Nephrology Flashcards
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 stenosis
Discuss 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 syndrome
List the emergent indications for dialysis
AEIOU
- Acidosis
- pH <7.2 and refractory to HCO3 or unable to give due volume overload
- metabolic acidosis with arrthymia - Electrolytes
- hyperkalemia with ECG changes unresponsive to treatment - Ingestions
- salicylates
- ethylene glycol - Overload
- volume overload unresponsive to therapy - Uremia
- neurologic symptoms
- pericarditis
- platelet dysfunction
- intractable n/v - severe renal failure creatinine >1060 or BUN >36
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
- Renin released into blood from juxtaglomerular apparatus in kidney in response to
- hypotension by baroreceptor in afferent arteriole
- hypovolemia from renal hypoperfusion and decreased NaCl delivery to macula densa
- hypotension and hypovolemia increase sympathetic output - Renin convert angiotensinogen (from liver) to angiotensin 1
- Angiotensin converting enzyme (lung) convert angiotensin I to angiotensin II
- Angiotensin bind to angiotensin receptor which increase extracellular volume and BP
- systemic arterial vasoconstriction
- increased thirst
- vasoconstriction of efferent glomerular arteriole to increase GFR
- increased Na and water reabsorption in proximal convoluted tubule - angiotensin II stimulate adrenal gland to release aldosterone
- aldosterone increase Na reabsorption - angiotensin II stimulate posterior pituitary gland to secrete ADH
- increase water reabsorption in collecting ducts
- ADH increase thirst
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