CKD Flashcards
why is CKD increasing in incidence?
- aging population
- increased prevalence of DM and HTN
what are some long term adverse outcomes from CKD?
- impaired kidney function
- end stage renal failure
- death
ckd is associated with significant;y increased risk of which medical problems?
- CVD
- stroke
what do the kidneys do?
- regulate water
- balance salts - sodium and potassium
- acid base balance
- calcium reabsorption/vitamin d activation
- blood pressure
- RBC production
- filter waste/excrete medication
what happens to the kidney as we age? around what age does this declines accelerate?
- kidney function slowly declines - natural process
- happens more rapidly after age 45
what factors can cause kidney injury?
- infection (post-strep glomerulonephritis)
- autoimmune process (lupus nephritis)
- medications
- volume depletion - n/v, diuretic use
- obstruction
how does the kidney respond to injury?
- increased filtration in remaining normal nephrons - adaptive hyperfiltration
- additional homeostatic mechanisms permit serum concentrations of sodium, potassium, phosphorus, calcium, and total body water to remain w/in normal range, particularly among those with mild-moderate renal failure
pros/cons adaptive hyper-filtration? manifestations of hyper-filtration?
- initially beneficial
- often results in long term damage to glomeruli of remaining nephrons
- manifested by proteinuria and an increase in circulating biomarkers or kidney disease (BUN/creatinine) and progressive renal failure
how is ckd defined?
- presence of structural or functional abnormalities of the kidney for 3 or more months, irrespective of cause
- persistence of kidney damage/decreased kidney function is necessary to distinguish it from acute kidney injury (aki) - in aki, appropriate eval for reversible causes should be performed
- decline in gfr to <60 for > 3 months
what are some risk factors for ckd?
- DM
- HTN
- CVD
- HLD
- obesity
- metabolic syndrome
- smoking
- HIV
- hep C
- malignancy
- fam hx ckd
- sickle cell trait
- urinary outflow obstruction
- hx aki
- persistent hematuria
- tx w/ potentially nephrotoxic drugs like NSAIDs
fam hx CKD, DM, HTN - african americans
- hispanics
- asians
- pacific islanders
- > 60 years old
- recurrent kidney stone disease
- frequent UTI
- inflammatory disease like RA, SLE
what are the 2 most common causes of CKD?
- DM, particularly type 2
- HTN
what is the initial presentation of diabetic kidney disease?
- microalbuminuria
how does HTN cause CKD?
nephrosclerosis occurs from long standing periods of uncontrolled HTN, contributing to end organ damage
who should be screened for CKD?
all individuals should be assessed routinely
what methods are used to screen for ckd?
- urine test for proteinuria - spot urine in the morning, measure albumin to creatinine ratio
- blood test for creatinine, a by-product of muscle metabolism in blood, and GFR
- BP monitoring, w/ goal <125-130/80
what factors are the 5 stages of CKD based on?
- cause of kidney disease
- 6 categories of eGFR
- 3 categories of albuminuria
why stage patients with CKD?
staging guides clinicians in managing patients with ckd by identifying those that have the most severe disease who are, therefore, at greatest risk of progression and complications
what are the 3 categories of albuminuria?
- A1, normal to mildly increased: < 30 mg/g or < 3 mg/mmol
- A2, moderately increased: 30-300 mg/g or 3-30 mg/mmol
- A3, severely increased: >300 mg/g or > 30 mg/mmol
what are the 6 categories of eGFR?
- G1, normal or high: > 90
- G2, mildly decreased: 60-89
- G3a, mildly to moderately decreased: 45-59
- G3b, moderately to severely decreased: 30-44
- G4, severely decreased: 15-29
- G5, kidney failure: < 15
what does albuminuria tell us?
- sensitive marker of CKD caused by DM, HTN, and glomerular disease
- microalbuminuria is inherent in the diabetes disease process but can also be associated with non-renal conditions (i.e. obesity, inflammation, cancer)
- increases vascular permeability
what is the BP goal for patients with CKD?
125-130/80 mmHg
less aggressive SBP of 135-140 in pts > 75+ with high burden of comorbidity or a DBP < 55-60 in older adults with postural hypotension
what is the tx for pts w/ proteinuria?
1st line: ACE-I or ARB
2nd line: loop or thiazide diuretic
3rd line: non-dihydropyridine CCB like nifedipine
what is the tx for pts w/o proteinuria but w/ edema?
1st line: loop diuretic
2nd line: ACE-I or ARB
3rd line: dihydropyridine CCB like amlodipine
what is the tx for pts w/o proteinuria and wo/ edema?
1st line: ACE-I or ARB
2nd line: dihydropiridine CCB
3rd line: diuretic
when do we prescribe non-dihydropiridine (nifedipine) vs dihydropyridine (amlodipine) CCBs?
- w/ proteinuria: non-dihydropyridine, i.e. nifedipine
- w/o proteinuria: dihydropyridine, i.e. amlodipine
how does ACE-Is work?
- angiotensin II is a potent chemical produced by the body that causes constriction of smooth muscle that surrounds blood vessels
- ACE-Is slow the action of the enzyme ACE and thus reduce angiotensin II
- result is dilation of blood vessels and reduction of BP
what is the glomerulus?
tiny, ball-shaped structure composed of capillary blood vessels actively involved in filtration of blood to form urine
what is gfr?
- volume of plasma filtered from glomerular capillaries into Bowman’s capsule each minute, expressed in mL/min
- gfr provides a great measure of filtering capacity of kidneys
how is gfr used clinically?
used to
- evaluate degree of renal impairment
- follow course of disease
- assess response to therapy
what is the best measure of kidney function?
gfr
what is normal gfr? how does it change with age?
- varies by age, sex, and body size
- approx 120-130 in young adults
- decreases by an avg of 1 per year after age 30
- gfr < 60 means loss of approx 1/2 kidney function and increased prevalence of CKD complications
what variables do most formulas use to estimate gfr?
- age
- sex
- race
- weight
- serum creatinine
what 3 formulas estimate GFR? which was the original formula used? which one is used now? why?
- CKD-EPI equation: currently used because most accurate
- Modification of Diet in Renal Disease (MDRD)
- Cockcroft-Gault formula: original formula used
what are some signs and symptoms of CKD?
- often asymptomatic! may present in advanced stages w/o any symptoms at all*
- weakness, fatigue
- decreased appetite
- difficulty with urination
- foamy or dark urine
- decreased libido
- swelling - periorbital, LE, generalized
what systems are affected by advanced stage kidney disease/uremia?
- CV
- GI
- neurologic
- metabolic
- psychosocial
- hematologic
what are some CV complications of advanced stage kidney disease/uremia?
- atherosclerosis
- HTN
- HF
- pericarditis
- pulmonary edema
what are some GI complications of advanced stage kidney disease/uremia?
- nausea
- vomiting
- anorexia
what are some neurologic complications of advanced stage kidney disease/uremia?
- peripheral neuropathy
- muscle cramps
- itching
what are some metabolic complications of advanced stage kidney disease/uremia?
- electrolyte abnormalities
- metabolic acidosis
- HLD
- alterations in vitamin d/calcium/phopsphorus metabolism
- mineral and bone density disorders
- hyperparathyroidism
what are some psychosocial complications of advanced stage kidney disease/uremia?
- depression
- fatigue
- insomnia
- suicide
- sexual dysfunction
- unemployment
what are some hematologic complications of advanced stage kidney disease/uremia?
- anemia
- leukopenia
- erythropoietin deficiency
how do we evaluate and manage ckd?
- determine etiology of CKD and evaluate for comorbidities
- collect pt and fam hx
- PE
- BP
- weight mgmt
what is more likely than progression to dialysis in any stage of CKD?
death
what should we assess to understand pt’s CVD risk?
- smoking status
- lipid levels
- ECG to evaluate LVH
what is the leading cause of kidney failure in the US?
DM
what is the a1c goal in those with CKD w/o proteinuria?
7% - preserves GFR
tighter control of a1c is associated with what?
more severe complications including hypoglycemia and death
what lab workup should we do for patients with CKD?
- renal function, at least annually for any patient at risk
- fasting lipid profile, A1c
- urine albumin to creatinine ratio (ACR)
- BP
- hgb if gfr < 45; calcium, phosphate, and parathyroid if gfr < 30
- renal US - evaluate kidney size and assess for possible structural abnormalities
how should we manage ckd?
- tx reversible causes of kidney failure
- prevent or slow progression of kidney disease
- tx complications of renal failure
- adjust drug doses when appropriate
- identification of patients appropriate for dialysis or renal transplantation
how many patients with ckd have htn?
approx 80-85%
how does tx of htn affect ckd?
slow progression of proteinuric CKD and reduces rate of CV complications
what meds should we use to tx htn in ckd?
aces or arbs
what are the reversible causes of renal failure?
decreased renal perfusion
- hypovolemia, i.e. vomiting, diarrhea, bleeding, diuretic use
- hypotension, i.e. myocardial dysfunction
- infection, i.e. sepsis
- meds that lower gfr, i.e. NSAIDs, ACE-Is
administration of nephrotoxic drugs
- frequent cause of worseing kidney function
- common offenders are aminoglycosides, NSAIDs, radiographic contrast material
urinary tract obstruction
- less common cause of worsening kidney function
- patient often with no symptoms referable to kidney/no change in UA/UO
- renal US often performed to r/o obstruction if pt has unexplained elevation of creatinine
how do we slow the progression of ckd?
- adequate BP control
- reduce proteinuria
- protein restriction
- statin therapy
- smoking cessation
what are some complications of renal failure?
fluid and electrolyte imbalance
- volume overload: Na and intravascular volume balance are usually maintained by homeostasis until GFR falls below 10-15mL/min
- hyperkalemia
- metabolic acidosis
- mineral and bone disorders - hyperphosphatemia
tx of chronic metabolic acidosis w/ bicarbonate may slow progression to ESRD
what are some clinical findings of CKD stages 3-5?
- anemia
- malnutrition
- metabolic bone disease
- neuropathy
- reduce level of functioning and well being
what kind of anemia do we normally see in ckd?
- usually normocytic, normochromic
- important to r/o other causes of anemia too, like iron deficiency
what causes anemia in ckd?
reduced production of hormone erythropoetin
what causes malnutrition in ckd?
- lower food intake
- decreased intestinal absorption
- metabolic acidosis
how do we manage malnutrition in ckd?
- assess weight, serum albumin level, and dietary history every 6-12 mo in stage 3 and every 1-3 mo in stages 4-5
- refer to dietician
- limit protein intake
- reduce sodium < 2g/day
- fluid restriction in ESRD
what causes metabolic acidosis in ckd?
primarily due to impaired renal ammonia synthesis and acid secretion
how often does metabolic acidosis affect ckd patients and what are some SE of it?
- 20% of pts in stages 4-5
- malaise
- fatigue
- acceleration of bone disease
- impaired synthesis of vitamin D
- muscle catabolism
- inflammation
how do we assess metabolic bone disease in those with ckd?
- alk phosphatase
- calcium
- phosphorus
consider - DEXA
- vitamin d
- PTH
what is the pathophysiology of metabolic bone disease in those with CKD?
as phosphorus levels rise, calcium is pulled from the bone causing bone disorders
what pharmacological interventions can we use to tx/prevent metabolic bone disease?
- phosphate binding drugs in advanced disease
- calcium and vitamin D supplements may be indicated
how does metabolic bone disease present clinically?
- fractures
- pain
- decreased mobility
- decreased strength
how does neuropathy present in ckd and what can we do to assess it?
- paresthesias
- sleep disturbances
- RLS
consider - sleep study
- nerve conduction studies
how do we assess functioning and well being in someone with ckd?
evaluate once and PRN
- assess social support
- health literacy assessment
- kidney disease QOL scale (KDQOL) - 36 item survey related to symptoms and burden of kidney disease
what does supportive care for older people with advanced ckd entail?
- pathway where RRT is not chosen but patients continue to receive healthcare from renal team
- aka “maximum conservative mgmt” or “non-dialytic care”
emerging themes in lit review are:
- shared decision making
- QOL
- role of educational resources
why is it important to think about drug dosing in ckd?
- inappropriate dosing in patients with ckd can cause toxicity and/or ineffective therapy
how do we adjust dosing in patients with ckd?
- loading doses don’t need to be adjusted for ckd patients
- guidelines for maintenance dosing often include dose reduction, lengthening the dosing interval, or both
what are some adverse renal effects of NSAIDs?
- acute renal failure/acute kidney injury
- nephrotic syndrome w/ interstitial nephritis
- CRF w/wo glomerulopathy, interstitial nephritis, and papillary necrosis
how does risk of AKI change with use of NSAIDs
risk is 3x higher in those that use NSAIDs than in those that don’t
what are some other adverse effects of NSAIDs?
- decreased potassium excretion - causes hyperkalemia
- decreased sodium excretion - causes peripheral edema, elevated BP, decompensation of HF
- blunts effect of antihypertensives
how do COX2 inhibitors compare to traditional NSAIDs in terms of adverse renal effects
less GI side effects but renal effects are the SAME
should we give NSAIDs to those with ckd?
- short term use generally safe in patients who are well hydrated and have good renal function
- avoid in chf, htn, and dm
- long term use should be avoided if possible - check creatinine every 2-4 weeks after initiation of therapy in at risk patients
are herbal remedies ok to take in ckd
- many pose a risk to ckd patients
- may contain undisclosed amounts of potassium or heavy metals that are toxic to kidneys
- may have vasoconstrictive compounds that can cause HTN
what are some indications for nephrology referral?
- acute or complex cvd
- anemia of ckd
- difficult to manage adverse SE of meds
- hyperkalemia (K > 5.5 despite tx)
- refractory proteinuria
- resistant HTN
- stage 4 CKD - GFR < 30
- unexplained decrease in GFR
