Chronic kidney-disease-1216842299045729-8

Chronic KidneyChronic Kidney
DiseaseDisease
LCDR Perry, MSC, US Navy

Chronic Kidney DiseaseChronic Kidney Disease
• Topics
– Background
– Causes
– Clinical findings
– Labs and imaging
– Complications
– Treatment
– Prognosis

• Essentials of diagnosis
– Progressive azotemia over months to years
– Symptoms and signs of uremia when nearing
end-stage dz
– HTN in majority
– Isosthenuria and broad casts in urinary
sediment are common
– Bilateral small kidneys on US

• National Kidney Foundation (NKF) defines
CKD as evidence of renal damage (based
on abnormal UA [proteinuria, hematuria]
or structural abnormalities found with US)
or GFR < 60 mL/min for 3 or more months

• Five stages of CKD

• Over 28 million affected…number increasing
daily
• Over 400,000 Americans currently treated with
renal replacement therapy
• Most common RF for CKD include DM, HTN,
CVD, FHx of CKD, and age > 60 yrs
• Major outcomes of CKD include CVD,
progression to renal failure, and development of
complications of impaired renal function, such as
anemia, d/o of mineral metabolism, and
secondary hyperparathyroidism

• In CKD, reduced clearance of certain
solutes principally excreted by the kidney
results in their retention in the body fluids.
The solutes are end products of the
metabolism of substances of exogenous
origin (eg, food) or endogenous origin (eg,
catabolism of tissue)

• CKD is rarely reversible and leads to
progressive decline in renal function. Reduction
in renal mass leads to hypertrophy of the
remaining nephrons with hyperfiltration, and the
glomerular filtration rate in these nephrons is
transiently at supranormal levels. These
adaptations place a burden on remaining
nephrons, leading to progressive glomerular
sclerosis and interstitial fibrosis, suggesting that
hyperfiltration may worsen renal function

• Symptoms develop slowly and are
nonspecific
• Pts may remain asymptomatic until renal
failure is far-advanced (GFR < 10-15
ml/min)
• Manifestations can include fatigue,
malaise, weakness, pruritis
• GI c/o anorexia, n/v, metallic taste and
hiccups are common

• Neurologic problems include irritability,
difficulty concentrating, insomnia, and
forgetfulness
• Menstrual irregularities, infertility,
and loss of libido are also
common as condition
progresses

• PE reveals a chronically ill-appearing pt
• Look for possible underlying cause (DM, lupus)
• HTN is common
• Skin may be yellow, with evidence of easy
bruising
• Uremic fetor (fishy breath) may be present
• Cardiopulmonary and mental status changes are
frequently noted also. See CMDT

• Labs
– Dx made by documenting elevations of BUN
and serum creatinine concentrations
– GFR…once < 60, refer to Nephrologist
– Persistent proteinuria is suggestive of CKD,
regardless of GFR level
– UA: broad, waxy casts (evidence of loss of
tubular concentrating ability)

• Labs (cont)
– May see anemia, metabolic acidosis,
hyperphosphatemia, hypocalcemia, and
hyperkalemia…with both acute and chronic
renal failure
– Further eval needed to differentiate between
acute and chronic renal failure
• Evidence of previously elevated BUN and
creatinine, abnormal prior UA, and stable but
abnormal serum creatinine on successive days is
most consistent with a chronic process

• Imaging
– Finding of small echogenic
kidneys b/l (<10 cm) by US
supports dx of CKD/irrev. dz
– Radiological evidence of renal
osteodystrophy is another helpful
finding
• Check phalanges of hands

• Complications (of uremia)
– Hyperkalemia
– Acid-base d/o
– Cardiovascular
– Hematologic
– Neurologic
– Disorders of mineral metabolism
– Endocrine d/o

• Hyperkalemia
– Potassium balance usually remains intact until
GFR < 10-20 mL/min
– Tx of acute hyperkalemia involves cardiac
monitoring, IV calcium chloride or gluconate,
insulin with glucose, bicarbonate, and sodium
polystyrene sulfonate
– Chronic hyperkalemia tx’d with dietary
potassium restriction, and sodium polystyrene
PRN

• Acid-base d/o
– Damaged kidneys are unable to excrete the 1
mEq/kg/d of acid generated by metabolism of
dietary proteins. The resultant metabolic
acidosis is primarily due to loss of renal mass
– Tx
• Maintain serum bicarb level at > 21 mEq/L
– Alkali supplements include sodium bicarbonate,
calcium bicarbonate, and sodium citrate

• Cardiovascular complications (HTN)
– HTN is most common complication of ESRD
– HTN control with weight loss and tobacco
cessation
– Salt intake reduced to 2g/day
– Initial RX to include ACE inhibitor or
angiotensin II receptor blocker (ARB)
• If serum potassium and GFR permit (recheck 1
wk)
– Goal BP is <130/80 mm Hg; for those with
proteinuria > 1-2 g/d, goal is < 125/75 mm Hg

• Cardiovascular complications (pericarditis)
– Pericarditis may develop with uremia
– Cause believed to be retention of metabolic
toxins
– Symptoms include CP and fever. May have
pulsus paradoxus and friction rub on exam
– Pericarditis is an absolute indication for
initiation of hemodialysis

• Cardiovascular complications (CHF)
– Pts with ESRD tend toward a high cardiac
output. Often have extracellular fluid overload,
shunting of blood through AV fistula for
dialysis, and anemia. In addition to HTN, this
causes increased myocardial work and
oxygen demand. There is also increased rate
of atherosclerosis. All of this contributes to
LVH and dilation, present in 75% of pts
starting dialysis. Tx with loop diuretics, ACE
inhibitors, and regulation of salt and water

• Hematologic complications
– Anemia
• Normochromic, normocytic
• Due to decreased erythropoiesis and RBC survival
• Many pts are also iron deficient
• Recombinant erythropoietin (epoetin alfa) used in
pts whose hematocrits are < 33%
• Iron supplement PRN also

• Hematologic complications
– Coagulopathy
• Mainly caused by platelet dysfunction
• Platelet counts only mildly decreased, but bleeding
time is prolonged
• Platelets show abnormal adhesiveness and
aggregation
• Pts may present with petechiae, purpura, and
increased bleeding during surgery
• Dialysis improves bleeding time but doesn’t
normalize it
• Tx goal = Hct increased to 30%

• Neurologic complications
– Uremic encephalopathy does not occur until
GFR falls below 10-15 mL/min
– Symptoms begin with diff. concentrating and
can progress to lethargy, confusion, and
coma
– Neuropathy found in 65% of pts on or nearing
dialysis but not until GFR is 10% of normal
– Earlier initiation of dialysis may prevent
peripheral neuropathies

• Disorders of mineral metabolism
– D/o of calcium, phosphorus, and bone are
referred to as renal osteodystrophy
– Most common d/o is osteitis fibrosa cystica –
the bony changes of secondary
hyperparathyroidism…affecting 50% of pts
nearing ESRD
– Radiographically, lesions most prominent in
phalanges and lateral ends of clavicles

• Disorders of mineral metabolism
– May also have osteomalacia or adynamic
bone dz
– All of the above may cause bony pain,
proximal muscle weakness, and spontaneous
bone fractures
– Tx may consist of dietary phosphorus
restriction, oral phosphorus-binding agents
such as calcium carbonate or Renogel, and
vitamin D
– Hyperparathyroidism tx’d with calcitriol or
Sensipar

• Endocrine d/o
– Circulating insulin levels are higher because
of decreased renal insulin clearance
– Glucose intolerance can occur in chronic
renal failure when GFR is < 10-20 mL/min.
This is mainly due to peripheral insulin
resistance
– Decreased libido and impotence are common.
Men have decreased testosterone; women
are often anovulatory

• Tx
– ACE/ARB to slow progression of proteinuria and CVD
– Maintain excellent diabetes control…keep HgA1C < 7
• Tx (Consults): early nephrology, vascular, general
surgery
• Tx (Dietary)
– Every pt should be eval by renal nutritionist
– Protein restriction
• In general, protein intake should not exceed 1 g/kg/d
– Salt and water restriction
• For the nondialysis pt approaching ESRD, 2 g/d of sodium is an
initial recommendation

– Potassium restriction
• Once GFR has fallen below 10-20 mL/min,
potassium intake should be limited to < 60-70
mEq/d
– Phosphorus restriction
• Phosphorus level should be < 4.6 mg/dL
• Phosphorus binders required if GFR < 20-30
mL/min
– Magnesium restriction
• No magnesium-containing laxatives or antacids

• Treatment (Dialysis)
– When conservative management of ESRD is
inadequate, hemodialysis, peritoneal dialysis,
and kidney transplantation are alternatives
– Dialysis should be started when pt has GFR
of 10 mL/min or serum creatinine of 8 mg/dL
– Diabetics should start when GFR reaches 15
mL/min or serum creatinine is 6 mg/dL

• Treatment (Dialysis)
– Other absolute indications for dialysis include
• Uremic symptoms such as pericarditis,
encephalopathy, or coagulopathy
• Fluid overload unresponsive to diuresis
• Refractory hyperkalemia…>7
• Severe metabolic acidosis (pH < 7.20)
• Neurologic symptoms such as seizures or
neuropathy

• Hemodialysis (choice for 90% of pts)
– Vascular access accomplished by an a/v fistula
(preferred) or prosthetic graft
– Infection, thrombosis, and aneurysm formation are
complications seen more often in grafts than fistulas.
Staphylococcus aureus is most common infecting
agent
– Pts typically require hemodialysis 3x/wk…sessions
last 3-5 hrs each
– Home dialysis also now available
– Ensure pt getting regular labs to include PTH and
ALK PHOS

• Hemodialysis

• Peritoneal dialysis
– The peritoneal membrane is the “dialyzer”
– Most common type is continuous ambulatory
peritoneal dialysis (CAPD)
• Pts exchange dialysate 4-6 times/day
– Continuous cyclic peritoneal dialysis (CCPD)
utilizes a cycler machine to automatically
perform exchanges at night
– Most common complication = peritonitis
• Most common pathogen = S aureus

• Peritoneal dialysis

• Total costs of both types of dialysis are
about the same ($35,000 - $60,000/yr)
• Pts undergoing dialysis have an average
life expectancy of 3-4 yrs
• Studies are conflicting regarding the
survival advantage assoc. with either
peritoneal dialysis or hemodialysis

• Kidney transplantation
– 1st - Dr Hamburger in 1952
– Up to 50% of all pts with ESRD are suitable for
transplant. Age becoming less of a barrier
– In general, not placed on list until GFR <15
– Living donor is best option
– Two-thirds of kidney transplants come from deceased
donors
– Average wait for cadaveric transplant is 2-4 yrs;
becoming longer as more pts go on the list while
donor pool does not expand
– One yr survival rate is approx. 98%

• CKD prognosis
– Mortality higher for pts on dialysis than for
age-matched controls
– Expected remaining lifetime for the age group
55-64 is 22 yrs, whereas that of ESRD
population is 5 yrs
– Most common cause of death is cardiac
dysfunction
– For those who require dialysis to sustain life,
but decide against it, death ensues within
days to wks

• Overall…medical care of CKD focuses on
delaying or halting progression of CKD
– Tx underlying cause(s)
– Tx HTN and Diabetes
– Avoid nephrotoxins
– Tx complications
• Lastly…watch out for meds that are
renally excreted. You will need to adjust
dose in pts with renal failure

ReviewReview
• Background
• Causes
• Clinical findings
• Labs and imaging
• Complications
• Treatment
• Prognosis

Chronic kidney-disease-1216842299045729-8

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