Renal Tubular Acidosis (RTA)

The Renal Tubular Acidosis or the RTA is the term used to define a particular disease which takes place when our kidney does not perform their usual function of excreting the acids through urine. As a result, the blood of the person becomes acidic in nature. If proper treatment is not provided, the chronic nature of acidity inside the blood can cause many abnormal growths. There can be a formation of stones in the kidney, a birth of a disease in the bone or any disease of the kidney that takes a chronic nature. It may often lead to total failure of the kidney.

The cells of the body uses some chemical reactions and they carry out certain works like converting the food energy and repairing of the tissues. Acids are generally produced by these chemical reactions. Presence of a certain quantity of acid inside the blood is a normal scenario. However accumulation of excess acids can also lead to a disease called – acidosis. The general body functioning gets disturbed. A healthy kidney helps in maintaining the acid-base balance of the body. Acid base balance is maintained by excreting the harmful acids into the urine and in turn getting back bicarbonates. These are alkaline. It can also be a base or a substance in the blood. Most of the acid that is formed by breaking down food parts in the body is neutralized by this bicarbonate. This change of form of the matters like bicarbonate within the blood and kidney structures is termed as transport.

In the famous book of Charles Dickens, “A Christmas Carol”, he has created a child named as Tiny Tim and that child has been diagnosed with RTA. In the story the character of Tiny Tom is seen as a small framed person with limbs deformed and always having a weak body. These are the symptoms and consequences of the disease RTA. Tiny Tim at last recovers when treated properly. The medical treatment given to Tiny Tim included the application of sodium bicarbonate and sodium citrate. It also had an alkaline agent which usually helps to neutralize the content of acid in the blood. However the good news is that with proper and effective medical treatment given to the patient he can definitely achieve the opposite results of RTA.

Diagnosis Of RTA

The diagnosis of RTA needs the checking of the balance of acid-base in the blood and urine of a human being. Doctors need to check that first. The reports might depict a higher quantity of blood than the acids in the body than it should be normally. The urine might also show a lesser amount of acidic nature than it should be. Then the reason behind such abnormality can be RTA. However, the doctors also think about other additional reasons for this. In case, the reason of such problems is certified to be RTA, then the next step is to identify the category of RTA the person is having. Things like the level of sodium and potassium and chloride present in the urine and the level of potassium in the blood will help doctors to identify the exact category of RTA present. The procedure of treatment of the RTA at first is aimed at neutralizing the amount of acid inside the blood. But for treating the main cause of such acidosis, other ways of treatment might also be applied.

Categories Of RTA

Type 1: Classical Distal RTA

This kind of RTA is termed as the classical distal RTA. The word “Distal” refers to far off or at a distance. This is referred to the location on the tube of the kidney where the urine is formed. This is where the malfunction starts exactly. This is quite at a distance from the location where the fluid from the blood gets into a tiny tube. This tube is also termed as tubule. The main function of the tubule is to collect the fluid and other harmful wastes from the urine.

This disorder is considered as the main malfunction or this can be a symptom of a certain disease. This can affect different parts of the human body. The research and studies reveal the presence of abnormal genes which are the cause such kind of disease. There can be other reasons like the systemic disease which can be also another cause of the formation of the classical distal RTA. These diseases act on the organ systems of the body and harm them badly. The presence of disorders like the syndrome of Sjögren as well as lupus can harm the distal tubule.

There are few other diseases and situations that are involved with the classical distal RTA. These are sickle cell anemia or hyperparathyroidism and hyperthyroidism. Other disease like the sickle primary biliary cirrhosis which is a kind of deafness is also included. This is due to hereditary reasons. There is also other kind of diseases like chronic active hepatitis, analgesic nephropathy. Many times when a kidney transplant is made it gets rejected by the body and that can also cause this kind of RTA. Other diseases involved are renal medullary cystic disease, chronic urinary tract infections and obstructive uropathy. These conditions generally result to abnormal accumulation of calcium inside the kidney and hence that in turn disrupts the proper functioning of the distal tubule.

The presence of classical distal RTA can cause the level of potassium to lower down at a big level. The kidneys instead of changing the potassium into the blood starts releasing too much of potassium in the urine. The level of potassium then drops down. Generally potassium helps to keep the nerve normal and keeps muscles healthy. They also regulates heart rate and incase of drop of this level, one can experience extreme weakness. This can result in an irregular heartbeat leading to paralysis or even death.

If the classical distal RTA is left untreated then it can result to an abnormal growth deformity amongst children. An enlargement of kidney and other disease in the bone for the adults can be seen. The main reasons for undergoing this kind of therapy is to stop such abnormal growth and make the body behave normally and also stopping the growth of stones in the kidneys. Acidosis can be treated using sodium bicarbonate or sodium citrate. These will in turn stabilize the low blood potassium and salt reduction of the body. This will also stop the accumulation of more calcium in the urine of the body. This is an alkali therapy and this can prevent growth of kidney stones and also make the kidney work normally. Thus failure of kidney can be stabilized. Incase of children, there might be a requirement for more supplements of potassium but for older children and adults they don’t need that. That is because the alkali therapy stops the release of potassium into the urine by the kidney.

Type 2: Proximal RTA

The Proximal RTA gets its name from the word “proximal”. This means nearness. This kind of RTA occurs at a near place where the fluid and harmful wastes of the blood enters the tubule.

This Proximal RTA is mostly prevalent in the children. It is a kind of malfunction known as Fanconi’s syndrome. In this kind of syndrome one can experience that glucose is secreted abnormally. There can be shortage of substance like the amino acids, citrate and phosphate in the urine inside the body. Even vitamin D and potassium level can be found to be very less.

The RTA of this category results from hereditary diseases from the earlier generations. They disturb the body’s usual way to breakdown food and the utilization of necessary nutrients. For example there is a rare disease named cystinosis. Over here cystine crystals gets accumulated in the bones and tissues. These are also called hereditary fructose intolerance and Wilson disease.

The proximal RTA can also be found in patients those who have been treated with ifosfamide. Ifosfamide is a medicine used while treating chemotherapy. There are few earlier medicines like acetazolamide or outdated tetracycline which can also lead to the formation of proximal RTA. For adults this proximal RTA can make many diseases more complicated like multiple myeloma. This is found in people who have transplanted their damaged kidneys but the body refuses to accept it.

Finding out the reasons behind the formation of this disease as well as its treatment is absolutely important. The chemical analysis of the body is done. Based on the report of blood and urine samples the treatment can be started. Large dosage of alkali might be given orally to children diagnosed with this disease. These alkalis are usually sodium bicarbonate or potassium citrate. These substances help in treatment of acidosis and also prevent disorder of blood like formation of kidney stones or a failure in growth. The levels of a normal functioning of the body are restored back when acidosis is treated properly. The right level of potassium helps. The bone hence gets matured thus preventing the occurrence of the renal disease. In order to solve bone problems, help of Vitamin D supplements can be taken.

Type 3: Hyperkalemic RTA

The third category of RTA is known as hyperkalemic. A general movement problem and transport malfunction in the distal tubule is the cause of hyperkalemic. Electrolytes named sodium, potassium and chloride moves in distal tubule but it gets disrupted. This type of hyperkalemic RTA is different from the classical distal RTA and proximal RTA. This is because high level pf potassium gets collected in the blood which should not be so. Hyperkalemic can be low hyperkalemic or high hyperkalemic. Whichever the form is, it can be a threat to the regular functioning of your heart as because potassium is very much needed for a healthy heart.

Type 4

This kind of RTA forms when the blood levels of the hormone named aldosterone gets lower or when the kidneys stops reacting. Adosterone assists the kidneys regulate levels of chloride, sodium and potassium in the blood. When the transport of certain electrolytes like the sodium, potassium and chloride is functioning wrongly then also Type 4 RTA occurs. Due to the use of certain drugs also this kind of RTA takes place.

The drugs that cause such Type 4 RTA are listed below:

Drugs like diuretics are given for treating a congestive heart failure like spironolactone or eplerenone
Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) which are used to stabilize blood pressure.
Antibiotic trimethoprim
The antibiotic pentamidine, which is used to treat pneumonia
Heparin, an agent used to prevent blood from getting clotted.
A category of painkillers like nonsteroidal anti-inflammatory drugs (NSAIDs)
Some immunosuppressive drugs used to prevent rejection.

The Type 4 RTA can also be created from certain diseases like HIV/AIDS, diabetic nephropathy and Addidons disease. There are other diseases like the urinary tract impairment, sickle disease of the cell, lupus. Amyloidosis, non-acceptance of a kidney transplant and removal or damage of both adrenal gland are also included.

Doctor have researched and found that for proper cure, the Type 4 RTA alkaline agents are needed. Use of low drugs and a lower level of potassium in the blood also matters a lot. People, if diagnosed early, can avoid a kidney failure. However, such therapy has to be maintained regularly throughout the life.
Important Things

The RTA or the Renal Tubular Acidosis is a kind of disease that is created when the kidney fails to do its usual functions of excreting the acids that gets accumulated through the urine. This can cause the blood of a person to remain acidic.
The never ending acidity nature of the blood can result in deformed and abnormal growth. Without proper treatment this can also lead to the formation of kidney stones, diseases of the bone, chronic kidney disease. It can also lead to a full failure of kidney.
If there is a possibility of RTA then the extra information regarding sodium, chloride and potassium levels present in the urine assists in getting the knowledge regarding the type of RTA a person have. The level of potassium presents in the blood also helps identifying that.
The main aim of such a therapy is to stabilize the content of acid in the blood. However, these treatments are required to find out the causes behind the formation of acidosis.
Research Reveals New Ways

There are two research centers named The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). They conduct researches and studies regarding various kinds of kidney diseases. They also conduct studies for renal tubular acidosis. The researchers that are looked after under NIDDK continuously do studies into the genetic and molecular mechanisms. These look after the balance of acid-base and stabilize its work inside the kidney. To treat RTA more and more effectively these studies and researches will be extremely beneficial.
Current research studies can be found at www.ClinicalTrials.gov.