The main clinical signs of MSK include the presence of blood in the urine and the formation of stone in the kidneys. These main ones are usually combined with other signs which underline some infection underway, frequently associated with intense pain and burning felt while urinating. The pain is caused by the stones produced in the kidney and is felt in the area around the lower back and abdomen. Stones are generally expelled through urine, but if their size is large enough they might cause serious blocks in the urine flow from the bladder.

These basic problems are often followed by the loss of the capacity of the kidneys to filter the waste products into the urine itself, which has to be seen as a consequence of the dilatation of the collecting tubules, or other typical renal complications such as tubular acidosis, kidney failure, urinary tract infection, urolithiasis/ureteric calculi, and haematuria (the presence of blood in the urea).

It should be remembered that a great number of affected individuals remain asymptomatic and show no clinical sign at all for many years.

• Pain

  While some patients report increased chronic kidney pain, the source of the pain, when a UTI or blockage is not present, is unclear at this time. Renal colic (flank and back pain) is present in 55% of patients. [en.wikipedia.org]

  The pain is caused by the stones produced in the kidney and is felt in the area around the lower back and abdomen. [symptoma.com]

  Pain was assessed using a standard verbal analog pain scale. Patients' pain score, plain abdominal radiograph, ultrasound examination, and urine analysis were routinely performed for each follow-up. [ncbi.nlm.nih.gov]

  When my scans didn’t show an active stone, I was sent home to deal with the pain on my own and told, “stones inside the kidneys do not cause pain,” yet the urine is still red and my blood pressure dangerously high (a sign of pain). [mskonlineproject.wordpress.com]

• Asymptomatic

  Patients frequently have episodic painless hematuria, but are often otherwise asymptomatic unless renal calculi or infections complicate the disease. [ncbi.nlm.nih.gov]

  Asymptomatic children with medullary sponge kidney In asymptomatic children with medullary sponge kidney, conduct regular surveillance for Wilms tumor and other abdominal tumors. [emedicine.medscape.com]

  Most cases are asymptomatic or are discovered during an investigation of blood in the urine. [en.wikipedia.org]

• Fever

  A 33-year-old man was admitted to our division for further evaluation of repeated fever and purulent sputa of more than 10 years duration. [ncbi.nlm.nih.gov]

  These include costovertebral angle tenderness and ipsilateral groin, which usually underline the presence of nephrolithiasis, and fever, tachycardia, and hypotension, suggestive of obstructing stones into the kidneys and the kidney ducts. [symptoma.com]

  Now, a few years later, I am having extreme pain, low grade fevers, and one urinary infection after another. I have been on antibiotics for 6 months now because as soon as one infection is treated, another comes up. [ourhealth.com]

  A 39-year-old woman presented 1 month ago with left flank pain, chills, and spiking fever over the past day. She reported having an episode of acute pyelonephritis with similar manifestations 6 months previously. Figure 2. [mdedge.com]

  Fever and chills Fever and chills are due to infections. Renal insufficiency Renal insufficiency is rarely seen. [kidneyabc.com]

• Chills

  A 39-year-old woman presented 1 month ago with left flank pain, chills, and spiking fever over the past day. She reported having an episode of acute pyelonephritis with similar manifestations 6 months previously. Figure 2. [mdedge.com]

  The main symptoms include severe pain in the side, back, abdomen, and groin, painful and burning urination, the presence of blood in the urine, fever, chills, and nausea. The condition might even lead to renal failure in 10% of the cases. [symptoma.com]

  Other symptoms can include painful or burning urination, cloudy urine, blood in the urine (hematuria), fever, chills and nausea. These symptoms depend on the cause and severity of urinary blockage. [kidney.org]

  Symptoms include pain and burning sensation while passing urine; pain in back, lower abdomen or groin; urine appears cloudy, dark and bloody and foul smelling; fever, chills and vomiting. [reversekidneydiseasenaturally.com]

  These conditions share similar symptoms such as burning or painful urination, foul-smelling urine, cloudy-dark or bloody urine, vomiting, fevers and chills, and pain in the lower abdomen, back and the groin. [health.in4mnation.com]

• Falling

  It has been historically diagnosed with intravenous pyelography (IVP), which is falling out of favor as an imaging modality. [ncbi.nlm.nih.gov]

  With the widespread use of the CT, IVP is rapidly falling out of favor as an imaging modality [ 19 ]. [karger.com]

  Tannen RL, Falls WF Jr, Brackett NC Jr. Incomplete renal tubular acidosis: some clinical and physiological features. Nephron. 1975;15:111-123. McPhail EF, Gettman MT, Patterson DE, Rangel LJ, Krambeck AE. [casereports.in]

  My nephrologist said people fall all over the spectrum in terms of how bad their pain is and how much it affects their lives, some over time even have the insides of their kidney's calcify and have it show up on ultrasounds. [lookfordiagnosis.com]

• Hypertension

  This article describes an adult female who underwent nephrectomy for renovascular hypertension due to multivessel fibromuscular dysplasia with small left kidney found to be associated with MSK. [ncbi.nlm.nih.gov]

  Bisceglia M, Galliani C (2008) Medullary sponge kidney associated with multivessel fibromuscular dysplasia: report of a case with renovascular hypertension. Int J Surg Pathol 16:85–90 Google Scholar 3. [link.springer.com]

  Hypertension is found in increased percentage in AS affected males. End-stage renal disease develops inevitably in males but with variable frequency in females. [kidneydoctor.com]

  […] a disorder in which dilated collecting tubules (1 to 7.5 mm in diameter) are found in one or more renal papillae. 1 In the absence of complications, it is a benign, asymptomatic condition in which glomerular filtration is normal and proteinuria and hypertension [nejm.org]

• Back Pain

  While some patients report increased chronic kidney pain, the source of the pain, when a UTI or blockage is not present, is unclear at this time. Renal colic (flank and back pain) is present in 55% of patients. Women with [dbpedia.org]

  I was diagnosed with Medullary Sponge Kidney a few years ago when I was having extreme back pain. The doctor sent me for a CT and an MRI. [ourhealth.com]

  The pain and constant what iffs throughout the day is really dictating my daily life. please if there is anyone else on here with these problems especially the flank pain, lower back pain, burning urination, fatigue, and well just feeling horrible please [patient.info]

  The common symptoms are kidney stone and repeated urinary tract infection, and sometimes patients may experience back pain and painless blood urine. - Polycystic kidney disease The most obvious symptom is pain in the back, flank or kidney area. [kidney-symptom.com]

• Costovertebral Angle Tenderness

  These include costovertebral angle tenderness and ipsilateral groin, which usually underline the presence of nephrolithiasis, and fever, tachycardia, and hypotension, suggestive of obstructing stones into the kidneys and the kidney ducts. [symptoma.com]

• Hematuria

  Sonography is very sensitive to the pyramidal nephrocalcinosis that complicates this disease and explains the frequent presenting symptom of hematuria in these children. [ncbi.nlm.nih.gov]

  Exercise-induced hematuria a fairly common cause of microscopic hematuria. Its presence in military recruits earned it the title "march hematuria." It is important to remember that hematuria is a symptom and not a disease. [kidneydisease.about.com]

• Flank Pain

  All patients in the study had chronic flank pain and multiple non-obstructing kidney stones. 50 patients had followup information available. The majority of patients who underwent this procedure experienced a reduction in their pain (83%). [kidneystoners.org]

  May present with flank pain, recurrent urinary tract infections (UTIs), haematuria (gross and microscopic), nephrolithiasis, and nephrocalcinosis. No specific treatment, and for many patients the condition is normally benign. [bestpractice.bmj.com]

  The pain and constant what iffs throughout the day is really dictating my daily life. please if there is anyone else on here with these problems especially the flank pain, lower back pain, burning urination, fatigue, and well just feeling horrible please [patient.info]

  A 39-year-old woman presented 1 month ago with left flank pain, chills, and spiking fever over the past day. She reported having an episode of acute pyelonephritis with similar manifestations 6 months previously. Figure 2. [mdedge.com]

• Kidney Failure

  Problems caused by MSK, include blood in the urine, kidney stones, and urinary tract infections. MSK rarely leads to more serious problems, such as total kidney failure. [diseaseinfosearch.org]

  For detailed information on treatment, see the articles on chronic kidney failure and end-stage kidney disease. Emedicine [usmleforum.com]

  Current research suggests that kidney failure rates among MSK patients are rare, yet I and many others have declining kidney function that continues to get progressively worse as we age. [ipetitions.com]

  Kidney failure occurs in about 10% of people with MSK. How is Medullary Sponge Kidney Diagnosed? If you have a history kidney stones or urinary tract infections, your doctor may use an imaging test to help confirm if you have MSK. [kidney.org]

• Renal Insufficiency

  The thorough clinical examination and proper evaluation is important in patient of urethral stricture with underlying chronic renal insufficiency to avoid delayed diagnosis, management and related complications. [ncbi.nlm.nih.gov]

  […] medullary sponge kidney is only necessary in complications like nephrolithiasis, urinary tract infection or renal insufficiency. [urology-textbook.com]

  Renal insufficiency Renal insufficiency is rarely seen. However, if urinary tract infection and nephrolithiasis are not controlled well, the risk of developing renal insufficiency will increase greatly. [kidneyabc.com]

  Treatment of medullary sponge kidney centers on management of complications, which include the following (see Treatment and Medication ): Renal stones Hematuria Distal renal tubular acidosis (RTA; type 1 RTA) Renal insufficiency (rarely) For discussion [emedicine.medscape.com]

  The blood chemistry reflect the degree of renal insufficiency. [kidneydoctor.com]

• Microscopic Hematuria

  Microscopic hematuria can arise from anywhere in the urinary tract, beginning with the kidneys and ending with the urethra. [kidneydisease.about.com]

  Urinalysis may reveal microscopic hematuria with or without kidney stone and pyuria. If the WBC increases, it implies infection( pyelonephritis).Analysis of stone composition provides information for preventive management. [kidneyabc.com]

  The hematuria can be microscopic or macroscopic and with or without the presence or stones [ 15 ]. Dysfunction of the renal collecting systems results in urinary acidification defects and decreased concentrating ability [ 6 ]. [karger.com]

Physical examination can reveal the first signs which indicate the diagnosis of MSK. These include costovertebral angle tenderness and ipsilateral groin, which usually underline the presence of nephrolithiasis, and fever, tachycardia, and hypotension, suggestive of obstructing stones into the kidneys and the kidney ducts. If patients show some of these signs, or all of them combined, they are strongly advised to send them to a specialist.

Imaging
MSK is often diagnosed when patients are analyzed for another reason altogether, such as renal stone, infections, or colic, as an incidental finding during radiological investigations. If the physician suspects MSK, he/she can employ intravenous urography to further confirm the diagnosis.

IVU
This test is frequently employed in the cases of recurrent stone formations. Stone formation can be combined with the presence of dilated collecting tubules which in turn can be associated or not with nephrolithiasis. It has to be noted that the contrast pools in the dilated tubules inside the tips of the papilla cause the formation of particular patters characterized by the typical appearance of "papillary blush" or "paintbrush". MSK might involve both kidneys, or just one, but can also frequently be limited in one single papilla.

Plain abdominal x-ray
Plain abdominal x-ray is less specific and sensitive than IVU, but has the advantage of being cheaper and faster, requiring a much lower level of radiation and being very useful when patients suffer from non-specific abdominal pain. Calyces, pelvis, or ureter can be easily detected and usually indicate stone formation [9]. Nephrocalcinosis can be present in 1 or more several papillae.

Ultrasound
Ultrasound too, as plain x-ray, can be used in case of non-specific abdominal pain. It has the disadvantage of being less specific and sensitive than IVU, but much more sensitive than plain x-ray.

Non-contrast CT
Non-contrast CT is ideal to detect stone formation, but cannot confirm the diagnosis of MSK, which still requires the use of other methodologies.

CT urogram
CT urogram is very useful to evaluate haematuria and provide high quality images of ureter, renal collecting systems, and the bladder [10].

Laboratory tests
The following tests can further confirm the presence of nephrolithiasis, UTI, and pyelonephritis:

• Serum electrolytes
• Uric acid
• Urea/creatinine (to assess renal function);
• Urinalysis (very useful to reveal microscopic haematuria associated or not with the presence of renal stones and pus, in a condition called pyuria)
• Calcium
• Phosphorus
• FBC

WBC count and urine culture can underline the presence of infection underway. Furthermore, stone-risk profiles can provide the physicians with a general clinical overview of the patients, which include metabolic risk factors for calcium stones like hyperoxaluria, hypercalciuria, hypocitraturia, or high pH levels in the urine. The analysis of stone composition should not be neglected, as it can provide precious information to organize a long-term preventive plan.

• Nephrolithiasis

  Our results suggest that medullary sponge kidney is a cause of nephrolithiasis. [ncbi.nlm.nih.gov]

  Treatment of Nephrolithiasis: Thiazide diuretics are suitable for the prevention of nephrolithiasis in nephrocalcinosis. Otherwise, the stone therapy does not differ to patients without medullary sponge kidney. [urology-textbook.com]

• Multiple Renal Cysts

  Spongy Kidneys With Increased Blood Pressure Spongy kidney is also called medullary sponge kidney (MSK) and it is a common renal cystic disease which is characterized by multiple renal cysts in the renal medulla. [kidney-cares.org]

  cyst Q61.01 Congenital single renal cyst Q61.02 Congenital multiple renal cysts Q61.1 Polycystic kidney, infantile type Q61.11 Cystic dilatation of collecting ducts Q61.19 Other polycystic kidney, infantile type Q61.2 Polycystic kidney, adult type Q61.3 [icd10data.com]

• Pyuria

  Laboratory evaluation revealed sterile pyuria, hypercalciuria, and hypocitraturia. The patient was subsequently treated with potassium citrate, hydrochlorothiazide, low sodium and low oxalate diet accompanied by high fluid intake. [ncbi.nlm.nih.gov]

  There may also be sterile pyuria. Flank pain, which in a few cases can be severe and intractable. [ 1 ] It may present with renal calculi and their complications including renal colic, haematuria, infection and urinary obstruction. [patient.info]

  […] should not be considered synonymous with urinary stones because it signifies a metabolic derangement and has broader implications Episodes of urinary tract infections may occur Polyuria and polydipsia may be prominent Hypertension less common Microscopic pyuria [learningradiology.com]

  […] nephrolithiasis, UTI, and pyelonephritis: Serum electrolytes Uric acid Urea/creatinine (to assess renal function); Urinalysis (very useful to reveal microscopic haematuria associated or not with the presence of renal stones and pus, in a condition called pyuria [symptoma.com]

Since many patients remain asymptomatic for many years and because of the benign nature of MSK itself, there is no specific treatment to suggest to effectively treat this disorder. When patients show clinical signs, particular attention should be given in treating UTI, removing the stone, and trying to prevent recurrence of infections and stone formation. Hematuria usually appears as a consequence of UTI or renal stones, and the underlying cause should be further investigated to avoid additional severe complications.

With UTI
If UTI occurs, physicians are advised to treat patients with antibiotics. Quinolones is the generally prescribed drug, while trimethoprim and sulfamethoxazole are particularly indicated when complicated UTI occurs. The classical duration of the antibiotic treatment is generally 14 days.

With nephrolithiasis (renal stones)
The identification of risk factors through 24-hour stone risk profiles, combined with appropriate diet modifications and drug administrations, can help prevent recurrent stone formation. Some clinical data seem to suggest that potassium citrate increases the level of urine citrate and decreases that of hypercalciuria in patients associated with high metabolic stone risk factors, even though the underlying molecular mechanism has not been clarified yet [11].

Patients are advised to keep fluid intake high by increasing it to more than 2 liters per day, so that urine output can be increased and the risk of developing renal stones and hypercalciuria can be reduced. In the cases of infected stones, treatment requires a longer course of antibiotics for removing the renal stones.

MSK is a benign disorder with no serious morbidity and mortality, even though renal insufficiency is a very frequent clinical consequence which occurs in up to 10% of the patients. Other possible clinical consequences include recurrent nephrolithiasis, with a significant associated morbidity, and renal failure after repeated pyelonephritis or urinary tract obstruction.

A significant morbidity is observed as a consequence of renal stone formation and recurrent UTI in around 10% of the cases. Kidneys are rarely completely obstructed, and since the stones are frequently very small in size and pass through the kidneys and their tubules spontaneously, usually there is no need of clinical interventions.

It is frequent to observe the appearance of chronic pain which is associated with the presence of no infection, stone, and obstruction, and in these cases patients are simply treated straight away with a regiment of painkillers. Today, patients with MSK and under high risk of developing further consequences are identified with a recently developed grading system that uses the findings obtained from intravenous urography [9].

The exact etiology of MSK is unknown. However, since a tight link has been found between MSK and the appearance of congenital pathological disorders such as Beckwith-Wiedemann's syndrome, hemi-hypertrophy, and congenital hepatic fibrosis [3], now experts tend to believe that genetic factors must play a pivotal role in the development of MSK.

According to this view, MSK has to be connected with anomalies in the embryogenesis of kidneys, like the disruption of the ureteric-bud/metanephric-blastema interface, perhaps caused by mutations in specific genes. These sequences include the gene for glial cell-derived neurotrophic factor, which plays a pivotal role in the survival of many types of neurons, and RET oncogene, a most important gene involved in the normal kidney development, parathyroid cell proliferation and development of the liver excretory system [3].

However, it is not possible to rule out the intervention of other possible factors, as suggested by the correlation with other disorders such as tubular acidosis that seems to cause the decrease of the urine citrate level and an alkaline pH in the urine. These in turn might cause the formation of stones in the kidney, a condition called nephrolithiasis, that occurs before stone formation itself [4].

Since many patients are asymptomatic and the disorder tend to manifest itself only after the 2nd or 3rd decade of life, the actual prevalence of MSK remains largely unknown. The results of the few studies conducted on this regard remain inconclusive, as the prevalence detected varies greatly from study to study [5] [6].

There are no conclusive data to confirm the role of gender as an important epidemiological factor for MSK. On the contrary, age might play an important role, as suggested by the high prevalence found among the elderly, although this could be explained as a consequence of the tendency of MSK to remain undiagnosed for many years. No significant data have been found to indicate the existence of significant epidemiological differences between people of different ethnic and racial groups.

The physiological changes which characterize MSK suggest the existence of some kind of developmental abnormality, although the nature of it has never been fully understood. However, experts believe that the disorder must result from the disruption of the interface between ureteral-bud and the metanephric blastema during embryonic development, as suggested by the connection of MSK wit kidneys malformations such as hemihypertrophy and Beckwith-Wiedemann syndrome.

Still limited are the data suggesting a possible association between MSK and genetic factors. Many studies have underlined the occurrence of key mutations in the glial cell-derived neurotrophic factor, a protein which appears to play a pivotal role in the renal development as well as neuron survival. The available data seem to suggest that the mutations in the glial cell-derived neurotrophic factor gene leads to an osteogenic differentiation in renal papillary cells that finally result in MSK at the end of renal development [7]. Furthermore, it is also possible to observe the presence of an autosomal dominant inheritance among the families with people affected by MSK [8]. It has to be noted that many cases can show no family history, and most of the data on this regard still remain inconclusive.

Physicians are strongly advised to screen patients with MSK using a 24-hour urine collection for the evaluation of stone risk factors such as hypercalciuria, hyperuricosuria, hypocitraturia, or hyperoxaluria [11]. Those patients who, after this test, show any sign of abnormality should be treated with potassium citrate to prevent the formation of renal stone. Physicians are advised to start treatment with an initial dose of potassium citrate of 20 mEq/day and adjust it accordingly. The urinary citrate levels should be kept around 450 mg/day and urinary pH levels below 7.5.

MSP is a benign disorder which occurs when dilatations of the collecting tubules in one or more renal papillae appear. The condition might involve both kidneys, but frequently patients are asymptomatic and MSP remains undiagnosed up until the 2nd or 3rd decade of life [1] [2].

The name of the disorder is a little bit misleading, because it seems to suggest the resemblance to a sponge, while the kidneys do not look like sponges at all. For this reason, alternative names have been suggested over the years, like tubular ectasia and cystic dilatation of the collecting ducts, but medullary sponge kidney still remains the main one.

MSK is a congenital disorder which occurs when small cysts appear in the renal tubules or the renal collecting ducts where urine is collected before removal. These cysts might reduce the quantity of urine getting out of the kidney. The disorder might affect one or both kidneys.

Cause
The exact cause of MSK is still unknown. The disorder is considered rare and generally appears with no specific family history, especially in women.

MSK is usually benign in nature, and can occur without the appearance of any specific symptom, even though it can cause a series of other related complications such as urinary tract infection or development of renal stones that block of the urine flow. If MSK causes symptoms, these usually appear during adulthood. The main symptoms include severe pain in the side, back, abdomen, and groin, painful and burning urination, the presence of blood in the urine, fever, chills, and nausea. The condition might even lead to renal failure in 10% of the cases.

Symptoms
Many people affected by MSK show no sign at all. Those that do show signs frequently report UTI and development of renal stone associated with the following signs:

• Burning/painful urination
• Presence of blood in the urine which appears cloudy, dark, and foul-smelling
• Pain, especially in the back, lower abdomen, and groin
• vomiting
• Fever associated with chills

Diagnosis
Physicians might consider the presence of the history of stone formation and urinary tract infections before deciding to try to confirm MSK with appropriate diagnostic methodologies. Frequently used for the diagnosis of MSK is intravenous urogram, a type of x-ray procedure in which a special dye in injected in the kidney to better visualize it and detect any other problems, particularly the presence of stones and cysts which block urine flow. Ultrasound and computed tomography scan are also frequently used as diagnostic tools.

Physicians might also use laboratory tests to confirm the diagnosis of MSK, like blood and urine tests to analyze the working of the kidneys and detect the presence of infections.

Treatment
After confirmation through diagnosis, kidneys should be constantly monitored to detect any change in the cysts or the formation of additional renal stones and infections in the urinary tracts. Infections are generally treated with antibiotics, while renal stones might require surgical procedures to be removed. After treatment, patients are advised to increase fluid intake, modify their diet, and get regular check-ups to prevent future episodes of MSK.

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