Renal tubular acidosis

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at December 6, 2016
StartDiseasesRenal tubular acidosis

From filtering out toxins to balancing body fluids, the kidneys perform a variety of important bodily functions. Renal tubular acidosis (RTA) occurs when the kidneys fail to acidify the urine usually as a result of damage or defects of the renal tubules. This acidosis can cause a variety of severe and even life-threatening complications.

Contents

Definition & Facts

Renal tubular acidosis (RTA) is a condition that occurs when there is an abnormal concentration of acid in the blood. The condition occurs when the kidneys fail to remove acids from the blood and channel them into the urine. RTA is more common in children than adults. 

The body contains cells that use chemical reactions to perform a variety of tasks such as repairing tissues and producing energy. As a result of these reactions, the cells produce acids in the blood. The acids must be removed from the body immediately to maintain the acid-base balance. Kidneys ordinarily maintain the balance by excreting acid through the urine.

When acid builds up in the blood, the functioning of the cells can be severely impaired and a variety of symptoms can ensue such as bone disease and chronic kidney disease.

Symptoms & Complaints

Renal tubular acidosis manifests itself in several ways. A person suffering from RTA may not think as quickly and clearly as he or she used to do. The symptoms of confusion may be temporary, or the patient may develop permanent confusion.

An RTA patient may have chronic fatigue. Fatigue occurs because the body’s enzymes cannot facilitate efficient digestion and metabolism hence resulting in less energy output. In addition, an acidic environment impairs the proper replication of cells in the body, which leads to impaired growth in children.

Someone with RTA may have an increased rate of breathing (hyperpnea) since the body is trying to compensate for the reduced energy produced by the cells. He or she may also develop kidney stones.

Children with RTA may develop soft bones. Soft bones are caused by the highly acidic environment that eats away the minerals in the bones. Most bones of RTA patients are soft and porous. Other common symptoms of RTA include bone pain, reduced production of urine, muscle pains, abdominal pain, back pain, and abnormal orientation of the skeleton

Causes

The causes of RTA vary depending on the type of the condition. Type 1 is the most common form of RTA, and it is caused by high amounts of calcium in the blood (hypercalcaemia). Sickle-cell disease, lupus, certain drugs, and autoimmune diseases are also common causes of the condition.

Type 2 RTA occurs when the damage is near the point where the tubules begin to project to other parts of the kidney. It is common among children and is connected to a disorder known as Fanconi anemia. Other causes include lack of Vitamin D, fructose intolerance, and certain medications.

Type 3 RTA may occur as a result of a combination of causes linked to types 1 and 2. It is considered an obsolete category.

Type 4 RTA occurs due to a transport disorder in which sodium, calcium, and potassium do not coordinate or move properly in the blood vessels. There is usually an excessive buildup of potassium in the blood due to this condition. Type 4 RTA can occur as a result of urinary infections, malfunctions of the immune system, sickle-cell disease, kidney cancer, the body’s rejection of a new kidney, and diabetes.

Diagnosis & Tests

Diagnosis of this condition involves a physical examination and an inquiry into the patient's medical history and family history. The doctor will perform various tests to assess the patient's pH balance.

He or she will take a sample of urine from the patient as well as a blood sample to check the acid-base balance. If the doctor finds abnormal results such as the urine being less acidic than it should be or the blood being more acidic than it should be, then this could be an indication of rental tubular acidosis.

However, there are other conditions that cause abnormal pH in the body. Therefore, the doctor should recommend additional tests to rule out the possibility of RTA. For instance, the doctor might recommend a comprehensive analysis of the body’s electrolytes such as sodium, calcium and potassium.

Treatment & Therapy

The goal of treatment is to restore the acid-base balance in the body. Treating RTA depends on what is causing the condition. If the cause of the problem is a drug, the doctor may recommend ceasing the drug or providing a safer alternative. If the RTA is due to an existing illness, the doctor will treat the illness.

A doctor will prescribe alkaline medicines which can reduce acidosis. Alkaline medications such as sodium bicarbonate will act as neutralizing agents and help reduce the level of acid in the blood. Treatment will address symptoms and complications. This can include treating bone disorders and eradicating kidney stones. Sometimes patients may need RTA treatment for life, especially children with genetic disorders.

Prevention & Prophylaxis

A healthy diet full of minerals may help reduce the incidences of RTA. A diet full of vegetables and high-fiber fruits is good for keeping the body’s acidic levels at the optimum level. People should avoid eating foods rich in proteins and acids.

Patients should also maintain regular contact with their home care physicians for checkups to identify the condition at its early stages and eradicate it. People with diabetes should be vigilant about controlling their condition to stave off complications.