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Acute Kidney Injury Edward L. Barnes, MD Chief Resident Conference July 5, 2012 Outline for Today • Workup • Pre-Renal • Intrinsic » Tubulointerstitial Disease » Glomerular Disease • Post-Renal 5/25/2017 2 Initial Work Up • Attempt to define the problem • What is the reason for the Acute Kidney Injury? • Typically broken down into where the etiology is occurring » Pre-Renal » Intrinsic Disease » Post-Renal 5/25/2017 3 Acute Kidney Injury • Which situation is worse » Creatinine 1.1 1.6 » Creatinine 2.8 3.3 • Is a Cr of 1 always normal? » 80 yo woman, frail with BMI 18 » 25 yo man, muscular with BMI 25 5/25/2017 4 Serum Creatinine vs. GFR • Remember this is a non-linear relationship 5/25/2017 5 Case #1 A 65-year-old man is admitted to the hospital because of fever and dysuria. Laboratory studies show a leukocyte count of 12,000/µL, a blood urea nitrogen level of 24 mg/dL, a serum creatinine concentration of 1.4 mg/dL, and pyuria. Empiric treatment with trimethoprim-sulfamethoxazole is started. Three days later, the pyuria and fever have resolved. The leukocyte count is 10,000/µL, blood urea nitrogen level is 24, and serum creatinine is 1.8 mg/dL. Urinalysis shows no leukocytes, casts or crystals. What are some potential causes of the increase in Cr from 1.4 to 1.8? 5/25/2017 6 Case #1 Which of the following is the most likely explanation for the rise in serum creatinine from 1.4 mg/dL to 1.8 mg/dL? A. B. C. D. E. Acute interstitial nephritis Acute pyelonephritis Acute tubular necrosis Obstructive uropathy Drug effect with reduced creatinine excretion 5/25/2017 7 Case #2 A previously healthy 74-year-old man is hospitalized with cough and chest pain. On physical examination, the blood pressure is 148/92 mm Hg, heart rate is 75/min, respiration rate is 18/min, and temperature is 37.8 °C (100 °F). The left lower lung field has scattered basilar crackles. The hematocrit is 34% and leukocytosis is present. The serum creatinine concentration is 2.3 mg/dL. Urinalysis shows a pH of 6.0, 1+ proteinuria, and no hematuria or ketonuria. What else do you want to know? 5/25/2017 8 Case #2 Which of the following is most useful in distinguishing acute from chronic renal failure in this patient? A. A previous hematocrit B. Previous serum creatinine concentration C. Blood urea nitrogen to creatinine ratio D. Microscopic urinalysis E. Renal ultrasonography 5/25/2017 9 Acute Kidney Injury • Step One: Define the Problem (History) » Prior Creatinine Measurements » All Medications, New Medications, Herbal Medications, Illicit Drug use » Recent contrast exposure • May have to explicitly ask about imaging » Volume loss, dehydration, decreased po intake » Flank Pain » Hematuria, Dysuria, Anuria 5/25/2017 10 Acute Kidney Injury • Step Two: Physical Exam » » » » » » 5/25/2017 Evaluate for dehydration Flank Pain Edema Tender, lower abdominal mass Rash Sinus abnormalities 11 Acute Kidney Injury • Step Three: Labs and Diagnostic Studies » Urinalysis: the liquid kidney biopsy » Urine “Lytes” • • • • Sodium Creatinine Urea (if on diuretics) Serum Chemistry » Fractional Excretion of Na (FENa) Urine Na x Plasma Cr Urine Cr x Plasma Na 5/25/2017 12 Acute Kidney Injury • Fractional Excretion of Na (FeNa) Urine Na x Plasma Cr Urine Cr x Plasma Na • FeNa <1 = Pre-Renal • FeNa >2 = Intrinsic • FeUrea <35% = Pre-Renal • FeUrea >35% = Intrinsic Disease 5/25/2017 13 Acute Kidney Injury • Other Labs to consider: » » » » » » » 5/25/2017 Urine Protein/Creatinine Ratio ANA, ANCA HIV, RPR Hepatitis Panel Complement Levels: C3, C4 SPEP/UPEP Hansel Stain 14 Urinalysis 5/25/2017 15 Color • Rhabdomyolysis (myoglobinuria) • Alkaptonuria 5/25/2017 16 Color Pseudomonas Lee J. N Engl J Med 2007;357:e14. 5/25/2017 17 Urinalysis: Protein • Only accounts for albumin • You may need to test for other proteins » Bence Jones protein in suspected Light Chain Disease or Multiple Myeloma 5/25/2017 18 Looking at the Urine 5/25/2017 19 Looking at the Urine Red Blood Cell Casts 5/25/2017 20 Looking at the Urine Dysmorphic Red Blood Cells 5/25/2017 21 Looking at the Urine Uric Acid Crystals 5/25/2017 Calcium Oxalate Crystals 22 PUTTING IT ALL TOGETHER 5/25/2017 23 Case #3 48 yo woman with PMH significant for HTN (treated with Lisinopril) presents with a chief complaint of vomiting and weakness. Baseline Cr is 0.8. Laboratory Studies are shown below: Na K BUN Cr 140 3.8 38 1.6 Urine Na Urine Cr 7 65 What type of Acute Kidney injury does this patient have? 5/25/2017 24 Case #3 • FeNa = 0.12% Pre-Renal Acute Kidney Injury 5/25/2017 25 Pre-Renal Acute Kidney Injury • Causes: » » » » » » Dehydration Shock Acute Volume Loss (bleeding) Abdominal Compartment Syndrome Decompensated Heart Failure End Stage Liver Disease (Hepatorenal syndrome) » Renal Artery Thrombosis 5/25/2017 26 Urinalysis • Urinalysis should be relatively normal • If patient is dehydrated, you may see Hyaline Casts • Urine Sediment will otherwise be bland 5/25/2017 27 Treatment • Correct the underlying perfusion abnormality if possible 5/25/2017 28 Case #3 48 yo woman with PMH significant for HTN (treated with Lisinopril) presents with a chief complaint of vomiting and weakness. Baseline Cr is 0.8. Laboratory Studies are shown below: Na K BUN Cr 140 3.8 38 1.6 Urine Na Urine Cr Urine Urea 7 65 135 How would you treat this patient? 5/25/2017 29 Pre-Renal Acute Kidney Injury • 48 yo woman with PMH significant for HTN presenting with: » Severe abdominal pain » Guarding on exam » Bladder pressure as measured by foley catheter is 34 mmHg » Cr is 1.9 (baseline 0.8) » Urine sediment is bland What is the diagnosis? 5/25/2017 30 Pre-Renal Acute Kidney Injury • 48 yo woman with PMH significant for HTN presenting with: » Altered mental status » Hypotension » Blood cultures positive for Pseudomonas aeruginosa » Cr is 2.7 (baseline 0.8) » Urine sediment is bland What is the etiology of the acute kidney injury? 5/25/2017 31 Pre-Renal Acute Kidney Injury • 48 yo woman with PMH significant for HTN, cirrhosis secondary to HCV presenting with: » » » » » » Altered mental status Hypotension Anasarca FeNa 0% (very low), Urine Na <5 Cr is 2.7 (baseline 0.8) Urine sediment is bland What is the etiology of the acute kidney injury? 5/25/2017 32 Case #4 48 yo woman with PMH significant for HTN (treated with Lisinopril and HCTZ) presents with a chief complaint of vomiting and weakness. Baseline Cr is 0.8. Laboratory Studies are shown below: Na K BUN Cr 140 3.8 38 2.6 Urine Na Urine Cr Urine Urea 85 65 135 How would you treat this patient? 5/25/2017 33 Case #4 • This patient is on chronic diuretic therapy, thus you must calculate the FeUrea: Urine Urea x Plasma Cr Urine Cr x Plasma Urea FeUrea= 14.21% Pre-Renal Acute Kidney Injury 5/25/2017 34 Case #5 48 yo woman with PMH significant for HTN (treated with Lisinopril and HCTZ) presents with a chief complaint of vomiting and weakness. Baseline Cr is 0.8. Laboratory Studies are shown below: Na K BUN Cr 140 3.8 38 2.5 Urine Na Urine Cr Urine Urea 65 45 265 What is the etiology of this patient’s Acute Kidney Injury? 5/25/2017 35 Intrinsic Acute Kidney Injury • Etiology of Intrinsic AKI: » Acute Tubular Necrosis (ATN) » Contrast Induced Nephropathy (CIN) » Rhabdomyolysis (Pigment Induced Nephropathy) » Acute Interstitial Nephritis (AIN) » Glomerulonephritis (multiple etiologies) » Cholesterol Emboli » Thrombotic Microangiopathy » and more… 5/25/2017 36 Case 23 yo man with no PMH, but was recently treated for Strep Throat presents with fatigue and overall feeling poorly. Physical Exam is normal. Cr 2.5 FeNa 2.3% What do you want to do next? 5/25/2017 37 Case Continued What is your diagnosis? 5/25/2017 Post-Streptococcal Glomerulonephritis 38 Glomerulonephritis • Defined by Red Blood Cell Casts in the urine sediment • Multiple etiologies of Glomerulonephritis exist, will be covered in detail elsewhere • Associations to remember: » Most Common: IgA Nephropathy » GN + Hemoptysis: ANCA or anti-GBM (Goodpasture’s Syndrome) » GN + Purpura: Think Vasculitis 5/25/2017 39 Case #6 54 yo man with PMH significant for HTN, Hyperlipidemia, presented to the MICU after being found down and resuscitated for approximately 20 minutes. After 3 days, patient has now been extubated and is doing well, however his Creatinine continues to rise. Creatinine on admission was 1.2, now 3.5 this morning. Cr 3.5 5/25/2017 FeNa 3.5% 40 Case #6 Continued You spin his urine and find… What is your diagnosis? 5/25/2017 Esson ML, Shrier RW. Diagnosis and Treatment of Acute Tubular Necrosis. Ann Intern Med. 5 November 2002;137(9):744-752 41 Acute Tubular Necrosis • Risk Factors: » Prolonged Hypotension » Nephrotoxic Agents • Classic description: “muddy brown casts” • Treatment » Remove inciting etiology (resuscitate, remove suspected medication) • If patient improves, suspect post ATN diuresis to occur (may take up to 1-3 weeks) • Some patients may progress to End Stage Renal Disease 5/25/2017 42 Case #7 68 yo man with PMH significant for HTN and Hyperlipidemia, admitted for a STEMI. Patient received PCI with stent to the Right Coronary Artery. Patient is doing well, but on day 3 of admission, Creatinine is noted to be elevated at 1.9. Baseline Creatinine was 0.9. No new medications other than Plavix. FeNa: 2.5% What is the suspected diagnosis? 5/25/2017 43 Contrast Induced Nephropathy • At Risk Patients: » Diabetes Mellitus » Chronic Kidney Disease • Occurs in approximately 3% of the population • Typically occurs 24-48 hours following contrast administration • Typically transient, improving over 1-3 weeks; however there is potential for progression to ESRD • Prevention » Hydration » Hold nephrotoxic agents (NSAIDs) • Treatment » supportive 5/25/2017 44 Case #8 • 68 yo man with PMH significant for HTN and Hyperlipidemia, admitted for a STEMI. Patient received PCI with stent to the Right Coronary Artery. Patient is doing well, however overnight, Cr increases from baseline (0.9) to 2.1 and the patient develops a new rash. No new medications other than Plavix. 5/25/2017 45 Case #8 What is this “rash”? Livedo Reticularis What is the diagnosis? Cholesterol Emboli Syndrome 5/25/2017 46 Case #9 22 yo man with no PMH presents with nausea, vomiting, and fatigue. The patient is a member of the wrestling team at UNC. Denies taking any new medications or supplements. Cr 2.9 (baseline 0.8) FeNa 2.6% Urine dipstick performed in your office indicates 3+ blood. You examine the urine, and the sediment is bland, no RBC or WBC are seen. What other labs would you want to know? What is the diagnosis? 5/25/2017 47 Case #10 78 yo man with PMH significant for HTN, and Benign Prostatic Hypertrophy. He has been taking over the counter allergy medications. Over the past 24 hours he has developed lower abdominal pain, decreased urine output. On laboratory studies: Cr 2.3 (baseline 1.0) Urine Sediment is bland FeNa 2.5% What is the next test that you want to order? 5/25/2017 48 Renal Ultrasound Presence of Hydronephrosis indicates post-renal Acute Kidney Injury 5/25/2017 49 Post-Renal Acute Kidney Injury • Hydronephrosis and Acute Kidney Injury is an Emergency • You must relieve the obstruction » Foley Catheter » Nephrostomy Tubes • Next you must identify the cause of the obstruction 5/25/2017 50 The End Acute Kidney Injury Pre-Renal 5/25/2017 Intrinsic Post-Renal 51