Medullary Sponge Kidney Causes
Scientists do not fully understand the cause of medullary sponge kidney or why cysts form in the tubules during fetal development. Even though medullary sponge kidney is present at birth, most cases do not appear to be inherited. Medullary sponge kidney is believed to be a result of abnormal renal development in utero. More specifically, scientists believe the ureteric bud which will give rise to the ureters interacts abnormally with the metanephric blastema tissue in the embryo which will produce much of the kidney substance.
There appears to be a genetic component to medullary sponge kidney disease. Some cases of medullary sponge kidney have mutations in the gene for glial cell-derived neurotrophic factor . Recent evidence 2) is that about five percent of patients diagnosed with medullary sponge kidney will have at least one relative with some degree of similar affliction. This kind of familial clustering can suggest an autosomal dominant gene expression or the actions of multiple genes giving that impression 3).
There is an association between medullary sponge kidney and hemihyperplasia, previously known as hemihypertrophy, which is a disorder in which one side of the body grows significantly more than the other side.
Medullary sponge kidney association with the following disease entities have been reported 4):
- Ehlers-Danlos syndrome
- Congenital hemihypertrophy/Beckwith-Wiedemann syndrome
- Caroli disease
Antibiotics May Be A Big Part Of Your Life
Frequent stone passage can create a sandpaper effect in your ureters and bladder, predisposing you to urinary tract infection. Antibiotics can be life savers for MSK patients, so dont be surprised if you find yourself on them multiple times a year.
It is important to get urinalysis testing for possible infection and to get a culture of the bacteria causing the infection to ensure the right antibiotic is prescribed to treat the infection.
It is also recommend to take a good probiotic your doctor approves of to help keep the good bacteria in your microbiome of your gut at proper levels and to prevent additional issues such as C-diff.
Occurrence In The United States
The exact prevalence of medullary sponge kidney is unknown. The frequency of medullary sponge kidney in the general population has been estimated to be 1 case per 5000 population, and the prevalence may be as much as 1 case per 1000 population in urology clinics. In addition, medullary sponge kidney has been identified in 12-20% of patients who form calcium stones.
Approximately 0.5% of patients undergoing intravenous urography are estimated to have medullary sponge kidney, while another 1% have papillary blush. No autopsy series have examined the prevalence of medullary sponge kidney specifically. In patients with nephrolithiasis, up to 20% may have mild degrees of medullary sponge kidney.
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Msk A Malformative Disease
Bilateral MSK and left kidney megacalycosis. Typical blushes are visible in all papillae in the right and left kidneys the left kidney is remarkable, however, for the associated dilated calyces with a normal renal pelvis, which rules out any obstructive cause and suggests a malformative origin.
If we consider MSK a malformative disease, then it can be classified as a developmental disorder and its pathogenesis should be sought in one of the numerous, complex developmental steps characterizing renal morphogenesis. Any hypothesis on the pathogenesis of MSK should explain the concomitant occurrence of alterations in the ureteric bud-derived pre-calyceal and collecting ducts , such as cysts, nephrocalcinosis and acidification and concentration defects, as well as in the metanephric blastema-derived nephron , such as proximal tubular defects.
Renal organogenesis depends on reciprocal inductive interactions between the ureteric bud and the metanephric blastema. Differentiation signals originating at the ureteric bud-metanephric blastema interface are necessary to coordinate the complex phenomena occurring in nephrogenesis, and among them a pivotal role is played by the glial cell line-derived neurotrophic factor and its receptor RET.
Schematic representation of the interplay in the nephrogenesis between the RET receptor on the ureteric bud and its ligand GDNF produced by the metanephric mesenchyme.
Why Stones Form In Msk
Elsewhere on this site we have pointed out that supersaturation is a force, a source of energy directed at forming solid phases such as stone crystals. The kinetic retardants in urine, which include citrate, stave off crystallization but can never prevent it: A supersaturated solution will eventually collapse into two phases, crystals and a residual solution precisely at the solubility point, devoid of extra free energy.
The stagnant flow as a result of the dilated MSK IMCD, and particularly the static conditions in the fluid filled blind ended cysts, are the probable reason those innumerable tiny stones form which end up packing the sponges with masses of crystals. How MSK patients produce larger stones, big enough to block the ureter is unknown. It is not true that MSK patients have remarkably high urine supersaturations or other physiologic abnormalities such as hypercalciuria and hypocitraturia. Possibly the tiny stones somehow leave their cysts and enter the urine where they act as nucleation centers.
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Medullary Sponge Kidney Diagnosis
A health care provider diagnoses medullary sponge kidney based on:
- a medical and family history
- a physical exam
- imaging studies
Medical and Family History
Taking a medical and family history can help diagnose medullary sponge kidney. A health care provider will suspect medullary sponge kidney when a person has repeated urinary tract infections or kidney stones.
No physical signs are usually present in a patient with medullary sponge kidney, except for blood in the urine. Health care providers usually confirm a diagnosis of medullary sponge kidney with imaging studies.
Medullary Sponge Kidney Complications
Complications of medullary sponge kidney include:
- hematuria, or blood in the urine
- kidney stones
- urinary tract infections
Recurrent nephrolithiasis is a major complication of medullary sponge kidney which often presents with renal colic, often accompanied by hematuria. Renal stones can result in UTI and urinary tract obstruction.
Medullary sponge kidney rarely leads to more serious problems, such as chronic kidney disease or kidney failure.
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What Are The Signs And Symptoms Of Medullary Sponge Kidney
Many people with medullary sponge kidney have no symptoms. The first sign that a person has medullary sponge kidney is usually a UTI or a kidney stone. UTIs and kidney stones share many of the same signs and symptoms:
- burning or painful urination
- fever and chills
People who experience these symptoms should see or call a health care provider as soon as possible.
Pearls And Other Issues
Associations with the following disease entities have been reported:
- Ehlers-Danlos syndrome
- Congenital hemihypertrophy/Beckwith-Wiedemann syndrome
- Caroli disease
Although medullary sponge kidney is generally described as a benign condition, as many as 10% of patients will develop renal insufficiency or failure throughout their lives.
Since medullary sponge kidney is associated with hypercalciuria, especially the renal calcium leak type, those with the disease are at risk of developing osteopenia, osteoporosis and secondary hyperparathyroidism.
While there is no specific treatment for medullary sponge kidney, those with renal stones and hypercalciuria or UTIs should be treated appropriately for these conditions.
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Msk As A Genetic Disease
MSK is considered a sporadic disease, though a handful of familial clusters of cases of MSK have been reported , in which MSK segregated as an autosomal dominant trait. The observation of familial clusters of MSK is nonetheless an experience shared by many nephrologists. In an effort to establish whether MSK is indeed an inheritable disorder, we have recently performed a systematic investigation on relatives of MSK patients in our cohort by means of interviews, renal imaging and biochemical studies. We observed familial clustering of MSK in 50% of cases with an autosomal dominant inheritance with a reduced penetrance and variable expressivity . If MSK is a developmental disorder, then genes governing renal development might be considered good candidate genes. We hypothesized that MSK might result from a disruption at the ureteric bud-metanephric mesenchyme interface, probably due to disease-causing mutations or specific polymorphisms of GDNF and RET genes, or particular GDNF/RET genotype interactions. Studying 55 apparently sporadic MSK cases and 85 healthy controls, we detected eight MSK patients heterozygous for two, hitherto unknown, rare variants of the GDNF gene located in a putative binding domain for PAX2, i.e. the c.-45G > C and c.-27 + 18G > A variants, which were both found significantly associated with MSK .
What Is The Treatment For Nephrocalcinosis
Nephrocalcinosis treatment aims to reduce the symptoms and prevent more calcium from building up in the kidneys. In this way, it will include methods to reduce the levels of calcium, phosphate and oxalate in the blood and urine.
These methods include changing the diet or taking certain medications and vitamin supplements. Treatment will also be directed at the underlying condition that is causing nephrocalcinosis.
Nephrologists generally treat all kidney-related medical conditions.
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Diet Does Make A Difference
Tracking what foods may trigger or worsen your MSK symptoms is a vital part to finding quality of life with this disease. Some MSK patients find that high oxalate, acidic foods such as tomato sauce or food additives such as citric acid exacerbate symptoms. Everyone is different and keeping a health log journal may help you discern what foods and drinks may be hurting your health.
You can also reach out to a renal dietician to help you form a diet plan that works for your lifestyle.
Life with MSK can be a major challenge, but dont lose hope that you can still live an amazing life despite this disease.
Asymptomatic Adults With Medullary Sponge Kidney
Advise patients about the benign nature of medullary sponge kidney, and inform them about the possibility of renal calculi and urinary tract infections due to the condition. Obtaining periodic urinalysis and abdominal radiographs is recommended, although guidelines for the frequency of radiologic surveillance in asymptomatic adults are unclear.
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The Emergency Room May Not Differentiate You From Another Average Stone Former
Kidney stones are one of the many reasons people visit the ER. In non-MSK patients, typically this is a random occurrence and they are prescribed pain meds, told to up their fluid intake and pass the stone at home.
Most MSK patients pass stones frequently. Some, arguably most people with MSK, require surgical intervention with stones at some point in their disease management course because other complications such as nephrocalcinosis, tubule plugging and renal duct blockages may be present.
When you visit the ER, understand that they are most likely going to treat based on their experience and may not fully understand what MSK is.
You need an educated nephrologist or urologist who can closely follow your care. Medullary sponge kidney care is much more involved than to average, occasional kidney stone occurrence.
Always head to your ER if you are feeling unbearable pain, have a high fever or cannot stop vomiting. Sepsis and renal obstruction are real threats to MSK patients and must be treated effectively in a timely manner.
Medications To Prevent Future Urinary Tract Infections And Kidney Stones
Health care providers may prescribe certain medications to prevent UTIs and kidney stones:
- A person with medullary sponge kidney may need to continue taking a low-dose antibiotic to prevent recurrent infections.
- Medications that reduce calcium in the urine may help prevent calcium kidney stones. These medications may include
- potassium citrate
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Diagnosis Of Msk Is Increasing
Urologists and nephrologists specializing in the treatment of kidney stones seem to encounter patients with medullary sponge kidney far more often than one would predict given the fact that this disease affects less than 0.5-1% of the general population.
One potential explanation is the high frequency of stones in such patients, nearly 70%. Stones call attention to themselves. Even so, referrals for MSK seem to be occurring at ever increasing rates, out of proportion to the prevalence of the disease.
Another explanation is that we can see more because of dramatic improvements in CT scanners and endoscopic equipment we use for stone removal.
Latest generation, thin slice CT scans can isolate tiny stones as small as a millimeter in size. Meanwhile, modern flexible endoscopes not only visualize every crevice of the renal collecting system but are able to do so in high definition. Consequently we can identify previously unrecognized variations in the appearance of stone forming kidneys, of particular interest here nephrocalcinosis on CT and tubular plugging on endoscopy.
But diagnostic capabilities may be progressing faster than our ability to comprehend the significance of what we see. As a result, one can misclassify patients as having MSK when the correct diagnosis is another more common finding such as nephrocalcinosis or tubule plugging.
Medullary Sponge Kidney Symptoms
Many people with medullary sponge kidney have no symptoms. The first sign that a person has medullary sponge kidney is usually a urinary tract infection or a kidney stone. Urinary tract infections and kidney stones share many of the same signs and symptoms:
- burning or painful urination
People who experience these symptoms should see or call a doctor as soon as possible.
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Medullary Sponge Kidney Diet
The following changes in diet may help prevent urinary tract infections and kidney stone formation:
- Drinking plenty of water and other liquids can help flush bacteria from the urinary tract and dilute urine so kidney stones cannot form. A person should drink enough liquid to produce about 2 to 2.5 quarts of urine every day 7).
- Reducing sodium intake, mostly from salt, may help prevent kidney stones. Diets high in sodium can increase the excretion of calcium into the urine and thus increase the chance of calcium-containing kidney stones forming.
- Foods rich in animal proteins such as meat, eggs, and fish can increase the chance of uric acid stones and calcium stones forming. People who form stones should limit their meat consumption to 6 to 8 ounces a day8).
- People who are more likely to develop calcium oxalate stones should include 1,000 milligrams of calcium in their diet every day. Adults older than 50 years should consume 1,200 milligrams of calcium daily 9). Calcium in the digestive tract binds to oxalate from food and keeps it from entering the blood and the urinary tract, where it can form stones.
- The potassium citrate supplementation also seems to help minimize the long-term bone loss that is sometimes associated with medullary sponge kidney. This bone loss is thought to be due primarily to the persistent renal leak type hypercalciuria although impaired urinary acidification has also been suggested. There is also a possible association with hyperparathyroidism.
Is Medullary Sponge Kidney A Chronic Kidney Disease
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. Moreover, can medullary sponge kidney cause kidney failure?
Medullary Sponge Kidney. MSK is usually a benign disorder without any symptoms, but it can lead to other problems, such as urinary tract infections and kidney stones, as a result of the urine flow being blocked. In many cases, MSK does not cause symptoms or problems, but when it does it usually happens during adulthood
Furthermore, how many people have medullary sponge kidney? Medullary sponge kidney affects about one person per 5,000 people in the United States.
Accordingly, is medullary sponge kidney fatal?
Medullary sponge kidney is a condition where cysts develop in the urine-collecting ducts and tubules of one or both kidneys. The exact cause of medullary sponge kidney is unknown and there is no cure. Medical treatment aims to manage the symptoms and reduce the risk of complications.
What causes spongy kidneys?
In some affected individuals, calcium stones may form in the kidneys . These stones can cause low back pain in the area of the kidneys and pain in the lower back and lower abdomen. A prominent feature of Medullary Sponge Kidney is the excretion of small stones with the urinary flow.
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Get Your Stones Analyzed
Researchers have reported that 12 to 20 percent of people who develop calcium-based kidney stones have medullary sponge kidney. Calcium phosphate and calcium oxalate stones are common on MSK patients.
There are many types of kidney stones and determining what specific kind your body makes may give you an insight into how to better manage them.
There are also diagnostic tests such as the 24 hour urine panel that can help physicians determine the underlying causes of kidney stone formation in order to possibly prevent future stones from occurring.
Since MSK is caused by a physical malformation, complete remission of stone forming may not be possible, however, it is possible to lessen the size and prevalence of stones.
Treatment For Medullary Sponge Kidney
There is no cure for medullary sponge kidney. Treatment may include:
- long-term, low-dose antibiotics to prevent urinary tract infections
- medication to discourage the formation of kidney stones
- drinking plenty of water to discourage the formation of kidney stones
- dietary changes such as reducing salt, protein, cholesterol and caffeine. Any changes should be made after talking with your doctor or dietitian
- avoiding non-steroidal anti-inflammatory drugs , since these types of medication can worsen kidney function in people with kidney disease
- a short course of high-dose antibiotics to treat abscesses
- surgery to drain abscesses, if they are particularly large or do not respond to antibiotic therapy.
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Medullary Sponge Kidney Prognosis
Medullary sponge kidney is usually a benign disorder without any serious morbidity or mortality. The majority of patients will have normal renal function throughout their lives. However, renal insufficiency or renal failure may occur in as many as 10% of patients with medullary sponge kidney 10). Renal failure is thought to arise from recurrent severe infections and extensive calculi formation.
A small number of medullary sponge kidney patients will describe chronic, severe pain. This group tends to produce substantially more kidney stones than other medullary sponge kidney patients and often require multiple hospitalizations for pain control. This suggests that 24-hour urine testing and aggressive metabolic treatment directed at nephrolithiasis prevention may be particularly worthwhile in this group of medullary sponge kidney patients 11). Very rarely, patients may develop renal failure as a result of repeated pyelonephritis or urinary tract obstruction.
In approximately 10% of patients with medullary sponge kidney, major morbidity is caused by repeatedly passing renal stones and by recurrent UTI. Complete obstruction of the kidney by renal stones is rare. Surgery is rarely required to remove the stones because they are usually very small and pass spontaneously.
A patient with medullary sponge kidney is estimated to pass 1.23 stones per year, compared with 0.66 stones per year in other people who form calcium stones.