RENAL Flashcards
Urinary System: Review
Removes metabolic wastes
Removes hormones from the body
Removes drugs other foreign material from body
Regulates water, electrolyte, acid-base balance
Secretes erythropoietin
Activates vitamin D
Regulate blood pressure through the renin-angiotensin-aldosterone system
Each kidney has over a million nephrons.
Renal corpuscles:
Glomerulus
Bowman capsule
Renal tubules: Proximal convoluted tubules Loop of Henle Distal convoluted tubules Collecting duct
Formation of Urine
Filtration
In renal corpuscles
Large volume of fluid passes from glomerular capillaries into the tubule (Bowman capsule)
Wastes, nutrients, electrolytes, other dissolved substances
Cells and protein remain in the blood.
Reabsorption
Reabsorption of essential nutrients, water, and electrolytes into the peritubular capillaries
Control of pH and electrolytes
Proximal convoluted tubules
Most of water reabsorption
Glucose reabsorption
Nutrients and electrolytes to maintain homeostasis
Antidiuretic hormone (ADH)
Secreted by the posterior pituitary
Reabsorption of water in distal convoluted tubules and collecting ducts
Aldosterone
Secreted by adrenal cortex
Sodium reabsorption in exchange for potassium or hydrogen
Atrial natriuretic hormone
Hormone from the heart
Reduces sodium and fluid reabsorption
Afferent and efferent arterioles of the glomerulus
Autoregulation and hormones control pressure in the glomerular capillaries by:
Vasoconstriction of afferent arteriole
Decreased glomerular pressure—decreased filtrate
Dilation of afferent arteriole
Increased pressure in glomerulus—increased filtrate
Vasoconstriction of efferent arteriole
Increased pressure in glomerulus—increased filtrate
Control of arteriolar constriction by three
factors:
Autoregulation
Local adjustment in diameter of arterioles
Made in response to changes in blood flow in kidneys
Sympathetic nervous system
Increases vasoconstriction in both arterioles
Renin
Secreted by juxtaglomerular cells when blood flow to afferent arteriole is reduced
Renin-angiotensin mechanism
Incontinence
Loss of voluntary control of the bladder
Enuresis
Involuntary urination by child age older than 4 years
Often related to developmental delay, sleep pattern, psychosocial aspect
Stress incontinence (more common in women)
Increased intra-abdominal pressure forces urine through sphincter.
Coughing, lifting, laughing
Multiple pregnancies
Overflow incontinence
Incompetent bladder sphincter
Older adults
Weakened detrusor muscle may prevent complete emptying of bladder—frequency and incontinence
Spinal cord injuries or brain damage
Neurogenic bladder—may be spastic or flaccid
Interference with CNS and ANS voluntary controls of the bladder
Retention
Inability to empty bladder
May be accompanied by overflow incontinence
Spinal cord injury at sacral level blocks micturition reflex
May follow anesthesia (general or spinal)
Straw colored with mild odor
Normal urine, specific gravity 1.010 to 1.050
Cloudy
May indicate the presence of large amounts of protein, blood, bacteria, and pus
Dark color
May indicate hematuria, excessive bilirubin, or highly concentrated urine
Unpleasant or unusual odor
Infection or result from certain dietary components or medication
Urinalysis: Urinary Infection
Heavy purulence and presence of gram-negative and gram-positive organisms
Urinalysis: Abnormal Constituents of Urine
1.Blood (hematuria)-
—Small amounts:
Infection, inflammation, or tumors in urinary tract
—Large amounts:
Increased glomerular permeability or hemorrhage
2.Elevated protein level (proteinuria, albuminuria)
Leakage of albumin or mixed plasma proteins into filtrate
3.Bacteria (bacteriuria)
Infection in urinary tract
4.Urinary casts
Indicate inflammation of kidney tubules
5.Specific gravity
Indicates ability of tubules to concentrate urine
Low specific gravity—dilute urine (with normal hydration)
High specific gravity—concentrated urine (with normal hydration)
Related to renal failure
6.Glucose and ketones
Found when diabetes mellitus is not well controlled
Blood Tests
• Elevated serum urea and serum creatinine levels
Indicate failure to excrete nitrogen wastes
Caused by decreased GFR
• Metabolic acidosis*
Indicates decreased GFR
Failure of tubules to control acid-base balance
• Anemia*
Indicates decreased erythropoietin secretion and/or bone marrow depression
*In the absence of other problems.
• Electrolytes
Depend on related fluid balance
• Antibody level
Antistreptolysin O or antistreptokinase titers
Used for diagnosis of poststreptococcal glomerulonephritis
• Elevated renin levels
Indicate kidney as a cause of hypertension
Radiologic tests
Radionuclide imaging, angiography, ultrasound, CT, MRI, intravenous pyelography
Used to visualize structures and possible abnormalities, flow patterns, and filtration rates
Clearance tests
Examples: creatinine or inulin clearance
Used to assess GFR
Cystoscopy
Visualizes lower urinary tract
May be used to perform biopsy or remove kidney stones
Biopsy
Used to acquire tissue specimens
Diuretic DrUGS
• Used to remove excess sodium ions and water from the body
o Increased excretion of water though the kidneys
o Reduces fluid volume in tissues and blood
o Prescribed for many disorders
—— Renal disease, hypertension, edema, congestive heart failure, liver disease, pulmonary edema
o Several different mechanisms to increase urine volume based on specific drug
o Some drugs are potassium-wasting and some are potassium-sparing.
Hemodialysis
Patient’s blood moves from an implanted shunt or catheter in an artery to machine
Exchange of wastes, fluids, and electrolytes
Semipermeable membrane between blood and dialysis fluid (dialysate)
After exchange is completed, blood returned to patient’s vein
Usually required three times a week
Potential complications!!!
Shunt may become infected.
Blood clots may form.
Blood vessels involved in shunt may become sclerosed or damaged.
Patient has an increased risk of infection with hepatitis B, hepatitis C, or HIV if Standard
Peritoneal Dialysis
Catheter with entry and exit points is implanted into the peritoneal cavity
Takes more time than hemodialysis
Major complication!!!!
Infection resulting in peritonitis
With both types of dialysis
Prophylactic antibiotics with either form of dialysis
Any additional problem occurring in patient such as infection may alter dialysis requirements
Caution is required with many drugs because toxic level buildup can occur.
Urinary Tract Infections (UTIs)
Common causative organism
Escherichia coli
More common in women because of:
Shortness of urethra
Proximity to anus
Other common predisposing factors:
Incontinence
Retention of urine
Direct contamination with fecal material
Cystitis and Urethritis
• Bladder wall (cystitis) and urethra (urethritis) are inflamed.
o Hyperactive bladder and reduced capacity
• Pain is common in pelvic area
• Dysuria, urgency, frequency, and nocturia
• Systemic signs may be present.
o Fever, malaise, nausea, leukocytosis
• Urine often cloudy, with unusual odor
• Urinalysis indicates bacteriuria, pyuria, microscopic hematuria
Pyelonephritis
One or both kidneys involved
From ureter into kidney
Purulent exudate fills pelvis and calyces
Pyelonephritis S&S
Signs of cystitis plus pain associated with renal disease
Dull, aching pain in lower back or flank area
Systemic signs include high temperature
Urinalysis
Similar to cystitis
Urinary casts are present.
Reflection of renal tubule involvement
Treatment with antibacterials
Inflammatory Disorders: Glomerulonephritis
Presence of antistreptococcal (ASO) antibodies
IN RESPONSE- Inflammatory response in glomeruli
Increased capillary permeability—leakage of some protein and large numbers of erythrocytes
Disorders—Glomerulonephritis MANIS
• Urine becomes dark and cloudy • Facial and periorbital edema—initially o General edema follows • Elevated blood pressure o Caused by increased renin secretion and decreased GFR • Flank or back pain o Edema and stretching of renal capsule • General signs of inflammation • Decreased urine output
Inflammatory Disorders: Glomerulonephritis
TESTS
Blood tests
Elevated serum urea and creatinine levels
Elevation of anti-DNase B, streptococcal antibodies, antistreptolysin, antistreptokinase
Complement levels decreased (use in renal inflammation)
Metabolic acidosis
Urinalysis
Proteinuria, hematuria, erythrocyte casts
No evidence of infection
GLOME TREATMENT
Sodium restriction possible Protein and fluid intake decreased in severe cases Drug treatment: 1.Glucocorticoids to reduce inflammation 2.Antihypertensives
Urolithiasis (Calculi)
Can develop anywhere in urinary tract
Stones may be small or very large.
Tend to form with:
Excessive amounts of solutes in filtrate
Insufficient fluid intake—major factor for calculi formation
Urinary tract infection
- Calculi composed of calcium salts, High urine calcium levels, Form readily with highly alkaline urine
- Uric acid stones- Hyperuricemia, Gout, high-purine diets, cancer chemotherapy, Especially with acidic urine
- Struvite and cystine stones
- Stone formation depends on predisposing factor.
Urolithiasis (Calculi) MANIS
Manifestations only occur with obstruction of urine flow.
May lead to infection
Hydronephrosis with dilation of calyces
If located in kidney or ureter and atrophy of renal tissue
Stones in kidney or bladder often asymptomatic
- Frequent infections may lead to investigation.
- Flank pain possible caused by distention of renal capsule
Renal colic caused by obstruction of the ureter
- Intense spasms of pain in flank area,Radiating into groin area, Lasts until stone passes or is removed
- Possible nausea and vomiting, cool moist skin, rapid pulse
- Radiological examination confirms location of calculi.
Urolithiasis (Calculi) (Cont.)
TREATMENT
Small stones will be passed eventually.
Extracorporeal shock wave lithotripsy (ESWL)
Laser lithotripsy
Drugs may be used to dissolve stones partially.
Surgery
Urolithiasis (Calculi) (Cont.)
PREVENTION
Treatment of underlying condition
Adjustment of urine pH through dietary modifications
Consistent increased fluid intake
Hydronephrosis
Secondary problem caused by:
Complication of calculi (Tumors, prostatic enlargement, Developmental abnormalities)
Frequently asymptomatic in early stages
Can be diagnosed with ultrasonography, radionucleotide imaging, CT, or renal scan
If cause is not removed—chronic renal failure
Tumors: Renal Cell Carcinoma
arising from the tubule epithelium
Tends to symptomatic in early stages
Often has metastasized to liver, lung, bone, or central nervous system at time of diagnosis
Treatment!!! is removal of kidney.
Tumors: Renal Cell Carcinoma
MANIS
Painless hematuria initially- Gross or microscopic
Dull, aching flank pain
Palpable mass
Unexplained weight loss
Anemia or erythrocytosis
Paraneoplastic syndromes- Hypercalcemia or Cushing’s syndrome
Tumors: Bladder Cancer
Most bladder tumors are malignant and commonly arise from transitional epithelium of the bladder.
!!!Diagnosed by urine cytology and biopsy
Tumors: Bladder Cancer MANIS
Early signs
Hematuria, dysuria
Infection common
Tumor is invasive through wall to adjacent structures.
Metastasizes to pelvic lymph nodes, liver, and bone
Predisposing factors
Tumors: Bladder Cancer
Working with chemicals in laboratories and industry
Particularly aniline dyes, rubber, aluminum
Cigarette smoking
Recurrent infections
Heavy intake of analgesics
Treatment
Tumors: Bladder Cancer
Surgical resection of tumor
Chemotherapy and radiation
Photoradiation successful in some early cases
Vascular Disorders: Nephrosclerosis
Thickening and hardening of the walls of arterioles and small arteries
Narrowing of the blood vessel lumen
Stimulation of renin
Increased blood pressure
Treatment Antihypertensive agents Diuretics Beta blockers Sodium intake should be reduced.
Congenital Disorders
Vesicoureteral reflux
Agenesis
-Failure of one kidney to develop
Hypoplasia
-Failure to develop to normal size
Ectopic kidney
-Kidney and ureter displaced out of normal position
“Horseshoe” kidney
-Fusion of the two kidneys
Adult Polycystic Kidney
Autosomal dominant gene on chromosome 16
First manifestations usually around age 40 years
Multiple cysts develop in both kidneys.
Enlargement of kidneys
Wilms’ Tumor
Most common tumor in children
Defects in tumor suppressor genes on chromosome 11
Acute Renal Failure
CAUSES
Acute bilateral kidney diseases
Severe, prolonged circulatory shock or heart failure
Nephrotoxins (Drugs, chemicals, or toxins)
Mechanical obstruction (occasionally)
Calculi, blood clots, tumors (Block urine flow beyond kidneys)
Acute Renal Failure (Cont.)
Sudden onset
Blood tests
-Elevated serum urea nitrogen and creatinine levels
Metabolic acidosis and hyperkalemia
Treatment
-Identify and remove or treat primary problem.
To minimize risk of necrosis and permanent kidney damage
-Dialysis
To normalize body fluids and maintain homeostasis
Chronic Renal Failure
Gradual irreversible destruction of the kidneys over a long period of time
Asymptomatic in early stages
Chronic Renal Failure: Stages
Decreased renal reserve
- Decrease in GFR
- Higher than normal serum creatinine levels
- No apparent clinical symptoms
Renal insufficiency
- Decreased GFR to about 20% of normal
- Significant retention of nitrogen wastes
- Excretion of large volumes of dilute urine
- Decreased erythropoiesis
- Elevated blood pressure
End-stage renal failure
- Negligible GFR
- Fluid, electrolytes, and wastes retained in body
- Azotemia, anemia, and acidosis (three As)
- All body systems affected
- Marked oliguria or anuria
- Regular dialysis or kidney transplantation To maintain patient’s life
Early signs OF CRF
Increased urinary output
General signs: Anorexia Nausea Anemia Fatigue Unintended weight loss Exercise intolerance
Bone marrow depression and impaired cell function
Caused by increased wastes and altered blood chemistry
Elevated blood pressure
Complete failure
OF CRF
• Oliguria • Dry, pruritic, hyperpigmented skin, easy bruising • Peripheral neuropathy • Impotence in men, menstrual irregularities in women • Encephalopathy • Congestive heart failure, dysrhythmias • Failure to activate vitamin D • Possible uremic frost on the skin • Systemic infections •
Diagnostic tests
Anemia, acidosis, and azotemia are the key indicators of chronic renal failure.
Treatment—all body systems are affected.
- Difficult to maintain homeostasis of fluids, electrolytes, and acid-base balance
- Drugs to stimulate erythropoiesis
- Drugs to treat cardiovascular problems
- Intake of fluid, electrolytes, protein must be restricted
- Dialysis or transplantation
