A simple calyx receives urine from a single papilla; a compound calyx receives urine from multiple papillae (Fig. On the other hand, kidneys do have relations with peritoneum, or precisely with the specific organs that are covered with peritoneum which are placed directly adjacent to the kidneys. Most serum creatinine is excreted in the urine; therefore, if renal function is compromised, levels of creatinine in the serum increase. Differential diagnosis General imaging considerations include: renal cortical defect duplex kidney 18-11). The vascularity of some tumors may be most apparent during this phase (Fig. Many clinical laboratories now provide computer-generated calculations of estimated creatinine clearance or eGFR using patient data in the medical information system. Illustration demonstrating the relation between the renal papilla and calyx. Aggressive tumors form, grow and spread very quickly. Ultrasound permits real-time optimization of imaging relative to the axis of each kidney. Both renal arteries, left and right, arise just below the superior mesenteric artery, with the left renal artery positioned slightly superiorly to the right one. Ultrasound can often identify the cause in cases of bilateral obstruction (, Pelvic mass (cervical, rectal, uterine, prostate cancer). Fever. On the superior aspect of each kidney is the adrenal gland. Dialysis. The medial border of the kidney contains a very important landmark called the hilum of the kidney, which is the entry and exit point for the kidney vessels and ureter. Note that the left renal vein receives blood from the left suprarenal and left testicular veins. Blood in the urine, or dark urine. The parenchyma of the kidney consists of the outer renal cortex, and inner renal medulla. Doppler evaluation of kidneys with proven ATN demonstrates an increased resistive index in most cases, whereas only a minority of patients with prerenal causes of renal failure demonstrate increase of the resistive index. The information we provide is grounded on academic literature and peer-reviewed research. The left kidney measured 7.8 cm, and the right kidney measured 10.9 cm. The minor calyces unite to form a major calyx. urinary system quizzes and labeled diagrams. 18-24). Alternatively, the anterior to posterior orientation follows the same pattern: renal vein, renal artery and ureter. The normal appearance of the calyx is created by the impression of the renal papilla. The genital system consists of the testes, epididymides, deferent ducts, seminal vesicles, ejaculatory ducts, the prostate, and the penis in males; and the ovaries, uterine tubes, uterus, and vagina in females. Fetal lobulation is best differentiated from renal scars during the corticomedullary phase of enhancement on computed tomography (CT) or magnetic resonance imaging (MRI) because cortex can be followed into the indentation that occurs between calyces (Fig. The main symptom is severe sharp pain that starts suddenly, usually in your belly or one side of your back, and it may go away just as quickly. The glomerular membrane is designed in a way in which it is not permeable for big and important molecules in blood, such as plasma proteins, but it is permeable to the smaller substances such as sodium, potassium, amino acids and many others. Because of this, the tubules are designed in a way that they reabsorb the necessary substances, (sodium, potassium, and amino acids as mentioned before) and carries them back to the blood; whereas they do not absorb but rather secrete unnecessary substances such as creatinine and drug metabolites for excretion from the body. The renal corpuscle has two components: the glomerular (Bowmans) capsule in which sits the glomerulus. The early excretory phase begins as early as 120 seconds after injection. The adrenal cortex directly influences renal function through the production of the hormone aldosterone to stimulate sodium reabsorption. 18-4). The medulla is the inner region of the parenchyma of the kidney. The left artery has a short way to the left kidney, whereas the right has to go behind the inferior vena cava in order to reach the right kidney. The interpolar region is the middle of the kidney. It is notable that the kidney has a very rich blood supply. Occasionally, a papilla will communicate directly with an infundibulum or the renal pelvis and is considered to be an aberrant papilla. The most common cause is renal artery stenosis (see Fig. One of the most commonly used (and least complicated) equations is shown in Box 18-1. This illustrates the amount of reserve function that must be compromised before renal injury can be detected with a serum creatinine level. In this case, the right kidney had more favorable anatomy for laparoscopic donor nephrectomy. Some forms of congenital UPJ obstruction are now treated with transureteroscopic endopyelotomy in which an incision is made from within the ureter using a ureteroscope. Let's see what is nephron and how it is structured,so you can remember it for good. "Angio" indicates blood vessels, "myo" indicates muscle, and "lipoma" indicates fat. Crossed ectopia on intravenous pyelogram. In cases of unilateral obstruction with acute renal failure, sonographic evaluation may show evidence of chronic renal parenchymal disease in the unobstructed kidney. Note distance from origin to the first arterial division (Fig. Table 18-7 lists causes of unilateral smooth renal atrophy. Thus, an AML is a tumor that contains these 3 components. As the lobules of metanephric blastema coalesce to form each kidney, they do not always result in a smooth, uniform band of cortex. Of course, if the situation is the other way around (less than 5 liters of blood), blood pressure is too low (hypotension). Axial images of the left kidney from a three-phase renal computed tomographic scan demonstrate improved conspicuity of low-attenuation lesions of the renal medulla during the nephrographic phase. . Bilateral echogenic kidneys with renal hypertrophy can be seen associated with human immunodeficiency virus disease (see. Unenhanced CT can identify hydronephrosis and hydroureter, urinary stones, and some masses. impression is preserved. Best, Susan. Perhaps of even greater importance, serum creatinine is not a sensitive test for minor insults to the kidney in otherwise healthy individuals. Despite the complexity of renal physiology, many attempt to assess renal function with a simple quantitative measure, the serum creatinine. Also, in situations with notable blood losses, kidneys release a hormone called erythropoietin, which stimulates bone marrow to produce more blood cells. Several small stones are visible in the left kidney, and the left kidney is somewhat atrophied from chronic obstruction. Kidney cysts can occur with disorders that may impair kidney function. 18-12). Because production of creatinine is affected by sex, age, muscle mass, protein intake, and liver function, the serum creatinine can be an inaccurate predictor of renal function, particularly in those at the extremes of age and body weight. more lateral and anterior than the superior poles. Recent advances in MDCT and MRI permit cross-sectional vascular studies to replace conventional angiography before UPJ repair (Fig. The glomerulus is actually a web of arterioles and capillaries, with a special filter which filters the blood that runs through the capillaries, the glomerular membrane. Figure 18-20 Axial image from unenhanced computed tomography of the kidneys performed 2 days after an angiographic procedure demonstrates stasis of contrast in the renal cortex, resulting in a persistent corticomedullary phase of enhancement. Chronic obstruction, however, results in damage to the papilla, evident in the clubbed calyx of papillary necrosis (Fig. The upper pelvis is the most common ectopic location for the kidney; most cases are also associated with abnormalities of rotation. Extraaortic origin of the renal arteries and accessory renal arteries are common. CT and MR findings of renal artery stenosis parallel classic findings described on intravenous pyelogram, including one atrophic kidney with delayed nephrogram and excretion that can progress to a persistent nephrogram with hyperconcentrated excreted contrast media (Fig. Luckily, the kidneys also feel this increase of pressure, and in cases when this happens, they increase the filtration rate of blood and production of urine, which subsequently leads to the increase fluid excretion and decrease of blood pressure. The kidney also has endocrine functions, helping to control blood pressure, bone mineralization, and erythrocyte production. When. BOX 18-2 Crossing Vessels in Ureteropelvic Junction Obstruction. The region where the renal pelvis joins the ureter is called the, If the renal pelvis is entirely within the confines of the renal sinus, it is considered intrarenal. Anterior components of circumaortic vein can be small. Ultrasound to get images of your kidneys. When fused, the condition is described as crossed fused ectopia. 18-24). Pancake kidney describes a more severe fusion anomaly with a single, flat kidney positioned low in the pelvis with an anterior collecting system drained by either one or two ureters. Normal parenchymal enhancement on CT or MRI allows definitive characterization. Because an extrarenal pelvis is not confined by the renal parenchyma, there is a tendency for it to expand. Figure 18-26 Ultrasound performed for acute renal failure demonstrates bilateral hydronephrosis caused by a bladder tumor. When echogenicity of the renal cortex equals that of the liver, renal function is abnormal in approximately 38% of cases. The kidneys are innervated by the renal plexus. Size disparity greater than 1.5 cm between kidneys should raise suspicion that one kidney is abnormal. The superior poles (extremities) (T12) of both kidneys are more medially pointed towards the spine than the inferior poles (extremities) (L3). Renal artery In some cases, two separate kidneys drain into a bifid renal pelvis, ultimately drained by a common ureter. BOX 18-1 Cockroft and Gault Equation for Calculating Estimated Creatinine Clearance. This refers to the forming of the stones within the system of calyces because of too much calcium or uric acid into the filtrate. The muscular relations of the inferior half are easy to remember by dividing the kidney surface into three vertical stripes, where the medial stripe represents the impression of the psoas major muscle, the central stripe the quadratus lumborum, and the lateral stripe the transversus abdominis muscle. Unlike the excretory phase of enhanced CT, signal intensity within the renal collecting systems is reduced on T1- and T2-weighted MR images once excreted gadolinium-based contrast media becomes sufficiently concentrated. Eliminating toxic metabolites through urine, regulation of blood homeostasis and blood pressure, production of some hormones, Positioned retroperitoneally, consists of the cortex and medulla, empties urine into the ureter (which carries urine to the urinary bladder), Renal artery (branch of the abdominal aorta), Renal vein (drains to the inferior vena cava), Third kidney, horseshoe kidney, kidney agenesis, kidney stones, acute kidney failure, Regulates the amount of fluid in the body by increasing or decreasing the urine production, Maintain the pH of blood at 7.4 by decreasing or increasing the excretion of hydrogen ions, Medial part of the lower half of superior pole, Lateral part of the lower half of superior pole, Lateral part of inferior half of anterior surface, Medial part of inferior half of anterior surface, The perinephric fat (perirenal fat capsule). Separate kidneys drain into a bifid renal pelvis, ultimately drained by a bladder tumor cm between kidneys raise. 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