Ch. 7 Urinary Function Notes PDF

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Chapter 7: Urinary Function Anatomy and Physiology 

Kidneys o



Renal capsule o





Surrounds the kidneys

Renal cortex o

Area immediately beneath the capsule

o

Contains the nephrons (functional unit of the kidney)

Renal hilum o



Secretes renin and erythropoietin

Opening in the kidney through which the renal artery and nerves enter and the renal vein and ureter exit

Renal pelvis o

Urine funnels through this through tubes called calyces 

The urine goes through the calyces and drains into the ureters 

The ureters transport the urine to the bladder 



Glomerular Filtration Rate (GFR) o

The speed at which blood moves through the glomerulus 

o

o

Normal GFR: 125 mL/min & 1,500 mL/day

Afferent arteriole (artery) 

Brings blood to the glomerulus

Efferent arteriole 



Urine exits out through the urethra

Blood exits through this

Renin-Angiotensin-Aldosterone System o

Low blood pressure  the kidneys secrete renin  renin converts Angiotensinogen to Angiotensin I  Angiotensin I is converted into Angiotensin II (vasoconstrictor)  blood pressure is going to rise 

Aldosterone causes salt retention, which conserves more water, leading to an increase in blood pressure



When blood pressure is too high, you would give someone an ACE inhibitor which lowers blood pressure

Conditions Resulting in Altered Urinary Elimination 1

Incontinence 

Involuntary loss of urine



Risk factors for urinary incontinence



o

Being female (stress incontinence)

o

Advancing age

o

Being overweight

o

Smoking

o

Other diseases (renal disease, diabetes mellitus)

Types of incontinence o

Enuresis: involuntary urination by a child after 4-5 years old, when bladder control is expected 

Can have psychological (anxiety) or structural (smaller than normal bladder) origins

o

Nocturnal enuresis: bed-wetting

o

Transient incontinence: urinary incontinence resulting from a temporary condition 

Conditions include delirium, infection, atrophic vaginitis, use of certain medications (diuretics, sedatives)

o

Stress incontinence: loss of urine from pressure (stress) exerted on the bladder by coughing, sneezing, laughing, lifting, etc

o

Urge incontinence: sudden and intense urge to urinate, followed by an involuntary loss of urine 

Overactive bladder: describes urge incontinence with no known cause

o

Reflex incontinence: urinary incontinence caused by trauma or damage to the nervous system

o

Overflow incontinence: inability to empty the bladder, or retention 

Indications include dribbling of urine and a weak urine stream



Chronic overdistension: occurs because of inability to interrupt work to void 

Nurse’s bladder; teacher’s bladder

o

Mixed incontinence: symptoms of more than one type of urinary incontinence are experienced

o

Functional incontinence: physical or mental impairments prevents toileting in time 

o

Common in people in nursing homes

Gross total incontinence: continuous leaking of urine, day and night, or periodic uncontrollable leaking of large volumes of urine

Neurogenic Bladder



Refers to all bladder dysfunction caused by an interruption of normal bladder nerve innervations 2





Factors disrupting bladder nerve innervations o

Brain or spinal cord injury

o

Nervous system tumors

o

Dementia

o

Diabetes mellitus

o

Parkinson’s disease

Clinical manifestations o

Overactive bladder (frequency and urgency)

o

Underactive bladder (hesitancy and retention)

Congenital Disorders



There are congenital disorders of the urinary system which are structural problems o

Renal agenesis: failure of an organ to develop in utero

Urinary Tract Infections



The lower urinary tract (bladder and urethra) is the most frequent site for the infection



Most infections invade the urethra from the meatus in the perineal area



Most often caused by E. coli



Clinical manifestations o

Urgency

o

Dysuria

o

Frequency

o

Haematuria (presence of blood in the urine)

o

Bacteriuria

o

Cloudy, foul-smelling urine

o

Symptoms of infection (fever, chills, fatigue)

Cystitis



Inflammation of the bladder



Urethra walls become red and swollen 3



Clinical manifestations o

Abdominal pain and pelvic pressure

Pyelonephritis



Infection that has reached one or both kidneys



Most often caused by E. coli



Common in those who require frequent medical attention, experience recurrent UTI’s, or have contracted an antibioticresistant bacterial strain



Kidneys become edematous and structures fill w/ exudate, compressing the renal artery



Clinical manifestations o

Similar to UTI symptoms

o

Flank pain

o

Increased blood pressure

Urinary Tract Obstructions



Particles collecting and forming stones to complex growth of tumors



Nephrolithiasis o

Presence of renal calculi (kidney stones)

o

More common in men and Caucasians

o

Conditions that increase the likelihood of the disease

o



Bone disease



Gout



Urinary stasis (immobility)

Clinical manifestations



Colicky pain



Bloody, cloudy, foul-smelling urine



Dysuria



Frequency



Nausea/vomiting



Fever/chills 4



Hydronephrosis o

Abnormal dilation of the renal pelvis and the calyces of one or both kidneys that occurs secondary to a disease

o

Clinical manifestations



Severity depends on the severity of urinary obstructions



Colicky flank pain or pressure



Bloody, cloudy, foul-smelling urine



Dysuria



Decreased urine output



Nausea/vomiting



Abdominal distension



UTIs

Tumors



Most urinary tumors are malignant



Wilms’ Tumor (nephroblastoma)



o

Rare kidney cancer that mostly affects children

o

Associated with genetic mutations on chromosome 11 as well as on the X chromosome

o

Higher in females and African Americans

o

Asian Americans have a lower risk

o

Clinical manifestations



Asymptomatic abdominal mass



High blood pressure



Hemihypertrophy (one side of the body grows more than other, causing asymmetry)



Hematuria



UTIs



Anorexia

Renal Cell Carcinoma o

Most frequently occurring kidney cancer in adults

o

Arises from the renal tubule

5

o

o

Risk factors



Being male



Dialysis treatment



Hypertension

Clinical manifestations



Typically asymptomatic in early stages



Painless hematuria



Anemia



Abnormal urine color (dark, rusty, brown)



Urinary retention



Palpable mass over affected kidney



Polycythemia (if the tumor secretes erythropoietin or an erythropoietin-like substance) 



Slow-growing blood cancer in which your bone marrow makes too many red blood cells

Bladder Cancer o

Any cancer that forms in the tissue of the bladder

o

Most are transitional cell carcinomas

o

Clinical manifestations



Painless hematuria



Abnormal urine color (dark, rusty, brown)



Urge incontinence



Dysuria



Frequency

Benign Prostatic Hyperplasia



Benign Prostatic Hyperplasia (BPH) o

Non-malignant enlargement of the prostate gland, that occurs as men age

o

Increase in proliferation enlarges the prostate gland

o

Clinical manifestations



Frequency



Urgency



Urinary retention 6



Difficulty initiating urination



Dribbling urine



Nocturia



Bladder distention



Overflow incontinence



Erectile dysfunction (ED)

Conditions Resulting in Impaired Renal Function



Polycystic Kidney Disease o

Inherited disorder characterized by numerous grape-like clusters of fluid-filled cysts in bothe the kidneys

o

Most common type is autosomal dominant PKD

o

Autosomal recessive PKD is less common and occurs in infancy or childhood; extremely serious

o

Clinical manifestations







Neonates



Potter facies (skin folds at the corner of the eyes on either side of the nose)



Pointed nose, small chin, and floppy low set ears



Large, bilateral, symmetrical masses on the flanks



Respiratory distress

Adults



Hypertension



Lumbar pain



Increased abdominal girth



Swollen, tender abdomen



Grossly enlarged, palpable kidneys

Neonates & Adults



Hematuria



Nocturia



Drowsiness

Inflammatory Disorders



Glomerulonephritis 7

o

Bilateral inflammatory disorder of glomeruli that typically follows streptococcal infection

o

The inflammatory changes impair kidney’s ability to excrete waste and excess fluid

o

Acute or chronic

o

Affects more men than women

o

Leading cause of kidney disease

o

Nephrotic Syndrome



Antibody antigens complexes lodge in the glomerular membrane triggering activation of the complement system



Inflammatory changes result in increased glomerular capillary permeability leading to: 

Proteinuria 

Indicates impaired glomerular function



Due to the loss of protein, the liver increases albumin, triglyceride and cholesterol production, which increases risk for atherosclerosis



Lipiduria



Hypoalbuminemia 

o

Low levels of protein in the blood



Massive generalized edema



Immunoglobins excreted in the urine increases the risk for infection

Nephritic Syndrome 

Inflammatory injury to the glomeruli that can occur when antibodies interact with normally occurring antigens in the glomeruli



Clinical manifestations 

Gross hematuria



Urinary casts and leukocytes



Low GFR



Azotemia (build-up of waste products)



Oliguria (decreased urine output)



High blood pressure

Renal Failure



Acute Renal Failure o

Sudden loss of renal function; abrupt onset 8

o

Generally reversible

o

Common in critically ill, hospitalized patients

o

Causes are divided into three categories







Prerenal conditions (initial phase)



Disrupts blood flow on the way to the kidneys



Extremely low blood pressure or blood volume



Heart dysfunction



Asymptomatic

Intrarenal conditions (Oliguric phase)



Directly damages the structure of the kidneys



Reduced blood supply within the kidneys



Hemolytic uremic syndrome



Renal inflammation



Toxic injury



Clinical manifestations o

Decreased urine output

o

Azotemia

o

Metabolic acidosis

o

Fluid volume excess

o

Electrolyte disturbances (increased disturbances)

Postrenal conditions (diuretic phase)



Interfere with urine excretion



Ureter obstruction



Bladder obstruction and dysfunction (BPH, tumors)



Clinical manifestations o

Increased urine output

o

Electrolyte disturbances (decreased disturbances)

o

Dehydration 9

o



Hypotension

Chronic Kidney Disease (CKD) o

Gradual loss of renal function that is irreversible

o

Scar tissue replaces injured nephrons

o

Stage I

 o

Stage II

 o

GFR continues to fall (GFR 30-59)

Stage IV

 o

GFR begins falling (GFR 60-89)

Stage III

 o

Kidney damage I present, but GFR is normal or high (greater than 90)

Falling (GFR 15-29)

Clinical manifestations



Slowly appears at 50% renal function



Hypertension



Polyuria w/ pale urine



Oliguria or anuria



Anemia



Pericarditis



Heart failure



Electrolyte imbalances (hyperkalemia, hypocalcemia, hypomagnesemia, hyperphosphatemia)



Azotemia



Edema of the feet/ankles

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