Kidney Fun and Failure

Transcription

1 Kidney Fun and Failure Tom Ozbirn, M.D. General Session 2, Saturday, 9/8/12 9:30 a.m. to 11:30 a.m. Thomas W. Ozbirn, Jr DO, FACP Nephrology Associates, PC Birmingham, Alabama 1

2 Objectives Understand Categories of AKI CKD ESRD Navigate confusing nomenclature of renal disease Understand basic renal function Understand consequences of loss of renal function Key coding issues Case 1 72 year old man admitted: recurrent CHF, CKD 4 ( Cr 3 ) and hypertension PMH DM x 16 years HTN, severe, x 10 years CKD with rising creatinine past years AAA, repaired 8 years ago Coronary Artery Ds, sp MI 2 years ago Data Chest X-Ray- CHF Urinalysis- 1+ protein Echocardiogram- normal LV function Renal Ultrasound- Rt kidney 7 cm, L kidney 10 cm MRA- occluded L renal artery, severe stenosis Rt renal artery 2

3 PTRA of Rt Renal Artery Brisk Urine output CHF resolution Blood pressure falls Creatinine falls 1.8 What is principal Diagnosis? CHF Hypertension with CKD Hypertension with CHF and CKD Atherosclerosis of Renal Artery Anatomy of Kidney Gross Features Paired retroperitoneal organs Upper pole opposite 12 th thoracic vertebrae cm in length Single renal artery Cortex and medulla Nephron Afferent/efferent arterioles PT 60-70% A II CAI Loop of Henle 20-25% flow loop Distal tubule 5% flow - Thiazide Collecting duct 4% aldo, ADH, K+ sparing 3

4 Renal Function and Disorders of Water and Sodium Balance Overview 50-60% BW 2/3 intracellular, 1/3 extracellular Body compartment electrolytes Sodium extracellular Potassium intracellular Osmolarity Different solutes but equal concentration H2O moves to compartment with higher solute 2 X sodium + glu/18 + BUN/2.8 Osmolar gap = EtoH, Methanol, Ethylene glycol Introduction CKD is a worldwide public health problem -Rising incidence and prevalence -In 2003, 100,499 patients entered ESRD programs and 82,000 died -Disproportionate share of healthcare resources 4

5 Introduction -Survival probability at 1,5,10 years is 80,40 and 18% -Growth due to changes in demographics -Difference in disease burden between racial groups -Under recognition of early stages - Under diagnosed Stages of CKD Stage 1- Albuminuria, normal GFR Stage 2- Albuminuria, GFR Stage 3- GFR Stage 4- GFR Stage 5- GFR < 15 or ESRD 5

6 Prevalence Presence of markers of kidney damage for > 3 months Presence of GFR < 60 ml/min for 3 months Elevated serum creatinine -0.8 to 1.3 in men -0.6 to 1.0 in women Decreased GFR -Cockcroft-Gualt -MDRD Racial Variations Racial and ethnic differences in ESRD 256 per million population in whites 982 per million population in African Americans 344 per million in Asian Americans 514 per million in Native Americans Age/gender ratio (AA/white) 6 to 1 Impact of CKD on Morbidity HTN, DM, CVD and PVD present in far greater proportion 3x increase in hospital days Older age, gender, race, cardiac disease and PVD are risk factors for hospitalization 6

7 Management of CKD Natural history -Initial injury from hematuria to renal failure -Post infectious GN- recover with little to no sequelae -Lupus nephritis-repeated insults and progression Management Adaptive hyperfiltration -Initially beneficial -Progressive renal insufficiency -Uremia -ACEi may slow progression -Rate of progression varies Association with CVD CKD is a risk factor for CVD Risk of death from CVD greater than the risk of ESRD Phosphate binders may increase Coronary Atherosclerosis 7

8 Progression of CKD Intraglomerular HTN Glomerular hypertrophy Hyperlipidemia Metabolic Acidosis Tubulointerstitial disease Secondary FSGS Progression of CKD ACEi/ARB Antihypertensive therapy given for renal and cardiac protection Reduced proteinuria Goal systolic BP 110 Therapy more effective in earlier stages 8

9 Progression of CKD Hyperlipidemia Metabolic Acidosis Protein restriction Smoking cessation JNC 7/ K/DOQI guidelines Treatment of Complications Volume overload -Homeostatic mechanisms until GFR<15 -Less able to respond to rapid infusions of sodium -Sodium restriction -Diuretics 9

10 Treatment of Complications Hyperkalemia -Aldosterone secretion and distal flow -Oliguric, increase K+ diet, increased tissue breakdown Metabolic Acidosis -Hydrogen ion retention -Serum bicarbonate rarely <10 Treatment of Complications Hyperphosphatemia -Reduce filtered phosphate load -Secondary Hyperparathyroidism -Dietary phosphate restriction -Protein restriction -Phosphate binders -CaxPO4 <55 Treatment of Complications Renal Osteodystrophy -Osteitis Fibrosa -Osteomalacia -Adynamic Bone Disease 10

11 Treatment of Complications Hypertension % of patients with CKD -Diuretics -Loop vs. Thiazides (less effective if GFR < 20) Sexual Dysfuntion -Amenorrhea common -50% of men with ED Treatment of Complications Anemia -Normocytic and Normochromic -Reduced production of Erythropoetin -Shortened RBC survival -Untreated, Hct stabilizes at 25 -CHOIR study -Address iron/esa issues Treatment of Complications Dyslipidemia -Common, especially hypertriglyceridemia -Limited data suggests lipid lowering may slow progression Malnutrition -Strong correlation between PCM and death -Decreased intestinal absorption -Renal diet 11

12 Treatment of Complications Uremic bleeding -Prolonged bleeding time secondary to impaired platelet function -ddavp, estrogen, dialysis Pericarditis Uremic Neuropathy Thyroid Dysfunction Predictors of Accelerated Progression Metabolic Syndrome Analgesics Obesity Smoking DM 12

13 Predictors of Accelerated Progression Greater Proteinuria Higher BP Black race Lower HDL Lower Transferrin Acute Renal Failure Abrupt decrease in Renal Function sufficient to result in retention of BUN and Creatinine Pre-renal vs intrinsic renal vs obstruction Most common is Acute Tubular Necrosis ie: ATN Frequency varies 2-5% of hospitalized 55% iatrogenic and sepsis ARF in Hospitalized Patients Pre-renal azotemia is most common 30-60% of cases 1-10% post renal Intrinsic renal disease - ATN most common 40-60% of ATN occur in post-op or trauma AIN, Acute GN, CCE, Ureteral obstruction or intrarenal obstruction 13

14 High-risk Setting for Acute Renal Failure Clinical Setting Renal Failure % General medical-surgical 3-5 Intensive care unit 5-25 Elective abdominal surgery 1-5 Open heart surgery 3-15 Abdominal aorta surgery 5-30 Severe burns Aminoglycoside therapy 5-20 Radiocontrast exposure 0-30 Rhabdomyolysis Sepsis Causes of Acute Renal Failure Prerenal azotemia Renal azotemia Post renal azotemia (obstruction of collecting system) Causes of Acute Renal Failure Prerenal azotemia Absolute decrease in effective blood volume Hemorrhage, skin losses (burns, sweating) gastrointestinal losses (diarrhea, vomiting) renal losses (diuretics, glycosuria) fluid pooling (peritonitis, burns) Relative decrease in blood volume (ineffective arterial volume) Congestive heart failure, sepsis, anaphylaxis, liver failure Arterial occlusion Bilateral thromboembolism, thromboembolism of solitary kidney 14

15 Prerenal Azotemia Is there hypotension? Is the patient on NSAIDS? ACEI? Renal Vascular disease? Check urine chemistries Prerenal Azotemia FeNa <1% Hepatorenal syndrome Glomerulonephritis Transplant rejection Contrast Myoglobin Partial Obstruction 15

16 Causes of Acute Renal Failure Renal azotemia Vascular causes Vasculitis malignant hypertension microscopic polyarteritis Acute glomerulonephritis Postinfectious glomerulonephritis anti-basement membrane-antibody disease Acute interstitial nephritis Drug-associated acute interstitial nephritis (methicillin nephrotoxicity) Causes of Acute Renal Failure Acute tubular necrosis Ischemia Prerenal azotemia (if severe enough) post surgical complication Sepsis syndrome Nephrotoxicity Exogenous nephrotoxins» Antibiotics (aminoglycosides, cephalosporin, amphotericin B)» iodinated contrast agents» chemotherapeutic agents (cisplatin)» solvents (carbon tetrachloride, ethylene glycol) Endogenous nephrotoxins» Intratubular pigments (hemoglobinuria, myoglobinuria)» intratubular proteins (myeloma)» intratubular crystals (uric acid, oxalate)» tumor lysis syndrome Causes of Acute Renal Failure Postrenal azotemia (obstruction of collecting system) Bladder outlet obstruction bilateral ureteral obstruction (unusual) ureteral obstruction in a solitary kidney 16

17 Complications of ARF Volume overload Hyponatremia Hyperkalemia Acidosis Other Electrolyte Imbalances Anemia Management of ARF Emergent intervention Supportive therapy Dialysis Dopamine Indications for Initiation of Dialysis Pericarditis Progressive Uremic Encephalopathy Bleeding diathesis Fluid overload refractory to diuretics Hypertension poorly responsive to meds Persistent metabolic disturbances Persistent nausea and vomiting 17

18 Prognosis of ARF 50-80% mortality of ARF associated with sepsis, hypotension and respiratory failure Oliguria 1 6 weeks Cost of dialysis and aggressive care is $128,000/life year saved Prevention is cornerstone in patient care Community Acquired ARF Azotemia either acute or chronic 36% > 70 Hypovolemia, NSAID, obstruction Dialysis if Severe hyperkalemia Severe metabolic acidosis Marked fluid overload Signs/symptoms of uremia 18

19 Tubulointersitial Disease Involves tubules and interstitium rather than glomeruli Obstructive Nephropathy Impaired outflow of urine Increased intratubular pressure, local ischemia, associated infection leading to TIN Diagnosis via ultrasound with Hydronephrosis +/- clinical suspicion Treatment is relieving obstruction Reversible Causes of Kidney Failure Nephrotoxic drugs -Aminoglycosides -NSAIDs -Iodinated contrast -? Gadolinium -Cimetidine,Tmp,Cefoxitin Urinary Tract Obstruction Reversible Causes of Renal Dysfunction Decreased renal perfusion -Hypovolemia -Hypotension -Infection/sepsis -Drugs -Sodium avidity 19

20 ATN Acute Tubular Necrosis Initial decrease in renal blood flow then return to normal within hours Tubular dysfunction persists Leakage of glomerular infiltrate Obstruction of flow by debris in lumen of tubules Decrease in glomerular capillary ultrafiltration Biochemical changes include mitrochondrial dysfunction, ATP depletion, oxygen free radicals Radiocontrast Common Risk factors: CKD, DM, volume depletion, other nephrotoxins NaCl prevention: 1ml/kg/hr X 8 to 12 hrs prior Fenoldopam, selective D1 Dopamine receptor agonist Acetylcysteine Sodium Bicarbonate 20

21 Angiotensin Converting Enzyme Inhibitors Hemodynamic Loss of autoregulation of renal blood flow 30% increase creatinine acceptable when started Aminoglycosides ATN in 10-20% Unrelated to therapeutic range Non oliguric 7-10 days of therapy urinary concentrating ability Potentiated by volume depletion, sepsis, liver ds, other nephrotoxins Once daily preferable NSAIDs Inhibitors of PGE synthesis Volume depleted states ie: CHF, Cirrhosis, DM, CKD, Nephosis, sepsis, age, diuretics Hyperchloremic metabolic acidosis 21

22 Rhabdomyolysis Trauma, ischemia, exercise, seizures, drugs, infections Metabolic derangements hypo K, hypo PO4 Cocaine, neuroleptic malignant syndrome and Hmg CoA reductase inhibitors Muscle pain, dark urine, blood +, RBC urine, CPK 1/3 develop ARF Rapid volume expansion and alkalinization Microalbuminuria Normal < 20 mg/day mg defines microalbuminuria > 300 mg/day Albuminuria -Earliest finding of diabetic nephropathy -Risk factor for cardiovascular disease (CVD) Nephrotic Syndrome Proteinuria Edema Hypoalbuminuria Hyperlipidemia 22

23 Causes of Nephrotic Syndrome Diabetes Mellitus ( DM ) Membranous Nephropathy Focal Segmental Glomerulosclerosis ( FSGN ) Minimal Change Disease Amyloidosis/Multiple Myeloma HIV Disease ( HIVAN ) Nephritic Syndrome Active intrinsic renal inflammation Hematuria Hypertension Acute Kidney Injury ( AKI ) Edema Renovascular Disease Large Vessel Renal Artery Disease ( RAS ) Small Vessel Renal Artery Disease Thrombotic Microangiography 23

24 Large Vessel Renal Artery Disease Etiology Atherosclerosis Fibromuscular Dysplasia ( young women ) Unilateral-Hypertension without CKD Bilateral-Hypertension with CKD Atherosclerotic Renal Artery Disease Risk Factors Smoking Diabetes Mellitus Hypertension Hyperlipidemia 24

25 Case Principal Diagnosis Atherosclerosis of Renal Arteries Associated Codes Hypertensive renal disease Congestive heart failure Diabetes mellitus Coronary atherosclerosis