Renal System Flashcards
Kidney Function
Regulate electrolyte concentration, acid-base balance, and amt of body fluids Detoxify and eliminate wastes Help control blood pressure (renin) Aid in RBC formation (erythropoiesis) Activates Vitamin D
Urine formation
GFR regulated by afferent & efferent arteriole constriction and relaxation
Actual urine excretion is ~1.5 L a day
Proximal convoluted tubule reabsorbs about 60% of nutrients and ions in the urine
The amount of a solute it can reabsorb is the transport maximum
Nutrients not reabsorbed pass out in the urine when renal threshold is reached.
Urine formation pt. 2
Loop of Henle
Controls concentration of urine
Reabsorbs more sodium & chloride than water
Ascending limb impermeable to water; solutes reabsorbed into blood supply, but water remains in the filtrate
Filtrate (now dilute) enters the distal convoluted tubule- “diluting segment”
Allows for excretion of free water
Late distal tubule & collecting tubule
Action of aldosterone
Regulation of K+ excretion
Serum Creatinine
0.6-1.2 mg/dL
Used as screening test for renal function
Inversely r/t GFR (low Creatine/High GFR)
A product of creatine metabolism in muscles therefore less accurate in elderly persons w/ decrease in muscle mass
Tells you more about kidney damage
BUN
8 – 20 mg/dL
Byproduct of protein metabolism
r/t GFR but less specific than creatinine
Influenced by protein intake, GI bleeding , & hydration status
Urinary tract infections (UTI)
The second most common bacterial infection seen by health care providers, effects more immunocompromised patients
Etiology Gram Negative Bacteria E-coli Staphylococcus saprophyticus Proteus mirabilis, Klebsiella pneumoniae, Enterobacter, Pseudomonas Gram-positive Staphylococcus aureus, group B streptococcus Complicated UTIs
Protection methods: Washout phenomenon Protective mucin layer Local immune responses and IgA Normal bacterial flora Lactobacillus in urethra of women Men: prostatic fluid protects urethra
Risk factors for UTI
Anatomical or structural factors Sexual activity Delayed postcoital urination Impaired voiding Catheters, other urinary instrumentations Constipation Reduction of estrogen
Signs and Symptoms for UTI
Frequency Urgency Dysuria: burning sensation Hematuria Cloudy, foul-smelling urine Flank pain (lower back) Elderly: Vague, abdominal discomfort & confusion
UTI Diagnosis
History and physical Urinalysis Proper collection is essential! Blood, WBCs, Nitrites (gram negative) Urine culture The GOLD STANDARD for diagnosis of complicated UTI ≥ 10,000/mL
UTI Prevention
Fluids Empty bladder Hygiene Cranberry juice Postcoital urination
TREATMENT:
Antibiotics
Force fluids
Acute Pyelonephritis
Complicated upper urinary tract infectious, inflammatory process, with abscess formation and tubular necrosis
Risk factors: UTI Vesicoureteral reflux Pregnancy Diabetes Catheter Immunosuppression Kidney stones
S/S of Acute Pyelonephritis
Symptoms of UTI plus…
Sudden onset fever, chills, unilateral or bilateral flank or groin pain. Pyuria, CVA tenderness. Possible sepsis and development of renal failure.
Geriatric –low-grade fever, malaise, confusion
Infants – irritability, poor skin perfusion, failure to thrive, GI symptoms, etc.
Can lead to renal scarring and damage
KIDNEY STONES
AKA kidney stones; nephrolithiasis; urolithiasis
More common in the United States than the rest of the world
Dietary preference – Foods high in animal protein
More common in white men
Before age 50
Negative risk factor: adequate fluid intake & regular physical activity
Kidney Stone Formation
Supersaturation of one or more salts: Presence of a salt in a higher concentration than the volume is able to dissolve the salt
Precipitation of a salt from a liquid to a solid state
Temperature and pH
Growth into a stone via crystallization or aggregation
Process by which crystals grow from a small nidus or nucleus to larger stones
Embedded in matrix
Presence or absence of stone inhibitors
Alkaline urinary pH: Increases the risk of calcium phosphate stone formation.
Acidic urine: Increases the risk of a uric acid stone.
Potassium citrate, pyrophosphate, and magnesium: Prevent stone formation.
Types of Stones
Calcium stones- ** Most common **
Calcium oxalate or calcium phosphate or combo
Struvite stones- contain magnesium ammonium phosphate
Associated w/ UTI & alkaline urine
Usually too large to pass. Lithotripsy or surgical removal
Uric acid stones (gout)
Cystine Stones- rare
