7/1/2013 ABIM Certification Exam: Nephrology Division of - PDF document

7/1/2013 ABIM Certification Exam: Nephrology Division of Nephrology Department of Medicine July 2013 UCSF CME Kathleen D. Liu, MD, PhD Associate Professor NEPHROLOGY Roadmap for today Department of Medicine  AKI (beyond ATN) Division of Nephrology  Glomerulonephritis  A few odds and ends…  Common electrolyte abnormalities  Acid-base 2 NEPHROLOGY Case Department of Medicine A 57-yr-old man is admitted after a motor Division of vehicle accident. He has sustained multiple Nephrology fractures and blunt chest and abdominal trauma. A left hemothorax is treated with a chest tube, an abdominal lavage reveals only minimal blood, and a noncontrast computed tomography (CT) scan of the abdomen is negative. He is volume-resuscitated with approximately 15 L of crystalloid. Twenty-four hours after admission, he is noted to have marked abdominal distension and low urine output. 1

7/1/2013 NEPHROLOGY Case Department of Medicine Physical Exam: Division of Tm 37.2 BP 135/86 HR 86 RR 16 UOP 100 cc/12h Nephrology CVP 18 Bladder pressure 28 Intubated, sedated Decreased breath sounds at bases Regular heart sounds, no m/r/g Abdomen distended and firm, hypoactive BS NEPHROLOGY Case Department of Medicine Labs: Division of Nephrology  Na 135  K 5.8  Cl 103  HCO3 24  BUN 46  Cr 2.3  Imaging: Small retroperitoneal hematoma,normal sized kidneys without hydronephrosis, marked ascites. NEPHROLOGY Case Question Department of Medicine Which of the following would be the most Division of appropriate next step? Nephrology A. Abdominal decompression B. Fluid resuscitation C. Placement of bilateral ureteral stents D. Initiation of renal replacement therapy 2

7/1/2013 NEPHROLOGY Acute Renal Failure/Kidney Injury Department of Medicine  Pre-Renal = Decreased kidney perfusion Division of Nephrology  Intra-Renal = Intrinsic kidney disease  Post-Renal = Obstructive nephropathy NEPHROLOGY Pre-Renal ARF: Kidney Hypoperfusion Department of Medicine  Dehydration, overdiuresis, hypovolemia Division of Nephrology – Abdominal compartment syndrome: Typically occurs after massive volume resuscitation  Hemorrhage  Hemodynamic effect: ACE/ARB and NSAIDs  Heart failure – Cardiorenal syndrome  Cirrhosis/End-stage liver disease – Hepatorenal syndrome NEPHROLOGY Pre-Renal ARF: Kidney Hypoperfusion Department of Medicine  Diagnosis Division of Nephrology – +/- Oliguria – High BUN:Creatinine ratio > 20 – Bland urine sediment, normal kidney US – Low FENa < 1% and low urine Na <10 mEq/L – High specific gravity, high urine osmolality – Rapid renal recovery with resuscitation  Therapy: Restore renal perfusion  Prognosis: Good, often rapid renal recovery – Exceptions: Cardiorenal and hepatorenal syndromes 3

7/1/2013 NEPHROLOGY Fractional Excretion of Sodium (FeNa) Department of Medicine  FeNa = (U Na * P Cr )/(P Na * U cr ) * 100 Division of Nephrology  <1% consistent with pre-renal state  Only useful when patient is oliguric (< 400 cc urine output/24 hours)  Confounded by use of diuretics NEPHROLOGY Case Department of Medicine A 40-yr-old man with end-stage liver disease Division of secondary to alcohol abuse is admitted to the Nephrology hospital with altered mental status. Home meds: Propranalol/rifaximin/lactulose/lasix/spironola ctone Physical exam: T 37.4 BP 90/50 HR 80 RR 16 O2 sat 95% RA No JVD appreciated Bibasilar rales + abdominal distension + fluid wave 1-2+ LE edema NEPHROLOGY Case Department of Medicine Labs: Division of Nephrology  Na 135  K 5.1  Cl 103  HCO3 24  BUN 46  Cr 2.3  U/A: 1.025/7/neg heme/gluc/nit/LE/prot  Imaging: Normal sized kidneys without hydronephrosis, marked ascites. 4

7/1/2013 NEPHROLOGY Case Question Department of Medicine Which of the following would be the most Division of appropriate next step? Nephrology A. Abdominal decompression B. Fluid resuscitation C. Placement of bilateral ureteral stents D. Initiation of renal replacement therapy NEPHROLOGY Pre-renal ARF: Hepatorenal Syndrome Department of Medicine  Severe end-stage liver disease patients Division of Nephrology  Intense renal vasoconstriction  Diagnosis of exclusion – Oliguria – Low urine sodium < 10 mEq/L, low FENa < 1% – Hyponatremia – Bland urine sediment – Normal US (no hydronephrosis) – No other identifiable cause – Lack of response to volume expansion NEPHROLOGY Pre-renal ARF: Hepatorenal Syndrome Department of Medicine  Treatment Division of Nephrology – Splanchnic vasoconstrictors (terlipressin, ornipressin), midodrine, octreotide – TIPS (transjugular intrahepatic portosystemic shunt) – Dialysis as bridge to liver transplant – Liver transplant 5

7/1/2013 NEPHROLOGY Case Department of Medicine A 39-yr-old woman with stage 4 ovarian carcinoma with bulky pelvic and Division of Nephrology retroperitoneal disease is admitted with complaints of shortness of breath and decreasing urine output. Physical exam: T 37.4, BP 130/90, HR 76, RR 16, UOP 35cc/6h + jugular venous distention Bibasilar rales + abdominal distension 1-2+ LE edema NEPHROLOGY Case Department of Medicine Labs Division of Nephrology  Na 135  K 5.7  Cl 107  HCO3 16  BUN 60  Cr 3.1  PO4 6.9  Uric acid 12.4 NEPHROLOGY Case Department of Medicine Imaging Division of  Abdominal ultrasound (outpatient study, 2 weeks Nephrology ago): moderate right-sided hydronephrosis, normal left kidney  Repeat ultrasound demonstrates moderate calyceal dilation on the left, with no dilation on the right but persistent hydronephrosis. Kidney size is normal bilaterally. 6

7/1/2013 NEPHROLOGY Case Question Department of Medicine Which of the following would be the most Division of appropriate next step? Nephrology A. CT scan with contrast B. Allopurinol and urinary alkalinization C. Emergent hemodialysis D. Percutaneous nephrostomy NEPHROLOGY Post-Renal ARF: Obstruction Department of Medicine  Urinary tract obstruction Division of Nephrology – Renal pelvis, ureters, bladder, prostate, urethra – Congenital and acquired lesions, BPH – Neurogenic bladder, medication effects  Nephrolithiasis  Malignancy – GI cancers – Prostate cancers – Uterine, cervical, ovarian cancers  Lymphadenopathy  Retroperitoneal fibrosis NEPHROLOGY Post-Renal ARF: Obstruction Department of Medicine  Clinical Division of Nephrology – Oliguric or non-oliguric – Can have type 4 RTA, metabolic acidosis – Foley does not definitively rule out obstructive nephropathy – Hydronephrosis on US, although negative US does not rule out obstructive nephropathy  Therapy – Correct obstruction – Urology consultation – Interventional radiology consultation: nephrostomy tubes 7

7/1/2013 NEPHROLOGY Post-Renal ARF: Obstruction Department of Medicine  Prognosis Division of Nephrology – More rapid recovery with rapid correction of obstruction – Can recover kidney function after prolonged obstruction – Post-obstructive diuresis from urinary concentrating defect NEPHROLOGY Case Department of Medicine A 65 year-old woman is admitted to the Division of hospital with newly diagnosed diffuse B cell Nephrology lymphoma for induction chemotherapy. 24 hours after induction chemotherapy, she is noted to be oliguric. Physical exam T 38.4, BP 95/60, HR 94, RR 24 Heart is normal. Lungs are clear, though she is mildly tachypneic Trace-1+ pitting edema NEPHROLOGY Case Department of Medicine Labs Division of  Na 138 Nephrology  K 6.0  Cl 95  HCO3 19  BUN 43 mg/dL  Creatinine 3.4 mg/dL  Ionized Ca 0.79 mmol/L  PO4 9.9 mg/dL  Uric acid 11.1 mg/dL 8

7/1/2013 NEPHROLOGY Case Question Department of Medicine What is the most likely diagnosis? Division of Nephrology A. Rhabdomyolysis B. Tumor lysis syndrome C. Cisplatin nephrotoxicity D. Sepsis associated ATN NEPHROLOGY Intra-Renal ARF: Acute Tubular Necrosis (ATN) Department of Medicine  Etiology Division of Nephrology – Ischemic = hypotension, sepsis, shock, hemorrhage – Toxic • Exogenous: intravascular radiocontrast, aminoglycosides, amphotericin, cisplatin, oxalate (ethylene glycol/anti-freeze ingestion) • Endogenous: rhabdomyolysis (myoglobin), hemolysis (hemoglobin), tumor lysis (urate)  Diagnosis – Muddy brown/pigmented casts in urine sediment – Elevated FENa > 1-2% – High urine Na > 20 mEq/L NEPHROLOGY Intra-Renal ARF: Acute Tubular Necrosis (ATN) Department of Medicine  Prognosis Division of Nephrology – Mortality: 40-70% in ICU ARF requiring dialysis – Slower recovery  Therapy – Supportive care – Dialysis as needed – Fluid and electrolyte management – Medication dosing adjustment for GFR – No proven therapies – No benefit: mannitol, furosemide, dopamine, ANP, thyroxine 9