Patho Ch 22 renal

Aldosterone

:produced in the adrenal glands - increases Na+ and H2O into the bloodstream from tubule fluid

Blood urea nitrogen

BUN test measures the amount of nitrogen in your blood that comes from the waste product urea urea is made in the liver when protein is broken down in your body and passed out your body thru urine

Postrenal Causes of AKI

Nephrolithiasis Prostatic hyperplasia Ureteral stricture Bladder tumor

Intrarenal Causes of AKI

Nephrotoxic drugs or agents Excessive hemoglobin in urine (eg, caused by a high amount of hemolysis) Excessive myoglobin in urine (eg, caused by a large amount of muscle injury) Excessive purines in urine (eg, cancer chemotherapy can cause high amount of DNA breakdown) Glomerulonephritis Pyelonephritis

The Multitasking Kidney

1- filters the blood of waste 2- develops a concentrated urine 3- secretes renin to control BP 4- secretes erythropoietin = RBCs at bone marrow 5- maintains acid-base balance 6- excretes excess K+ 7- synthesizes component of vitamin D

intrarenal

drugs direct damage to kidneys by inflammation, toxins, drugs, infection, or reduce blood supply

Pyelonephritis S/S

Abdominal or CVA tenderness Flank pain Nausea and vomiting Fever Chills Dysuria Urinary frequency Microscopic hematuria Pyuria (WBCs in urine) +Leukocyte esterase test of urine Costovertebral tenderness, fever, and pyuria are classic signs of pyelonephritis. Urinalysis Urine culture and sensitivity In females, pelvic examination should be done to rule out gynecological problems.

Hormones That Work at the Nephron

Aldosterone ADH

Intrarenal Dysfunction Is Caused by:

Any condition that directly harms the kidney Examples: trauma to kidney, infection of kidney, nephrotoxic drugs NSAIDs (ibuprofen) ASA ACE inhibitors, angiotensin-receptor blockers Statin drugs that cause rhabdomyolysis Some antibiotics Heroin and other illicit drugs Poststreptococcal glomerulonephritis Pyelonephritis Autoimmune diseases

Prerenal Dysfunction of the Kidney Caused by:

Any condition that directly or indirectly decreases renal perfusion may lead to prerenal dysfunction. Prerenal dysfunction occurs because of reduced cardiac output or severe hypovolemia (low blood volume). Large blood loss from the body, as in hemorrhage, is a common cause of prerenal kidney injury because of ischemia.

Blood Urea Nitrogen (BUN)

BUN increases when: 1-the kidney dysfunctions 2-high protein diet is consumed (proteins = amino acids = nitrogen compounds) 3-dehydration concentrates the blood urea. Seen in 16-19 old men eating too much meat = atkins diet

BUN vs. Serum Creatinine

BUN rises with dehydration, high protein diet, or high muscle breakdown. Serum creatinine = better measure of kidney function

Chronic Renal Failure (CRF)

CRF is an irreversible, progressive disease process. Gradual in onset, the disease may develop over months to years, with 90% to 95% of the nephrons affected. CRF usually progresses to ESRD; as CRF progresses, kidney function deteriorates to the point that the kidney is unable to excrete waste products or control volume status. Hemodialysis or kidney transplant are the only options to support life. # causes of chronic renal failure with DM, HTN, glomerulonephritis, and polycystic kidney disease as leading etiologies.

Types of stones

Ca stones - most common bc ca oxalate is found in food struvite - occure with ppl that get infections like UTI can be very large uric acid stones - ppl who dont drink enough fluids cystine stones - hereditary disorders known as cystinuria

Postrenal Dysfunction

Caused by obstructive uropathy, a problem that prevents urine outflow from the kidney Examples: kidney stone or prostate gland hyperplasia

Nephrotic Syndrome Signs and symptoms:

Costovertebral angle (CVA) tenderness Hypervolemia Hypertension Low oncotic protein edema Hyperlipidemia Oliguria Common causes: glomerulonephritis, diabetes, autoimmune disease KEY SIGN of GLOMERULAR INJURY: loss of albumin from the blood into the urine.

Common Signs of Kidney Disorder

Costovertebral angle (CVA) tenderness Proteinuria (microalbuminuria) Hematuria

Creatinine Clearance

Creatinine clearance is sometimes used to assess the GFR. The test requires measurement of both blood and urine creatinine and 24-hour urine volume. The amount of creatinine filtered at the glomerulus is the total amount of creatinine that appears in the urine. A decr creatinine clearance indicates decr GFR and impaired renal function.

Serum creatinine

Creatinine is a breakdown product of muscle that is completely excreted and can act as a measure of kidney filtration. High serum creatinine = kidney dysfunction

Major Insults to the Kidney

Direct trauma Hemorrhage leads to ischemia Hypertension glomerular injury Diabetes mellitus diabetic nephropathy Hypertension harms the kidney and kidney failure causes hypertension.

Polycystic Kidney Disease

Genetic disorder that affects the kidneys and other organs. looks like marbles in tissue Because of the development of cysts in the renal tissue, renal function is impaired. pain, calculi, infection, HTN (pushing on blood vessels activating renin) Cysts also develop in other organs of the body, such as the liver.

Azotemia

High blood urea nitrogen (BUN)

Hydronephrosis

In postrenal kidney dysfunction, urine backs up within the ureter and into the kidney, which can lead to hydronephrosis, a fluid-filled swollen kidney.

End-Stage Renal Disease (ESRD)

In the past, ESRD was called UREMIA (meaning urine in the blood). Kidney is dysfunctional; numerous nephrons damaged; blood not being filtered Very low GFR

Pyelonephritis

Infection of the kidney most commonly caused by: Obstructive uropathy (obstruction somewhere along the urological pathway) Ascending infection from bladder Vesicoureteral reflux Bladder catheterization most comm cause is Escherichia coli

Acute Tubular Necrosis (ATN)

Ischemia and hypoxia = damage the renal tubules = ATN = the most common cause of acute kidney injury (AKI). With ischemia, there is sloughing of the cells of nephron tubules into the tubular lumen. The lumen becomes blocked, preventing fluid from flowing through them, thereby reducing urine formation. Unless reversed = renal failure will occur.

Prerenal Causes of AKI

Ischemia of the kidney Hemorrhage Hypovolemic shock Cardiogenic shock Septic shock

According to the National Kidney Foundation, the Progression of CRF Usually Occurs in Five Stages:

Once GFR is lower than 10/20 mL/min (normal 90 to 120 mL/min) --> dialysis is initiated, patient evaluated for kidney transplant. Stage 1: kidney damage with normal or increased GFR (greater than 90 mL/min) Stage 2: mild reduction in GFR (60 to 89 mL/min) Stage 3: moderate reduction in GFR (30 to 59 mL/min) Stage 4: severe reduction in GFR (15 to 29 mL/min) Stage 5: kidney failure (GFR lower than 15 mL/min)

How Does Hyperuricemia Occur?

Purines -> breakdown into uric acid. Purines are derived from the DNA of animal cells or cancer cells. High purine levels in the bloodstream occur with high ingestion of meats or whenever there is high cellular breakdown as in chemotherapy treatment of malignancy. high uric acid can be caused by gout, which is a metabolic disorder.

Kidney positions

R lower than L

Nephrolithiasis S/S

Severe abdominal pain flank pain around to groin; colicky pain caused by ureter spasms Hematuria Crystalluria incr in male over 40, nausea/vomiting,

Complication of Nephrolithiasis Infection or Hydronephrosis

Stone can cause back pressure into the renal pelvis, a condition called hydronephrosis. Hydronephrosis occurs when edema and distention of the renal pelvis occurs. Prolonged hydronephrosis causes compression of the kidney tissue, ischemia, and irreversible kidney damage.

Nephrotic Syndrome

Term used whenever the glomerulus is damaged and yields protein in the urine (proteinuria) and low oncotic pressure (causing edema).

Nephrolithiasis Dx

UA cystoscope IVD Renal stone analysis KUB (X-ray) Serum: Ca, Oxalate, uric acid

What Is Urea?

Urea is a breakdown product of PROTEIN METABOLISM.

Proteinuria

When glomeruli are injured, they become hyper permeable to proteins and other substances in the bloodstream (so there is less protein in the blood - edema!) As the body loses albumin with glomerular injury, the liver attempts to replace albumin by increasing the synthesis of albumin. The liver increases the synthesis of LDL when it increases synthesis of albumin high LDL results. protein is filtered out of the blood at the glomerulus, loss of protein from te bloodstream (hypoalbuminemia) --> low colloid oncotic pressure --> edema

Acute Kidney Injury(Acute Renal Failure)

abrupt insult to the kidney that causes a rapid decrease in renal filtration function. Common cause is ischemia (reduced renal blood flow) of the kidney. bc decline of function, there is an accumulation of nitrogenous waste products in the body. normal renal function can return, usually within 2 weeks to 3 months Decr glomerular filtration of the blood in AKI leads to azotemia, high serum creatinine, and fluid retention.

Urine Analysis Using Reagent Strips

specific gravity - 1.001 = 1.030 pH 6.5 - 7.5 G = - K= - P = - B = - Bil = - Urio = - N = - Leu = -

nephritic syndrome = glomerular nephritis

b/c glamerular damage = a lot of albumin and protein in urine = proteinuria, now blood doesn't have albumin/protein = edema see IgG in urine and other immunoglobins = live makes more = hyperlipidemia (fat in blood)

Prerenal

sudden and sever drop in blood pressure (shock) or interruption of blood flow to the kidneys from severe injury or illness

postrenal

sudden obstruction of urine flow due to enlarged prostate, kidney stones, bladder tumor, or injury

Prerenal dysfunction:

caused by decreased blood flow and perfusion to the kidney.

As an individual ages

the normal GFR rate diminishes. Peak kidneys function occurs at age 30 years and for each year after, GFR decreases by 1 mL/min until age 70 years, when GFR is 70 mL/min. reduction in GFR in elderly = accumulation of toxins in the blood, particularly drug metabolites.

Intrarenal dysfunction:

develops secondary to actual injuries to the kidney itself.

Urinalysis

dipstick method chemical reactions cause color change on 10 different pads on test strip leukocytes nitrite urobilinogen protein pH blood ketones biliruben glucose

Nephrolithiasis

formation of stones, also called calculi, in the kidney Stones travel down the ureter/bladder. Males - 35 years

Glomerular Filtration Rate (GFR)

glomerulus filters approximately 90 to 120 mL/min of blood, which is pushed through Bowman's capsule because of high hydrostatic pressure. renal blood filtered per unit of time is known as the glomerular filtration rate (GFR), and it is directly related to renal perfusion. Disease processes that decr blood pressure and renal perfusion result in a decreased GFR.

Glomerulonephritis SS

headache incr BP facial edema lethargic low grade fever weight gain proteniunuria hematuria oliguria dysuria

Recovery

healthy nephrons take over function of damaged nephrons; kidney function resumes

Goodpasture's Syndrome

immunological disease of the kidney. aka - antiglomerular basement membrane (anti-GBM) disease. acute, rapidly progressive type of glomerulonephritis caused by circulating antibodies. Antibodies are directed against collagen in the glomerular basement membrane. Antibodies may also be directed against collagen in the lungs. malaise, chills, fever; dyspnea, hemoptysis, pain, Pulmonary hemorrhage is possible. Hematuria, edema, HTN, renal failure.

Glomerulonephritis

immunological mechanism triggers inflammation that damages the membranes of the glomerulus. It is an autoimmune disease or poststreptococcal disorder. Group A beta hemolytic streptococcus (GABHS) -> pharyngitis -> stimulates-> streptococcal antibodies-> attack the streptococcus and the glomeruli membranes-> glomerular damage-> proteinuria + edema + hypertension + hematuria

Oliguria

inadequate amount of urine. lower than 400 mL of urine output per day or lower than 20 mL of urine per hour.

Risk factors for Ca oxalate and Ca phosphate stones

incr ca concentration in urine bc genetics, parathyroid gland, high diet of oxalates (chocolate, spinach, nuts) IBD, surgery, obesity

Nephrolithiasis risk factors

infection, urinary stasis, immobility, hyper calcemia, incr UA, urinary oxalate level Genetic susceptibility Dehydration Hypercalcemia; excessive calcium intake Hyperparathyroidism Gout Hyperuricemia Urinary tract infection; proteus Immobility

glomerular nephritis

inflammation of nephrons GABHS (strep) --> glomerular damage (filter, holes too big, loss RBC is urine = hematuria) --> leads to nephritic syndrome

AKI Can Be Divided Into Four Phases:

initial insult oliguria diuresis recovery

What Happens When the Kidneys Dysfunction?

insufficient filtration of the blood of waste; nitrogen buildup causes RBC and platelet lysis hemolysis, thrombocytopenia, and confusion, stupor: encephalopathy does not develop a concentrated urine secretes excess renin to raise BP does not secrete erythropoietin to manufacture RBCs does not maintain acid-base balance does not excrete excess K+ does not synthesize a component of vitamin D; decreases Ca++ absorption

Renin angiotensin system

kidneys sense decr in BP and release renin from JGA renin convert angio to angio 1 lungs angio converting enzyme (ACE) convert angio 1 to angio 2 angio 11 causes vasoconstriction = incr BP angio 2 stimulates adrenal glands to release ADH in kidneys aldosterone promotes the reabsoption of Na and H2O circulating BV incr = incr BP

Diuresis

large unconcentrated urine outflow; kidney is not concentrating urine properly

Oliguria

low GFR, lack of urine output, fluid overload

Obstructive Uropathy -> Stagnant Urine

obstructed outflow of urine, stagnant urine acts as a medium for bacterial growth, which can ascend into the kidney to cause pyelonephritis. Within stagnant urine, calcium can precipitate and often forms a stone.

The Causes of Kidney Dysfunction Are Divided Into Three Categories Based Upon the Mechanism of Injury:

pre, intr, post

Initial insult

prerenal, intrarenal, or postrenal condition that disrupts kidney function

Nephrotic Syndrome Causes Immunocompromise

proteins are lost in nephrotic syndrome = immunoglobulins are lost to the urine as well. This incr susceptibility to infection. incr loss of protein in the urine, there is loss of antithrombin III and plasminogen, the natural thrombolytic substances in the body. incr the risk of thromboembolism.

Postrenal dysfunction:

related to obstruction of urine outflow from the kidneys.

Antidiuretic hormone (ADH):

released from the posterior pituitary gland - increases H2O into the bloodstream from tubule fluid

IV contrast-enhanced imaging studies

should be avoided in patients with renal impairment because radiopaque dye can cause renal failure. Dehydration markedly increases this risk.