Hydronephrosis is distension and
dilationDilation refers to an enlargement or expansion in bulk or extent, the opposite of contraction. It derives from the Latin dilatare, "to spread wide".In physiology:* Pupillary response, dilation of the pupil of the eye...
of the
renal pelvisThe renal pelvis is the funnel-like dilated proximal part of the ureter in the kidney.It is the point of convergence of two or three major calyces...
and
calyces, usually caused by
obstructionObstruction is the act of blocking or impeding some performance* Obstruction theory, in mathematics* Obstruction of justice, the crime of interfering with law enforcement* Obstructing government administration* Propagation path obstruction...
of the free flow of
urineUrine is a liquid waste product of the body secreted by the kidneys by a process of filtration from blood called urination and excreted through the urethra. Cellular metabolism generates numerous waste compounds, many rich in nitrogen, that require elimination from the bloodstream...
from the
kidneyThe kidneys are paired organs, which have the production of urine as their primary function. Kidneys are seen in many types of animals, including vertebrates and some invertebrates. They are part of the urinary system, but have several secondary functions concerned with homeostatic functions. ...
, leading to progressive
atrophyAtrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, disuse or lack of exercise or disease intrinsic to the tissue itself...
of the kidney.
The signs and symptoms of hydronephrosis depend upon whether the obstruction is
acuteAcute may refer to:* Acute angle* Acute accent* Acute * Acute * Acute toxicity* The Acute - an alternative Rock band from Edinburgh, Scotland...
or
chronicChronic may refer to:* Chronic , a persistent and lasting disease or medical condition, or one that has developed slowly* Chronic toxicity,* The Chronic, a 1992 album by Dr. Dre...
, partial or complete, unilateral or
bilateralBilateral may refer to any concept including two sides, in particular:*Bilateralism, describing the political and cultural relations between two states.*Bilateral symmetry, symmetry between two sides of an organism....
. Unilateral hydronephrosis may occur without any symptoms, while acute obstruction can cause intense pain.
Blood tests can show raised
creatinineCreatinine is a break-down product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body ....
and
electrolyteIn chemistry, an electrolyte is any substance containing free ions that behaves as an electrically conductive medium, usually when in a solution...
imbalance.
Hydronephrosis is distension and
dilationDilation refers to an enlargement or expansion in bulk or extent, the opposite of contraction. It derives from the Latin dilatare, "to spread wide".In physiology:* Pupillary response, dilation of the pupil of the eye...
of the
renal pelvisThe renal pelvis is the funnel-like dilated proximal part of the ureter in the kidney.It is the point of convergence of two or three major calyces...
and
calyces, usually caused by
obstructionObstruction is the act of blocking or impeding some performance* Obstruction theory, in mathematics* Obstruction of justice, the crime of interfering with law enforcement* Obstructing government administration* Propagation path obstruction...
of the free flow of
urineUrine is a liquid waste product of the body secreted by the kidneys by a process of filtration from blood called urination and excreted through the urethra. Cellular metabolism generates numerous waste compounds, many rich in nitrogen, that require elimination from the bloodstream...
from the
kidneyThe kidneys are paired organs, which have the production of urine as their primary function. Kidneys are seen in many types of animals, including vertebrates and some invertebrates. They are part of the urinary system, but have several secondary functions concerned with homeostatic functions. ...
, leading to progressive
atrophyAtrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, disuse or lack of exercise or disease intrinsic to the tissue itself...
of the kidney.
Signs and symptoms
The signs and symptoms of hydronephrosis depend upon whether the obstruction is
acuteAcute may refer to:* Acute angle* Acute accent* Acute * Acute * Acute toxicity* The Acute - an alternative Rock band from Edinburgh, Scotland...
or
chronicChronic may refer to:* Chronic , a persistent and lasting disease or medical condition, or one that has developed slowly* Chronic toxicity,* The Chronic, a 1992 album by Dr. Dre...
, partial or complete, unilateral or
bilateralBilateral may refer to any concept including two sides, in particular:*Bilateralism, describing the political and cultural relations between two states.*Bilateral symmetry, symmetry between two sides of an organism....
. Unilateral hydronephrosis may occur without any symptoms, while acute obstruction can cause intense pain.
Blood tests can show raised
creatinineCreatinine is a break-down product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body ....
and
electrolyteIn chemistry, an electrolyte is any substance containing free ions that behaves as an electrically conductive medium, usually when in a solution...
imbalance.
UrinalysisA urinalysis is an array of tests performed on urine and one of the most common methods of medical diagnosis. A part of a urinalysis can be performed by using urine dipsticks, in which the test results can be read as color changes....
may show an elevated pH due to the
secondarySecondary is an adjective meaning "second" or "second hand". It may refer to:* Secondary education* A secondary consumer in an ecological sense* Secondary dominant, in music...
destruction of
nephronNephron is the basic structural and functional unit of the kidney. Its chief function is to regulate the concentration of water and soluble substances like sodium salts by filtering the blood, reabsorbing what is needed and excreting the rest as urine...
s within the affected
kidneyThe kidneys are paired organs, which have the production of urine as their primary function. Kidneys are seen in many types of animals, including vertebrates and some invertebrates. They are part of the urinary system, but have several secondary functions concerned with homeostatic functions. ...
.
Symptoms that occur regardless of where the obstruction lies include
loinThe loin are the sides between the lower ribs and pelvis, and the lower part of the back. It is often used when describing the anatomy of humans and quadrupeds . The anatomical reference also carries over into the description of cuts of meat from some such animals, eg...
or
flankFlank may refer to:* Flank, the side of either a horse or a military unit*Flanking maneuver in military tactics* Flank , the waveform edge formed when a signal goes high or low...
painPhysical Pain is the unpleasant feeling common to a headache and a stubbed toe. It typically consists of negative affect and aversion, and has location, duration, intensity and a distinctive quality...
. An enlarged
kidneyThe kidneys are paired organs, which have the production of urine as their primary function. Kidneys are seen in many types of animals, including vertebrates and some invertebrates. They are part of the urinary system, but have several secondary functions concerned with homeostatic functions. ...
may be palpable on
examinationTo examine somebody or something is to inspect it closely; hence, an examination is a detailed inspection or analysis of an object or person....
.
Where the obstruction occurs in the lower urinary tract, suprapubic tenderness (with or without a history of
bladderIn anatomy, the urinary bladder is the organ that collects urine excreted by the kidneys prior to disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor...
outflow obstruction) along with a palpable bladder are strongly suggestive of acute
urinary retentionUrinary retention also known as ischuria is a lack of ability to urinate. It is a common complication of benign prostatic hypertrophy , although anticholinergics may also play a role, and requires a catheter or prostatic stent...
, which left untreated is highly likely to cause hydronephrosis.
Upper urinary tract obstruction is characterised by pain in the
flankFlank may refer to:* Flank, the side of either a horse or a military unit*Flanking maneuver in military tactics* Flank , the waveform edge formed when a signal goes high or low...
, often radiating to either the
abdomenIn vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
or the
groinIn human anatomy, the groin areas are the two creases at the junction of the torso with the legs, on either side of the pubic area. A pulled groin muscle usually refers to a painful injury sustained by straining the hip adduction muscle....
. Where the obstruction is
chronicIn medicine, a chronic disease is a disease that is long-lasting or recurrent. The term chronic describes the course of the disease, or its rate of onset and development. A chronic course is distinguished from a recurrent course; recurrent diseases relapse repeatedly, with periods of remission in...
,
renal failureRenal failure or kidney failure is a situation in which the kidneys fail to function adequately. It is divided into acute and chronic forms; either form may be due to a large number of other medical problems....
may also be present. If the obstruction is complete, an enlarged kidney is often palpable on examination.
Etiology
The obstruction may be either partial or complete and can occur anywhere from the
urethral meatusThe urinary meatus is the external orifice of the urethra, from which urine is ejected during urination and semen is ejected during ejaculation....
to the
calycesThe minor calyx, in the kidney, surrounds the apex of the malpighian pyramids. Urine formed in the kidney passes through a papilla at the apex into the minor calyx then into the major calyx....
of the
renal pelvisThe renal pelvis is the funnel-like dilated proximal part of the ureter in the kidney.It is the point of convergence of two or three major calyces...
.
The obstruction may arise from either inside or outside the urinary tract or may come from the wall of the urinary tract itself. Intrinsic obstructions (those that occur within the tract) include blood clots, stones, sloughed papilla along with tumors of the kidney, ureter and bladder. Extrinsic obstructions (those that are caused by factors outside of the urinary tract) include pelvic or abdominal tumours or masses, retroperitoneal fibrosis or neurological deficits. Strictures of the ureters (congenital or acquired), neuromuscular dysfunctions or schistosomiasis are other causes which originate from the wall of the urinary tract.
Tests
Prenatal diagnosis is possible.
Blood (U&E, creatinine) and urine (MSU, pH) tests should be taken. IVUs, ultrasounds, CTs and MRIs are also important tests. Ultrasound allows for visualisation of the ureters and kidneys and can be used to assess the presence of hydronephrosis and / or hydroureter. An IVU is useful for assessing the position of the obstruction. Antegrade or retrograde pyelography will show similar findings to an IVU but offer a therapeutic option as well.
The choice of imaging depends on the clinical presentation (history, symptoms and examination findings). In the case of
renal colicRenal colic is a type of pain commonly caused by kidney stones.-Presentation:The pain typically begins in the loin region and often radiates to the hypochondrium or the groin. The pain is often colicky due to ureteric peristalsis, but may be constant...
(one sided loin pain usually accompanied by a trace of blood in the urine) the initial investigation is usually an intravenous urogram. This has the advantage of showing whether there is any obstruction of flow of urine causing hydronephrosis as well as demonstrating the function of the other kidney. Many stones are not visible on plain
X-rayX-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 10 to 0.01 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays...
or IVU but 99% of stones are visible on CT and therefore CT is becoming a common choice of initial investigation. CT is not used however, when there is a reason to avoid radiation exposure, e.g. in pregnancy.
Prognosis
Left untreated,
bilateralBilateral may refer to any concept including two sides, in particular:*Bilateralism, describing the political and cultural relations between two states.*Bilateral symmetry, symmetry between two sides of an organism....
obstruction (occurring to both
kidneyThe kidneys are paired organs, which have the production of urine as their primary function. Kidneys are seen in many types of animals, including vertebrates and some invertebrates. They are part of the urinary system, but have several secondary functions concerned with homeostatic functions. ...
s rather than one) has a poor prognosis.
Treatment
Treatment of hydronephrosis focuses upon the removal of the obstruction and drainage of the urine that has accumulated behind the obstruction. Therefore, the specific treatment depends upon where the obstruction lies, and whether it is acute or
chronicIn medicine, a chronic disease is a disease that is long-lasting or recurrent. The term chronic describes the course of the disease, or its rate of onset and development. A chronic course is distinguished from a recurrent course; recurrent diseases relapse repeatedly, with periods of remission in...
.
Acute obstruction of the upper urinary tract is usually treated by the insertion of a
nephrostomyA nephrostomy is an artificial opening created between the kidney and the skin which allows for the drainage of urine directly from the upper part of the urinary system .-Uses:...
tube. Chronic upper urinary tract obstruction is treated by the insertion of a
ureteric stentA ureteral stent, sometimes as well called ureteric stent, is a thin tube inserted into the ureter to prevent or treat obstruction of the urine flow from the kidney. The length of the stents used in adult patients varies between 24 to 30 cm. Additionally, stents come in differing diameters or...
or a
pyeloplastyPyeloplasty is the surgical reconstruction or revision of the renal pelvis to drain and decompress the kidney. Most commonly it is performed to treat an uretero-pelvic junction obstruction if residual renal function is adequate....
.
Lower urinary tract obstruction (such as that caused by bladder outflow obstruction secondary to prostatic hypertrophy) is usually treated by insertion of a urinary catheter or a suprapubic catheter.
Surgery is not required in all cases.
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