Functions of the Kidney

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Functions of the Kidney

• Maintain electrolyte, acid-base balance
• clear the blood of toxins
• Make EPO, active Vitamin D
• gluconeogenesis, hormone metabolism

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Kidney disorders

• Hyponatremia
• Hypokalemia
• Metabolic Alkalosis
• chloride responsive
• chloride unresponsive
• Metabolic Acidosis
• anion gap
• non-anion gap

• Hypernatremia
• Hyperkalemia
• Calcium
• Phosphate
• Magnesium

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Renal Failure

• A growing epidemic
• 350,000 on renal replacement therapy
• 80-90,000 new every year
• Over one million thought to be in pipeline

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Creatinine

• Normal 0.8-1.2mg/dl lower in pregnancy and
  cirrhosis and chronically ill/aged, higher in
  muscleheads, pts taking creatine and in rhabdo.
• Cephalosporins/ketosis change assay to increase
  creat, cimetidine and trimethoprim block
  secretion to increase

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BUN

• Normal 5-10mg/dl
• Increased with ?GFR, heavy GI bleed, TPN,
  hypercatabolic states (steroids, sepsis) and
  prerenal volume depletion-( gt20x creat), such as
  CHF, cirrhosis, nephrosis, sepsis and salt
  depletion.
• When gt100mg/dl, often associated with uremia

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Hematuria

• Definition
• straightforward- gt3-5 RBCs per high power field
• Definitions may vary

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Causes of hematuria

• Anatomic
• Kidney
• Ureters
• Bladder
• Urethra
• Prostate or GYN

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URINALYSIS
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URINALYSIS
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URINALYSIS
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Proteinuria

• Microalbuminuria-dip (-), 30-300 mg/day of
  albuminuria. Seen in diabetes, vascular dz
• Dip() urine, 300mg-2 g seen in glomerular and
  tubular disease
• Dip () urine, gt 2g/day, glomerular disease
• Dip (-) urine, still can be overflow protein from
  myeloma, use SSA or UPEP

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IVP
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Renal Ultrasound
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CT (spiral)
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Hypertension

• Defined as resting, repeated BP gt 140/90
• Risk parallels severity of increased BP and other
  risks for vasc. Dx-male, AA, smoking, diabetes,
  cholesterol, age
• Treat mild BP with diet, weight loss, exercise
• Move onto drugs when above fails
• Approx 5 of pts have secondary causes, more when
  BP severely elevated

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HTN- secondary causes

• Truncal obesity- Cushings
• Labile HTN - Pheo
• Bruits- Renal artery stenosis
• Decreased fem pulses- Coarctation
• Abdominal/flank mass- Polycystic kidneys
• Increased creat/edema- Renal disease
• Hypercalcemia- Hyperparathyrodism
• Hypokalemia- Hyperaldosteronism/licorice/
  Liddles syndrome

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HTN- Rx

• Diabetics, renal disease with proteinuria,
  Cardiac injury- ACE inhibitors
• Must watch for reversible hyperkalemia, renal
  insufficiency, cough, angioedema
• Think bilateral renal artery stenosis when acute
  renal failure occurs.
• Do not use ACEi or ARBs in pregnancy

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Glomerular disease

• Hematuria, proteinuria or both
• RBC casts, especially when proliferative
• Nephritis hematuria, hypertension, renal
  insufficiency and edema
• Nephrosis proteinuria (nephroticgt3.5g/d) with
  edema, hypoalbuminemia and hypercholesterolemia
• Idiopathic or part of systemic disease

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FSGS
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Membranous
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MPGN
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Diabetes
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Amyloid
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IgA Nephropathy
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Chronic renal failure

• Diabetes
• HTN
• Glomerular disease (IgA, membranous, FSGS)
• PCKD
• SLE
• Interstitial disease
• Heriditary/ Congenital

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PKD

• Autosomal dominant (1 in 800)
• gt 2 cysts/kidney by age 30
• Large cysts with chance of infection/hemorrhage,
  assoc with berry aneurysm, diverticulosis, floppy
  valves, other organ cysts (liver/panc/ovarian)
• Treat infection with Cipro
• NO Rx for disease yet

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ADPCKD
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Interstitial disease

• Reflux nephropathy with pyelo
• NSAIDS/TYLENOL/Pb/heavy metals
• SLE/Sjogrens/Sarcoid/TB
• Chinese herbs
• Usually mild HTN, mild proteinuria, pyuria
• hypercalcemia for granulomatous disease

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Chronic renal failure

• Clearance- if inadequate, dialysis/transplant
• Anemia- normochromic,normocytic treated with EPO
  and iron
• Bones- high phos and low Vit D cause low Ca,
  high PTH--Rx with PO4 binders and Vit D
• Access- potential for steal/infection/high output
  heart failure

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Stalling ESRD

• Blood pressure control
• ACE inhibitors/ ESRD
• Low salt, low protein diet
• ? Treatment of underlying disease
• Preventing toxicities

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HYPERKALEMIA
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Treating anemia

• Improves energy, sexual function, mentation,
  quality of life and possibly reduces LVH, angina,
  death
• Effective treatment with iron, EPO, NESP
• Careful to screen for other causes of anemia

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Protecting the bones

• Limit phosphate intake
• Phosphate binders
• Calcium or Renagel
• Vitamin D
• Monitor labs

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Protect the heart??

• Exercise
• Healthy diet
• NO SMOKING, Limited EtOH
• ? Lipid management
• ?Aspirin

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Dialysis

• Start for low clearance, esp if poor nutrition
• Outcome marker is albumin
• Hemodialysis most common, initial comp is
  dysequilibrium from rapid decrease of osmolality.
  Chronic complications of hypotension and
  cramping, arrythmia
• Death from heart disease, infection, cancer,
  access failure, discontinuation

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Peritoneal dialysis

• Must do large volume, frequent exchanges for
  adequacy
• Less anemia and high blood pressure
• Peritonitis less common but still well
  represented. Usually Staph (70-80) or E. coli
  (15-20). Rarely fungal
• Treat with appropriate antibiotic IP, pull
  catheter if fungal or fails RX

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Transplant

• Highly effective- 90 1 year success
• LRDgtCAD
• Problems are immunosuppression, rejection
• Infections are early bacterial (post-op), viral
  after 1 month (CMV), PCP in first
  yearprophylaxis effective
• Technical problemsobstruction and renal artery
  stenosis have usual sequelae/RX

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Transplant

• Loss of kidney function
• Death (cards late, infection early)
• Chronic rejection
• Cyclosporine toxicity
• Recurrent disease
• FSGS, MPGN, membranous, IgA, oxalosis
• NOT heriditary disease (PKD, cystinosis, Alport)