What Is Medullary Sponge Kidney

Overview

The kidneys are vital organs in the body. They are vital for homeostasis and regulating bodily fluids. These organs are designed to complete their assignment specifically. As such, any alteration to their internal composition will affect the kidneys’ performance significantly.

There are several problems that can inhibit these organs from performing optimally. One of them is the medullary sponge kidney. When it comes to kidney disease, it is difficult (near impossible) for the symptoms to go unnoticed. However, very few people observe the symptoms of medullary sponge kidneys.¹

Most people who have this condition may never observe that they do. More often than not, these individuals may require a medical diagnosis when they become adults. Other times, they may only discover that they have medullary nephrocalcinosis when it leads to a complication or other diseases.²

Considering the risk, it is important to enlighten people about this disease. This article will share comprehensive information about this abnormal medical condition. Readers will learn about the causes of this disease, the signs of its occurrence, and ways to manage or treat it.

Causes of medullary sponge kidney

The first step to fully understand a medical condition is to identify its possible cause(s). In most cases, kidney problems are caused by human habits and lifestyle. This includes smoking, excessive alcohol, and drug abuse. Unlike most other kidney-related issues, a birth defect causes the medullary sponge.

This is caused by irregular wide openings in the renal papillary. These dilations are caused by abnormal organ development in the child. They may be spherical or oval in nature and cause the kidney to be larger than normal.

There are several components in the kidney, each of which helps in the filtration process. The collecting ducts are the final phase of the waste management and expulsion process. They help to secrete important compositions of bodily fluids before they are expelled from the body.

For a better understanding, let’s paint a mental picture of how the kidneys work. After receiving liquids, the middle region of your kidneys transfers these fluids into funnel-shaped tissues. From there, they are sent to tiny tubes that lead into larger collecting ducts. The area connecting the funnel structures to the collecting ducts is known as the renal papilla.³

At this point, your body extracts the necessary fluids and transports leftover waste to your bladder. From there, you will pass it out as urine through the urethra. This is the standard process of a normal kidney.

In the case of the medullary sponge kidney, the collecting ducts are not properly formed. It either has a very tiny passage connecting it to the structure or is blocked by cysts. As a result, bodily fluids cannot be filtered, processed, and excreted very well.³

Although it has been established to be a birth defect, researchers cannot ascertain why the tubes leading to the collecting ducts are tiny. More so, there is no proven reason for the formation of cysts in the tubules during foetal formation. Despite being a birth defect, there is no concrete evidence to prove that children inherit the disease from their parents.

Signs and symptoms of medullary sponge kidney

First, it is essential to highlight that people suffering from medullary sponge kidneys do not experience any symptoms. Even when they do, it is usually later on in life, when they are within 20 to 30 years of age.

Even then, these signs are a result of the complications arising from having the health condition, not the disease itself. The reason is that the medullary sponge kidney hampers the expulsion of urine from the body.

When this happens, the following complications may most likely occur:^4,5

• Urinary tract infection
• Kidney stones
• Haematuria (bloody urine)

Besides these three health conditions listed above, there are other complications arising from the medullary sponge kidney. They include:

• Kidney failure
• Damaged kidney or chronic kidney disease

These complications can occur individually or together. For example, MSK patients can be infected with a urinary tract infection and notice that they experience bloody urine.

Here are some signs that can result from having medullary sponge kidneys:

• Painful urination resulting from a burning sensation
• Urine with a terrible smell
• Pains in the lower abdomen, groin, or lower back
• Bloody or dark-coloured urine
• Vomiting

These signs are not set in stone and cannot serve as a diagnosis for MSK patients.⁶ Anyone who observes one or more of these symptoms should seek medical attention.

Management and treatment for medullary sponge kidney

The medullary sponge kidney is a birth defect that later expresses itself in adulthood.^7,8 Considering that scientists have not been able to discover its actual cause, this explains why they are unable to reverse the medical condition. Instead, the focus has shifted to treating complications that often arise from having the defect.

The first step is treating the urinary tract infections that occur in MSK patients. Doctors will prescribe antibiotic medications that kill off the bacteria. Meanwhile, the medical practitioner considers factors like the type of bacteria, the severity of the infection, and the patient’s medical history to ascertain the duration of treatment and type of medication.

If the patient is urinating dark, cloudy, or bloody urine, the doctor will conduct a further diagnosis to identify the root cause. If the problem is UTI, the procedure above will be applied.

Kidney stones

In the case where the patient has kidney stones, the stones need to be removed. More often than not, small kidney stones pass through the urinary canal without treatment. The most a doctor will do is prescribe oral or intravenous pain medication. Besides alleviating the pain, these drugs help to keep the patient hydrated during the course of treatment.

If the kidney stones are large enough to stop the passage of urine, the MSK patient will need the following forms of treatment:

• Shockwave therapy: a medical procedure that breaks the large kidney stone into smaller sizes that can be passed out through urine.
• Ureteroscopy: the combination of a tube-like tool with an eyepiece and a laser to find and break down large kidney stones.
• Percutaneous nephrolithotomy: the use of a nephroscope to locate the stones and remove the stones through an incision in the patient’s back.

Note: the procedures involved in removing large kidney stones require some level of anaesthesia. It ranges from local to general anaesthesia.

Chronic kidney disease or kidney failure

In the case of chronic kidney disease, such patients may require dialysis. This process involves the artificial removal of excess fluids from the kidney. Some people may have to use prescribed medication to manage their condition for the rest of their lives.

Meanwhile, the medications do not eradicate the problem. Instead, they manage conditions like high blood pressure, diabetes and other complications that are associated with kidney diseases. The reason is that chronic kidney diseases do not have any known cure.

In addition to dialysis, conditions like kidney failure may require a transplant. A kidney is taken from a living or deceased donor. However, there must be a match between the donor and the recipient for the process to work efficiently. 

Diagnosis

Earlier on, we outlined the possible symptoms of a medullary sponge kidney. However, we also stated that these are not clear indicators of the presence of this medical condition. Instead, people should consult medical practitioners for a thorough check.

Should you go for proper medical examinations, these are some of the measures that the doctor will consider:

Medical history

Although there is no proof that medullary sponge kidney is inherited, the healthcare provider must factor in a patient’s family history. They will also check the individual’s medical records to see if they had previous cases of UTI or kidney stones. Accounting for these details will significantly help with recommending the proper form of treatment.

Physical examination

Depending on the symptom, the doctor can conduct a physical exam on the patient. This usually applies to people with bloody, dark, or cloudy urine. Samples are taken to be tested further. Other than that, there is not much physical assessment to be done. The reason is that the symptoms are not visible to the naked eye.

Body scan and imaging

For a more detailed diagnosis, doctors will use various forms of body scans and imaging. They range from ultrasound to computerised tomography scans. The former uses a device known as a transducer to create images of the patient’s internal organs by bouncing waves off the organ. It helps to display calcium deposits and stones in the kidneys.

A CT scan uses an X-ray to create images of the internal organ. Unlike ultrasound, this process uses a machine that conducts a full body scan. The tube-like machine runs radioactive rays through the body to ascertain the current conditions of the individual’s internal organs.

Intravenous pyelogram

Unlike the other methods mentioned above, diagnosis via intravenous pyelogram involves injecting a special dye into the patient’s vein. The liquid travels through the body and is passed out as urine. Depending on the colouring of the urine, a health practitioner can ascertain the level of blockage in the kidneys. This process is often done by a CT scan technician.

FAQs

How can I prevent medullary sponge kidney?

There are no proven ways to prevent medullary sponge kidneys. However, people can inculcate healthy changes to their lifestyle and diet. They should drink more water, reduce their sodium and calcium intake, and limit their consumption of animal proteins. The focus should be on reducing the chances of UTI and kidney stone formation.

How common is the medullary sponge kidney?

The medullary sponge kidney is a very rare disease. It occurs in one in every 5000 people.

Who is at risk of medullary sponge kidney?

Although there are no certain indicators, studies show that medullary sponge kidney is more common in people assigned female at birth (AFAB). Nonetheless, there are still several other factors that put people at risk.

When should I see a doctor?

People should see a doctor once they notice one or more of the following symptoms:

• Painful urination resulting from a burning sensation
• Urine with a terrible smell
• Pains in the lower abdomen, groin, or lower back
• Bloody or dark-coloured urine
• Vomiting

Summary

The medullary sponge kidney is a very rare disease that literally stays hidden within the body. Even when it manifests, people do not experience the symptoms until after many decades of their lives. Despite its seeming rarity, this medical condition is very harmful and poses a significant threat to those suffering from it.

Considering this factor, it is essential for people to be proactive and quickly identify if they have this medical condition. Early detection can help prevent further complications. Individuals should visit a medical practitioner for advice once they notice certain unusual symptoms.