CKD Flashcards
Acute Kidney Injury
Sudden loss of kidney function due to non-renal conditions (drug).
Often reversible but can be permanent if precipitating factor is not corrected.
Common cause of AKI
Dehydration
Presentation of AKI
BUN: SCr ration greater than 20:1 plus
Decrease urine output
Dry mucus membranes
Tachycardia
Chronic Kidney Disease
A progressive loss of kidney function over months or years.
How is CKD severity measured?
Glomerular filtration rate (GFR)
Creatinine Clearance ( CrCl)
Albumin in the urine
End- Stage Renal Disease (ESRD)
Total and Permanent Kidney Failure
Fluid and waste accumulation
Dialysis or Transplant is needed
What are the most common causes Of CKD?
Diabetes
Hypertension
What is the function of the Nephron?
Control the concentration of sodium and water.
This regulate blood volume and in turn blood pressure.
What is the glomerulus ?
Large filtering unit that is located within the bowman capsule.
Afferent arteriole delivers blood into the glomerulus
Efferent arteriole unfiltered substance exit nephron here.
If the glomerulus is healthy?
Only substances less than 40,000 daltons including most drugs can pass through into the filtrate.
Large substance ( proteins and protein bound drugs) are not filtered and stayed in the blood.
If the glomerulus is damaged?
Some Albumin passes into the urine
Albumin + GFR assess CKD severity (nephropathy).
What is Proximal Tubule?
Entry point of nephron
Reabsorb filtered Na, Cl, Ca and water into bloodstream.
*Blood pH is regulated by the exchange of Hydrogen and Bicarbonate ions.
What is the Loop of Henle?
Descending limb (down): water is reabsorb
Ascending limb (up): Na and Cl ions are reabsorb
*If antidiuretic hormone (ADH) or Vasopressin is present water passes through the walls of the ascending limb and is reabsorbed into the blood; less water excreted in the urine (anti-diuresis)
Loop of Henle and Diuretics?
Loop diuretic inhibit the Na-K pump in the ascending limb ; less Na and Ca is reabsorb back into the blood.
Long term Ca depletion can decrease bone density.
Na concentration increase in filterate , less water is reabsorb and both are excreted in the urine.
What is the distal convoluted tubule?
The farthest point away from entry to nephron
Regulate K, Na, Ca and pH
Distal convoluted tubule and Diuretics?
Thiazide diuretic inhibit the Na-Cl pump
Thiazides( 5% Na reabsorb) is a weaker diuretic than loops (25% Na reabsorb).
Thiazides increases Ca reabsorption therefore long-term use has protective effect on bone.
What is the Collecting Duct?
Network of tubules and ducts that connects nephrons in each kidney to a ureter.
Involve with WATER and ELECTROLYTE balance affected by ADH and aldosterone
Urine Filtrate= Ureter to bladder then out the body via Urethra
Aldosterone role in distal convoluted tubule and collecting ducts?
Works in the tubule and duct to increase Na and water reabsorption but decrease K reabsorption.
Aldosterone Antagonist ( Spironolactone and Eplerenone) block aldosterone; more Na and water is excreted in the urine but serum K increases.
What is Drug Induced Kidney Disease (DIKD?
Linked to numerous medications
Acute and reversible; irreversible to CKD if drug is not stop.
Common in hospital setting and contributes to morbidity and mortality.
Drugs that cause kidney disease?
Aminoglycosides
Amphotericin B
Cisplatin
Cyclosporine
Loop diuretic
NSAIDS
Polymyxins
Radiographic Contrast Dye
Tacrolimus
Vancomycin
What are the two common laboratory markers use to estimate kidney functions and what do they measure?
BUN( blood urea nitrogen): measure amount of nitrogen in the blood that come from urea, a waste product of protein metabolism
SCr ( serum creatinine) : waste product of muscle metabolism
As kidney function declined BUN and SCr increases.
SCr Normal Range: 0.6 - 1.3 mg/dL
What common equation is use for CrCl?
Cockcroft Gault Equation
CrCl (mL/min) = (140-age)/(72*Scr) ×weight x 0.85 (female)
What weight to use to calculate CrCl?
Use Actual Body weight if less than calculate Ideal Body Weight
Use Ideal Body Weight if BMI is in normal range
Use Adjusted Body Weight if BMI is in overweight range
IBW = ( 45.5 or 50 kg) + 2.3kg (inches over 5ft)
AdjBW= IBW + 0.4(TBW - IBW)
What’s calculate CrCl use for?
To determine dosing adjustments and medication contraindications.
Calculate CrCl accuracy is decreased?
When a patient has very low muscle mass (frail elderly patients)
Low muscle mass = low Scr
Overestimate CrCl
Calculate crockcroft gault CrCl can be inaccurate in patients with ?
Obesity
Liver disease
Pregnancy
High muscle mass
Very young children (crockcroft gault not preferable)
ESRD or unstable kidney function (crockcroft gault not preferable)
Drug dosing is usually base on CrCl but sometimes is base on GFR.
Which drug dosing can be base on GFR?
SGLT2 inhibitor
Metformin
How is GFR Calculated?
Calculated using the Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI).
What is albumin in relation to CKD?
The primary protein that is measured in the urine to assess kidney disease.
Known as Albuminuria or Proteinuria
What is KDOQI guidelines recommendations?
Use GFR and degree of ALBUMINURIA (levels in urine) along with cause of CKD to Determine the degree/ stage of renal impairment.
Which levels of GFR and/or Albumin suggests a patient have CKD?
GFR less than 60 mL/ min/1.73m3
Albuminuria greater than or equal to 30 mg/mmol
ACE and ARBs role in CKD?
ACE and ARBs are FIRST- LINE drugs to prevent progression of disease in patients with CKD, Diabetes, and/or HTN if Albuminuria is present.
Works by inhibiting RAAS causing efferent arteriolar dilation.
Reduce pressure in the glomerulus, decrease Albuminuria and provide cardiovascular protection.
What to expect in SCr when starting treatment with ACE inhibitor or ARBs?
Scr can increase up to 30%
If more than 30% increase D/C medication and referred patient to nephrologist.
What should be monitored when on ACE Inhibitor and ARBs?
Scr and K. 1 to 2 weeks after initiating
NEVER use both class together
They increase Potassium (K)
Advice pt to avoid K supplement and salt substitutes (KCl)
MAXIMIZED Dose for Renal protection
What is KDIGO Guidelines Recommended BP goal for CKD patient?
No Proteinuria: Less than 140/90 mmHg
Proteinuria: Less than 130/80 mmHg
Reasons to MODIFY DRUG THERAPY in CKD
Drug is Eliminated through the Kidneys: modify to avoid accumulation and SE/toxicity; Reduce dose and/or extend interval
The drug can cause or worsen kidney disease( Nephrotoxic)
Drug become less effective as kidney function declines (ex. Thiazide, and Nitrofurantoin)
Drug is CONTRAINDICATIONED at a specific level of kidney impairment because accumulation is unsafe. (Ex. Bleeding risk with anticoagulants)
Drug can cause further kidney damage ( ex. NSAIDS)
Drug can cause more harmful effects than usual when kidney function is reduced (ex. Hyperkalemia with aldosterone antagonist)
Dose Adjustments may be required or necessary when:
CrCl is less than 60 mL/min (1/2 of normal)
CrCl is less than 30 mL/min (1/4 of normal; additional adjustments may be needed or drug may be CONTRAINDICATED)