Horseshoe kidney overview

Jump to navigation Jump to search
https://https://www.youtube.com/watch?v=mdKt8kLGfVA&t=5s%7C350}}

Horseshoe kidney Microchapters

Home

Patient Information

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating Horseshoe kidney from other Diseases

Epidemiology and Demographics

Risk Factors

Screening

Natural History, Complications and Prognosis

Diagnosis

Diagnostic Study of Choice

History and Symptoms

Physical Examination

Laboratory Findings

Electrocardiogram

X-Ray

CT

MRI

Echocardiography and Ultrasound

Other Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Primary Prevention

Secondary Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

Horseshoe kidney overview On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of Horseshoe kidney overview

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on Horseshoe kidney overview

CDC on Horseshoe kidney overview

Horseshoe kidney overview in the news

Blogs on Horseshoe kidney overview

Directions to Hospitals Treating Horseshoe kidney

Risk calculators and risk factors for Horseshoe kidney overview

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:

Overview

Horseshoe kidney is the congenital disorder of kidneys in which the isthmus of both kidneys fuse together during embryonic development leading to appearance of "Horseshoe". It is the most common fusion defect of kidneys.

Historical Perspective

Classification

Based to morphology, horseshoe kidney is classified into 3 main types.

  1. 'U' Shaped, when the lower poles of kidneys fuse together.
  2. Inverted 'U' shaped when upper poles of kidneys fuse together.
  3. 'L' Shaped when one vertically placed kidney fuse with another horizontally placed kidney leading to 'L' shape.

Pathophysiology

Most people with horseshoe kidneys are totally asymptomatic and their kidneys function normally throughout their lives. About quarter of cases are found incidentally, usually during a CT scan due to some other problem. Nonetheless, there are lots of other patients who are predisposed to certain medical issues. These issues include:

  1. Ureteropelvic junction obstruction : It is the most common problem in horseshoe kidney. It is caused by crossing of ureter over the fused isthmus leading to its obstruction.
  2. Kidney Stones : Stones usually occur when there is obstruction leading to decreased urine output and stasis of urine which create environment for stone formation.
  3. Recurrent infections : Again due to stasis of urine, because stasis of urine create medium for bacterial growth
  4. Hydronephrosis : Basically it is caused by back-flow of urine due to obstruction of ureteropelvic junction.
  5. Increased incidence of certain cancers such as renal cell carcinoma, wilms tumor and carcinoid tumors.

Causes

During early fetal development, the kidneys are developed in the pelvis and then later they move upwards in abdomen. Sometimes due to unknown reason the lower ends of both kidneys fuse together forming a 'U' shaped single kidney. Although the exact cause is unknown, but there are two main theories. One theory suggests that during the fifth week of fetal development both kidneys are so close together leading to mechanical fusion of lower end of both kidneys. This kind of fusion creates the fibrous isthmus because it is made of connective tissue. Other theory suggests that posterior nephrogenic cells, which are the cells responsible for formation of kidney, migrate to wrong place leading to joining of lower end of both kidneys. This time it is called parenchymal isthmus because it is made of kidney cells.

The horseshoe kidney remains lower in abdomen than normal kidneys due to blockade caused by inferior mesenteric artery during its movement from pelvis to abdomen in 7-8 weeks of development.

Differentiating Horseshoe kidney from Other Diseases

There are other forms of kidney fusion defects. Usually they can be differentiated based on appearances on CT scan.

Epidemiology and Demographics

  • It is fairly common condition with 1 case in every 500 live births.
  • Males cases are twice more common than female cases.
  • Although it has been seen in members of same families, but no any particular gene has been found to cause this disease.

Risk Factors and Associations

There are no particular gene discovered yet which are directly related to horseshoe kidney but it has been seen associated with other genetic disorders such as Turner syndrome and Edwards syndrome, further suggesting that has links to some genes.

Screening

There is no particular screening test for horseshoe kidney itself, although CT scanning or renal ultrasonography can be used to screen for the presence of stones, masses, or hydronephrosis.

Natural History, Complications, and Prognosis

  1. Hydronephrosis
  2. Renal stones
  3. Urinary tract infections
  4. Renal Cancer

Diagnosis

Diagnostic Study of Choice

Intravenous pyelography protocol computed tomography is the best initial test

History and Symptoms

1 in every 3 patients remain asymptomatic throughout their lives. Other patients present with symptoms secondary to urinary tract infections, renal stones and obstruction. These symptoms include dysuria, flank pain and fever.

Physical Examination

Because the kidneys are lower in abdomen, a midline lower abdominal mass can be felt during physical examination.

Laboratory Findings

Urine routine (DR) and urine culture should be done to look for any sign of urinary infection and serum creatinine and electrolytes should be done to check the kidney function.

Electrocardiogram

X-ray

Ultrasound

Renal Ultrasound can be used to look for presence of any stones, masses, obstruction or hydronephrosis.

CT scan

CT Scan is imaging technique of choice. CT Scan of abdomen and pelvis with and without contract is used to look for location of kidneys.

MRI

MRI is also helpful in diagnosing horseshoe kidney, and is used in conditions where CT Scan is not recommended or available.

Other Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Interventions

Surgery

Primary Prevention

Secondary Prevention

References


Template:WikiDoc Sources