potassium levels are low, which causes symptoms
ranging from muscle weakness to paralysis. Type 2
RTA also causes mild dehydration and low blood
potassium levels. With Type 4, blood potassium
levels are high. There are no symptoms until
potassium levels become dangerously high, which
causes muscle paralysis and irregular heartbeat
(arrhythmia). People with RTA may have frequent
urinary tract and bacterial kidney infections and
urinate excessively. Children with RTA often
experience slow growth, show signs of anorexia,
and have symptoms such as vomiting, constipation,
and soft bones (rickets).
How is it diagnosed?
To diagnose RTA, your doctor will take a
complete medical history and perform a thorough
physical examination. He or she will study your
pattern of symptoms, and check the levels of acid
and potassium in a blood sample. Additional blood
and urine tests will confirm the type of RTA.
What is the treatment?
Types 1 and 2 RTA are treated with a
bicarbonate solution. Bicarbonate is baking soda,
and it helps to neutralize the acid. You will need
to drink this solution every day for a period of
time specified by your doctor. You may also need
to take a potassium supplement to raise blood
potassium levels, vitamin D, and antibiotics,
depending upon your symptoms. Treatment of Type 4
RTA requires a change in diet to lower potassium
levels, as well as drinking plenty of fluids. You
may need to take a drug called a diuretic, which
helps the kidneys excrete more urine. Your doctor
will determine if any additional treatment is
needed when an underlying disease is causing your
symptoms.
Self-care tips
If you have Type 1 or 2 RTA, in which potassium
levels are low, be sure to include foods that are
rich in potassium in your diet. These include
bananas, oranges, tomatoes, spinach and other
green leafy vegetables, melons, peas and beans,
and potatoes. If you have Type 4 RTA, you’ll want
to reduce the amount of these foods in your diet.
If there is a history of RTA in your family, you
may want to consider genetic counseling before
considering pregnancy.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
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