Friday, March 22, 2013

Flank pain: case presentation and MCQ

History:
Flank pain


Images:




Question:
1- Which choice best fits the findings involving the L kidney?
 

A
    Renal cell carcinoma. 
B
    Renal lymphoma. 
C
    Urinoma. 
D
    Hematoma. 
E
    Abscess. 







?
2- Here is an ultrasound image obtained the day before the CT. Which choice most likely describes the history?
A
Tuberous sclerosis.
B
Gunshot wound.
C
Acute urinary obstruction.
D
Encounter with nephrologist.
E
Renal vein thrombosis.

For the question: "Here is an ultrasound image obtained the day before the CT. Which choice most likely describes the history?" 





Here is some ultrasound images obtained AFTER the CT







http://education.auntminnie.com/QuestionMark.GIF
3- Please respond to the following with TRUE or FALSE.
T or F
There is evidence for an AV fistula.
T or F
There are elevated velocities of the arcuate arteries.




































Answers
1- D: Hematoma (Large perinephric hematoma)
2- D: Encounter with nephrologist (Correct. The patient has a complex history and presented with renal failure. Patient underwent left renal core biopsy under ultrasound guidance (needle visible on the image), and the next day began experiencing left sided flank pain. (Nice job! You gave the correct answer on the first try.) 
3- For the T/F Question: "There is evidence for an AV fistula." 
For the T/F Question: "There are elevated velocities of the arcuate arteries." 

Findings:
Initial image demonstrates core biopsy needle sampling the left kidney.
CT without contrast demonstrates heterogeneously hyper dense material effacing the left kidney and left perirenal space. Other findings unrelated to kidney:  Changes of diffuse mesenteric edema.  Postsurgical changes consistent with the prior multivisceral transplant are seen, with some altered enteric anatomy.  Small bowel wall thickening.


Ultrasound demonstrates heterogeneous echo texture of the left renal fossa.  Doppler ultrasonography demonstrates an arcing, anomalous renal arterial to renal venous connection within the left kidney.  There are elevated velocities of the arcuate arteries in the mid left kidney.  There is a mildly elevated resistive index of the main renal artery, measuring 0.81.


Diagnosis:  Left renal biopsy complicated by perinephric hematoma and AV fistula



Key points:
  • Percutaneous organ biopsy has a relatively low rate of major complications. In the radiology literature, the rate of major hemorrhage associated with kidney biopsy has been reported to be as low as 0.7% (1).
  • Renal arteriovenous (AV) malformations can be congenital or acquired; the acquired variety are typically referred to as AV fistulas (AVF). The most common cause of AVF is iatrogenic (>15% of renal biopsies), followed by trauma. Patients with pre-existing hypertension are thought to be at greater risk for AVF following biopsy.
  • Commonly a patient will present with hematuria or renal colic. On physical exam, a bruit may be auscultated. The fistulas will often close spontaneously, and thus conservative treatment is standard. Larger AVF can induce hypertension and/or CHF, and rarely a patient may also present with hypotension secondary to hemorrhage; in these types of situations,  transcatheter embolization (as selective as possible) is the typically preferred management. Surgical resection is reserved for malignant AVF, as well as AVF not responsive to embolization.
  • Catheter, CT or MR angiography can be utilized to diagnose AVF, with visualization of direct arterial to venous communication, with an early draining vein. Pseudoaneurysm formation and hematoma may also be indentified. Doppler Ultrasound may also be able to identify a direct arterial to venous communication, as well as arterialized flow of the draining vein.
References:
1.  Atwell, T et al. Incidence of Bleeding After 15,181 Percutaneous Biopsies and the Role of Aspirin. AJR 2010; 194:784-789.
2.  Cardella, J et al. Quality Improvement Guidelines for Image-guided Percutaneous Biopsy in Adults. J Vasc Interv Radiol 2003; 14:S227–S230.
3.  Wakefield M, et al. Renal Arteriovenous Malformation. eMedicine.medscape.com. Updated 3/10/2009.
4.  Walker T. Dx: Renal Arteriovenous Fistula. StatDx.com. Amirsys, Inc. 2005-2011.



Improving Prostate Cancer Detection in Veterans Through the Development of a Clinical Decision Rule for Prostate Biopsy Owen T Hill, Thomas J Mason, Skai W Schwartz, Philip R Foulis


Abstract

Background We sought to improve prostate cancer (PC) detection through developing a prostate biopsy clinical decision rule (PBCDR), based on an elevated PSA and laboratory biomarkers. This decision rule could be used after initial PC screening, providing the patient and clinician information to consider prior to biopsy.
Methods This case–control study evaluated men from the Tampa, Florida, James A. Haley (JH) Veteran's Administration (VA) (N = 1,378), from January 1, 1998, through April 15, 2005. To assess the PBCDR we did all of the following: 1) Identified biomarkers that are related to PC and have the capability of improving the efficiency of PC screening; 2) Developed statistical models to determine which can best predict the probability of PC; 3) Compared each potential model to PSA alone using Receiver Operator Characteristic (ROC) curves, to evaluate for improved overall effectiveness in PC detection and reduction in (negative) biopsies; and 4) Evaluated dose–response relationships between specified lab biomarkers (surrogates for extra-prostatic disease development) and PC progression.
Results The following biomarkers were related to PC: hemoglobin (HGB) (OR = 1.42 95% CI 1.27, 1.59); red blood cell (RBC) count (OR = 2.52 95% CI 1.67, 3.78); PSA (OR = 1.04 95% CI 1.03, 1.05); and, creatinine (OR = 1.55 95% CI 1.12, 2.15). Comparing all PC stages versus non-cancerous conditions, the ROC curve area under the curve (AUC) enlarged (increasing the probability of correctly classifying PC): PSA (alone) 0.59 (95% CI 0.55, 0.61); PBCDR model 0.68 (95% CI 0.65, 0.71), and the positive predictive value (PPV) increased: PSA 44.7%; PBCDR model 61.8%. Comparing PC (stages II, III, IV) vs. other, the ROC AUC increased: PSA (alone) 0.63 (95% CI 0.58, 0.66); PBCDR model 0.72 (95% CI 0.68, 0.75), and the PPV increased: 20.6% (PSA); PBCDR model 55.3%.
Conclusions These results suggest evaluating certain common biomarkers in conjunction with PSA may improve PC prediction prior to biopsy. Moreover, these biomarkers may be more helpful in detecting clinically relevant PC. Follow-up studies should begin with replicating the study on different U.S. VA patients involving multiple practices.

Wednesday, March 20, 2013

Renal physiology (Part 4):acid-base balance



Renal physiology: acid-base balance

The normal pH of extracellular fluid (ECF) is 7.4.

The Henderson-Hasselbalch equation describes the relationship between pH and the concentration of conjugate acid and base.
So, Acid-base disorders are due to alterations in bicarbonate [HCO3-] or CO2
·         Metabolic acid-base disorders are due to change in bicarbonate.
·         Respiratory acid-base disorders are due to change in CO2.

Buffering systems: limit [H+] fluctuation in the blood by eliminating excess acid produced by the body.

1.      Bicarbonate buffer system (main): H+ + HCO3- ↔ H2CO3 ↔ H2O + CO2
·         Bicarbonate buffering system is the main buffering of ECF acids and is regulated by both the kidneys and lungs.
·         In kidney, 85% of HCO3 is reabsorbed by PCT into blood in exchange of Cl- buffering ECF H+.
2.      Phosphate system: H+ + HPO42- ↔H2PO4-
3.      Protein buffers: H+ + Protein- ↔ HProtein
[Abbreviation: H2O = water; CO2 = carbon dioxide; HCO3- = bicarbonate; H2CO3 = carbonic acid; H+ = hydrogen ions; HPO42- = phosphate ions; H2PO4- = phosphoric acid].

Normal Arterial blood gases values:
PH = 7.35-7.45
pCO2 = 35-45 mm Hg
pO2 = 80-95 mm Hg
O2 saturation = 95-99%
HCO3 = 22-26 mEq/L

[Abbreviation: pCO2 = pressure of arterial carbon dioxide; pO2 = pressure of arterial O2; HCO3- = bicarbonate].
5 - Steps Guide to ABG Analysis
1.      Is pO2 normal (sample arterial or mixed)? It may decrease with hypoxia.
2.      Is the pH normal, acidotic or alkalotic?
3.      Are the pCO2 or HCO3 abnormal?  Which one appears to influence the pH?
4.      If both the pCO2 and HCO3 are abnormal, the one which deviates most from the norm is most likely causing an abnormal pH. 
5.      Check the pO2.  Is the patient hypoxic?
Diagnosis of various acid-base balance disorders
Respiratory Acidosis

pH
pCO2
HCO3
Acute
< 7.35
> 45
Normal
Partly Compensated
< 7.35
> 45
> 26
Compensated
Normal
> 45
> 26

Respiratory Alkalosis

pH
pCO2
HCO3
Acute
> 7.45
< 35
Normal
Partly Compensated
> 7.45
< 35
< 22
Compensated
Normal
< 35
< 22

Metabolic Acidosis

pH
pCO2
HCO3
Acute
< 7.35
Normal
< 22
Partly Compensated
< 7.35
< 35
< 22
Compensated
Normal
< 35
< 22

Metabolic Alkalosis

pH
pCO2
HCO3
Acute
> 7.45
Normal
> 26
Partly Compensated
> 7.45
> 45
> 26
Compensated
Normal
> 45
> 26

Monday, March 11, 2013

Augmentation Cystoplasty (final part)


References
1.      Adams MC, Joseph DB. Urinary Tract Reconstruction in Children. In: Wein AJ, Kavoussi LR, Novick AC, Partin AW, Peters CA. Walsh-Campbell Urology. 9. Philadelphia, PA: Saunders Elselvier; 2007:Ch. 124.
2.      Cespedes RD, McGuire EJ. Bladder Augmentation. In: Glenn JF, Graham SD, Keane TE. Glenn's Urology. 6. Lippincott Williams and Wilkins; 2004:23.
3.      Dahl DM, McDougal WS. Use of Intestinal Segments in Urinary Diversion. In: Wein AJ, Kavoussi LR, Novick AC, Partin AW, Peters CA. Campbell-Walsh Urology. 9. Philadelphia, PA: Saunders Elselvier; 2007:Ch. 80.
4.      Lapides J, Diokno AC, Silber SJ, Lowe BS. Clean, intermittent self-catheterization in the treatment of urinary tract disease. J Urol. Mar 1972;107(3):458-61. [Medline].
5.      Kokorowski PJ, Routh JC, Borer JG, Estrada CR, Bauer SB, Nelson CP. Screening for malignancy after augmentation cystoplasty in children with spina bifida: a decision analysis. J Urol. Oct 2011;186(4):1437-43. [Medline].
6.      Wiener JS, Antonelli J, Shea AM, Curtis LH, Schulman KA, Krupski TL, et al. Bladder augmentation versus urinary diversion in patients with spina bifida in the United States. J Urol. Jul 2011;186(1):161-5.[Medline].
7.      Ellsworth PI, Borgstein NG, Nijman RJ, Reddy PP. Use of tolterodine in children with neurogenic detrusor overactivity: relationship between dose and urodynamic response. J Urol. Oct 2005;174(4 Pt 2):1647-51; discussion 1651. [Medline].
8.      Obermayr F, Szavay P, Schaefer J, Fuchs J. Outcome of augmentation cystoplasty and bladder substitution in a pediatric age group. Eur J Pediatr Surg. Mar 2011;21(2):116-9. [Medline].
9.      Gurung PM, Attar KH, Abdul-Rahman A, Morris T, Hamid R, Shah PJ. Long-term outcomes of augmentation ileocystoplasty in patients with spinal cord injury: a minimum of 10 years of follow-up. BJU Int. Aug 18 2011;[Medline].
10.     Herschorn S, Hewitt RJ. Patient perspective of long-term outcome of augmentation cystoplasty for neurogenic bladder. Urology. Oct 1998;52(4):672-8. [Medline].
11.     Leng WW, Blalock HJ, Fredriksson WH, English SF, McGuire EJ. Enterocystoplasty or detrusor myectomy? Comparison of indications and outcomes for bladder augmentation. J Urol. Mar 1999;161(3):758-63. [Medline].
12.     Hedican SP, Schulam PG, Docimo SG. Laparoscopic assisted reconstructive surgery. J Urol. Jan 1999;161(1):267-70. [Medline].
13.     Braren V, Bishop MR. Laparoscopic bladder autoaugmentation in children. Urol Clin North Am. Aug 1998;25(3):533-40. [Medline].
14.     Challacombe B, Dasgupta P. Reconstruction of the lower urinary tract by laparoscopic and robotic surgery.Curr Opin Urol. Nov 2007;17(6):390-5. [Medline].
15.     De E, Pisters LL, Pettaway CA. Salvage prostatectomy with bladder neck closure and continent catheterizable bladder augmentation: 31 month follow-up by patient report and incontinence symptom index. J Urol. 2005;173 (4) abstract 283:78.
16.     De E, Pisters LL, Pettaway CA, Scott S, Westney OL. Salvage prostatectomy with bladder neck closure, continent catheterizable stoma and bladder augmentation: feasibility and patient reported continence outcomes at 32 months. J Urol. Jun 2007;177(6):2200-4; discussion 2204. [Medline].
17.     Desai MM, Gill IS, Goel M, Abreu SC, Ramani AP, Bedaiwy MA, et al. Ureteral tissue balloon expansion for laparoscopic bladder augmentation: survival study. J Endourol. Jun 2003;17(5):283-93. [Medline].
18.     Pattison M, Webster TJ, Leslie J, Kaefer M, Haberstroh KM. Evaluating the in vitro and in vivo efficacy of nano-structured polymers for bladder tissue replacement applications. Macromol Biosci. May 10 2007;7(5):690-700. [Medline].
19.     VĂ­ctor D, Burek C, Corbetta JP, Sentagne A, Sager C, Weller S, et al. Augmentation cystoplasty in children without preoperative mechanical bowel preparation. J Pediatr Urol. Aug 8 2011;[Medline].
20.     Van Voskuilen AC, Oerlemans DJ, Weil EH, van den Hombergh U, van Kerrebroeck PE. Medium-term experience of sacral neuromodulation by tined lead implantation. BJU Int. Jan 2007;99(1):107-10.[Medline].
21.     Patel AK, Patterson JM, Chapple CR. The emerging role of intravesical botulinum toxin therapy in idiopathic detrusor overactivity. Int J Clin Pract Suppl. Dec 2006;(151):27-32. [Medline].
22.     Patel AK, Chapple CR. Botulinum toxin injection therapy in the management of lower urinary tract dysfunction. Int J Clin Pract Suppl. Dec 2006;(151):1-7. [Medline].
23.     Patel AK, Patterson JM, Chapple CR. Botulinum toxin injections for neurogenic and idiopathic detrusor overactivity: A critical analysis of results. Eur Urol. Oct 2006;50(4):684-709; discussion 709-10. [Medline].
24.     Schurch B, Denys P, Kozma CM, Reese PR, Slaton T, Barron RL. Botulinum toxin A improves the quality of life of patients with neurogenic urinary incontinence. Eur Urol. Sep 2007;52(3):850-8. [Medline].
25.     van Kerrebroeck PE, van Voskuilen AC, Heesakkers JP, Lycklama a Nijholt AA, Siegel S, Jonas U, et al. Results of sacral neuromodulation therapy for urinary voiding dysfunction: outcomes of a prospective, worldwide clinical study. J Urol. Nov 2007;178(5):2029-34. [Medline].
26.     Flood HD, Malhotra SJ, O'Connell HE, Ritchey MJ, Bloom DA, McGuire EJ. Long-term results and complications using augmentation cystoplasty in reconstructive urology. Neurourol Urodyn. 1995;14(4):297-309. [Medline].
27.     Rivas DA, Chancellor MB, Huang B, Epple A, Figueroa TE. Comparison of bladder rupture pressure after intestinal bladder augmentation (ileocystoplasty) and myomyotomy (autoaugmentation). Urology. Jul 1996;48(1):40-6. [Medline].
28.     Gilbert SM, Hensle TW. Metabolic consequences and long-term complications of enterocystoplasty in children: a review. J Urol. Apr 2005;173(4):1080-6. [Medline].
29.     Rink RC, Hollensbee D, Adams MC. Complications of Bladder Augmentation in Children and Comparison of Gastrointestinal Segments. AUA Update Series. 1995;14:122-7.
30.     Castellan M, Gosalbez R, Perez-Brayfield M, Healey P, McDonald R, Labbie A, et al. Tumor in bladder reservoir after gastrocystoplasty. J Urol. Oct 2007;178(4 Pt 2):1771-4; discussion 1774. [Medline].
31.     Filmer RB, Spencer JR. Malignancies in bladder augmentations and intestinal conduits. J Urol. Apr 1990;143(4):671-8. [Medline].

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