Renal Tubular Acidosis

What Is Renal Tubular Acidosis?

Renal tubular acidosis is an illness that happens when the kidneys are damaged and can’t remove a waste, called acid, from the blood. 

Untreated renal (REE-nul) tubular acidosis can affect a child's growth, cause kidney stones, and other problems like bone or kidney disease. Fortunately, treatment is very helpful at preventing these things from happening. So it’s important to start treatment as soon as the condition is diagnosed.

What Happens in Renal Tubular Acidosis?

Each time a person’s body exercises, digests food, or heals damaged tissue, chemical reactions take place in its cells. These reactions put acid in the blood.

The kidneys’ main job is to remove waste — including acid — and extra water from the blood through tiny tubes called tubules. The waste is turned into urine (pee). This cleans the blood.

But with renal tubular acidosis, the kidney’s tubules are damaged, so they can’t remove the acid.

What Causes Renal Tubular Acidosis?

There are a few different types of renal tubular acidosis, and each has its own cause. They’re named based on the part of the tubule that’s damaged:

• Distal renal tubular acidosis: This is the most common type of renal tubular acidosis. It can be inherited (passed down in families) or caused by high blood calcium, sickle cell disease, autoimmune problems like lupus and Sjogren syndrome, or the use of some medicines.
  
  Sometimes, this can cause other problems with how the body moves nutrients, like potassium, in and out of the blood. If too much potassium builds up in the blood, it’s called hyperkalemic renal tubular acidosis. This can be caused by urinary tract infections (UTIs), autoimmune disorders, sickle cell disease, diabetes, kidney transplant rejection, or some medicines.
• Proximal renal tubular acidosis: This mostly happens in newborns and is caused by a disorder called Fanconi's syndrome. Other causes include vitamin D deficiency, fructose intolerance, some medicines, and some metabolic conditions that run in families. 

What Are the Signs & Symptoms of Renal Tubular Acidosis?

Often, kids with renal tubular acidosis don't have any symptoms. They might not know they have the condition until it shows up on a blood test or urine (pee) test.

When symptoms do happen, they can include:

• poor growth
• kidney stones
• confusion or feeling very tired
• fast breathing and heart rate
• peeing less often
• muscle weakness
• muscle cramps and pain in the back and belly
• rickets

If your child shows any of these signs, see a doctor right away. The sooner treatment starts, the more helpful it will be.

How Is Renal Tubular Acidosis Diagnosed?

To diagnose renal tubular acidosis, doctors do an exam and order blood tests and urine tests.

How Is Renal Tubular Acidosis Treated?

Treatment depends on the cause:

• If a medicine is causing renal tubular acidosis, the doctor will suggest stopping it or changing the dose. Usually this is enough to make the problem go away.
• If another other condition causes renal tubular acidosis, the doctor will treat it. The child also will take alkaline medicines, such as sodium bicarbonate or sodium citrate, to help balance and lower the amount of acid in the blood.

Treatment for renal tubular acidosis helps most kids. Some might need to take alkaline medicines for the rest of their lives. But sticking to their treatments keeps them healthy.

What Else Should I Know?

Often the medical team will suggest a diet rich in fruits and vegetables and lower in animal sources of protein to help kids with the condition. Talk to the health care team to make sure your child’s diet has the best sources of nutrition.