Kidney Stones, Radiology of Renal Stones - Assignment Example

Radiology of Renal Stones John Doe Some UK Somewhere in the UK Introduction As one of the more common diseases that affects tens of thousands every years. Nephrolithiasis has the distinction of being both a primary and secondary cause of flank pain in patients. Renal calculi, as they are known, has been recognized in humans for millenia. (Wolf 2011) As a urological disorder, it is one of the most painful disorders patients experience. Therefore, it is not unusual to have patients on opioid derived medications due to the extreme discomforts they experience. Most commonly read books such as Harrisons Principles of Internal Medicine (2008)and Kumar and Clarks Clinical Medicine have extensive and useful information on the development, presentation, and treatment of renal stones and their many different types and will be referenced extensively here. Treatments for kidney stones ranges from surgical removal for patients with stones that are lodged in the urinary tubes and cannot be displaced by non-surgical interventions like lithotripsy to merely passing the stone without any medical interventions whatsoever. The following pages will cover a comprehensive analysis of a patient with nephrolithiasis and what is done diagnostically and medically to find, treat, and correct the problem using all available customary treatment protocols. Diagnostics and Imaging Most common presentations for nephrolithiasis are similar to the following: A caucasian male, aged 40 years, presents with what he describes as excruciating pain in his left flank. He has noted mild discoloration of his urine and notes that from time to time in the past few days he has had difficulty urinating and felt like something was backing up the urine into his kidney. He notes no prior infection or fever and his temperature at presentation is 98.3F (36.8C). He denies smoking, drinks only moderately (1-2 beers per week), and exercises 3-4 times per week. Patient states he is a health nut and regularly makes smoothies with lots of milk and yogurt. His family came from a poor area of the country and worked to develop a bakery chain in several cities. The above is statistically accurate as a profile for a patient presenting with renal colic due to possible stone disease. Most patients are male, between 35 – 45, and have come from socio-economically challenged families who increased their status and therefore adequate nutrition and access to a wider variety of foods leading to an increase in fatty content among other things. In many patients, a decrease in the amount of liquids increases the risk of developing nephrolithiasis. (Harrisons 2008) While men are at greater risk of developing renal stones, women are not immune and some recent research suggests that increased incidence of urinary tract infections accounts for the majority of cases of female stone formation and are strongly associated with with recurrent urinary tract infections. Imaging for UTIs is follows a general course, depending on the physician being presented to and how the patient is at the time of initial interview. Illustration 1 shows where the stone likely resides when presenting to the A&E or personal physician. In many cases, the flank pain is so difficult for the patient that immediate treatment with narcotics may be warranted. In most cases, the pain subsides as the stone moves around in the urinary system, so an abeyance of the pain is also very likely and probable. Initial diagnostics will be with a standard X-ray or CT scan. Illustrations 2 and 3 show how a stone is found or seen on XR or CT, but if not found it does not mean the stone is not present only that it is radioopaque and cannot be seen by this conventional method. CT scans and MRI have been found to be equally effective in finding stone formations which are detectable beyond the micro-stone level, (Smelka et al 2007, 900) Further, the types of stones and their formation are largely governed by independent processes. Calcification in the kidney, if found in the renal pelvis and not the renal ureters can be virtually undetectable since it causes little to no discomfort in the patient.(Wolf 2011) Hence, the average everyday activities are unaffected and the patient never reports the trouble since there isnt any. However, stones like this can be found incidentally if a patient has an abdominal CT in which the scan covers the area where the two kidneys lie. In CT scans, the artifact is seen due to density differences in the scan and its ability to detect bone, bone-like structures, density variations like air in bowel and many other important findings. In the illustration to the left, we find that the likely diagnosis, without supporting evidence is likely to be calcium oxalate. Based simply on odds, Kumar (2007) states that 75-85% of all patients stones will be of that type. As seen left, they are radiolucent and easily seen and identified. Radiological examination and reading can identify the level and location of the stone without invasive surgical investigation. From this point, Lithotripsy can be ordered and performed either at a later scheduled date or immediately if the facility warrants and has the availability. The main objection, or considerations to be given in choosing CT scan are those of radiation exposure with CT scans. While it is true that CT scans do emit radiological artifacts to their patients, the net benefit is far beyond the risk and most physicians world-wide opt for this device when investigating flank pain with mild to moderate hematuria. (Harrison 2008) Traditional XR technology also emits radiation when looking at target areas, but is considered safe enough for general diagnostic uses compared to surgical intervention. In contrast to the other aforementioned diagnostic procedures, ultrasound alone emits no radiation and is well documented to be accurate in finding and locating renal stones. Illustration 3 shows the stone found in the middle of the graphic . A sonogram uses the difference in tissue density to find and identify areas of inflammation, possible cancer formations, calcifications which can be seen as white due to their increased density, and many other uses. In several studies, sonography was adequate for detection among stones not in the distal portion of the ureters and was the preferred choice for pregnant patients where CT and MRI were hazardous to the unborne child.(Middleton 1988, 239) Most patients, if they present at an A&E care facility will have one of those diagnostic procedures ordered for them. Secondary lab results can be given to determine urine sedimentation, possible passage of stones concurrent to flank pain and labs to determine possible evidence of other causes of renal stones if the imaging shows the stone to be radio-opaque. A wide range of diagnostic capabilities could be performed to determine the location and type of stone within hours of initial presentation. Stone Types Stones consist of several types, the following table (Table 1-1) will assist in showing the variability and likely causes of the disease in the UK. Type of renal stone Approximate frequency (%) Calcium oxalate usually with calcium phosphate 65 Calcium phosphate alone 15 Magnesium ammonium phosphate (struvite) 10-15 Uric acid 3-5 Cystine 1-2 Causes of the stones are found to be from: (Lange 2007) 1. increased calcium intake 2. decreased excretion of calcium in endocrine pathologies 3. decreased fluid intake 4. high protein intake with concomitant metabolic acidosis and increased GFR 5. high sodium diet with higher than normal dietary Ca++ excretion predisposing to stone formations 6. metabolic variances in patients not accounted for due to biochemical variability in humans Secondary causes of stone formations usually are caused from imbalances in the calcium chemistry in the blood. Lange (2010) lists the secondary causes of stones from the following: Hyperparathyroidism (potential tumor) Increased gut absorption of calcium Hyperuricosuria Hyperoxaluria Hypocitraturia Hypomagnesuria All of these secondary causes are treatable either with currently available medications or surgery, however identification of these causes is rather extensive and can take weeks if not months depending on access to a physician or treatment specialists whose availability may be difficult to access acutely. Medical Management of Renal Stones Renal stone disease treatment protocols can range from urgent and emergent to routine. IN cases of severe dehydration in which the stones are the result of the current metabolic condition, immediate rehydration is of course necessary.(Harrisons 2008) However, the stone treatment must also focus on infection possibility, scarring of the ureters and kidneys, potential for renal failure, and identification of a patient with one possible functional kidney. (Lange 2007) In causes of stone disease caused via infections, the treatment is to treat the cause of the infection first and not the stone disease itself first. (Wolf 2011) At the very least, the treatments should run coincidental to each other and not run the risk of a furtherance of the disease in either case. In infected hydronephrosis, immediate hospitalization is required to treat and maintain adequate renal function. Preservation of the kidney is the important goal along with elimination of the bacterial species that are causing the infection. Most kidney infections are not emergent and can be treated with out patient services, however, in patients with a stone diagnosed via one of the aforementioned technologies, the stone can cause more trouble and even, if large enough, cause renal failure due to its size and obstructive behaviors.(Kumar 2007) Antibiotics should be used that cover the most common infectious agents such as Escherichia coli and Staphylococcus, Enterobacter, Proteus, and Klebsiella species. (St Lezin, 1992, 360) Lithotripsy is a common non-surgical means of treating renal stones found both within the renal organ itself, or to those found in the ureters and bladder. By sending shock waves into the renal tissues focused by a beam of sound both horizontally and vertically into predetermined zones or poles of the kidney, the stone is broken up into smaller passable fragments which can pass into the bladder and then later thru the urethra and out of the body. (Wolf 2011) When stones are too large to break up via non-surgical techniques, then obviously surgical interventions are required. Common removal via surgery can entail many variable types however. One such type is the percutaneous nephrolithotomy or nephrolithiasis. In this procedure, a routine incision is made on the dorsal aspect of the patient and the kidney is incised to insert a tube into the kidney. If a nephrolithiasis is chosen due to the excessively large size of the stone, the appropriate shock waves are forced thru the tube to the stone which is then removed through the tube. While it is more invasive and recovery times for the patient range from 5 days to 3 weeks depending on the extent of the treatment, stone size, and many other factors stone free rates of approximately 99% are achieved. (Wen 2007, 409) Conclusions It is with great advances in science that we find ourselves in such a place as to treat acute flank pain, which in many cases can be excruciating with simple, yet effective non-invasive procedures second only to our abilities to diagnose them without removing the stone themselves for confirmation. The MRI and CT scan have greatly aided clinical diagnostics and enabled us to look at the precise location of such a small thing, yet something that can cause such pain in patients until they are removed. The addition of the CT and MRI along with Ultrasound and the Xray are great clinical enhancements to the clinical staffs ability to move a patient from a disease state to one of returning health. Resources Used Belitsky, Philip. "WebMD." April 11, 2011.http://www.webmd.com/kidney-stones/percutaneous-nephrolithotomy-or-nephrolithotripsy-for-kidney-stones (accessed August 13, 2011). Cooper JT, Stack GM, Cooper TP. 2000. “Intensive medical management of ureteral calculi.” Urology. 56 no.4, :575-8 Kasper DL, Braunwald E, Fauci AS, Hauser SL, Longo DL, Jameson JL, Loscalzo J. 2008. Harrisons principles of internal medicine (17th ed.). New York: McGraw-Hill Medical Publishing Division McPhee,Steven J.2010. Pathophysiology of Disease: An Introduction to Clinical Medicine. 6 ed. Lange Medical Series. Gary D Hammer. New York City: Lange Medical, Middleton WD, Dodds WJ, Lawson TL, Foley WD. 1988.Renal calculi: sensitivity for detection with US. Radiology. 167 no.1 : 239-44. Sakhaee K. 2008.“Nephrolithiasis as a systemic disorder.” Curr Opin Nephrol Hypertens. ; 17(3):304-309 Smelka, R C et al. 2007." Imaging strategies to reduce the risk of radiation in CT studies, including selective substitution with MRI.." Journal of Magnetic Resonance Imaging 25, no. 1 : 900-909. St Lezin M, Hofmann R, Stoller ML. 1992 .Pyonephrosis: diagnosis and treatment. British Journal of Urology. Oct; 70(4): 360-3 Thomas, Ben. Tolley, David; 2008."Concurrent urinary tract infection and stone disease: pathogenesis, diagnosis and management ." Nature Reviews Urology 5, no.1 : 668-675. Wen CC, Nakada SY. 2007.“Treatment selection and outcomes: renal calculi.” Urological Clinician of North America. 34 no. 3 :409-19 Wolf Jr, J Stuart. "Nephrolithiasis." 2011.http://emedicine.medscape.com/article/437096-overview (accessed August 13, 2011). Read More