Assessing Clients with Urinary Elimination Disorders

Chapter 28

Structures of the Urinary System

Kidneys - Function 1. Balance electrolyte and water 2. Excrete waste 3. Regulate acid-base balance 4. Secrete hormones 5. Form urine 6. Regulate blood pressure Will affect the entire body.

Structures of the Urinary System

Ureters transport urine from the kidneys to the bladder

Bladder storage site for urine holds 300-500cc

Urethra channels urine to the outside of the body

Kidneys

Each kidney has 3 regions: Cortex- (Outer region) Contains glomeruli which are small

clusters of capillaries. Glomeruli are part of the nephrons which are the functional units of the kidney

Each kidney contains 1 million nephrons which process blood to make urine!!

Medulla- (inner region) nephrons form the renal pyramids. They channel urine into branches of the innermost region or the renal pelvis.

Pelvis- Urine is channeled from the pelvis through the ureter and into the bladder for storage.

Formation of Urine

Glomerular Filtration fluids and electrolytes go through a membrane

Tubular Reabsorption nutrients are reabsorbed

Tubular Secretion waste is secreted

Nephron is functioning unit which functions in glomerular filtration.

Process of urine formation

Glomerular Filtration- Blood from the renal artery is filtered in the glomerulus. The filtered product which contains water, salts, nutrients and waste products is called the glomerular filtrate.

Tubular Reabsorption- Nutrients and salts are actively reabsorbed and transported to the peritubular capillary network and some water is passively reabsorbed into the peritubular capillaries

Tubular Secretion- Some substances are actively secreted from the peritubular capillaries into the distal tubule for removal from the body.

Glomerular Filtration

Passive process where fluids and solutes move from the blood in the glomerulus into the Bowman’s capsule

The amount of fluid filtered from the blood into the capsule per minute is called glomerular filtration rate or GFR.

GFR is the most accurate indicator of kidney function. What lab test tells us what GFR is?

Normal GFR is in adults 120/125 mL per minute.

What controls GFR? -Blood pressure and blood volume. A drop in blood pressure and or blood volume will cause the

GFR and urine output to fall. / Renal failure in high risk patients trauma/ severe blood loss.

Reabsorption and Secretion

Tubular reabsorption- Healthy kidneys all organic nutrients such as glucose, and amino acids are reabsorbed.

Water and electrolyte reabsorption is continuously regulated and adjusted to maintain homeostasis.

This all happens in the proximal tubules.

Tubular Secretion- Excess potassium and waste products such as hydrogen ion, creatinine and ammonia are eliminate from the body. This process regulates the acid-base balance in the body.

Urine Concentration

Loop of Henle urine is concentrated. And further wastes are excreted through reabsorption and secretion..

Antidiuretic hormone- Determines the final concentration or dilution of the urine.

When ADH is secreted water is reabsorbed in the distal tubule and collecting duct and urine is more concentrated.

When ADH is not secreted, water cannot be reabsorbed and the urine is more dilute. What substances cause ADH to be secreted or not secreted?

Receptors in the hypothalamus detect changes in osmolality and blood volume, thus stimulating ADH production and release as needed.

Urine is about 95% water and 5% solutes.

Urine Concentration and Endocrine Function Solutes normally excreted in the urine- Urea, sodium,

potassium, phosphate, sulfate, creatinine, uric acid, calcium, magnesium, and bicarbonate.

The kidney also produces renin and erythropoietin and they activate Vitamin D.

Renin- Is an enzyme made by the juxtaglomerular apparatus in the kidney. It converts the plasma protein angiotensin to angiotensin 1. A1 is converted to A2 in the lungs.

Angiotension 2- is a potent vasoconstrictor that raises blood pressure, it also stimulates the adrenal glands to release aldosterone which promotes sodium and water retention. Drugs such as ACE inhibitors work on the Angiotension system to reduce blood pressure.

The effect of the Angiotensin system is to raise the BP and BV.

Endocrine Function- Kidney

Erythropoietin- a substance produced by the kidney in response to cellular hypoxia. It stimulates the bone marrow to produce red blood cells.

Vitamin D- Is inactive when it enters the body either through the diet or by exposure to ultraviolet light. It is activated in two steps by the liver and then the kidney.

Age Related Changes in the Kidney: Nephrons are lost with aging, thus kidney mass and GFR are

reduced. By age 80 GFR may be less than half of what it was at 30. The kidneys are less able to concentrate urine. Increased risk for dehydration. Potassium excretion may be

decreased in older, thus electrolyte imbalances are a risk!

Formation of Urine

Assessment of Urinary Function

Health Assessment Interview “Any burning on urination?” “Any difficulty in starting a stream?” Bladder control? Ask about Pregnancy Family history of kidney disease Alcohol and caffeine

dysuria, nocturia, hematuria, oliguria, polyuria

Physical Assessment

Inspection Skin Abdomen Urine

Percussion for CVA tenderness, suprapubic pain, bladder. Palpation- Kidneys?

Physical Assessment Palpation

bladder palpate over the symphysis pubis for distension

Urinalysis - how collected, why collected?

Characteristics of Normal Urine

Color - pale to deep yellow, clear Odor - aromatic Specific Gravity - 1.001-1.030 pH - 4.5-8.0 Protein - negative to trace Glucose - negative Ketones - negative WBCs 0-5 RBCs 0-5 Casts - negative to occasional

Laboratory Tests

UA- Urinalysis is a key part of the diagnostic evaluation of the urinary system.

Urea- is formed in the metabolism of dietary and body proteins. Creatinine is produced by muscle cell metabolism. Both substances are eliminated from the body by the kidneys by

filtration and secretion; neither is reabsorbed, thus BUN and Serum creatinine levels in the blood are effective indicators of renal function.

Creatinine Clearance test requires 24 hour urine sample- Another indicator of GFR./ Blood at the same time.

KUB- Abdominal X-ray evaluate the size, shape and position of organs in the urinary tract.

IVP-Intravenous pyelography- contrast medium and x-ray to evaluate the urinary tract.

NCLEX

Digoxin 0.25mg daily has been prescribed for an 80 yo client. The nurse observes closely for: A. Evidence of drug excretion without the desired effect B. Excretion of the drug unchanged in the urine C. Impaired urination due to the effects of the drug D. Manifestations of drug toxicity due to impaired excretion

NCLEX

During the assessment of a client’s renal system, the nurse is unable to palpate the kidneys. This finding is indicative of:

A. inflammation B. chronic renal disease C. nothing D. polycystic kidney disease

NCLEX

A client is admitted with an infection of the ureters. The nurse realizes that this infection could include which of the following structures of the kidney?

A. cortex B. Medulla C. Pelvis D. Adrenal glands

NCLEX

During the assessment of a client with multiple injuries, the nurse notices a large hematoma located at the left costovertebral angle. Which additional body system should this nurse assess?

A. gastrointestinal B. renal C. spinal D. respiratory

NCLEX

A client is experiencing a sudden decrease in systemic blood pressure. Which of the following will occur within the kidney to help control this blood pressure drop?

A. Juxtaglomerular cells will release renin B. GFR will increase C. Renal vessels will dilate D. Hydrostatic pressure will increase

NCLEX

A client is voiding large amounts of highly diluted urine. The nurse realized the dilution or concentration of urine is determined by which of the following?

A. Presence of urea B. Quantity of chloride C. Patency of the ureters D. Action of antidiuretic hormone

NCLEX

A client experienced a temporary reduction of oxygen due to an asthma attack. The nurse realized that this drop in oxygen level will have which impact on the client’s renal functioning?

A. nothing B. stimulate the absorption of calcium and phosphate C. stimulate bone marrow to produce more red blood

cells D. produce large amounts of dilute urine