Chronic Kidney Disease Flashcards
Basic functional unit in kidney is “_____”
nephron
Each kidney has about ___ ____ nephrons
1 million
Plasma fluids & solutes are filtered (except ____ _____)
plasma proteins
- if they’re proteins it’s an indication of kidney disease
What are the 2 major kidney functions?
- Remove WASTE material ingested
or produced by metabolism - Control VOLUME and ELECTROLYTE composition of body fluids
Normally blood flow to kidneys is about ___ of cardiac output (_____)
22%
1100 ml/min
Outline the blood flow to kidneys starting with the renal artery
Renal artery enters kidney via hilum, branches to smaller arteries, AFFERENT arterioles, and glomerular capillaries
Outline the blood flow exiting the kidneys starting with the distal end
Distal ends of capillaries of glomerulus coalesce to form EFFERENT arterioles, capillary network, and peritubular capillaries that surrounds renal tubules
What are the 6 main parts of a kidney nephron?
- Bowman’s capsule
- Proximal tubule
- Loop of Henle
- Distal tubule
- Connecting tubule
- Collecting tubule
What is the Glomerulus?
CLUSTER of tiny CAPILLARIES that receives blood from the AFFERENT arteriole
(& is surrounded by Bowman’s capsule)
Blood passes through these capillaries & FILTERED
under PRESSURE into BOWMAN’S capsule
What happens if the Glomerulus is damaged?
If DAMAGED, can lead to chronic kidney disease (CKD)
What is the Glomerular Filtration Rate (GFR)?
volume of blood filtered by GLOMERULUS/MIN
What is the normal GFR (adult)?
100–125 ml/min
What does GFR depend on?
depends on AGE and GENDER
(increase GFR in males generally, as age increases level of GFR decreases)
What is estimated GFR & what is it used for?
- ESTIMATED GFR is calculated using equations
- used for STAGING CKD and drug dosing
What are the major functions of the kidney?
- Excretion of metabolic WASTE products and chemicals
- Regulation of WATER and ELECTROLYTE balances
- Regulation of body fluid OSMOLALITY and electrolyte concentrations
- Regulation of ARTERIAL PRESSURE
- Regulation of ACID-BASE balance
- Regulation of ERYTHROCYTE production
- Secretion, metabolism, and excretion of HORMONES
- GLUCONEOGENESIS
What does urine formation result from?
- glomerular filtration
- tubular reabsorption
- tubular secretion
What is urinary excretion (i.e. what is it calculated by)?
Excretion = Filtration - Reabsorption + Secretion
Describe what happens in the Proximal convoluted tubules?
- PLASMA fluid filtered from GLOMERULUS flows into Bowman’s capsule and then PROXIMAL tubule
- About 80% of the glomerular ultrafiltrate is REABSORBED into blood as it passes through PROXIMAL tubule
(80% of total - not of just glucose for ex) - Nutrients (GLUCOSE, AMINO ACIDS, electrolytes eg Na+, K+, Cl-, HCO3-) are reabsorbed
- Some molecules are SECRETED into the tubules (eg CREATININE, URIC ACID, some DRUGS
- from blood –> tubules
What is imp. about creatinine?
by-product of metabolism in muscle
is secreted but not reabsorbed in the proximal convoluted tubule –> gives indication of how well the kidneys are working
Proximal tubules have ___ _____ for ___ and _____ reabsorption
HIGH CAPACITY
ACTIVE
PASSIVE
In proximal tubule reabsorption disorders (eg Fanconi Syndrome) patients may present:
- bone disease (rickets)
- metabolic acidosis
- hypophosphatemia
- hypokalemia
What is an example of a proximal tubule reabsorption disorder?
Fanconi syndrome
The proximal tubules:
- Reabsorb about 65% of the filtered Na+, K+, Cl-, HCO3-
- Reabsorb ALL filtered GLUCOSE and AMINO ACIDS.
- secrete ORGANIC ACIDS, BASES, and HYDROGEN ions into tubular lumen
What happens in the Loop of Henle?
- Fluid flows from proximal tubule into loop of Henle
- Primary role of the loop of Henle is REABSORPTION of
WATER, Na+ AND Cl-, Mg2+ - LOOP DIURETICS BLOCK reabsorption of Na+ and WATER in ascending loop of Henle (eg furosemide –> potent diuretic that reduce edema in pathology cases)
What happens in the Distal convoluted tubule?
- Reabsorption of Na+ and WATER
- Secretion of K+, H+, PO4-
- THIAZIDE diuretics
(eg hydrochlorothiazide, chlorthalidone, metolazone)
What happens in the Thin descending loop of Henle?
- HIGHLY permeable to WATER and MODERATELY permeable to most SOLUTES
- has FEW mitochondria and LITTLE or no active REABSORPTION.
What happens in the Thick ascending loop of Henle?
- reabsorbs about 25% of filtered Na+, K+, Cl-
- reabsorbs LARGE amounts of Ca2+, HCO3-, Mg2+
- secretes H+ into tubular lumen
What happens in the Early distal tubule?
- has MOST characteristics of THICK ascending loop of Henle
- reabsorbs Na+, Cl-, Ca2+, Mg2+
- IMPERMEABLE to WATER and UREA
What happens in the Late distal tubules and cortical
collecting tubules?
- PRINCIPLE cells REABSORB Na+ from lumen, SECRETE K+ into lumen
- Type A INTERCALATED cells REABSORB K+, HCO3-, SECRETE H+
- WATER reabsorption from this tubular segment is controlled by antidiuretic hormone (ADH)
What happens in the Collecting duct?
- REABSORB Na+
- SECRETE K+ (ALDOSTERONE dependent)
- ALDOSTERONE ANTAGONISTS (eg spironolactone, eplerenone)
- Antidiuretic hormone (ADH; vasopressin): controls H2O
permeability in collecting duct - ADH DEFICIENCY causes DIABETES INSIPIDUS
- ACID-BASE balance: EXCRETION of ACIDS
ADH deficiency causes…
diabetes insipidus
- b/c body tries to get rid of glucose so urinates a lot
What happens in the Medullary collecting ducts?
- ACTIVELY reabsorb Na+ and secrete H+
- PERMEABLE to UREA (urea reabsorbed in these tubular segments)
- reabsorption of WATER in medullary collecting
ducts is controlled by ADH
ADH plays an imp. role in…
reabsorption of water
Describe the control of acid base balance by kidneys
Kidney regulates acid base balance and maintain blood pH within the normal range (7.35–7.45)
pH<7.35 =
Acidosis
Renal correction of acidosis:
↑ excretion of H+
↑ reabsorption of HCO3 −
pH>7.45 =
Alkalosis
Renal correction of alkalosis:
↓ secretion of H+
↑ excretion of HCO3 −
What controls BP by kidneys?
Renin-Angiotensin System (RAS)
Describe hormone production by kidneys
Kidney produces ERYTHROPOIETIN, the hormone that stimulates production of red blood cells (RBC) in the BONE MARROW.
During _____, production and release of erythropoietin from the kidneys are INCREASED.
anemia
- tries to produce/release more RBCs
When OXYGEN level in BLOOD FALLS below normal, kidneys respond by SECRETING erythropoietin.
When OXYGEN level in BLOOD FALLS below normal, kidneys respond by…
secreting erythropoietin.
In CHRONIC KIDNEY DISEASE, erythropoietin level is _____ contributing to _____ in those patients.
REDUCED
ANEMIA
What is the definition of Chronic Kidney Disease (CKD)?
Chronic Kidney Disease (CKD) is a term used to describe conditions that DAMAGE kidneys or cause REDUCED kidney function over months or years (>3 MONTHS).
What are the causes of Chronic Kidney Disease (CKD)?
- DIABETES
- HIGH BLOOD PRESSURE
- glomerulonephritis (INFLAMMATION of glomeruli)
- interstitial nephritis (inflammation of tubules and
surrounding structures - PROLONGED urinary tract OBSTRUCTION (eg enlarged prostate, kidney stones, cancers)
- RECURRENT kidney INFECTION (pyelonephritis)
- Inherited kidney disease (polycystic kidney disease)
- vesicoureteral reflux (urine back up into kidneys)
What are the 3 MAIN causes of Chronic Kidney Disease (CKD)?
- Diabetic kidney disease
- Hypertensive nephrosclerosis
- Glomerulonephritis
Describe how Diabetic kidney disease relates to Chronic Kidney Disease (CKD)
- Patients with DIABETES (both types) are at RISK of chronic kidney disease
- Characterized by GLOMERULOSCLEROSIS & TUBULOINTERSTITIAL FIBROSIS
- function of tissues in kidney damage over time & therefore will have some parts being non-functional
- Patients with diabetes should be screened YEARLY for CKD
Describe how Hypertensive nephrosclerosis relates to Chronic Kidney Disease (CKD)
- LONG term hypertension (>10 years)
- POORLY controlled hypertension
- Characterized by GLOMERULOSCLEROSIS and REDUCED glomerular blood flow
- Unlike diabetic CKD, it is associated with LOWER levels of PROTEINURIA (<0.5 g/d)
(may not be diagnosed b/c may not have symptoms)
Describe how Glomerulonephritis relates to Chronic Kidney Disease (CKD)
- Caused by ACTIVATION of IMMUNE system leading to INFLAMMATION of glomerulus
- VIRUSES, BACTERIA, PROTEINS, etc. can promote activation of immune system (eg POST-STREPTOCOCCAL glomerulonephritis)
- May cause SEVERE proteinuria (>2 g/day)
- Treatment by IMMUNOSUPPRESSANT drugs (only if REALLY needed - inf. should be eliminated before using those drugs)
Factors that can increase risk of chronic kidney disease:
- DIABETES
- HIGH BLOOD PRESSURE
- heart (cardiovascular) disease
- SMOKING
- OBESITY
- race (↑Black, native American or Asian American)
- family history of kidney disease
- abnormal kidney structure
- older age
** frequent use of drugs that can damage kidneys (only given when needed, current dose & used when needed)
What are signs & symptoms of CKD?
- fatigue, weakness, loss of appetite
- mental confusion
- nausea, vomiting (b/c of imbalance in electrolytes for ex)
- peripheral neuropathies
- bleeding, ANEMIA (b/c less RBC prod.)
- EDEMA (puffy ears, legs & ankles)
- WEIGHT GAIN due to accumulation of FLUID)
- not real weight gain
- hypertension
- METABOLIC ACIDOSIS
- changes in urine output (volume, consistency)
- foaming urine (indicates albuminurea)
What are the blood test in CKD?
- serum creatinine (↑)
- estimated glomerular filtration rate (eGFR) (↓)
- blood urea nitrogen (BUN) (↑)
- potassium (↑)
- phosphorus (↑)
- glucose (to check diabetes)
- triglycerides and LPL
- CBC (hemoglobin (↓), RBC (↓) (help test anemia)
- albumin (↓) (losing albumin daily)
- bicarbonate (↓); metabolic acidosis
What is the Creatinine blood test?
- Creatinine is a byproduct of MUSCLE METABOLISM that is filtered at glomerulus and is NOT reabsorbed.
- Creatinine is used as a MARKER of glomerular filtration rate (GFR).
- Serum creatinine levels remain within normal range in healthy individuals.
- In chronic kidney disease, IMPAIRED renal FILTRATION leads to elevated serum creatinine levels.
** MUSCLE loss during chronic diseases can lead to ELEVATED creatinine level.
_____ loss during chronic diseases can lead to ELEVATED creatinine level.
MUSCLE
- b/c muscle mass is reduced, the creatinine is down (b/c linked to muscle mass)
What is the Urine test for CKD?
** protein (albumin ↑)
** blood (↑ RBC in urine)
** RBC and WBC casts
- renal tubular epithelial cells/cylinders are indication of urine problem in kidneys
- albumin/creatinine ratio (ACR)
What are other diagnostic tests for CKD?
- biopsy (needle) and histopathology assessment (tissue sections)
- imaging (ultrasound, CT scan, MRI)
What is Stage 1 eGFR result & what does it mean for CKD?
90 or higher
- mild kidney damage
- kidneys work as well as normal
What is Stage 2 eGFR result & what does it mean for CKD?
60-89
- mild kidney damage
- kidneys still work well
What is Stage 3a eGFR result & what does it mean for CKD?
45-59
- mild to moderate kidney damage
- kidneys don’t work as well as they should
What is Stage 3b eGFR result & what does it mean for CKD?
30-44
- moderate to severe damage
- kidneys don’t work as well as they should
What is Stage 4 eGFR result & what does it mean for CKD?
15-29
- severe kidney damage
- kidneys are close to not working at all
What is Stage 5 eGFR result & what does it mean for CKD?
less than 15
- most severe kidney damage
- kidneys are very close to not working or have stopped working (failed)
What are the treatment of symptoms for CKD?
- EDEMA/SWELLING: low sodium diet; diuretics
- HYPERKALEMIA (↑blood K+): low potassium diet, drugs
- HYPERPHOSPHATEMIA (↑blood phosphorus):
low phosphorus diet, phosphate binding drugs - HYPERMAGNESEMIA (↑blood magnesium)
- avoid medications that contain magnesium (e.g. certain antacids, Mg supplements, multi-vitamins)
- METABOLIC ACIDOSIS: sodium bicarbonate tablets
- ANEMIA: injectable erythropoietin
- HYPERTENSION: low Na+ diet, anti-hypertensive drugs
- BLOOD GLUCOSE (if diabetic): diet, hypoglycemic drugs
- UREMIC PRURITUS:
- keep skin moisturized - steroid creams
- medications
- UVB phototherapy
- GOUT (due to impaired uric acid secretion): uric acid lowering drugs (eg allopurinol)
- CONTROL RISK FACTORS (smoking, obesity)
What are the end-stage renal disease treatment strategies for CKD?
- dialysis
- kidney transplant
- supportive care
(irreversible)
What are important pharmacologic concentrations?
- ADJUST drug DOSES for kidney function (based on GFR)
- Avoid NEPHROTOXIC drugs (eg anti-inflammatory (NSAIDS) such as ibuprofen, naproxen, high doses ASA)
- Try to avoid drugs that are ELIMINATED by KIDNEY
- Over the counter drugs: pharmacist/physician ADVICE
- HERBAL drugs are NOT recommended
