Hydronephrosis

Overview

Definition

Hydronephrosis is defined as the dilation of the renal pelvis Renal pelvis Kidneys: Anatomy and calyces due to obstruction of urine outflow.

Epidemiology

• Incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency: about 3.1%
• Hydronephrosis resolves spontaneously in 50% of cases.
• Children:
  • Most often a transient and physiologic state
  • Most cases resolve spontaneously by 2 years of age.
• Adults:
  • Men = women before age 20
  • Women > men between 20 and 60 years of age:
    • Due to pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care and gynecologic malignancy Malignancy Hemothorax
    • Hydronephrosis is seen in 80% of pregnant women.
  • Men > women after 60 years of age, due to prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. disease

Etiology

Children:

• Transient/physiologic
• Ureteropelvic junction Ureteropelvic junction Urinary Tract: Anatomy obstruction:
  • Intrinsic stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) of the proximal ureter
  • Extrinsic compression Compression Blunt Chest Trauma by an aberrant or accessory renal artery Renal artery A branch of the abdominal aorta which supplies the kidneys, adrenal glands and ureters. Glomerular Filtration
• Vesicoureteral reflux Vesicoureteral Reflux Vesicoureteral reflux (VUR) is the retrograde flow of urine from the bladder into the upper urinary tract. Primary VUR often results from the incomplete closure of the ureterovesical junction, whereas secondary VUR is due to an anatomic or physiologic obstruction. Vesicoureteral Reflux
• Multicystic dysplastic kidney
• Megaureter
• Ureterocele Ureterocele A cystic dilatation of the end of a ureter as it enters into the urinary bladder. It is characterized by the ballooning of the ureteral orifice into the lumen of the bladder and may obstruct urine flow. Urinary Tract Obstruction
• Posterior urethral valves
• Urethral stricture Stricture Primary Sclerosing Cholangitis or atresia Atresia Hypoplastic Left Heart Syndrome (HLHS)

Adults:

• Intrinsic causes:
  • Kidney:
    • Nephrolithiasis Nephrolithiasis Nephrolithiasis is the formation of a stone, or calculus, anywhere along the urinary tract caused by precipitations of solutes in the urine. The most common type of kidney stone is the calcium oxalate stone, but other types include calcium phosphate, struvite (ammonium magnesium phosphate), uric acid, and cystine stones. Nephrolithiasis (most common cause in young adults)
    • Renal cysts Renal Cysts Imaging of the Urinary System
    • Cancer
  • Urinary outflow tract:
    • Ureteropelvic obstruction
    • Ureteral stricture Stricture Primary Sclerosing Cholangitis
    • Iatrogenic Iatrogenic Any adverse condition in a patient occurring as the result of treatment by a physician, surgeon, or other health professional, especially infections acquired by a patient during the course of treatment. Anterior Cord Syndrome injury to ureters Ureters One of a pair of thick-walled tubes that transports urine from the kidney pelvis to the urinary bladder. Urinary Tract: Anatomy
    • Neurogenic bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess
    • Cystocele Cystocele A hernia-like condition in which the weakened pelvic muscles cause the urinary bladder to drop from its normal position. Fallen urinary bladder is more common in females with the bladder dropping into the vagina and less common in males with the bladder dropping into the scrotum. Pelvic Organ Prolapse
    • Urethral stricture Stricture Primary Sclerosing Cholangitis
    • Malignancy Malignancy Hemothorax of the ureter, bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess, or prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid.
• Extrinsic causes:
  • Pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care
  • Benign Benign Fibroadenoma prostatic hyperplasia Hyperplasia An increase in the number of cells in a tissue or organ without tumor formation. It differs from hypertrophy, which is an increase in bulk without an increase in the number of cells. Cellular Adaptation
  • Retroperitoneal Retroperitoneal Peritoneum: Anatomy fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans
  • Gynecologic malignancies
  • Retroperitoneal Retroperitoneal Peritoneum: Anatomy or pelvic masses

Pathophysiology

• Obstructing the outward flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure of urine → urine accumulation and ↑ pressure in the urinary tract Urinary tract The urinary tract is located in the abdomen and pelvis and consists of the kidneys, ureters, urinary bladder, and urethra. The structures permit the excretion of urine from the body. Urine flows from the kidneys through the ureters to the urinary bladder and out through the urethra. Urinary Tract: Anatomy.
• The GFR GFR The volume of water filtered out of plasma through glomerular capillary walls into Bowman’s capsules per unit of time. It is considered to be equivalent to inulin clearance. Kidney Function Tests persists initially, contributing to ↑ pressure within the urinary tract Urinary tract The urinary tract is located in the abdomen and pelvis and consists of the kidneys, ureters, urinary bladder, and urethra. The structures permit the excretion of urine from the body. Urine flows from the kidneys through the ureters to the urinary bladder and out through the urethra. Urinary Tract: Anatomy.
• GFR GFR The volume of water filtered out of plasma through glomerular capillary walls into Bowman’s capsules per unit of time. It is considered to be equivalent to inulin clearance. Kidney Function Tests ↓ significantly after several hours
• High pressure is transmitted upward → dilation of the collecting tubules Collecting tubules Straight tubes commencing in the radiate part of the kidney cortex where they receive the curved ends of the distal convoluted tubules. In the medulla the collecting tubules of each pyramid converge to join a central tube (duct of Bellini) which opens on the summit of the papilla. Kidneys: Anatomy and renal calyces.
• ↑ Hydrostatic pressure Hydrostatic pressure The pressure due to the weight of fluid. Edema inside the collecting system → compression Compression Blunt Chest Trauma of the renal and especially inner medullary vasculature, which causes:
  • Impaired concentrating ability
  • Ischemic tubular atrophy Atrophy Decrease in the size of a cell, tissue, organ, or multiple organs, associated with a variety of pathological conditions such as abnormal cellular changes, ischemia, malnutrition, or hormonal changes. Cellular Adaptation
  • Interstitial fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans
• Recovery of renal function depends on the duration and extent of the obstruction.

Clinical Presentation

Clinical manifestations vary depending on the acuity of symptom onset, the degree, and the site of the obstruction. Possible presentations include:

• Asymptomatic (slowly developing or partial obstruction):
  • Tumor Tumor Inflammation
  • Congenital Congenital Chorioretinitis ureteropelvic junction Ureteropelvic junction Urinary Tract: Anatomy obstruction
  • Pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care
• Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways:
  • Caused by acute complete or incomplete obstruction
  • Determined by site of obstruction
  • Upper urinary tract Urinary tract The urinary tract is located in the abdomen and pelvis and consists of the kidneys, ureters, urinary bladder, and urethra. The structures permit the excretion of urine from the body. Urine flows from the kidneys through the ureters to the urinary bladder and out through the urethra. Urinary Tract: Anatomy obstruction causes flank pain Flank pain Pain emanating from below the ribs and above the ilium. Renal Cell Carcinoma.
  • Lower urinary tract Urinary tract The urinary tract is located in the abdomen and pelvis and consists of the kidneys, ureters, urinary bladder, and urethra. The structures permit the excretion of urine from the body. Urine flows from the kidneys through the ureters to the urinary bladder and out through the urethra. Urinary Tract: Anatomy obstruction results in suprapubic pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways with radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma to the labia or testicle.
• Changes in urine volume:
  • Anuria Anuria Absence of urine formation. It is usually associated with complete bilateral ureteral (ureter) obstruction, complete lower urinary tract obstruction, or unilateral ureteral obstruction when a solitary kidney is present. Acute Kidney Injury is seen with complete urethral (or bilateral ureteral) obstructions, which result in bilateral hydronephrosis.
  • Polyuria Polyuria Urination of a large volume of urine with an increase in urinary frequency, commonly seen in diabetes. Renal Potassium Regulation:
    • Due to impaired concentrating ability
    • Seen with partial bilateral obstruction
• Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension:
  • Most common in acute unilateral hydronephrosis
  • Occurs through activation of the renin-angiotensin system
• Decreased GFR GFR The volume of water filtered out of plasma through glomerular capillary walls into Bowman’s capsules per unit of time. It is considered to be equivalent to inulin clearance. Kidney Function Tests is seen in partial or complete bilateral hydronephrosis.
• Hematuria Hematuria Presence of blood in the urine. Renal Cell Carcinoma
• Fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever: if urinary stasis causes infection
• Urinary retention Urinary retention Inability to empty the urinary bladder with voiding (urination). Delirium
• Palpable bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess

Diagnosis

The diagnosis of hydronephrosis is made by imaging, which also often identifies the cause. History, exam, and lab findings can help suggest the underlying etiology as well.

History

• Fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever
• Hematuria Hematuria Presence of blood in the urine. Renal Cell Carcinoma
• Symptoms of lower urinary tract Urinary tract The urinary tract is located in the abdomen and pelvis and consists of the kidneys, ureters, urinary bladder, and urethra. The structures permit the excretion of urine from the body. Urine flows from the kidneys through the ureters to the urinary bladder and out through the urethra. Urinary Tract: Anatomy obstruction:
  • Hesitancy
  • Dribbling
  • Prolonged micturition
  • Weak stream
• Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways:
  • Location
  • Quality Quality Activities and programs intended to assure or improve the quality of care in either a defined medical setting or a program. The concept includes the assessment or evaluation of the quality of care; identification of problems or shortcomings in the delivery of care; designing activities to overcome these deficiencies; and follow-up monitoring to ensure effectiveness of corrective steps. Quality Measurement and Improvement 
  • Duration
  • Radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma
• Symptoms of urinary tract Urinary tract The urinary tract is located in the abdomen and pelvis and consists of the kidneys, ureters, urinary bladder, and urethra. The structures permit the excretion of urine from the body. Urine flows from the kidneys through the ureters to the urinary bladder and out through the urethra. Urinary Tract: Anatomy infection:
  • Dysuria Dysuria Painful urination. It is often associated with infections of the lower urinary tract. Urinary Tract Infections (UTIs)
  • Urgency
  • Incontinence
• Nausea Nausea An unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses. Antiemetics and vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia

Physical exam findings

The following exam findings, if present, can help identify the cause of hydronephrosis:

• Costovertebral angle tenderness (suggests nephrolithiasis Nephrolithiasis Nephrolithiasis is the formation of a stone, or calculus, anywhere along the urinary tract caused by precipitations of solutes in the urine. The most common type of kidney stone is the calcium oxalate stone, but other types include calcium phosphate, struvite (ammonium magnesium phosphate), uric acid, and cystine stones. Nephrolithiasis or upper tract infection)
• Abdominal examination Abdominal examination The abdominal examination is the portion of the physical exam evaluating the abdomen for signs of disease. The abdominal examination consists of inspection, auscultation, percussion, and palpation. Abdominal Examination:
  • Palpable kidney or bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess
  • Tenderness
• Digital rectal examination Digital Rectal Examination A physical examination in which the qualified health care worker inserts a lubricated, gloved finger of one hand into the rectum and may use the other hand to press on the lower abdomen or pelvic area to palpate for abnormalities in the lower rectum, and nearby organs or tissues. The method is commonly used to check the lower rectum, the prostate gland in men, and the uterus and ovaries in women. Prostate Cancer Screening:
  • Prostatic enlargement
  • Prostatic nodules
  • Sphincter tone
• Pelvic exam (women):
  • Pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care
  • Pelvic mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast

Diagnostic testing

Laboratory studies:

• Urinalysis Urinalysis Examination of urine by chemical, physical, or microscopic means. Routine urinalysis usually includes performing chemical screening tests, determining specific gravity, observing any unusual color or odor, screening for bacteriuria, and examining the sediment microscopically. Urinary Tract Infections (UTIs) in Children:
  • Pyuria Pyuria The presence of white blood cells (leukocytes) in the urine. It is often associated with bacterial infections of the urinary tract. Pyuria without bacteriuria can be caused by tuberculosis, stones, or cancer. Urinary Tract Infections (UTIs) suggests the presence of inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation.
  • Leukocyte esterase Leukocyte esterase Kidney Function Tests or nitrites indicate infection.
  • Hematuria Hematuria Presence of blood in the urine. Renal Cell Carcinoma may indicate the presence of stones, malignancy Malignancy Hemothorax, or infection.
• Basic metabolic panel Basic Metabolic Panel Primary vs Secondary Headaches:
  • ↑ BUN and creatinine are seen in bilateral hydronephrosis and indicate renal compromise.
  • Hyperkalemia Hyperkalemia Hyperkalemia is defined as a serum potassium (K+) concentration >5.2 mEq/L. Homeostatic mechanisms maintain the serum K+ concentration between 3.5 and 5.2 mEq/L, despite marked variation in dietary intake. Hyperkalemia can be due to a variety of causes, which include transcellular shifts, tissue breakdown, inadequate renal excretion, and drugs. Hyperkalemia and acidosis Acidosis A pathologic condition of acid accumulation or depletion of base in the body. The two main types are respiratory acidosis and metabolic acidosis, due to metabolic acid build up. Respiratory Acidosis indicate severe renal insufficiency.

Imaging

Diagnostic findings:

• Dilation of the collecting system in 1 or both kidneys Kidneys The kidneys are a pair of bean-shaped organs located retroperitoneally against the posterior wall of the abdomen on either side of the spine. As part of the urinary tract, the kidneys are responsible for blood filtration and excretion of water-soluble waste in the urine. Kidneys: Anatomy
• Imaging typically assesses:
  • Kidneys Kidneys The kidneys are a pair of bean-shaped organs located retroperitoneally against the posterior wall of the abdomen on either side of the spine. As part of the urinary tract, the kidneys are responsible for blood filtration and excretion of water-soluble waste in the urine. Kidneys: Anatomy
  • Ureters Ureters One of a pair of thick-walled tubes that transports urine from the kidney pelvis to the urinary bladder. Urinary Tract: Anatomy
  • Bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess
• Notation of dilated structures (and nondilated structures) can help identify the location of the obstruction (e.g., a dilated proximal right ureter with a normal bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess and contralateral structures = right ureteral obstruction Ureteral obstruction Blockage in any part of the ureter causing obstruction of urine flow from the kidney to the urinary bladder. The obstruction may be congenital, acquired, unilateral, bilateral, complete, partial, acute, or chronic. Depending on the degree and duration of the obstruction, clinical features vary greatly such as hydronephrosis and obstructive nephropathy. Vesicoureteral Reflux)

Imaging in adults:

• Ultrasonography:
  • Best 1st-line test in most individuals
  • Preferred over CT for pregnant women
  • Not as sensitive as CT in detecting ureteral stones
  • Primarily used to rule out obstruction and identify abnormal structures
  • Allows for simultaneous assessments of surrounding structures (e.g., prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. and gynecologic structures)
  • Findings:
    • Urine-filled dilated compartments are hypoechoic Hypoechoic A structure that produces a low-amplitude echo (darker grays) Ultrasound (Sonography) (dark)
    • Calcified stones are hyperechoic Hyperechoic A structure that produces a high-amplitude echo (lighter grays and white) Ultrasound (Sonography) (white) with posterior shadowing
    • Can identify damage to the renal parenchyma (e.g., cortical thinning), cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change/masses, and urinary retention Urinary retention Inability to empty the urinary bladder with voiding (urination). Delirium.
• CT:
  • Best imaging method to diagnose stones → 1st-line test when obstructing stones are suspected
  • Provides complementary information to ultrasounds, especially when evaluating cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change and masses
• IV pyelography:
  • Contrast material is injected into the veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology and a series of X-rays X-rays X-rays are high-energy particles of electromagnetic radiation used in the medical field for the generation of anatomical images. X-rays are projected through the body of a patient and onto a film, and this technique is called conventional or projectional radiography. X-rays are taken over the course of approximately 1 hour. 
  • Assess how the contrast material is filtered into and moves through the urinary system.
  • Has low false positive False positive An FP test result indicates that a person has the disease when they do not. Epidemiological Values of Diagnostic Tests rate compared to ultrasonography
  • Used infrequently for follow-up of stones or assessment of anatomy after stone removal

Imaging in children:

• Ultrasonography:
  • Test of choice in children, infants, and prenatally
  • Grading Grading Methods which attempt to express in replicable terms the level of cell differentiation in neoplasms as increasing anaplasia correlates with the aggressiveness of the neoplasm. Grading, Staging, and Metastasis of antenatal hydronephrosis has been developed for prenatal and postnatal ureteropelvic-junction–type hydronephrosis based on findings.
• Voiding cystourethrography:
  • The bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess is filled with contrast material via a urethral catheter; fluoroscopic images are then taken while filling and voiding the contrast material.
  • Best imaging study to diagnose suspected vesicoureteral reflux Vesicoureteral Reflux Vesicoureteral reflux (VUR) is the retrograde flow of urine from the bladder into the upper urinary tract. Primary VUR often results from the incomplete closure of the ureterovesical junction, whereas secondary VUR is due to an anatomic or physiologic obstruction. Vesicoureteral Reflux
• Diuretic renography:
  • A radionucleotide and diuretic are injected intravenously and a series of images are taken as the marker moves through the kidney and urinary system.
  • Best for differentiating obstructive vs. nonobstructive hydronephrosis
  • Assesses function of each individual kidney (i.e., how much of the “workload” is done by each kidney)
• Magnetic resonance urography:
  • Better defines the anatomy
  • Used for surgery planning
  • Often requires general anesthesia General anesthesia Procedure in which patients are induced into an unconscious state through use of various medications so that they do not feel pain during surgery. Anesthesiology: History and Basic Concepts or heavy sedation in children

Management

Management depends on the cause of obstruction, the degree of metabolic abnormality, and the presence of infection.

General recommendations

• Analgesia Analgesia Methods of pain relief that may be used with or in place of analgesics. Anesthesiology: History and Basic Concepts:
  • NSAIDs NSAIDS Primary vs Secondary Headaches (1st line)
  • Acetaminophen Acetaminophen Acetaminophen is an over-the-counter nonopioid analgesic and antipyretic medication and the most commonly used analgesic worldwide. Despite the widespread use of acetaminophen, its mechanism of action is not entirely understood. Acetaminophen
  • Oxycodone Oxycodone A semisynthetic derivative of codeine. Opioid Analgesics
  • Hydrocodone Hydrocodone Opioid Analgesics
• Fluid replacement
• Antibiotics if infection present:
  • Trimethoprim Trimethoprim The sulfonamides are a class of antimicrobial drugs inhibiting folic acid synthesize in pathogens. The prototypical drug in the class is sulfamethoxazole. Although not technically sulfonamides, trimethoprim, dapsone, and pyrimethamine are also important antimicrobial agents inhibiting folic acid synthesis. The agents are often combined with sulfonamides, resulting in a synergistic effect. Sulfonamides and Trimethoprim– sulfamethoxazole Sulfamethoxazole A bacteriostatic antibacterial agent that interferes with folic acid synthesis in susceptible bacteria. Its broad spectrum of activity has been limited by the development of resistance. Sulfonamides and Trimethoprim
  • Nitrofurantoin
  • Cephalosporins Cephalosporins Cephalosporins are a group of bactericidal beta-lactam antibiotics (similar to penicillins) that exert their effects by preventing bacteria from producing their cell walls, ultimately leading to cell death. Cephalosporins are categorized by generation and all drug names begin with “cef-” or “ceph-.” Cephalosporins
  • Fluoroquinolone
• Correction of metabolic abnormalities
• Management of the underlying cause:
  • Nephrolithiasis Nephrolithiasis Nephrolithiasis is the formation of a stone, or calculus, anywhere along the urinary tract caused by precipitations of solutes in the urine. The most common type of kidney stone is the calcium oxalate stone, but other types include calcium phosphate, struvite (ammonium magnesium phosphate), uric acid, and cystine stones. Nephrolithiasis:
    • Alpha and calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes channel blockers (e.g., tamsulosin Tamsulosin A sulfonamide derivative and adrenergic alpha-1 receptor antagonist that is used to relieve symptoms of urinary obstruction caused by benign prostatic hyperplasia. Antiadrenergic Drugs, nifedipine Nifedipine A potent vasodilator agent with calcium antagonistic action. It is a useful anti-anginal agent that also lowers blood pressure. Class 4 Antiarrhythmic Drugs (Calcium Channel Blockers))
    • Extracorporeal shockwave lithotripsy: High-energy shockwaves cause stones to fragment.
    • Percutaneous nephrolithotomy
    • Ureteroscopic or laparoscopic/open surgery
  • Benign Benign Fibroadenoma prostatic hyperplasia Hyperplasia An increase in the number of cells in a tissue or organ without tumor formation. It differs from hypertrophy, which is an increase in bulk without an increase in the number of cells. Cellular Adaptation:
    • α₁-receptor blockers (e.g., tamsulosin Tamsulosin A sulfonamide derivative and adrenergic alpha-1 receptor antagonist that is used to relieve symptoms of urinary obstruction caused by benign prostatic hyperplasia. Antiadrenergic Drugs)
    • 5α-reductase inhibitors (e.g., finasteride Finasteride An orally active 3-oxo-5-alpha-steroid 4-dehydrogenase inhibitor. It is used as a surgical alternative for treatment of benign prostatic hyperplasia. Androgens and Antiandrogens)
  • Retroperitoneal Retroperitoneal Peritoneum: Anatomy fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans: corticosteroids Corticosteroids Chorioretinitis
  • Ureteropelvic junction Ureteropelvic junction Urinary Tract: Anatomy obstruction: pyeloplasty
  • Obstructing masses: consultation for surgical management (e.g., hysterectomy consult for an individual with large fibroid uterus Uterus The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The uterus has a thick wall made of smooth muscle (the myometrium) and an inner mucosal layer (the endometrium). The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Uterus, Cervix, and Fallopian Tubes: Anatomy causing obstruction)
  • Malignancy Malignancy Hemothorax: chemotherapy Chemotherapy Osteosarcoma and/or radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma to reduce tumor Tumor Inflammation bulk in some malignancies (e.g., lymphoma Lymphoma A general term for various neoplastic diseases of the lymphoid tissue. Imaging of the Mediastinum)

Relief of obstruction

The goal is to decrease the pressure in the collecting system.

• Indications:
  • Complete obstruction
  • Presence of infection
  • Evidence of compromised renal function
• Lower urinary tract Urinary tract The urinary tract is located in the abdomen and pelvis and consists of the kidneys, ureters, urinary bladder, and urethra. The structures permit the excretion of urine from the body. Urine flows from the kidneys through the ureters to the urinary bladder and out through the urethra. Urinary Tract: Anatomy obstruction:
  • Urethral catheterization
  • Suprapubic catheterization
• Upper urinary tract Urinary tract The urinary tract is located in the abdomen and pelvis and consists of the kidneys, ureters, urinary bladder, and urethra. The structures permit the excretion of urine from the body. Urine flows from the kidneys through the ureters to the urinary bladder and out through the urethra. Urinary Tract: Anatomy obstruction:
  • Placement of retrograde ureteric stents
  • Percutaneous nephrostomy: subsequent antegrade stenting can be done.

Prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas

• Chronic hydronephrosis causes ischemic injury, resulting in cortical and medullary atrophy Atrophy Decrease in the size of a cell, tissue, organ, or multiple organs, associated with a variety of pathological conditions such as abnormal cellular changes, ischemia, malnutrition, or hormonal changes. Cellular Adaptation, and permanent loss of renal function.
• Hydronephrosis is reversible if the obstruction is promptly relieved.

Differential Diagnosis

• Peripelvic cyst: cyst arising from renal hilus Hilus Lungs: Anatomy. A peripelvic cyst is contiguous to the renal pelvis Renal pelvis Kidneys: Anatomy and calyces; its exact etiology is not known. These cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change are thought to be congenital Congenital Chorioretinitis or to arise from lymphatic obstruction. Peripelvic cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change are asymptomatic, but they can distort the renal pelvis Renal pelvis Kidneys: Anatomy on imaging. Diagnosis is with imaging, usually contrast-enhanced CT. Management includes percutaneous drainage Percutaneous Drainage Echinococcus/Echinococcosis or marsupialization.
• Pyelonephritis Pyelonephritis Pyelonephritis is infection affecting the renal pelvis and the renal parenchyma. This condition arises mostly as a complication of bladder infection that ascends to the upper urinary tract. Pyelonephritis can be acute or chronic (which results from persistent or chronic infections). Typical acute symptoms are flank pain, fever, and nausea with vomiting. T Pyelonephritis and Perinephric Abscess: bacterial infection of the upper urinary tract Urinary tract The urinary tract is located in the abdomen and pelvis and consists of the kidneys, ureters, urinary bladder, and urethra. The structures permit the excretion of urine from the body. Urine flows from the kidneys through the ureters to the urinary bladder and out through the urethra. Urinary Tract: Anatomy resulting in kidney inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship may present with fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, flank pain Flank pain Pain emanating from below the ribs and above the ilium. Renal Cell Carcinoma, nausea Nausea An unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses. Antiemetics, vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia, and costovertebral angle tenderness. Diagnosis is based on history, physical examination findings, urinalysis Urinalysis Examination of urine by chemical, physical, or microscopic means. Routine urinalysis usually includes performing chemical screening tests, determining specific gravity, observing any unusual color or odor, screening for bacteriuria, and examining the sediment microscopically. Urinary Tract Infections (UTIs) in Children, and urine cultures. Other diagnostic workup includes CBC, imaging, and blood cultures. Pyelonephritis Pyelonephritis Pyelonephritis is infection affecting the renal pelvis and the renal parenchyma. This condition arises mostly as a complication of bladder infection that ascends to the upper urinary tract. Pyelonephritis can be acute or chronic (which results from persistent or chronic infections). Typical acute symptoms are flank pain, fever, and nausea with vomiting. T Pyelonephritis and Perinephric Abscess can be managed in the outpatient or inpatient setting depending on the presence of risk factors and the severity of the disease. Management includes the administration of analgesics, antibiotics, and antipyretics.
• Congenital Congenital Chorioretinitis megacalyces: rare, usually unilateral, condition caused by the underdevelopment of medullary pyramids resulting in the dilation of the calyces without obstruction. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with congenital Congenital Chorioretinitis megacalyces are asymptomatic, but they can present with a urinary tract Urinary tract The urinary tract is located in the abdomen and pelvis and consists of the kidneys, ureters, urinary bladder, and urethra. The structures permit the excretion of urine from the body. Urine flows from the kidneys through the ureters to the urinary bladder and out through the urethra. Urinary Tract: Anatomy infection due to stasis. Diagnosis is based on imaging with ultrasonography, IV pyelography, or CT scan with contrast. Stones and infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease are treated appropriately. Surgery is not required.