Renal Failure Flashcards
What conditions are at a higher risk for developing AKI?
- Hypertension
- Congestive cardiac failure
- Diabetes
- Multiple myeloma
- Chronic infection
- Myeloproliferative disorder
What are some examples of causes of Prerenal acute kidney dysfunction?
- Once MAP <80mmhg steep decline in GFR
- Hypovolemia
- Decreased cardiac output
- Decreased effective circulating volume
- Impaired renal autoregulation
What is Pre-renal Injury?
-Most common cause of renal failure (50-80%)
-Results from poor renal perfusion
-Reversed with restoration of renal perfusion/glomerular pressure
-BUN/Creatinine ratio > 20:1
-Calculate fractional excretion of
sodium (FeNa)
-Urinalysis often reveals hyaline
casts
What is is FeNa?
- FeNa = (UNa x PCr/PNa x UCr) X 100
- FeNa < 1% is suggestive of pre-renal azotemia
- FeNa >1% intrinsic renal failure
- FeNa >4% post-renal failure
What is Prerenal Treatment?
Volume expanding fluid (IVNS, LR, Packed RBCs if bleeding)
What is Intrinsic Renal Diseases?
-Acute Interstitial Nephritis (AIN)
-Acute Tubular Necrosis (ATN) 90% most
common*
-Glomerular Diseases
-Pyelonephritis
-Malignancy (MM)
-Renal artery embolism/thrombus (renal infarction)
-Vasculitis
What is Acute Interstitial Nephritis (AIN)?
-Typically allergic reaction to medication
-Post-infectious
-Autoimmune
What is the “classic presentation” of Acute Interstitial Nephritis?
- After recent new drug exposure
- Fever
- Skin rash
- Peripheral eosinophilia
- Oliguria
What is Medications associated with acute interstitial nephritis (AIN)?
-Antibiotics (B-lactams, sulfonamides, vancomycin,
erythromycin, rifampin)
-Acyclovir
-NSAIDS (can cause either direct toxicity or
allergy)
-Anticonvulsants (Phenytoin, valproate, carbamazepine)
What is Treatment of AIN?
- Discontinuation of offending agent often leads to reversal of renal injury
- Glucocorticoid therapy may accelerate renal recovery (6 week taper prednisone or IV methylprednisolone pulse 3 days)
- Damage may be permanent if long duration of exposure and high degree of tubular atrophy and interstitial fibrosis
What are Potential Nephrotoxins that cause ATN?
-NSAIDs -Chemotherapeutic agents -Aminoglycosides -Amphotericin -Vancomycin -Radiocontrast dye -Poison (ethylene glycol, heavy metals)
What is Acute Tubular Necrosis (ATN)?
acute tubular cell injury, usually reversible unless severe, prolonged
- Ischemia
- Sepsis
- Toxins
Laboratory Data for Acute Tubular Necrosis (ATN)?
- Pigmented granular casts (muddy-brown casts) on urinalysis
- Cr/BUN elevation
- FeNa >2%
What is Treatment for ATN?
-Aggressive volume replacement– hydrate (If nephrotoxic agent, volume depletion)
-If Oliguria present and extracellular-volume normalized consider loop-diuretic high dose (100-200mg Lasix) to improve urine output
-Protein restriction
-If it’s due to nephrotoxic agent, remove
offending agent
-Dialysis
What is Glomerular diseases?
- Infectious Disease associated Syndromes Post-streptococcal glomerulonephritis
- Nephrotic syndrome (Minimal change disease)
- Diabetic nephropathy
- Hypertensive nephropathy
What is Post-streptococcal glomerulonephritis (PSGN)?
-Immune complex containing strep Ag deposited in
affected glomeruli
-Antihypertensives, salt restriction, diuretics
How is PSGN Diagnosed?
- Hematuria, proteinuria, RBC casts
- Positive throat, skin culture (only 25% due to timing)
- Elevated titers of abs to strep products
What is the treatment for IgA nephropathy?
- ACE-/ARB
- Steroids
- Renal transplant
What are Classic clinical presentation of Henoch Schonlein Purpura?
- Rash (especially LE’s and buttocks)
- Abdominal pain/vomiting
- Arthralgias (knees, ankles)
- Edema (hands, feet, scalp, ears)
- Elevated Cr/BUN
- Urine hematuria/proteinuria
What is Nephrotic Syndrome?
- Heavy proteinuria (>3.5g/24hr)
- Hypoalbuminemia (<3 g/dL)
- Peripheral edema
What is the Etiology of Nephrotic Syndrome?
Membranous Nephropathy
- Minimal Change Disease
- Amyloidosis (secondary)
- Systemic Lupus Erythematosus (secondary)
- Membranoproliferative glomerulonephritis
- Focal segmental glomerulosclerosis (FSGS)
- IgA Nephropathy
What is Minimal Change Disease?
- 70-90% of nephrotic syndrome in childhood but only 10-15% of nephrotic syndrome in adults.
- Abrupt onset edema; nephrotic syndrome
- Average urine protein – 10gm/day
- Hypoalbuminemia
- HTN
- More suceptible to infection with gram+ organisms
What are the treatments for Minimal Change Disease?
- 30% of children have spontaneous remission but all children are treated with steroids
- 90-95% of children develop complete remission after 8 weeks of steroid therapy
- 80-85% of adults develop complete remission after 8 weeks of steroid therapy
- Prednisone is first line therapy (up to 16 weeks of therapy)
- ESRD is rare but may have relapses
What is vascular AKI?
-Thrombus, embolus, dissection,
vasculitis
-TTP, HUS, DIC
What is Postrenal renal failure?
- Prostatic obstruction (hypertrophy, stricture or malignancy)
- Bladder CA, stone, clots
- Ovarian/cervical/retroperitoneal malignancy
What is Postrenal AKI Treatment?
Relieve the obstruction
What is Polycystic Kidney Disease?
- Multisystem and progressive genetic d/o with cyst formation and enlargement of the kidney (and other organs ie. Pancreas, liver, spleen)
- 50% require transplant/dialysis by 60yo
- Screen family members as autosomal dominant
- Intracranial aneurysm x2 as common as general population (10%)
- ESRD
What are signs and symptoms of Polycystic Kidney Disease?
-Pain (Abdomen, flank, back) -Enlargement of cysts -Hemorrhage into cyst or perinephric hematoma -Infectious (UTI, pyelonephritis, abscess, infected cyst) -Nephrolithiasis (20-30%)
Diagnosis of Polycystic Kidney Disease?
Urinalysis (Hematuria, 1/3 microalbuminuria)
Treatment for Polycystic Kidney Disease?
- Blood pressure management (ACE-/ARB – slows progression of disease)
- Pain control (Avoid NSAIDs, Surgical cyst decompression (can be done by IR), Nephrectomy)
- Recurrent infections (50% develop UTI (mostly women), May develop infected cysts)
- Hematuria (Hydrate and if substantial transfuse, Very suceptible to trauma (60% hemorrhage))