Genitourinary System October 20, 2009 Heather Gates RN, BSN

Structures of the Urinary System Two kidneys Two ureters One urinary bladder One urethra

Figure 28.1 The urinary system Source : “ Pearson Education/PH College”

Kidney’s Primary Functions Fluid volume Electrolyte composition Acid-base balance

Figure 28.2 The nephron

Overall Health of the Client Depends Strongly Upon the Kidneys Additional kidney functions Secrete renin - regulate blood pressure Secrete erythropoietin - stimulates red blood cell production Produce calcitrol (active form of vitamin D) - help maintain bone homeostasis

Impaired Kidneys Drugs accumulate to high levels Toxicity Most medication dosages will need to be reduced Administering the average dose to a patient in renal failure can kill the patient

Diuretics Diuretics increase urine output Useful in the treatment of: Hypertension Heart failure Kidney failure Pulmonary edema Liver failure or cirrhosis Most work by blocking sodium reabsorption in the nephron

Diuretics (cont’d) Blocking reabsorption of sodium keeps more water in the filtrate The more water in the filtrate, the greater the volume of urine Different diuretics act at different sites along the nephron

Loop or High-Ceiling Diuretics - Most Effective Class of Diuretic Block reabsorption of sodium and chloride in the loop of Henle Used to reduce edema associated with: Heart failure Hepatic cirrhosis Chronic renal failure

Loop or High-Ceiling Diuretics - Most Effective Class of Diuretic (cont’d) Some also used in the treatment of hypertension Furosemide (Lasix) - most commonly prescribed loop diuretic See drug profile in Chapter 16

Table 28.1 Loop Diuretics

Loop Diuretic - Adverse Effects Rapid excretion of large amounts of water May produce dehydration and electrolyte imbalances Loop diuretics reserved for clients with moderate to severe fluid retention

Figure 28.3 Sites of action of the diuretics

Thiazides Most commonly prescribed diuretic overall Block reabsorption of sodium at the distal tubule and increase water excretion Used to treat mild to moderate hypertension Less efficacious than the loop diuretics Not effective in clients with severe renal disease

Table 28.2 Thiazide and Thiazide-like Diuretics

Thiazides - Adverse Effects Less side effects than that of loop diuretics Minor, rarely block treatment Dehydration Orthostatic hypotension Hypokalemia Patient education to avoid adverse effects Drink water Drink beverages containing electrolytes Eat a balanced diet

Drug Profile - Thiazide Diuretic Chlorothiazide (Diuril) Actions and uses Adverse effects and interactions Mechanism in action

Potassium-Sparing Diuretics Less effective than loop diuretics Produce a mild diuresis without affecting blood potassium levels Block the exchange between sodium and potassium in the tubule Causes sodium to stay in the tubule and leave through the urine More potassium is retained by the body

Table 28.3 Potassium-sparing Diuretics

Drug Profile Spironolactone (Aldactone) Actions and uses Adverse effects and interactions Mechanism in action

Miscellaneous Diuretics Carbonic anhydrase inhibitors Prevent formation of carbonic acid water and carbon dioxide Example - acetazolamide (Diamox) Decreases intraocular fluid pressure in patients with glaucoma Osmotic diuretics Maintain urine flow in clients with acute renal failure or during prolonged surgery Example - mannitol Very potent diuretic; only given IV

Table 28.4 Miscellaneous Diuretics

Monitoring with Diuretics Labs Potassium levels Electrolytes levels BUN and creatinine levels Adverse Effects Hypokalemia Dehydration (thirst, dry mouth, weight loss, headache) Dizziness (postural hypotension) Hyperkalemia (potassium-sparing diuretic)

Renal Failure Acute versus Chronic Diuretics Cardiovascular agents Chronic - erythropoietin (Epogen, Procrit)

Chronic Renal Failure Occurs over months or years Many cases occur in patients with a history of hypertension or diabetes mellitus May be undiagnosed for a long time

Erythropoietin Hormone secreted by the kidney Stimulates red blood cell (RBC) production Decreased secretion of erythropoietin in renal failure

Synthetic Erythropoietin Epoetin alfa (Epogen, Procrit) Used to treat problems caused by decreased RBCs Chemotherapy - to counteract anemia Prescribed prior to blood transfusions or surgery Treat anemia in patients with HIV Administered three times per week until RBCs are increased

Nursing Interventions Monitor kidney function tests Communicate with physician Know which drugs can be nephrotoxic Encourage diet changes associated with medication administration (potassium rich foods) Encourage or restrict water intake depending on the medication and disease process

Sex Hormones Steroids produced from cholesterol Most produced by the male and female gonads Small amount secreted by adrenal cortex Male and female hormones present in both sexes

Estrogen Estrogen - three different hormones Estradiol Estrone Estriol

Estrogen (cont’d) Functions of estrogen in the female Maturation of the reproductive organs Appearance of secondary sex characteristics Metabolic effects on the brain, kidneys, blood vessels, and skin Maintain low blood cholesterol levels Facilitate calcium uptake by the bones Ovaries stop secreting estrogen about age 50– 55

Progesterone Functions of progesterone (along with estrogen) in the female Promotes breast development Regulates menstrual cycle During pregnancy maintains endometrium Prevents premature labor contractions

Testes Produce the Male Hormone Testosterone Functions of testosterone in the male Maturation of the male sex organs Secondary sexual characteristics of the male Metabolic effects on muscle

Regulation of Ovaries and Testes Hormones from the pituitary FSH - regulates sperm and egg production LH (sometimes called interstitial cell- stimulating hormone in males) Triggers ovulation Promotes the release of estrogen and progesterone by ovary Regulates the production of testosterone

Oral Contraceptives Low doses of estrogens and progestins Nearly 100% effective Most oral contraceptives are a combination of estrogen and progestin

Estrogen-Progestin Oral Contraceptives Prevent ovulation Stop secretion of FSH and LH by pituitary - negative feedback Make lining of uterus less favorable to receive embryo

Menopause - the Permanent Cessation of Menses Ovaries stop secreting estogen Number of unpleasant symptoms result

Estrogen Replacement Therapy Prescribed to Relieve Many menopausal symptoms and osteoporotic bone fractures Potential, long-term consequences of estrogen loss Estrogen usually combined with a progestin Higher doses are used than in oral contraceptives More side effects

HRT Risks Based on New Research HRT had been used widely for the past 20 years Recent studies raised questions regarding the safety of HRT Increased risk of: Coronary artery disease Stroke Venous thromboembolism

HRT Risks Based on New Research (cont’d) Collaborate with healthcare provider Women need to make an informed decision regarding HRT

Drug Profile - Hormone Replacement Therapy (HRT), Estrogen and Estrogen + Progestin Conjugated Estrogens (Premarin) and Conjugated Estrogens with Medoxprogesterone (Prempro) Actions and uses Adverse effects and interactions Mechanism in action

Nursing Interventions Encourage breast self-check Instruct client to report lumps immediately and to maintain routine visits Monitor for Thrombophlebitis client should report any pain in calves, dypnea, chest pain, headache, seizures or anxiety Monitor for hypertension & cardiac disorders Encourage Smoking Cessation

Nursing Interventions (cont’) Monitor blood and urine glucose levels Instruct client on proper adminsitration of medication missed dose could equal pregnancy Encourage compliance and follow-up Monitor client for vision changes HRT