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Medullary Sponge Kidney

MSK

Medullary Sponge Kidney (MSK) is defined as a particular renal condition characterized by the presence of diffuse and bilateral medullary cysts as a consequences of abnormalities present in the terminal collecting ducts.


Presentation

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.

Asymptomatic
  • Patients frequently have episodic painless hematuria, but are often otherwise asymptomatic unless renal calculi or infections complicate the disease.[ncbi.nlm.nih.gov]
  • Most cases are asymptomatic or are discovered during an investigation of blood in the urine.[en.wikipedia.org]
  • Medullary sponge kidney is a benign asymptomatic developmental anomaly of the kidney mostly seen in adult females. Presentation in childhood is uncommon.[ncbi.nlm.nih.gov]
  • A 22-year-old woman with hemoglobin SC who was hematologically asymptomatic, developed gross hematuria associated with urinary tract infection, without any urological antecedents.[ncbi.nlm.nih.gov]
  • One child was asymptomatic; the others had hematuria or a urine-concentrating defect. Renal function and size were otherwise normal, as was liver function. The diagnosis was made at excretory urography according to criteria established in adults.[ncbi.nlm.nih.gov]
Chills
  • 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]
  • The patient shall suffer from fever and chills Causes Medullary sponge kidney is basically from an unknown cause. There are some known factors being related to the disease condition and it involves genetics.[mrdoctor.org]
Hypertension
  • He kept normotensive in spite of hyperaldosteronism until nine months after the initiation of replacement therapy with glucocorticoid and thyroxine for hypopituitarism, when he became hypertensive.[ncbi.nlm.nih.gov]
  • 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]
  • […] 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]
  • The remaining twelve sections cover various types of diseases, including hypertension, urological problems, and urinary tract concerns.[books.google.de]
  • I was told it is Essential hypertension inst... Hoping to have MSKKELLY contact me for some information but I also thought I would introduce myself especially as I'm sure many of you wo... Hello everyone.[medhelp.org]
Tachycardia
  • 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]
Back Pain
  • Renal colic (flank and back pain) is present in 55% of patients. Women with[dbpedia.org]
  • 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]
  • 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]
  • Renal colic (flank and back pain) is present in 55% of patients. Women with MSK experience more stones, UTIs, and complications than men.[en.wikipedia.org]
  • 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]
Neglect
  • The neglected issue of stone pathogenesis was also evidenced. This commentary discusses several considerations in biomarker validation, and how urinary proteomics breaks new ground in MSK research. Copyright 2016 International Society of Nephrology.[ncbi.nlm.nih.gov]
  • The analysis of stone composition should not be neglected, as it can provide precious information to organize a long-term preventive plan.[symptoma.com]
Hematuria
  • A 22-year-old woman with hemoglobin SC who was hematologically asymptomatic, developed gross hematuria associated with urinary tract infection, without any urological antecedents.[ncbi.nlm.nih.gov]
  • 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]
  • Clinical manifestations include urinary tract infections, renal stones, and hematuria. It can be associated with other developmental disorders.[ncbi.nlm.nih.gov]
  • We report a patient with medullary sponge kidney (MSK) who presented with hematuria and nephrotic-range proteinuria. Renal biopsy revealed a diagnosis of renal AA amyloidosis. No secondary factors contributing to renal amyloidosis were demonstrated.[ncbi.nlm.nih.gov]
Flank Pain
  • 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]
  • May present with flank pain, recurrent UTIs, haematuria (gross and microscopic), nephrolithiasis, and nephrocalcinosis. No specific treatment, and for many patients the condition is normally benign.[bestpractice.bmj.com]
  • Gdor and co-authors, “Multi-Institutional Assessment of Ureteroscopic Laser Papillotomy for Chronic Flank Pain Associated with Papillary Calcifications”, Journal Of Urology 2011.[kidneystoners.org]
  • 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]
  • If problems do occur, it can cause pain in the side and back (known as flank pain), abdomen or groin. Other symptoms can include painful or burning urination, cloudy urine, blood in the urine (hematuria), fever, chills and nausea.[kidney.org]
Nocturia
  • Symptoms Early in the disease, symptoms may include: •Excessive urination (polyuria) •Low blood pressure •Need to urinate at night (nocturia) •Salt cravings •Weakness Late in the disease, symptoms of kidney failure may develop, which include: •Coma •Confusion[usmleforum.com]
  • While overt acidosis and polyuria are rarely seen, incomplete dRTA and nocturia are common. Renal acidification has been proposed by Fabris et al. [ 9 ] to be the primary defect leading to the genesis of other metabolic abnormalities of MSK.[karger.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]
  • Lang EK, Macchia RJ, Thomas R, Watson RA, Marberger M, Lechner G, Gayle B, Richter F: Improved detection of renal pathologic features on multiphasic helical CT compared with IVU in patients presenting with microscopic hematuria.[karger.com]
Dysuria
  • It predisposes to calculus formation (often with increased urinary calcium excretion) and UTI, so the most common presenting symptoms are the following: Renal colic Hematuria Dysuria Medullary sponge kidney is benign, and long-term prognosis is excellent[merckmanuals.com]

Workup

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
  • RESULTS: Nephrolithiasis was confirmed radiographically in 39/56 patients (69.6%). No patient without evidence of nephrolithiasis developed a stone event, whereas 13/39 (33%) of those with nephrolithiasis developed a recurrent stone event.[ncbi.nlm.nih.gov]
  • CTU effectively demonstrates the characteristic radiologic findings of MSK including collecting tubule dilatation, medullary nephrocalcinosis, nephrolithiasis, and medullary cysts.[ncbi.nlm.nih.gov]
  • Our results suggest that medullary sponge kidney is a cause of nephrolithiasis.[ncbi.nlm.nih.gov]
  • Urinary tract infection, nephrolithiasis, hematuria and hypercalciuria are the common complications.[ncbi.nlm.nih.gov]
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]
  • 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 Polycystic kidney, unspecified Q61.4 Renal dysplasia Q61.5 Medullary[icd10data.com]

Treatment

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.

Prognosis

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].

Etiology

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].

Epidemiology

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.

Sex distribution
Age distribution

Pathophysiology

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.

Prevention

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.

Summary

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.

Patient Information

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.

References

Article

  1. Fick GM, Gabow PA. Hereditary and acquired cystic disease of the kidney. Kidney Int. 1994 Oct; 46(4):951-64.
  2. Gambaro G, Feltrin GP, Lupo A, et al. Medullary sponge kidney (Lenarduzzi-Cacchi-Ricci disease): a Padua Medical School discovery in the 1930s. Kidney Int. 2006 Feb; 69(4):663-70.
  3. Diouf B, Ka EH, Calender A, et al. Association of medullary sponge kidney disease and multiple endocrine neoplasia type IIA due to RET gene mutation: is there a causal relationship? Nephrol Dial Transplant. 2000; 15:2062-2063.
  4. Maschio G, Tessitore N, D'Angelo A, et al. Medullary sponge kidney and hyperparathyroidism: a puzzling association. Am J Nephrol. 1982; 2:77-84.
  5. Mayall GF. The incidence of medullary sponge kidney. Clin Radiol. 1970; 21:171-174.
  6. Parks JH, Coe FL, Strauss AL. Calcium nephrolithiasis and medullary sponge kidney in women. N Engl J Med. 1982; 306:1088-1091.
  7. Mezzabotta F, Cristofaro R, Ceol M, et al. Spontaneous calcification process in primary renal cells from a medullary sponge kidney patient harbouring a GDNF mutation. J Cell Mol Med 2015; 19:889.
  8. Goldman SH, Walker SR, Merigan TC Jr, et al. Hereditary occurrence of cystic disease of the renal medulla. N Engl J Med. 1966; 274:984.
  9. Forster JA, Taylor J, Browning AJ, et al. A review of the natural progression of medullary sponge kidney and a novel grading system based on intravenous urography findings. Urol Int. 2007; 78(3):264-9.
  10. Koraishy FM, Ngo TT, Israel GM, et al. CT urography for the diagnosis of medullary sponge kidney. Am J Nephrol. 2014; 39:165-170.
  11. Fabris A, Lupo A, Bernich P, et al. Long-term treatment with potassium citrate and renal stones in medullary sponge kidney. Clin J Am Soc Nephrol. 2010; 5:1663-1668.

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Last updated: 2019-07-11 20:42