Urology/Renal Flashcards
What are the average values for acid/base disorders?
“24/7 40/40”
-24 (HCO3, base)/ 7.40 (pH), 40 (CO2, acid)
What is the three-step approach to acid-base disorders?
Look at your PH (7.35-7.45 normal)
- < 7.35 = acidosis
- > 7.45 = alkalosis
Next look at your PCO2 is it normal, low, or high (35 to 45 normal)
- increased CO2 and decreased PH = respiratory acidosis
-decreased CO2 and increased PH = respiratory alkalosis
-If you don’t see a change in the CO2 in relation to the PH then take a look at the HCO3
Finally look at the HCO3 is it normal, low, or high (20-26 normal)
-decreased HCO3 and decreased PH = metabolic acidosis
-Increased HCO3 and increased PH = metabolic alkalosis
What is acute renal failure?
- Stage 1: Normal GFR (>90)
- Stage 2: Early GFR (60-90)
- Stage 3: Moderate GFR (3a 45-59) (3b 30-44)
- Stage 4: Severe GFR (15-29)
- Stage 5: Kidney failure (GFR < 15 = dialysis)
What are the causes of renal vascular disease?
Diabetic kidney disease #1
- hypertension
- smoking
- vascular disease aka renal artery stenosis
- glomerular disease
- renal cysts
- genetics (autoimmune, SLE, polycystic kidney disease, Alport’s syndrome)
What is the presentation of acute kidney injury or acute renal failure?
- an abrupt or rapid decline in renal filtration function
- elevated serum creatine and decrease GFR
- azotemia a rise in blood urea nitrogen (BUN) concentration
What are the causes of acute renal failure?
prerenal, intrinsic, ans postrenal
What are the causes of prerenal (before the kidneys) acute renal failure?
- this is due to decrease blood flow to the kidneys
- remember the nephrons are intact
- hypovolemia (most common)
- NSAIDs, IV contrast, ACEI, ARBS (renal artery stenosis)
- treatment = creatine improves with IV fluids
- low blood pressure
- heart failure
What are the causes of intrinsic (in the kidneys) acute renal failure?
- renal aka intrinsic direct damage to the kidneys
- nephrotoxic drugs = aminoglycosides (Gentamicin)
- cyclosporine
- tumor lysis syndrome
- vasculitis (SLE, sarcoidosis)
- crystals from gout
- myoglobin from rhabdomyolysis
What are the pearls of intrinsic renal failure?
cellular casts is the hallmark = RBC CASTS
-tx: IV fluids remove drugs if present and sometimes Lasix to get the kidneys moving
What are the causes of post renal (downstream from the kidney) acute renal failure?
- there is some type of obstruction in the ureters such as kidney stones
- BPH, tumors
- congenital or structural abnormalities
- remove the obstruction or fix the structural abnormality
What are the causes of acute renal failure?
rapid but usually reversible reduction in renal excretory function sufficient to cause azotemia
- ATN, interstitial nephritis, glomerulonephritis
- azotremia: retention of nitrogenous waste
- uremia: symptomatic azotemia, with n/v/lethargy
- acute: sudden, hours/days and is reversible
- chronic: progressive, irreversible
- oliguria: urine output < 400 ml/day
How is acute renal failure dx?
CBC, BUN, Cr, electrolytes (Ca, phosphate), UA, postvoid residula bladder volume
-tx: depends on cause
What is the prerenal mechanism?
perfusion (50%) - kidney working fine but things that perfuse it aren’t
- ex: volume loss, heart failure, loss of peripheral vascular resistance (espies/anesthesia)
- weak, decreased urine output, dizziness, sunken eyes, tachy, orthostatic
- fractioal excretion of sodium is normal
- urine specific gravity >1.030, Bun/Cr > 20, urine osm > 500
- tx: fluids, cardiac support, treat shock
What is renal mechanism?
- RC casts = glomerulonephritis
- WBC casts = pyelonephritis
- muddy casts = ATN
- hyaline casts = normal
- waxy = chronic renal disease
- urine specific gravity <1.010, BUN/Cr <10, urine ism < 300
What is post-renal mechanism?
obstructive - most likely prostate
- usually low/no urine output
- place foley Cath to find the source of obstruction; renal US to look for tumor/hydroephrosis
What is ATN?
from kidney ischemia/toxins; UA shows muddy brown casts
- damaged tubules means can’t concentrate urine = high FENa
- prerenal failure is MC cause
- drugs: amp B, cisplatin, aminoglycosides, NSAIDs, ACE
- ischemic: dehydration, shock, sepsis
- fraction excretion of sodium > 2% + muddy, pigmented granular casts + high urine osm
What is interstitial nephritis?
- immune-mediated response
- drugs: PCN, sulfa, NSAIDs, phenytoin
- US: WBC casts + eos + hematuria
- dx: renal biopsy, discontinue offending drug, steroids, dialysis if needed, usually self-limiting
What is glomerulonephritis?
IGA nephropathy, post infectious, membranoproliferative
- UA: oliguria, hematuria, RBC casts
- causes: group A strep, IGA, anti-GBM, ANCA
- post-strep glomerulonephritis = MC infectious cause of acute glomerulonephritis: either from strep pharyngitis or strep skin infection (impetigo) = hematuria, HTN, periorbital edema
- dx: proteinuria + RBC in urine; usually caused by group A beta-hemolytic strep
What is chronic kidney disease?
a progression on ongoing loss of kidney function (GFR) defined as less than 60 mL/min/1.73 m2 or presence of kidney damage (proteinuria, glomerulonephritis or structural damage from polycystic kidney disease) for > 3 months
-measurement of GFR is the gold standard - the Cockcroft - gault formules (requires age, body weight, and serum creatinine) or Modificationof diet in renal disease equation
What is the etiology of chronic kidney disease?
diabetes, hypertension, glomerulonephritis
What are the findings of chronic kidney disease?
fatigue, pruritus, Kussmaul respirations, asterisks (flapping tremor), muscle wasting, broad waxy casts
What are the stages of chronic kidney disease?
- Stage 1: GFR > 90 mL/min
- asymptomatic
- Stage 2: GFR 60-89
- asymptomatic
- Stage 3: GFR 30-59
- Stage 4: GFR 15-29
- dialysis and kidney transplant
- Stage 5: GFR < 15
- kidney transplant
What is the management of chronic kidney disease?
blood pressure control <130/80, ACE or ARB A1c 6.5-7.5%
-patients with chronic renal failure typically present with hypocalcemia, hyperphosphatemia, and metabolic acidosis
What is acute interstitial nephritis?
- etiology: immune-mediated response
- drugs: PCN, sulfa, NSAIDs, phenytoin etc.
- Immunologic and infectious disease: strep, SLE, CMV, Sjogren’s, Sarcoidosis
- urinalysis: WBC casts and eosinophils