Renal lecture

• Intrarenal


  Directly with the kidneys
• Prerenal


  Blood flow reduction
• Postrenal


  After urine formation (stones, bladder)
• Acute renal dysfunction

  • Sudden and most of the time reversible loss of kidney function
  • 62% of individuals have more than one risk
• Etiology/Risks of acute renal dysfunction

  • Decrease of blood flow (prerenal)
  • Indication that you might have it (Intrarenal)
  • Postrenal
• Hypotension

  Not enough pressure to push the blood out
• Dehydration

  Not enough fluid in the body → kidneys are not able to remove waste products properly, leads to a decrease in circulating blood
• Myoglobinuria

  intrarenal

  
  

  Large molecules that are release into the urine due to muscle cell break down, they can promote the formation of kidney stone when they combine with other substances in the urine causing urinary obstruction
• Hemoglobinuria

  intrarenal

  
  

  Large molecules that are release into the urine due to red blood cells, they can promote the formation of kidney stone when they combine with other substances in the urine causing urinary obstruction
• Exposure to radiocontrast dyes (CT Scan)

  intrarenal

  
  

  The dye used contains iodine which can be toxic to the kidneys, they can cause vasoconstriction reducing blood flow to the kidneys, can be more damaging for those with pre-existing kidney problems and diabetes pts
• Decrease in urine output to <1mL/kg/ht

  There's a big problem if an adult is putting out <30 ml/hr
• Uncontrolled diabetes

  intrarenal

  
  

  It happens through a condition called diabetic nephropathy which can lead to damage of the glomeruli(tiny blood vessels in the kidney, acts as filter), making the filters(glomeruli) leak protein into the urine causing extra strain
• Having extra protein in the urine

  Causes strain because the protein can cause narrowing of the kidney blood vessels
• Chronic hypertension

  intrarenal

  
  

  Narrowing of the blood vessels → reduce blood flow , activation of RAAS (vasoconstriction), renal artery stenosis(narrowing of the renal arteries)
• Nephrotoxic medications (aminoglycoside)

  This type of medication can cause damage by squeezing the blood vessels to tight and form crystals in the kidney which can lead to obstruction and impairment of urine flow
• NSAIDs: Ibuprofen

  intrarenal

  
  

  Can make blood vessels in the kidney narrower reducing blood flow, reduce the levels of prostaglandin and inhibits prostaglandin synthesis (prostaglandin helps in keeping the kidney's blood vessel relax and open)
• Autoimmune disorders

  It can make antibodies that mistakenly attack our own body and that includes the kidney
• Kidney stones

  Block the flow of the urine causing backup and pressure in the kidney
• Bladder cancer

  Obstruction of the urine flow leading to hydronephrosis which is the urine backing up to the kidney, increasing pressure
• Prostate enlargement

  Because it can compress the urethra (tube that takes the urine from the bladder out of the body), leading to complete or partial obstruction of the urine, this obstruction can cause the urine to back up into the kidney increasing the pressure making the kidney tissue to swell and stretch
• Creatine (Cr)

  High elevation means the kidney are not working correctly because the are supposed to be getting rid of this product, when muscle breakdown they release Cr
• Urea nitrogen (BUN)

  High elevation mean the kidney are not properly working, from protein
• Acute tubular necrosis (intrarenal disease)

  • A condition in which the renal tubules are damaged due to ischemia, these tubules are responsible for filtering out waste products and maintaining electrolyte balance. They will cause an obstruction
  • Recoverable
  • Most common cause of intrarenal disease
• Etiology of acute tubular necrosis

  • Ischemic ATN: reduction of blood flow to the kidneys
  • Nephrotoxic ATN: exposure to nephrotoxic substances that directly damage the renal tubular cells
• Ischemic ATN

  Causes include, hypotension, dehydration, decreased cardiac output
• Nephrotoxic ATN

  Nephrotoxic agents: imaging dyes (CT Scan), aminoglycoside, NSAIDs
• Glomerulonephritis

  • Inflammation of the glomeruli which are the tiny filters that are responsible for filtering waste products and excess fluid from the blood
  • Hypersensitivity type 3
• Glomerulonephritis etiology

  Infection: most common infection is streptococcal. The body detects a foreign invader and starts to create antibodies to attack and get rid of the bacteria, once this happens immune complexes(antibodies bound to protein from the bacteria) can form and make their way through the bloodstream where they can be deposited in the glomeruli, this will cause an inflammatory response causing the glomeruli to start leaking protein and blood cell into the urine
• Glomerulonephritis is seen 7-21 days after the infection began
• Glomerulonephritis can lead to more serious kidney disease and even kidney transplant
• Goodpasture's Syndrome

  • The body produces antibodies that attack the basement membrane of the kidney. Is a more aggressive form of glomerulonephritis. Leads to inflammation and tissue damage
  • Hypersensitivity type 2
  • Early diagnosis and tx are crucial to prevent irreversible damage
• Tx for Goodpasture's Syndrome

  Plasmapheresis(removing plasma from the blood) and immunosuppressants
• Nephrolithiasis (kidney stones)

  • Formation of kidney stones, or calculi
  • 12% of men, 7% of women
  • Dehydration increases risk
  • Recurrence is common (52%)
• Common forms of kidney stones

  • Calcium oxalate: 75-80% of all stones
  • Struvite: 15% (magnesium, ammonium, phosphate)
  • Uric acid: 7%, excess of uric acid in the urine (diet high in purines or medical condition)
  • Cystine: <1%, caused by genetic disorder → excessive excretion of cystine in the urine
  • CaSUCy
• Predisposing factors for kidney stones

  • Age >40 years, male
  • Dietary (purines, calcium, oxalate)
  • High sodium diet
  • Gastric bypass surgery
  • Hypercalciuria(elevated level of calcium in the urine), hyperparathyroidism (regulate calcium, stimulates the kidney to reabsorb more calcium), hyperuricemia(elevated levels of uric acid)
  • Inflammatory bowel disease
  • Dehydration
• Pyelonephritis

  • Type of UTI (urinary tract infection)
  • Infection of renal pelvis and interstitium
  • Acute or chronic
  • Bacteria usually ascend from lower urinary tract like the ureters
• Most common cause of pyelonephritis

  Bacterial infection(E.coli, Proteus, Pseudomonas), that may result from urine reflux or obstructions
• Polycystic kidney disease

  • Genetic disorder characterized by the formation of fluid-filled cysts in the kidney
  • Most common form is autosomal-dominant
  • Most common hereditary cause of renal disease
  • Accounts for 6-8% of dialysis pt
  • Defect in polycystin-1 or polycystin-2 help kidneys cells communicate and work well
  • Fluid -filled cysts in both kidneys proliferate within the kidneys and fibrotic changes occur over time
  • Progression to renal failure is slow, rarely before age 40
• Renal failure types

  • Renal insufficiency: decline in GFR(glomerular filtration rate) to about 25% of normal
  • Renal failure: decline in GFR to 15-20% of normal
  • End-stage renal failure: 10% or less of normal GFR
  • One does not see actual symptom in renal failure types
• Chronic renal failure causes

  • Family history
  • Age>60 years
  • Atherosclerosis
  • Chronic glomerulonephritis
  • Diabetes
  • Nephrotoxic medications