Discuss the KDIGO definition and stages of acute renal failure
Acute Renal Failure if any of the following:
- urine volume <0.5mL/kg/hr for 6 hrs
- increased serum creatinine by 26.5 within 48hrs
- increased serum creatinine by >1.5x baseline within 7 days
Stage 1 Any of the following
- increase in serum creatinine by >26.5
- increase in serum creatinine by 1.5-1.9x baseline
- urine <0.5mL/kg/hr for 6-12hrs
Stage 2 Any of the following
- Increase in serum creatinine by 2-2.9x baseline
- urine <0.5mL/kg/hr for >12hrs
Stage 3 any of the following
- increase in serum creatinine by >353.6
- increase in serum creatinine by >3x baseline
- urine volume <0.5mL/kg/hr for >24hrs
- anuria for >12hrs
- Initiation of renal replacement therapy
Discuss the definition and stages of chronic renal failure
Chronic Renal Failure if Any of the Following
- GFR <60mL/min/1.73m2 for >=3mon
- kidney damage for >3mon as defined as structural or functional abnormalities with or without decreased GFR
- proteinuria, hematuria
- polycystic kidney disease, hydronephrosis
Stage 1
- kidney damage with normal or high GFR >90
Stage 2
- kidney damage with mildly decrease GFR: 60-89
Stage 3
- moderately decreased GFR 30-59
Stage 4
- severely decreased GFR 15-29
Stage 5
- kidney failure GFR <15 or requiring dialysis
Discuss the presentation of acute renal failure
Volume - overload resulting in peripheral and pulmonary edema Uremia - malaise, fatigue - n/v - pruritus - restless leg syndrome - encephalopathy - pericarditis - glove and stocking sensory neuropathy Metabolic acidosis with increased anion gap
Discuss the presentation of chronic renal failure
Metabolic Syndrome - hypertension, hyperlipidemia - CHF Anemia - decreased EPO Electrolyte abnormality - hyperkalemia - hyperphosphatemia - hypocalcemia Renal Osteodrystrophy - bone lytic lesion due to increase PTH Platelet Dysfunction Hormone Imbalance - thyroid hormone Malnutrition
Discuss the pre-renal causes of renal failure
Acute
- Fluid loss
- renal loss from diuretic
- GI loss from diarrhea, vomiting
- shock
- decreased circulating volume from CHF, cirrhosis, nephrotic syndrome
- Vascular
- thromboembolism
- aortic dissection
- Medication
- NSAID from constriction of afferent arteriole
- ACE inhibitor through dilatation of efferent arteriole
- diuretics
Chronic
- fluid loss
- hypervolemic state
- vascular
- renal artery stenosisDiscuss the renal causes of renal failure
Acute
- Acute Tubular Necrosis (most common cause of hospitalization for ARF)
- any prolonged pre-renal cause
- medication: Aminoglycosides, Vancomycin, Methotrexate
- rhabdomyolysis, tumour lysis syndrome
- IV contrast
- Acute Interstitial Nephritis
- medication: all antibiotics, NSAID, PPI, phenytoin
- infection: Legionella, strep, EBV
- Glomerular Nephritis
- nephrotic syndrome
- nephritic syndrome
- Intrinsic Renal Vascular
- microangiopathy and hemolytic anemia: TTP, malignant hypertension
- cholesterol emboli
- vasculitis
Chronic
- instrinsic tubular and interstitial disease
- polycystic kidney disease
- nephrolithiasis
- sarcoidosis
- Sjogren’s
- Glomerular Nephritis
- nephrotic: diabetic
- nephritic
- Intrinsic Renal Vascular Pathology
- nephrosclerosis due to hypertension
Discuss the post-renal causes of renal failure
Tumor - male: BPH, prostate cancer - female: cervical, ovarian - bladder Structural Urologic Obstruction - bladder stones - strictures along urinary tract - papillary necrosis Neurogenic Bladder - multiple sclerosis - diabetes mellitus
Discuss how to differentiate different causes of renal failure
Rule out Post-Renal
- put in foley catheter to relieve post-bladder obstruction
- would get urine outflow
- pelvic and renal ultrasound
Rule in Pre-renal
- hypovolemia
- medications
Differentiate Pre-Renal and Renal on Urinalysis
- Urine Na concentration: <20 in pre-renal
- Fractional excretion of Na: <1% in pre-renal
- Fractional excretion of Urea: <35% in pre-renal
- Sediment and protein:
- Muddy brown casts in ATN
- WBC casts and eosinophils in AIN
- proteinuria, RBC cast in GN
Differentiate between nephrotic and nephritic syndrome
Urine Analysis - heavy proteinuria in nephrotic vs mild - PCR >200 in nephrotic - 24hr urine protein >3g in nephrotic - hematuria and RBC casts in nephritic Urine Appearence - frothy in nephrotic - gross hematuria in nephritic Labs - low albumin and increased lipids in nephrotic - high creatinine and urea in nephritic Systemic Features - edema in nephrotic - hypertension and peripheral edema in nephritic
List the differential for nephrotic syndrome
Systemic Nephrotic Syndrome - Diabetic nephropathy - hypertensive nephropathy - multiple myeloma - amyloidosis Renal Nephrotic Syndrome - minimal change glomerulopathy - focal segmental glomerulosclerosis such as in HIV, malignant hypertension - Membranous nephropathy in hematological malignancy, HIV, hepatitis
List the differential for nephritic syndrome
Low Complement (C3/C4)
- systemic nephritic syndrome
- SLE
- endocarditis
- cryoglobunemia such as Hep C
- renal nephritic syndrome
- post-infectious (strep) glomerulonephritis
- membranoproliferative glomerulonephritis such as HIV, Hep B/C, IV drug use
Normal Complement
- systemic nephritic syndrome
- IgA nephropathy
- Alport syndrome
- Renal nephritic syndrome
- Wegner's granulomatosis
- Churg-Strauss syndrome
- Goodpasture syndromeList the emergent indications for dialysis
AEIOU
Discuss the management of acute renal failure
Treat Reversible Causes
- remove nephrotoxic medication
- restore volume
- remove urological obstruction
- glycemic control in diabetes
- immune suppressive therapy in glomerulonephritis
Slow Progression and Prevent Complications
- control BP
- address cardiovascular risk factors
- heavy proteinuria then protein restricton
- CKD with proteinuria then ACEi or ARB
Treat Complications of CKD
- anemia symptomatic and hemoglobin <100 then EPO replacement with Eprex or Darbepoetin
- hyperkalemia then K restriction and bind resin
- hyperphosphatemia then phosphate restriction and CaCHO3 binder (Tums)
- metabolic acidosis protein restriction and NaHCO3
- volume overload: Na and water restriction and diuretics
- Renal osteodystrophy: active vitamin D, PTH inhibitor
- Platelet dysfunction: dDAVP, cryoprecipitate
Renal Replacement
- peritoneal or hemodialysis
- surgical kidney replacement
Discuss the renin-angiotensin-aldosterone system
Discuss the mechanism of action of ACEi and ARB and contraindications and adverse effects
Mechanism of action - ACEi inhibit ACE to reduce angiotensin II formation therefore inhibiting Na and water retention and vasoconstriction - ARB block AT1 receptor to inhibit Na and water retention and vasoconstriction Contraindication - renal failure - hyperkalemia - hypotension, hypovolemia - black - pregnancy - liver failure - renal artery stenosis Adverse Effects - hyperkalemia - decreased GFR causing ARF - chronic cough and angioedema in ACEi
List the causes of bilateral and unilateral leg edema
Bilateral
- CHF
- CKD
- Decreased protein: cirrhosis, nephrotic syndrome, protein losing enteropathy, malnutrition
- Vasodilatation: trauma, burns, sepsis, anaphylaxis
- hypothyroidism
- medication (NSAID, CCB, diabetic medication, anticonvulsants - Pregabalin, Gabapentin)
- pregnancy
Unilateral
- Venous obstruction
- thrombosis
- venous insufficiency
- Lymphatic obstruction
- lymph node dissection
- malignancyDiscuss the treatment for leg edema
Treat Underlying Cause
Non-Pharmacological
- reduce Na intake
- compression stocking
- lie in supine position
Pharmacologic
- Furosemide 10-40mg PO
- can add thiazide
- Spironolactone and Furosemide for cirrhosisList the Cockcroft-Gault Equation
CrCl: [(weight in kg)(140-age)x1.23]/Serum Cr
- for women multiply by 0.85
Discuss the pathophysiology, presentation and management of polycystic kidney disease
Pathophysiology - Autosomal dominant with PKD1 and PKD2 genes Presentation - Asymptomatic - Hematuria Extra-Renal Manifestations - Hepatic cysts - Mitral valve prolapse - Cerebral aneurysm - Diverticulosis Complications - UTI - HTN - Chronic renal failure Investigation - renal ultrasound - CT abdo with contrast Management - prevention of complications - genetic counselling