Kidney disease is the most common renal disorder. Kidney stones and urinary tract infections also impact many people. The genitourinary system includes the kidneys, urinary bladder, ureters, urethra, male and female reproductive organs, and specific structures within the kidneys. Blood flows through the kidney into the afferent arteriole and then the glomerulus, the main filter. It then enters the efferent arteriole, followed by the peritubular capillaries, where it is reabsorbed. Urine forms in the nephrons. The nephrons are composed of the glomerulus, the glomerular capsule, the proximal convoluted tubule, loop of Henle, and the distal convoluted tubule. In the glomerular capsule, filtrate from the blood—which contains salts, minerals, glucose, water, and metabolic wastes—passes through a membrane. Next, it passes through the rest of the nephron; after which it is converted into urine. This urine passes through the proximal convoluted tubule and loop of Henle to be further concentrated. In the distal convoluted tubule, the composition of urine is further refined based on the body’s needs. Two hormones, antidiuretic hormone and aldosterone, are involved in adjusting the urine composition. The juxtaglomerular apparatus in the kidneys can release renin, an enzyme that can cause reactions in the body such as an increase in blood pressure. Diuretics are chemicals that increase urinary output. As urine collects in the bladder, the micturition reflex causes it to contract, producing the urge to void. Urinary tract infections can move into the upper urinary tract when a bacterial infection in the lower urinary tract is not treated. The anatomy of the urethra is different in males and females. The female urethra is shorter and therefore more prone to urinary tract infection. Symptoms of urinary tract infection include painful urination, frequent urges to urinate, difficulty urinating, and possibly referred pain to the shoulder or neck. The urine may have a foul odor and be cloudy. Kidney stones result when an excess of insoluble salts or uric acid crystallizes in the urine. Symptoms include severe pain in the flank that may migrate forward to the groin. The pain may cause an increased blood pressure and pulse. Acute renal failure is a sudden decrease in filtration through the glomeruli, resulting in a release of toxins into the blood. The three types of acute renal failure are prerenal, intrarenal, and postrenal. Signs and symptoms range from hypotension, tachycardia, dizziness, and thirst, to pain, oliguria, distended bladder, hematuria, and peripheral edema. Chronic renal failure is progressive and irreversible inadequate kidney function. Nephrons become damaged, losing their functionality and causing a buildup of wastes and fluid in the blood. Symptoms include an altered level of consciousness, lethargy, nausea, headaches, cramps, anemia, bruised skin, edema in the extremities and face, hypotension, tachycardia, or possibly seizures or coma. A powdery buildup of uremic acid (uremic frost) may appear on the skin. Hyperkalemia may be noted on the ECG. Renal dialysis is a procedure for removing toxic wastes and excess fluids from the blood. Dialysis patients usually have a shunt through which they are connected to the dialysis machine. They are vulnerable to problems such as hypotension, a potassium imbalance, disequilibrium syndrome, or air embolism. Kidney trauma can cause flank pain and hematuria. Management is the same as for other types of abdominal trauma. Suspect a bladder injury in any patient who has trauma to the lower abdomen or pelvis. Symptoms include inability to urinate, blood at the urethral opening, and tenderness of the suprapubic region. Management follows basic trauma principles. Blunt trauma to the testicles can cause painful hematomas, testicular rupture, or testicular torsion. The scrotum may be tender and swollen. Lacerations or avulsions should be treated with gentle compression and ice packs. Blunt trauma to the penis can cause a large hematoma and pain. Management follows basic trauma principles. Vaginal trauma can cause hematomas and ecchymoses in the lower pelvic area and on the external female genitalia, bleeding from the vagina, and tenderness on palpation of the lower pelvis. Assessment of renal and urologic emergencies is the same as with other medical patients. It may be difficult to determine the source of pain, as it may be visceral (cramp, aching) or referred (in another area of the body). Focus on addressing life threats and providing supportive care. Note whether the patient seeks a particular position that reduces the pain. Determine where the pain began. Obtain a thorough history using the SAMPLE and OPQRST mnemonics. In the physical exam, use the four-quadrant system and abdominal region mapping. Perform cardiac monitoring, and do not give urologic patients anything by mouth. Consult with medical control to administer pain medication. Patients with a urinary tract infection or kidney stone should receive a bolus of IV fluid. Allow kidney stone patients to assume a position of comfort. For patients with acute or chronic renal failure, support the ABCs. It may be necessary to administer medications to regulate acidosis, electrolyte imbalances, and fluid volume. Provide psychological support and transport in a calm fashion.