L7 MRD515 Urinary System PDF

URINARY SYSTEM MRD515  LEARNING OBJECTIVES Describe the anatomic components of the urinary system and their functions. Describe Discuss the role of other modalities in imaging the urinary system, particularly sonography and computed Discuss tomography....

URINARY SYSTEM MRD515  LEARNING OBJECTIVES Describe the anatomic components of the urinary system and their functions. Describe Discuss the role of other modalities in imaging the urinary system, particularly sonography and computed Discuss tomography. Discuss common congenital anomalies of the urinary system. Discuss Characterize a given condition as inflammatory or neoplastic. Characterize Identify the pathogenesis of the pathologies cited and the typical treatments for them. Identify Describe, in general, the radiographic appearance of each of the given pathologies. Describe  ANATOMY AND PHYSIOLOGY The urinary system consists of two kidneys, two ureters, a urinary bladder, and a urethra. The kidneys are responsible for the formation and excretion of urine. Urine is produced through processes of filtration and reabsorption, involving the filtration of up to 180 liters of blood per day. On average, about 1 to 1.5 liters of urine are produced daily.  The kidneys are retroperitoneal, located between Kidney Anatomy the twelfth thoracic vertebra and the third lumbar vertebra. The hilus is the notch on the medial surface of each kidney, where structures like the renal artery, vein, lymphatics, and nerves enter and exit. The functional unit of the kidney is the nephron, composed of the glomerulus, Bowman's capsule, and various convoluted tubules. Blood is filtered in the glomerulus and then flows through the nephron, resulting in urine production. Urine exits the nephron through a collecting tubule and eventually drains into the renal pelvis. Ureters The ureters are approximately 10 inches in length and extend from the kidneys to the urinary bladder. They enter the bladder obliquely in the posterolateral portion. The primary function of the ureters is to transport urine from the kidneys to the bladder. Urinary Bladder The bladder is located posterior to the symphysis pubis and serves as a reservoir for urine. It is muscular and capable of distension. Valves at the junction of the ureters and bladder prevent the backflow of urine.  Urethra The urethra is a tube that connects the urinary bladder to the exterior of the body. In females, it is shorter (approximately 1 to 1.5 inches), while in males, it is longer (approximately 8 inches). In males, the urethra passes through the prostate gland and also plays a role in the reproductive system. The male urethra is classified into three portions: prostatic, membranous, and cavernous. Urination occurs through the urinary meatus, which is the external opening of the urethra. Clinical Findings and Symptoms: IMAGING a) Urinary disorders can be suggested by abnormal CONSIDERATIONS laboratory results and clinical symptoms, including frequent urination, polyuria (excessive urination), oliguria (low urine output), dysuria (painful urination), and obstructive symptoms. b) Abnormal urine color can also be indicative of certain conditions. Kidney and Bladder Pain: a) Kidney pain is typically located in the flank or back around the level of the twelfth thoracic vertebra. b) Bladder pain, often resulting from cystitis, is usually limited to the urinary bladder. Laboratory Tests Various laboratory tests are conducted to assess renal function and diagnose urinary disorders. These tests include serum creatinine, blood urea nitrogen (BUN), and glomerular filtration rate (GFR). Elevated levels of creatinine and BUN may indicate kidney function impairment. Normally, the GFR should be 90 milliliters per minute per 1.73 meters cubed (mL/min/1.73 m2) or greater. Intravenous contrast agents should not be used in patients with a BUN greater than 50 milligrams per deci- liter (mg/dL) or a serum creatinine greater than 3 mg/dL.  KUB Radiography Kidney, ureter, bladder (KUB) radiography is used to visualize the size and location of the kidneys. Kidneys may be visible radiographically because of the perirenal fat capsule that surrounds them. It is a preliminary step for intravenous urography (IVU), which helps assess bowel preparation and visualize radiopaque calculi. Intravenous Urography (IVU) IVU is a diagnostic procedure used to assess the urinary system. It involves injecting contrast agents and obtaining a series of X-ray images to evaluate the renal pelvis, calyces, ureters, and bladder for abnormalities urinary tract obstructions, tumors, or calculi. This exam has been largely replaced by CT urography. Cystography Cystography is used to study the lower urinary tract. It involves retrograde filling of the bladder with contrast material and is commonly used to identify vesicoureteral reflux (VUR) and other bladder-related issues.  Sonography Sonography (ultrasound) is a noninvasive method for imaging the kidneys and evaluating various renal disorders, including kidney stones, hydronephrosis, renal masses, and renal cysts. Computed Tomography (CT) CT is valuable for imaging the kidneys, especially in detecting renal masses, renal calculi, obstruction, renal infection, and staging tumors. It is often used with contrast agents to enhance visualization. Renal Angiography Renal angiography is an invasive procedure used to assess vascular disorders in the kidneys, such as renal artery stenosis, aneurysms, or congenital anomalies. Magnetic Resonance Imaging (MRI) MRI, with or without contrast agents, is used for renal evaluation, including renal masses, vascular anomalies, and bladder tumors. It provides high-quality soft tissue imaging. Interventional Procedures These techniques are used for treating kidney stones, renal masses, and other renal conditions. Several minimally invasive procedures, including i. percutaneous nephrostography - A procedure to visualize the renal pelvis and urinary system by injecting contrast material through the skin  Interventional Procedures ii. extracorporeal shock wave lithotripsy (SWL) - A treatment that uses shock waves to break kidney stones into small pieces. iii. percutaneous radiofrequency ablation - A procedure that heats and removes kidney tumors using electrical currents. iv. percutaneous cryoablation - A treatment that freezes and eliminates kidney tumors or abnormal tissue. Urinary Tubes and Catheters Different types of tubes and catheters are used to manage urinary disorders, including nephrostomy tubes (connects the kidney pelvis to the outside of the body) ureteral stents (one end in the kidney pelvis and the other in the bladder) Foley catheters (inserted into the bladder through the urethra) suprapubic catheters (surgically inserted through the abdominal wall directly into the bladder, urine drain from bladder). Proper placement and care are crucial to prevent complications. CONGENITAL AND HEREDITARY DISEASES The urinary system can have various anomalies caused by developmental errors. These anomalies fall into different categories: 1. Number and Size Anomalies of the Kidney 2. Fusion Anomalies of the Kidney 3. Position Anomalies of the Kidney 4. Renal Pelvis and Ureter Anomalies  Number and Size Anomalies of the Kidney Renal Agenesis or Aplasia: This rare condition results in the absence of one kidney (unilateral) and an unusually large kidney on the other side, known as compensatory hypertrophy. Supernumerary Kidney: Involves the presence of a third, small kidney without attachment to a normal kidney. It can lead to symptoms, often due to infection. Hypoplasia: Occurs when a kidney develops smaller than normal but contains normal nephrons. It is usually associated with an overdeveloped kidney on the other side. Hyperplasia: Involves the overdevelopment of a kidney and is often associated with renal agenesis or hypoplasia in the other kidney.  Horseshoe Kidney: The lower poles of the kidneys are joined across the midline by a band of tissue, Fusion Anomalies causing rotation anomalies. Kidney function is generally not affected, but it may require surgery of the Kidney if there's ureteral obstruction. Crossed Ectopy: One kidney lies across the midline and is fused with the other. Both kidneys may show various anomalies in position, shape, and rotation.  Position Anomalies of the Kidney Malrotation: Involves incomplete or excessive rotation of the kidneys as they ascend from the pelvis during development. It's generally not clinically significant unless it causes obstruction. Ectopic Kidney: Refers to a kidney that is out of its normal position, often lower than usual. It may be asymptomatic but can lead to issues like ureteropelvic junction obstruction (UPJ) or vesicoureteral reflux (VUR). Nephroptosis: Kidney prolapse, where the kidney drops toward the pelvis when a person is upright. It may require intervention in severe cases. Renal Pelvis and Ureter Anomalies Double Renal Pelvis: May occur alone or with a double ureter and can impair renal drainage, increasing the risk of infection and kidney stones. Ureterocele: A cyst-like dilation of the ureter near its opening into the bladder. It can cause obstruction and require surgical intervention. Ureteral Diverticula: Dilated ureteric remnants that may cause issues and are typically diagnosed through imaging. Urethral Valves: Mucosal folds protruding into the posterior urethra, causing urinary flow obstruction, typically in males. They are usually diagnosed during infancy and require early surgical correction to prevent renal damage.  PKD is a genetic disorder that leads to the formation of numerous cysts in the Polycystic Kidney kidneys. It can be autosomal recessive or Disease (PKD) autosomal dominant. Autosomal recessive PKD typically affects children and can lead to childhood renal failure. Autosomal dominant PKD is usually asymptomatic in childhood but can result in end-stage renal disease in adults. It is diagnosed through imaging techniques like ultrasound and CT scans and may require various treatments. Medullary Sponge Kidney: Involves congenital dilatation of renal tubules, leading to urinary stasis (retention) and an increased risk of calcium phosphate deposits (nephrocalcinosis). It may cause kidney stones and infections, and treatment involves managing these complications. INFLAMMATORY DISEASES  Common bacterial infections that can affect people of all ages and genders. More common in infants due to birth defects Urinary Tract and become more frequent in girls around the age of 10. Infection (UTI) Women are more prone to UTIs than men. The main cause of UTIs is gram-negative bacteria, which usually enter the urinary system through the urethra and can reach the bladder and kidneys. More common in sexually active women, especially those using specific birth control methods. Procedures like cystoscopy or catheter placement increase the risk of UTIs. Typically, antibiotics are used to treat UTIs. Pyelonephritis Kidney infection that affects the renal pelvis and calyces. Any blockage or slow urine flow in the urinary tract can increase the risk of kidney infection. Usually caused by E. coli, Proteus, or Pseudomonas bacteria. This condition is more frequent in women, especially during pregnancy and after using a urinary catheter. Common symptoms include fever, flank pain, and feeling unwell, and urinalysis shows the presence of pus in the urine. Treatment typically includes antibiotics. Chronic Recurrent or persistent kidney infection, often caused by chronic reflux of infected urine from the bladder into Pyelonephritis the renal pelvis. This condition is associated with anatomical abnormalities, such as ureteral duplication or urinary tract obstruction, and can result in kidney scarring, atrophy, and a reduction in kidney size. It may also lead to hypertension. Treatment focuses on controlling hypertension, removing obstruction causes, and using antibiotics.  Acute Glomerulonephritis Inflammatory condition of the renal parenchyma caused by an antigen-antibody reaction within the glomeruli. It is often a result of streptococcal infections in the upper respiratory tract or middle ear. This condition mainly affects children and usually leads to complete recovery. Radiographically, the kidneys may appear larger due to edematous accumulation. Treatment includes diuretics, anti-inflammatory medications, steroid therapy, and, in severe cases, renal dialysis.  Cystitis Acute or chronic inflammation of the bladder, commonly caused by bacterial infections like E. coli. More common in women due to their shorter urethra, which allows easier bacterial access to the bladder. Symptoms include pain during urination and frequent urination. Severe cases of cystitis can lead to upper urinary tract infections, such as pyelonephritis. Radiographically, vesicoureteral reflux (VUR), the backward flow of urine into the ureters, may be observed, often due to structural abnormalities or neurogenic bladder dysfunction (roughening of bladder wall/bladder trabeculae) Treatment involves antibiotics and fluid intake to prevent complications. URINARY SYSTEM CALCIFICATIONS Urinary calculi, or stones, are common and form mainly from calcium and salts in urine when the body's balance is disrupted. They can result from factors like metabolic disorders, high calcium intake, or concentrated urine due to metabolic rates. Men, especially after 30, are more prone to these calcified stones. While most calculi show up on X-rays and other imaging, some are made of pure uric acid, making diagnosis trickier. They usually form in the kidneys and can lead to pain (colic) and blockages. Treatment options include lithotripsy, surgery, and removal via catheters or lasers. Prophylactic measures are advised to prevent recurrence.  Bladder wall calcification is rare and can result from calcium deposition in tumors outside the bladder. Prostatic calcifications are small calcium spots below the bladder and typically don't indicate prostate issues. Distinguishing urinary tract calcifications from other types of calcifications (e.g., gallstones, vascular calcifications) requires precise imaging techniques and location analysis. To confirm that calcifications are in the kidneys, they should stay within the kidney outline on both frontal and oblique images. For gallstones, oblique abdominal images can reveal if the calculus in question is anterior to the kidney. DEGENERATIVE DISEASES Nephrosclerosis This condition involves the thickening of small kidney blood vessels, occurring with aging, hypertension, and diabetes (hardening of kidney) It leads to kidney atrophy and may cause infarction, resulting in a smaller kidney size. Management includes treating hypertension, diuretic use, and dietary restrictions. Renal Failure Often the result of chronic conditions like glomerulonephritis or PKD, renal failure leads to impaired kidney function. Uremia, characterized by elevated urea levels due to inadequate excretion, is common. Imaging helps locate causes, and treatment may involve dialysis or transplantation. Hydronephrosis This obstructive condition causes kidney pelvis and calyces dilation due to factors like kidney stones, tumors, or inflammation. Early relief of the obstruction can reverse changes. Imaging techniques like sonography and CT help diagnose and evaluate the degree of obstruction. NEOPLASTIC DISEASES Masses can create filling defects in the urinary tract, visible when they displace or stretch the collecting system. Almost all solitary masses are either malignant tumors or simple cysts. Profuse hematuria from a blood clot can also cause a filling defect, but differentiating between blood clots and tumors can be challenging. Renal Cysts Renal cysts are common in adults, usually asymptomatic but can cause issues like rupture, hemorrhage, infection, or obstruction. They can be detected using imaging techniques like CT, MRI, and sonography. Cysts have well-defined margins and do not show a nephrogram phase after contrast injection, distinguishing them from tumors. Renal Cell Carcinoma (RCC) RCC is the most common malignant kidney tumor, primarily affecting men over 50. Its cause is uncertain, but factors like chronic inflammation, smoking, obesity, and hypertension may contribute. Symptoms include hematuria, flank pain, fever, or a palpable mass. Imaging, especially CT, helps assess tumor density, metastasis, and vascular involvement. Early detection and surgical removal offer a significant cure rate, with alternatives like ablation therapies and immunotherapy. Nephroblastoma (Wilms Tumor) This malignant childhood renal tumor usually presents before age 5, often discovered as a large abdominal mass. It is associated with the deletion or inactivation of the WT1 or WTX (X chromosome) tumor suppressor gene and may be inherited or sporadic in origin. Imaging, including CT and sonography, helps assess its extent and spread. Staging is crucial for determining treatment, with a high cure rate for early-stage disease. Bladder Carcinoma More common in men, bladder carcinoma is linked to smoking and industrial chemicals. Hematuria is the primary symptom. Diagnosis is confirmed through cystoscopy and biopsy. Imaging techniques like CT, sonography, and MRI assist in staging. Treatment varies based on tumor invasiveness, with options including transurethral resection, cystectomy, chemotherapy, radiation therapy, and immunotherapy. Distant metastases usually occur late in the disease. THANK YOU Pathology Imaging Modalities of Choice Additive or Subtractive Pathology Congenital anomalies Sonography in the fetus Subtractive Lower urinary tract Cystography and sonography Additive, if reflux is present anomalies Sonography, CT with and without contrast, Polycystic kidney disease Additive MRI with and without contrast Medullary sponge kidney Sonography Additive IVU, CT with and without contrast, Pyelonephritis Additive sonography Abdominal and pelvic CT without contrast, Cystitis Additive cystography and sonography Nephrosclerosis Angiography and sonography Subtractive Nephrocalcinosis Sonography, CT, and KUB Subtractive Renal failure Sonography, CT, and angiography Subtractive Calcifications CT, sonography, KUB Additive Hydronephrosis Sonography, CT, and IVU Additive Sonography, CT with and without contrast, Renal cyst Additive MRI with and without contrast Renal cell carcinoma CT, MRI, and chest radiography Additive Nephroblastoma Sonography Additive Bladder carcinoma Sonography Additive