Topic Discussion: Non Dilated Obstructive Uropathy

Anuric renal failure has very few causes. The top three are usually: hydronephrosis, hydronephrosis and hydronephrosis! But sometimes, it’s the sonogram and imaging that sways you away from the diagnosis. The sonogram reads- no hydronephrosis and or dilatation.  But clinically, the only thing that makes sense to you is obstruction? What do you do then?

Non dilated obstruction is not uncommon especially in patients with cancer that effects the retroperitoneal regions. There is so much cancer mass that there is no ROOM for the kidney to expand. But doesn’t mean that hydronephrosis is not present. The syndrome of non-dilated obstructive uropathy (NDOU) and AKI is well reported. However, the literature suggests that this syndrome is rare, accounting for less than 5% of cases of urinary obstruction.

One of the earlier studies had looked at a series of patients at a single center and found that most common cause of these type of situations were cancers ( likely RP related)- so prostate, colon, bladder, lymphomas and other series have found cervical cancer as well.  Antegrade urography had found the obstruction in all of the cases in that one series. 

The first ever case of this was described by Ormand in 1948 with someone with retroperitoneal fibrosis.

A more recent study from Mayo Clinic has a case series of 3 cases. Despite the absence of dilatation on renal imaging, strong suspicion for NDOU led to decompression procedures with prompt recovery of kidney function in all three patients - two required percutaneous nephrostomy tube placements and/or ureteric stents and one responded to simple Foley catheter drainage. Here is another case series summarizing the data.

Treatment is usually diagnostic.  Given the pathology and the cause of the obstruction being present after the ureteral stents are placed, they usually only temporize the treatment. Percutaneous nephrostomy is usually the best procedure in such situations. 

When one encounters such cases, Urology and IR help is critical in getting the right diagnosis and prompt treatment.  

CLINICAL CASE 46 ANSWERS AND SUMMARY

WHICH OF THE FOLLOWING ARE TRUE REGARDING NEPHROPTOSIS?

1.It is a term applied to movement of the native kidney in response to a change  in the posture of the patient  61%

2.It can also be seen in a transplanted kidney 23%
3.Female gender, Lax musculature of abdomen and obesity are 
risk factors for this to happen in a transplanted kidney 30%
4.Patients usually complain of significant nocturnia and not much urination during the day 46%
5.There was a HOUSE MD episode on this diagnosis   30%


Nephroptosis (floating kidney or renal ptosis) is an abnormal condition in which the kidney drops down into the pelvis when the patient stands up. It is more common in women than in men. It can be seen in transplanted kidney as well. Look below for some references.  Female gender and lax musculature are risk factors.  Given the posture related function of the kidney- patients sometimes only urinate when they are in the lying down position. Most common symptoms although are pain, acute colic episodes, hematuria and nausea and vomiting. And yes, there was a house MD episode of this diagnosis. So all answers are correct.

It is interesting to look at the history of this disorder. The incidence of this might be greater than we think as we often forget this diagnosis.  In 19th century, Nephropexy was performed and one of the most common procedure done for nephroptosis and not its almost extinct.  One of the articles listed below calls " nephropexy for nephroptosis .. is listed among other ineffective treatments of imaginary diseases".  It is more common in females, with right side effecting more(70%) and 10% can be bilateral. The pathophysiology behind this might be: ptosis causing intermittent ureteric obstruction- hydronephrosis( positional), ischemia,traction and simulation of visceral nerves and leading to stones and infections. 

When you have acute hydronephrosis associated with this- it is called Dietl's crisis. Transplant kidneys can get this form of obstruction as well.  Look below for more details on this entity on references listed.

Ref:

http://www.ncbi.nlm.nih.gov/pubmed/19935816

http://www.ncbi.nlm.nih.gov/pubmed/18990154

http://ndt.oxfordjournals.org/content/11/8/1637.long

http://www.ncbi.nlm.nih.gov/pubmed/11452171

IN THE NEWS:- Renal Cell Cancer Research Update 2011

Renal Cell Cancer(RCC) has been in the limelight recently. Two recent studies provided some interesting links. In a large prospective study, regular use of  NSAIDs was associated with a 51% increased risk of RCC after adjusting for multiple variables, according to a report in Archives of Internal Medicine 2011 issue.
The absolute risk differences for regular users compared with nonusers of nonaspirin NSAIDs were 9.15 per 100,000 person-years for the women and 10.92 per 100,000 person-years for the men. This was an analysis of over >75,000 patients. In addition, longer use of nonaspirin NSAIDs was associated with increasing risk. This is the largest prospective trial to look at this link. 
In another study recently, researchers have identified an association between RCC and multiple myeloma. They looked at over 57,000 patients diagnosed with RCC as a primary malignancy and over 33,000 diagnosed with multiple myeloma as a primary malignancy. The researchers found 88 multiple myeloma cases in the RCC cohort. Multiple myeloma was 1.51 times more likely to be found in RCC patients than in the general population, according to the investigators. They identified 69 RCC cases in the multiple myeloma cohort. RCC was 1.89 times more likely to be present in patients with multiple myeloma than in the general population.

The first study is suggests a link we knew all along but a prospective study confirms it. The second study is novel and not a common association usually thought about. In other words, should we be screening for RCC in MM patients or vice versa?

Ref:

http://www.ncbi.nlm.nih.gov/pubmed/21911634
http://www.ncbi.nlm.nih.gov/pubmed/21091979

TOPIC DISCUSSION: Wunderlich Syndrome

Wunderlich syndrome can be seen in dialysis patients.  It is spontaneous non traumatic renal hemorrhage.  Usually this is seen in angiomyolipomas and sometimes even in urothelial cell cancers. Some cancers are common in dialysis patients, renal cell or urothelial can be seen.  Usually the syndrome presents with back pain, flank pain or hip pain.  CT scan can diagnosis it. If they are not making urine, blood in the urine might not be noted.  A high index of suspicion in at-risk patients therefore is important to timely identify and manage this disease.

A recent AJKD article describes this entity.

Ref:

http://www.ncbi.nlm.nih.gov/pubmed/21684433

http://www.ncbi.nlm.nih.gov/pubmed/21566314

Concept Map of CAKUT

Based AJKD Core Curriculum in Nephrology: Kidney Development 2011
by Walker and Bertram

ref:
http://www.ncbi.nlm.nih.gov/pubmed/21514985

TOPIC DISCUSSION: Spontaneous Perinephric Hemorrhage

If you have someone who presents to you with a spontaneous renal hemorrhage, what causes come to your mind? Things to keep in your mind are:


Renal Cell Cancer
Angiomyolipoma
Abscess
Hemorrhagic cyst
Arteriovenous Malformations
Idiopathic


The above list was based on a radiology study of 18 patients where a cause was discovered ultimately by CT scan rather than Ultrasound.

http://www.ncbi.nlm.nih.gov/pubmed/2672096
http://www.ncbi.nlm.nih.gov/pubmed/2300864
http://www.ncbi.nlm.nih.gov/pubmed/11517829
Image source: http://www.catscanman.net/blog/

Medicine for residents: a little step towards cost effectiveness - renal ...

Medicine for residents: a little step towards cost effectiveness - renal ...: "A renal ultrasound is a very good study that gives a lot of useful information for a lot of kidney diseases. Especially...in Acute Kidney in..."

TOPIC DISCUSSION: Urinary Diversions

When someone has a bladder surgery and complete removal of the bladder, there are three ways a new bladder can be created. Its important to know this information as nephrologist so that we understand what the anatomy is.

1. Neobladder(urethera diversion): a new bladder is created using the intestines and connected directly to the urethera and patient can urinate like they normally do. It sits in the body.
2. Ileal Conduit. a segment of the intestine is linked up to the ureters creating a diversion that directs urine through a stoma into a bag sitting outside the body.
3. Indiana Pouch : a pouch is made from parts of the intestine that hooks up to the ureters in the abdomen and connected to a stoma outside and a catheter needs to be inserted to drain the urine.

CONSULT ROUNDS: CAUSES OF UPJ OBSTRUCTION

Obstruction is a common cause of Acute Kidney Injury in many patients we encounter. Sometimes we see what is referred to as UPJ or Urteropelvic Junction Obstruction. Just wanted to briefly go over the causes of that entity. Adult patients with an UPJ obstruction will commonly present to medical attention due to the development of kidney stones on the affected side, infections or blood in the urine. Rarely, the patient will describe back pain whenever he/she drinks a lot of fluid. This is called "Dietl's crisis".


The most common causes are usually
Congenital
Strictures
Crossing vessel or band pressing on the UPJ
Instrinsic Stenosis
Decreased peristalsis through UPJ


Other less common causes
Renal Cyst at that location
Aortic Aneurysm
Eisonophilic ureteritis
Xanthogranalumatous Pyelonephritis
What do they mean by crossing vessel?
In adults, the obstruction of the ureter can be caused by an extra blood vessel, usually an artery that supplies the lower part of the kidney. As a person gets older, this vessel gets bigger. Since this blood vessel will usually lie over the ureter, it can cause obstruction. This is called a "crossing vessel".


http://www.ncbi.nlm.nih.gov/pubmed/19193425