Presentation on theme: "Presented by: Haya M. Al-Malaq. Renal Failure 2 Outlines Part I – Lab Evaluation of RF. Part II – AG induced ATN. Part III – Amphoteracin B induced nephrotoxicity."— Presentation transcript:
Renal Failure 2 Outlines Part I – Lab Evaluation of RF. Part II – AG induced ATN. Part III – Amphoteracin B induced nephrotoxicity. Part IV – Post-renal ARF.
Renal Failure 3 Definition It is an abrupt decline in glomerular and tubular function, resulting in the failure of the kidneys to excrete nitrogenous waste products & to maintain fluid & electrolyte homeostasis. Increase in > 50% over baseline Cr & GFR <10mL/min, or <25% of normal Azotemia is a consistent feature of acute renal failure (ARF), oliguria (UOP <400-500 mL/d) is not. Anuria i.e. UOP < 0.5 ml/kg/h
Renal Failure 4 History & Physical Examination Shows the cause of ARF. Is the patient on any medications. A thorough physical examination in used conjunction with the history can be invaluable in confirming the cause of ARF.
Renal Failure 6 GFR GFR: Normal GFR: 100 ml/min/1.72m 2
Glomerular Filtration Rate (GFR) The total kidney GFR is equal to the sum of the filtration rate of all the functioning nephrones and represent the total functional mass of the kidney. It is a reliable index that can be used to evaluate the progression of renal disease. Markers that are freely filtered at the glomerulus are best indicator for accurate measurement of GFR (ideally should be inert, freely filtered without secretion, reabsorption metabolism or production by tubules) Renal Failure 7
BUN BUN is produced by the liver, transported in the blood, excreted by the kidneys. The conc. of BUN reflects KF b/c it is completely filtered, reabsorbed & secreted. ARF, CRF r the common cause of elevated BUN. Normal BUN level (8-18 mg/dl or 3.0-6.5 mmol/l). Renal Failure 8
BUN Do NOT quantify the extent of kidney dysfunction. Hi prot intake or catabolism, GI bleeding, hydration status, terminal stage of liver disease all affect BUN level. Renal Failure 9
Creatinine & Creatinine Clearance Most widely used clinical measurement of CLcr. Produced at a constant rate of non-enzymatic hydrolysis of muscle stores. So individual muscle mass, age, sex are predictors of Cr production. It is freely filtered & about 10-20 % secreted. Cimetidine & trimethoprim inhibit Cr secretion & so increase SrCr with out affecting GFR. Renal Failure 10
Renal Failure 11 Determination of CLcr by Cockcroft-Gult Equation CLcr = (140 – Age) (IBW) (72) (SrCr in mg/dl) Male IBW= 50 + ( 2.3 * height > 60 inches ) Female IBW= 45 (2.3 * height > 60 inches ) * 0.85 in females
Renal Failure 12 Limitation of this method is that it produce falsely high CLcr in the early stages of ARF & falsely low CLcr when ARF is resolving. CG is also in accurate in patients that have low muscle mass as elderly, obese, or cachectic.
Renal Failure 13 Determination of CLcr by 24 Hour Urine Collection CLcr (ml/min) = Uv (ml) * Ucr (mg/dl) 0.5 (SrCr1 + SrCr2) SrCr1(mg/dl)= at the beginning of urine collection SrCr2 (mg/dl)= at the end of urine collection
Renal Failure 14 Limitation of this method is that the accuracy of the calculation depends on the accuracy of the urine collection process.
Case H.H is a 43 yo 80 kg man being treated for G-ve septic shock. HPI: He was admitted to the hospital 6 days ago but he has spent the last 3 days intubated in the medical respiratory ICU b/c of hypotension, respiratory failure and altered mental status. Hospital course: Since admission he has received ceftriaxone 2g/d, gentamycin 140 mg IV q8hrs. Renal Failure 16
Case Admission labs: BUN 13 mg/dl (8-18) SrCr 0.9 mg/dl (0.5-1.2) WBC 23,500 cells/mm3 (4000-9000) with left shift (90% PMN & 12% Bands) Serial bl & urine & sputum culture were +ve for Acinetobacter Baumanii sensitive to ceftriaxone & gentamycin. In addition to the previous antibiotics current medications include norepinephrine IV 18 g/min, pancuronium 0.02 mg/kg IV q3hrs, famotidine 20 mg IV q12hrs, lorazepam IV 2mg/hr. Renal Failure 17
Case H.H VS include T 38.6 oC; BP 90/40 mmHg; P 135 beats/min; RR 20 breaths/min New Labs: BUN 65 SrCr 5.4 WBC 16,500 with left shift. Over the last 2 days the urine output started to decline & today is 700 ml/24 hrs (1,500-2,500). Renal Failure 18
Case Given the history and lab data what is the source of HH ARF? How does AG induced ATN presents & what is the MOA? Is extended interval AG dosing less nephrotoxic than multiple daily dosing? Renal Failure 20
Case H.H remained febrile for the next several days despite being covered by broad spectrum AB. His gentamycin & ceftriaxone were stoped 3 days ago & imipenem 500mg IV q12hrs was started. Today he is febrile 39 oC, blood fungal culture optained 5 days ago was positive for candida tropicalis sensitive only to Ampho B. Labs : BUN 75; SrCr 6.1; WBC 17,500, UOP 600 ml/day * 3d Renal Failure 22
Case Are there any concerns with administration of Ampho B to H.H if he still remains in ATN? How do lipid based Ampho B products reduces nephrotoxicity? Renal Failure 23
Causes & Symptoms Obstruction of urine flow by stone, malignancy (prostate, cervix), prostatic hypertrophy, bilateral ureter stricture and bladder outlet obstruction (as in prostatic hypertrophy). Onset of S & S are gradual; presents as decreased force of urine stream, dribbling, or polyurea. Drugs my ply a role in crystal formation so should be included in the differential diagnosis. Renal Failure 26
Nephrolithiasis Common with genetic predisposition. Risk factors: Low urine volume. Hypercalciuria. Hyperoxaluria. Hyperuricosuria. Chronic hi or lo urine PH. Renal Failure 27 Types: Calcium stones (70-80%). Struvite (Mg Al ph, 2-20%, can result in irreversible kidney damage). Uric acid (chemotherapy pts). Crystal (rare herditory disorder).
Presentation & Treatment TA is a 48yo man, ER Cc: sharp pain radiating to the groin, dysuria, hematouria,*4hr similar to a previous episode of Ca nephrolithiasis. HPI: On questioning he admits that he had not been drinking much fluids over the past wk owing to a busy work schedule and his urine volume has been markedly lower than usual. Renal Failure 28
Presentation & Treatment Labs: BUN 34 mg/dl (5-20) SrCr 1.5 mg/dl (0.5-1.2) Urine sampled showed large amount of Ca oxalate crystals which indicates that the pt passed a kidney stone. What Sub & obj data suggest nephrolithiasis and how to prevent this from occurring in the future? Can drugs crystallize the urine & cause ARF? Renal Failure 29