Renal System Flashcards
Chronic Kidney Disease
Structural or functional abnormality of the kidney for at least 3 months. >10% of US has chronic kidney disease
End Stage Renal Disease
Require a kidney intervention to stay alive. Those of african discent are 8X more likely
Ocular systems from renal disease
Calcium deposits on lid or conj, lid edema, corneal changes, aniridia (missing iris), cataracts, uveitis, ONH edema, drusen around the macula, retina changes
Optometric Considerations with renal disease
Optometric prescribed meds can cause renal side effects and dosage must be altered with renal disease. Renal disease also increase risk of ARMD, dry eye, and red eye.
Kidney Functions
Excretory: remove waste, regulate composition of blood (amt of water, [] of ions, acid-base balance) and excrete foreign substances.
Endocrine: involved with calcium output and regulation, erthropotient (development of RBC) and things like prostoglandins and nitric acid.
Renal Veins
Blood returns to heart through inferior vena cava
Renal artery
major branch from aorta. 20% received is filtered. Blood flows at about 1.2 l/min.
Ureter
Creates urine. Enters at hilus. Connectes kidney to bladder.
Medulla
One of the functioning parts. Contains many tubules and ducts. Has a higher na [] then cortex so there is a osmotic gradient.
Pelvis
Flat funnel cavity that collects urine into the ureter. It is called pylo when it is affected.
Cortex
Outer 1/3 of kidney. Has most of the filtration units.
Nephron
Found in cortex and medulla. Produces urine and functions to clear blood. 1 million nephron in each kidney. Ball of capillaries at the beginning (glomerulus) and then long then tube with hairpin loop. Closed at one end.
Peritubular Capillaries
Surround the nephron. Absorb water and solutes which leave renal tubules and will be taken back to the body. Provides blood supply to renal tissue.
Bowman’s Capsule
Surrounds the glomerulus. Located in the cortex. Closed at the beginning of the nephron (vascular pole) and open end is called urine pole.
Juxtaglomerular cells
Located in the afferent arterioles (turn into glomerulus). Sense pressure changes. Produce store, and excrete renin.
Glomerulus
Surrounded by bowman’s capsule. Fenstrated capillaries with incomplete BM and podocytes (support slits). Ball held together by mesangial cells with phagocytic abilities and contractile capabilities.
What other structures is the glomerulus similar to?
Choriocapillaries and RPE Cells.
Placing pressure on arterial flow?
Will decrease pressure at glomerulus and decrease flow
Placing pressure on efferent flow?
Will increase pressure at glomerulus and increase flow
Decreasing flow rate?
Will increase filtration as more particles can fall into glomerulus
Increasing flow rate?
Will decrease filtration as more particles will escape being filtrated.
Sympathetic effects on Nephron
Causes constriction of arterial flow (will cause slower blood flow and less pressure) This in turn will cause release of renin which will make angiotensin to constrict efferent arterioles. This will increase pressure. Therefore we will have greater pressure with slower rate which will allow more filtration to occur with less blood flow. These systems act to keep a constant rate of filtration. This is auto regulation. Cannot auto regulate with really high or low pressures!
Parasympathetic effect on Renal system
No significant effect! TRICK QUESTION!
Filtration
Occurs passively in the glomerlus. It has 2-3X higher pressure then other capillary beds.
Glomerulus selective permeability
Size (big cannot be filtrated)
Charge (glomerulus is neg. charged so repels other neg)
Configuration (this has a minimal effect). Higher []=more filtration.
What is the filtrate
Water, glucose, ions, amino acids, bicarbonate.
Reabsorption
Substance in the filtrate is pulled back into the body. Can be both passive or active. Reabsoprtion commonly occurs with Na+ reabsorption.
Modifers of reabsorption
- Concentration of molecules-the more there are the more the transporters can gather (up to a point)
- Flow-faster flow results in decreased ant of time to gather molecules.
Reabsorption of water
Occurs along tubules. This is major. Only 1% total urine becomes a filtrate.
Reabsoprtion in different parts of tubules
Proximal (80) Loop of hence (6) Distal (9) collecting (4). Only 1% becomes urine.
Secretion
Addition of substances to the filtrate. Occurs with unwanted components such as AB or ammonia. Can be passive (follows water) or a transporter.
Filtration at glomerulus
Filtrates water, NaCl, HCO3, K, Glucose, amino acids, creatinine, and urea. NO LARGE PROTEIN OR RBCs.
Reabsoprtion at proximal tubules
Reabsorb water, NaCl, K, HCO3, Glucose, and amino acids.
Secrete uric acid and organic acids
A diuretic here to mess with Na is ineffective as rest of system will compensate.
Descending loop of henle
Only permeable to water so reabsorption of water occurs. It is in the medulla in a hyper osmotic state
Ascending loop of henle
Inpermable to water but have active transport of NaCl and K reabsorption. Diuretics that work here will decrease NA reuptake but will cause a decrease in K as the collecting duct with trade NaCL for K when it realizes Na is low.
Distal Tubule
Secretes K and H. Reabsorbs NaCl (increased with aldosterone), H20, and Ca++ which is increased with PTH.
Collecting Duct
Has reabsorption of H20 (increased with vasopressin), and a NaCl and K transporter (increased with aldosterone) and urea (to keep osmotic gradient correct)
Excrete H20, NaCl, K, HCo3, Creatinine, and urea. Diuretics that work here are K sparing. Work by effecting aldosterone by preventing naCL reuptake and K loss.
What substance is not reabsorbed anywhere in the system?
Creatinine!
Why do diabetics pee a lot?
The body cannot reabsorb all of the glucose and it causes an osmotic drag that causes water to not be reabsorbed.
Macula Densa cells
At junction of ascending and proximal tubule and near afferent arteriole. Respond to decrease Na and CL in the filtrate (these means that the patient is dehydrated as there is less flow so more Na and Cl were able to be reabsorbed). Sends a message to juxtaglomerular cells to release renin.
Renin Function
INCREASE BP!
Kidney releases renin and liver angiotensigin which combine to angiotenosin I. ACE from lungs convert angiotenosin I to angiotenosin II. II causes vasoconstriction of arterioles, increase thirst, acts on kidney to increase Na and h20 reabsorption. Also acto on pituitary to release vasopressin. This will act on adrenal cortex to also release aldosterone. This increase Na reabsorption and water reabsorption.
Kidney Endocrine functions
Renin, erythropoiten, calcitriol, and glucose
Erythropoiten
Released by renin in response to hypoxia. Stimulates bone marrow to produce RBCs
Calcitriol
Converts vitamin D to active metabolic form Vitamine D3. D3 is important in absorbing calcium from intestines
Glucose function in renin
Still being investigated. Know that they convert lactic acid to glucose. Can target for diabetes.
Autocrine
A hormone that binds to a receptors and affects the function of the cell that produced it.
Kindey autocrine functions
Endothelins, NO, and renal prostaglandins.
Endothelins
Produced by renal system for autocrine function. Tend to cause increased vasoconstriction and increased salt and water retention resulting in increased BP.
Nitric Oxide
Autocrine in renal. Cause more water to be excreted. Helps macula dense provide feedback (altering function)
Renal prostaglandins
Autocrine in renal.. Increase blood flow to kidney by preventing vasoconstriction. Impair water reabsorption by blocking vasopressin in collecting duct, preventing water and sodium reabsorption, and prevents potassium excretion so more water is excreted.
Acid base balance with the kidney
The body keeps the pH at around 7.4. Excess hydrogen ions will combine with bicarbonate. Kidney will regenerate bicarbonate, excrete hydrogen ions when blood too acidic, and excrete bicarbonate ions when blood too basic.
Glomerular Filtration rate
Estimation. Have patient ingest inulin as filtrated by kidney and then not messed with. Measured clinically by collecting timed blood and urine samples to see how fast the substance is removed. Not popular as pt. has to stay in clinical all day
Creatinine Clearance Rate
Creatinine is produced by muscle metabolism. Filtered by kidney and not reabsorbed. Urine is collected for 24 hours with a blood draw at the end. Normal is 100 ml/min. Less then 60 is significant for kidney disease. Only use if searching for kidney disease.
Serum Creatinine Level
Depends on gender and size of individual. When value increases it indicated poor kidney function. If value doubles the kidney function has called to half its function. If it triples it has fallen to 25%. Used as a screening test!
BUN Test
Urea is an end product of protein metabolism. Generally 50% excreted and 50% reabsorbed. A slow filtration rate will result in more urea to be reabsorbed. The level will INCREASE with decreasing kidney function.
Azotemia
This is an increase in the BUN test with no symptoms.
Urinalysis
Look at content of the urine. Expect no blood, protein, or glucose. Albumin in urine is a sign of kidney involvement in DM.
Potassium and phosphate tests
Levels tend to increase in the blood with kidney failure.
Calcium, Ph, Bicarbonate in the serum
Levels tend to decrease in the blood with renal failure.
NGAL
Neutrophil gelatinase-associated lipocalin. Very favorable as it is used to detect acute renal failure (all others look at chronic) so that you can fix and allow kidney to heal itself.
Cystoscopy
Put a camera up into the bladder. Allows for visualization and biopsy of the bladder.
Ultrasound
For evaluation of tumors and structural abnormalities.
Radiological exams
CAT can detect tumors. Radiopaque iodine contrast allows visualization of urinary structures. Intravenous pyelogram allows X-ray visualization of renal tissue as dye is cleared by the kidneys.
Ways to describe kidney disease
- Acute or chronic (3 months or more)
- What systemic disease causes it (i.e. diabetic Renal failure)
- Type of tissue involved (i.e. glomerular kidney failure)
- pre/post renal or intersitial (pre= something is blocking blood flow to the kidney before the renal is encountered. Occurs with shock. intersitial=there is something wrong with the kidney itself. Post=something occurring after the kidney and causing backup)
Most common cause of kidney failure
Diabetes is number one and hypertension is number two
Common first signs of kidney disease
High blood pressure (due to renin release), swelling of the legs (less urine output), pulmonary edema (more fluid in the body and must push against that and heart must work harder), fatigue, HA, weight loss, N&V (above due to change in ions). Itching (build up of ions. Phosphate particularly causes) Have an increased tendency to bleed (don’t release erythropotient to create blood cells to stop bleeding) and have cognitive impairment.
Uremia
Occurs when the patient has clinical signs and symptoms of azotemia.
Chronic Kidney Disease symptoms
- Anaemia (pallar, lethargy, breathlessness. Due to decreased erythropotien and RBC)
- Platelet abnormability (epistaxis-bleeding, bruising. Due to decreased RBC)
- Skin-pigmentation (kidney normally gets rid of melanocyte stimulating hormone but doesn’t anymore) and Pruitis (itching due to ion imbalance)
- GI Tract-anorexia, NV, diarrhea. Due to acid base/balance and waste build up
- Endocrine/gonads-amenorrhea, ED, infertility. Hormones involved
- polyneuropathy-tingling of fingers and toes.
- CNS-Confusion, coma, seizures. Waste products build up
- CVS-Uremic pericarditis (uremia build up), hypertension, peripheral vascular disease, Heart failure (due to fluid build up)
- Renal-nocturia (pee at night), polyuria (need to pee a lot), salt and water retention.
- Renal osteodystrophy-osteomalaca, muscle weakness, bone pain, hyperparathyroidism (low calcium) osteosclerosis.
What are the most common and first signs and symptoms of CKD?
Anorexia, NV, diarrhea.
Acute Renal Failure
An abrupt decrease in renal function. Commonly due to meds, ischemia (most common. Occurs with surgery), auto-immune dis, infections. DECREASED URINE OUTPUT IS THE MOST COMMON SIGN! Remove cause and allow kidney to heal. If patient survives there is a 90% chance of full recovery.
Medications causing ARF
- NSAIDS-inhibits prostoglandins and stops vasodilation from occurring. Will recover with discontinuation.
- Hypersensitivy-not dose related. Meds bind to proteins of the kidney while cleared and indicated as foreign. Start an immune reaction. Can be type I (anaphylactic) or type IV (delayed)
- Toxicity-Occurs with overdose and typically comes within a week of treatment. Prognosis for recover is good.
Aminoglycoslides
Nephrotoxicity occurs in about 10% of patients
Radiographic contrast agents and ARF
Increase risk of ARF. Tell pt. to hydrate to minimize risks.
Acute tubular necrosis
A common form of intrinsic ARF (damage to the renals themselves). Response to acute ischemia or nephrotoxic insult. Decrease in GFR occurs in minutes to days. Damage of tubular epithelial cells decreases ion transport and cells can slough off and block tubules and can alter the medulla and increase intratubular pressure and cause collapse. Insult damages vasculature and results in increased endothelial with decreased NO and prostoglandins so results in vasoconstriction. Causes reduced volume of urine, increased fluid in body and increased waste products in the blood.
Malignant Hypertension
An example of intrinsic ARF. Symptoms-HAs possibly occipital, NV, Visual scotoma and spots. Char=diastolic BP >120. ONH edema, encephalopathy, CV abnormalities, renal failure (causing the increased HTN). A vicious cycle occurs where there is damage to kidney that results in increased permeability of small vessels, that results in fibrosis of vessels to stop leaks, that leads to ischemia to kidney, that rsults in renin release and more vasoconstriction.
Glomerular disease
Affects the glomerulus. Included nephrotic syndrome, nephritic syndrome, and mixed: membranoproliferative glomerulonephritis
Nephrotic syndrome
Have a derangement of capillary walls so they are more leaky. Have massive proteinuria (seen as bubbly pee), hypoalbuminemia (as it is escaping in the pee. Causes production of all plasma proteins including lipoproteins) and has hyperlipiduria and hyperlipedimia. There is also an impaired breakdown of lipoproteins so there is an increased risk of thromboembolism. Will have generalized edema (eyelids often first. Decreased albumin in blood shifts balance. Pitting edema. and decreased blood to kidneys causes release of renin (HTN possible but not universal. Not expected as fluid is in tissue and not the blood vessels so there is less fluid in blood vessels)*** NOTE: no oligouria like in nephritic.
Common causes of nephrotic syndrome
Diabetes and HTN (most common), lupus, NSAID induced, membranoproliferative glomerulonephritis, idiopathic.
TX for nephrotic syndrome
Try to get control over protein loss. ACE inhibitors or Angtiotensogen receptor blocker will decrease protein in urine by decreasing filtration rate to improve charge and size selectivity of glomerular BM. Use diuretics (especially loop to remove fluid). Fluid and sodium restrictions, Thrombo-prophylaxis for first 6th months to stop clot development. Can use immune suppression in children and some adults (90% respond to corticosteroids but proteinuria recurs in more then 66%)
Acute glomerulonephritis AKA acute nephritic syndrome
Acute inflammation of glomeruli with hematuria* (blood vessels of tubules are leaking). One of the first manifestations may be oliguria* (reduction in urine output). Mild edema usually on the eyelids and face first. Retention of salt causes fluid retention and HTN* (fluid retention in vasculature unlike nephrotic syndrome)
Causes of nephritic syndrome
- prior streptococcal infection-occurs 12-14 days after infection. Inflammation from ag-ab rxn. More common in kids, summer and autumn. Post strep in northern US and post impetigo in southern US.
- staphylcocci and gram neg bacteria: subacute bacterial endocarditis (valves aren’t working right and bacteria can grow here), dental abscess, and shunt infections
- Lupus-consider if no prior infections
- Can be idiopathic
TX for nephritic syndrome
Salt restrictions, diuretics and other HTN meds. Complete recovery in 90-95%. Can take 1-2 years for some.
Nephrotic vs. nephritic
Nephrotic has loss of protein with hyperalbuminurea and hyperlipidema and hyperlipidurea (increased risk of stroke). There is pitting edema but normally no increased HTN as in tissue and not vessels. Treat with loop diuretics, ACE inhibitor or ARB (decrease flow and allow more correct filtration), thrombi prophylaxis, and immunosuppresents.
Nephritic syndrome has hematouria, oligouria, and HTN (fluid in vasculature) Treat with loop diuretics and HTN, decrease salt and fluid.
Membranoproliferative glomerulonephritis AKA dense deposit disease
Immune damage to capillaries and mesangium. Three subtypes of unknown cause. Can cause HTN and signs of nephrotic syndrome (mix of nephrotic and nephritic)
Type II Membranoproliferative glomerulonephritis
Associated with bilateral central clustered drusen. Often found in tens. Initially VA and VF unchanged. Longer term have poor night vision, Subretinal neovascularization macular, macular detachment, central serious retinopathy, and retinal atrophy.
Tubulointerstitial nephropathy
A group of inflammatory kidney diseases that primarily involves the intersitium and tubules. Spares glomerulus and renal vessels. Can be acute or chronic. often caused by pyelonephritis (bacterial infections of renal pelvis). If non-infections called interstitial nephritis (drugs and metabolic disorders or physical injuries)
TINU (acute idiopathic tubulointeristial nephritis and uveitis)
Occurs in females 10-33 (bimodal 10-15 and 28-33). Bilateral uveitis in majority (77). Ocular systems occur first in 33% and are often recurrent. Conj injections, fine KP, iridocyclitis. Fever, weight loss, fatigue (50). Use oral corticosteroids to treat uveitis.
Acute pyelonephritis
Inflammation of the kidney and renal pelvis. Almost always bacteria getting to the kidney by the bladder and ureters. Almost exclusively in women (common in pregnancy). Will have fever, dysuria (painful urination), back pain, and pyuria (pus in urine). usually very responsive to AB.
Chronic pyelonephritis
slowly progressing disease that kills the kidneys. Often only signs are not feeling well so diagnosed late. usually some pyuria. Primary underlying disorders is frequent UTI rom obstruction, vesicoureteric reflex (pressure on glomerulus as there is a blockage that causes urine to travel backwards), or diabetic nephropathy. Many will wind up on renal dialysis.
Diabetic nephropathy
Most common cause of ESRD in US. Direct result of metabolic changes in DM. (good blood sugar level is protective). Have microalbuminuria and proteinuria. ACE inhibitors and ARB reduce protein in urine. Nephrotic syndrome and azotemia develop 3-5 years after proteinuria. ESRD 1-5 yrs after that. Accelerated decline with HTN, infection, nephrotoxins.
Diabetic Neuropathy Pathology
Occurs due to glomerulus membrane thickening, renal atherosclerosis (affects both afferent and efferent arterioles and changes blood flow to kidneys), and pyelonephritis (increased suspectiblity to infection)
Fabry Disease
Error of glycosphingolipid metabolism due to enzyme (alpha-galactosidase A) defect. X-linked recessive but carrier can show some symptoms (more common M) Difficult to diagnose due to variable signs and symptoms (most caused by build up of lipids in tissues).
Fabry Disease Symptoms
Children will have burning sensation in hands, raised rash on butts, decreased ability to sweat, corneal whorl or verticillata (present in over 90%. Deposit in bowman’s). Some other ocular signs are conj vessel tortuosity and sacular dilation, retinal venous dilation with hemorrhages possible or a spoke like cataract.
Systemic problems with fabry
Renal failure is common (proteinuria, azotemia, uremia. Due to glycolipid deposition and damage to renal vessels. 50% affected by age 35 if treated). Cardiovascular disease, cerebrovascular disease, GI disfunction.
Testing for fabrys
Enzyme assay (measure amount of alpha-GAL enzyme activity) Genetic testing (evaluate for mutation)
Treatment for Fabry
Enzyme replacement with agalsidase beta given IV. Recombinate agent given every 2 weeks, protects kidney function.
Nephrolithiasis (urolithiasis)
Formation of calculus in the collecting system. Travels and gets stuck in ureters. Blocks urine flow. Can occur with meds (zcetazolaminde), dehydration, or gout. Made of calcium, mg, uric acid or cysteine. M more commonly have symptoms. 20-45. Hematuria and severe pain!
Nephrolithiasis treatment and diagnosis.
Diagnosed with a CAT scan. Treat with pain meds (allow to pass). Meds to allow spontaneous passage (Alpha-adrenergic blockers and calcium channel blockers). Dietary modifications to stop another. AB while allowing to pass. Shockwave lithotripsy (breaks up the stone if it cannot pass) Surgery in intense cases.
Renal Cell Carcinoma
90% malignant tumors of the kidney. M>F. Greater frequency in cigarette smokers. Associated with von Hippel-Lindau Disease (bleeding in the eye). Prescent with painless hematuria. Classic triad is Hematuria, dull flank pain, palpable flank mass (only 20% have this). Can also have a long standing fever, elevated sedimentation rate (longer for red blood cells to settle) and systemic signs of cancer. Develops form the proximal tubules and is highly vascular
Renal Cell Carcinoma TX
Usually treated by surgical removal of the kidney (if before metastasize). Today experimenting with percutaneous cryoablation (lower temperature of kidney). Resistant to chemo. Anti-VEGF and anti-PDGRF are having some success. Immune modulators are also being explored (aldesleukin). 5 year survival rate of 70% if no metastasis.
Wilms’ Tumor
Second most common renal malignancy. 3rd most common organ tumor in children <10. Can grow really big and result in ab distention. High incidence in children with aniridia. Treat with radiotherapy, nephrectomy and chemotherapy. 90% survive for two years.
Treatment for CRF
- remove cause if known
- Treatment of HTN (decrease progression)
- Treatment of secondary manifestations (Heart disease, edema, anemia)
- Restriction of dietary protein until on dialysis
- Avoid toxic meds
- short or long term dialysis
- Renal transplantation
Anti-HTN drugs
- Diuretics-pull water out. work best in the beginning as kidney will adapt
- Beta-blockers-Lower HR and Relaxes smooth muscle
- Calcium channel blockers-relaxes smooth muscle.
- ACEi*
- Antiotensin II antagonist (ARB)*
- Renin inhibitors
What drugs are used with diabetics to try and decrease protein in the urine
- ACEi
- ARB
- Renin inhibitors.
Diuretics
Decrease sodium reabsorption so increase urine output and initially reduce blood volume. Blood volume may return to normal if kidney is working. Usefull in patients with HTN due to renal disease.
Hydrochlorothiazide
Thiazide. Works on distal tubule.
Chlorthalidone
Thiazide. Works on distal tubule.
Bumetanide
Loop diuretic. Works on ascending.
Furosemide
Loop diuretic. Works on ascending
Spironolactone
Potassium sparing diuretic. Works on collecting duct.
Triamterene
Potassium sparing diuretic. Works on collecting duct.
Acetazolamide
Carbonic anhydrase inhibitor. Works on the proximal tubule to stop absorption of bicarbonates. Used for glaucoma or disc edema. Can cause renal stones
Mannitol
osmotic diuretics. Used in glaucoma
Urea
Osmotic diuretics. used in glaucoma