elimination

newborns: gfr

• GFR lower than adults because of immature function, and kidney unable to rapidly excrete excess fluid » risk for fluid volume overload

• less able to concentrate urine because tubules are short and narrow and kidneys are limited in ability to dilute urine

• closely monitor for dehydration and over hydration due to limitations

• unable to concentrate urine at the age of 3 months

newborns: voiding patterns

• void within the first 24hours

• if haven’t voided within 48 hours after delivery, they should be assessed for fluid intake, bladder distention, restlessness and/or pain

• normal: 5-25 times every 24 hours, 25mL/kg per day

• cloudy urine due to mucus content and increased specific gravity, but will decrease and change to more straw colored with increased fluid intake

toddlers and preschoolers: urinary elimination

• most develop urinary control between 2 and 5 years

• control during daytime normally precedes nighttime control

  • may need diaper or pull ups

• require reminders on flushing and handwashing

• require instruction in wiping for girls

school age children: urinary elimination

• kidneys double in size between 5-10

• urinate between 6-8 times per day

• enuresis is common around 5 years

  • can be problematic when child goes to school because they should have established control by this age

  • pull ups are are great, if accident happens, it won’t be as embarrassing

  • inform pediatrician

• nocturnal enuresis (bedwetting) prevalent in deep sleepers

  • will grow out of it by age 7, not a problem until after this age

older adult: renal function

• declines at around 45 years

• with age, decrease in size and number of nephrons

• blood flow to the kidney decreases as a result of atrophy in supplying blood vessels (arteriosclerosis)

• urine is more dilute

• excrete more fluid and electrolytes at night than during the day that can interrupt sleep

older adult: renal function consequences

• impaired excretion of drugs and their metabolites

• become more susceptible to drug overdose and other adverse effects

• decreased ability to concentrate urine » increased susceptibility to dehydration, a problem that is further complicated by a decline in the thirst response further contributing to the risk of dehydration

• bladder becomes more fibrous » muscles of pelvic floor weaken and are unable to contract as efficiently resulting in the inability to completely empty the bladder, which may lead to incontinence and increased risk for UTIs

meconium

• full term infants within 8-24 hours of life

• thick, tarry, black or dark green stool

• formed in utero from amniotic fluid contents, intestinal secretions, and shed mucosal cells

transitional stool

• brownish green, part meconium and part fecal matter

• when newborn/infant begin to eat for about 1-2 days

newborns and infants: defecation

• breast fed babies have more bowel movements, up to 10 per day

  • mustard, yellow seedy appearance

• formula fed babies can have about 5 per day

  • firmer stool that ranges in color from tan to yellow or green

• bowel movement decreases in frequency at 1-2 months of age

• as intestines matures, bacterial flora increases

• when solid foods are introduced babies stool becomes more firmer and less frequent, more odor

toddlers: bowel elimination

• some control of bowel starts at around 1.5-2 years

• successful training by 3-4 years

• child becomes aware of discomfort of soiled diaper and sensation that indicates the need to have a bowel movement

intussusception

• telescoping of the intestines

• most common cause of intestinal blockage in children < 3 years

• can be managed with instilling enema or with surgery

school age children and adolescents: bowel elimination

• similar to adults

• patterns vary in frequency, quantity, and consistency

• may delay having a bowel movement for play or other activity

• important for parents to teach the child that they should listen to their bodies to prevent future discomfort or complications

older adult population: bowel elimination

• constipation is common

  • caused by reduced activity levels, inadequate fluid and/or fiber intake, muscle weakness, and medication side effects

• bowel patterns range from 3 times a day to 3 times a week and often change

• adequate fiber in diet, regular exercise, and drinking 6-8 glasses of fluids daily are essential measures to prevent constipation

• teach that consistent use of laxatives inhibits natural defecation reflexes and will cause chronic constipation, interfere with electrolyte balance, and reduce absorption of various vitamins

• change in bowel habits over weeks should notify PCP

nephritis

• inflammation of the kidneys

• glomerulonephritis: infection of glomerular capillary membrane

• acute post infectious glomerulonephritis: response to strep throat

glomerulonephritis pathophysiology

• glomerular damage from immune complex reaction after streptococcal infection with group A beta-hemolytic strep

• antigen-antibody complexes localize in glomerulus » body reacts and causes inflammation in the kidney » glomerular membranes thicken » obstructs capillaries and decreases gfr » increase in vascular permeability allowing protein and rbcs to be excreted at higher rate » loss of protein and osmotic pressure in vascular system increases kidney’s retention of sodium and water » edema in child

glomerulonephritis clinical manifestations

• abrupt onset, occur 10-14 days after initial infection

• hematuria, proteinuria, salt and water retention, azotemia (high levels of nitrogen waste products in the blood)

• urine brown, or cola colored

• HTN and edema due to sodium and water retention

• edema noted in face, especially around eyes (periorbital edema) as well as hands and arms

• fever, weight gain, fatigue, loss of appetite, headache, n/v

glomerulonephritis diagnostics

• throat culture to detect infection by group a- beta hemolytic streptococci

• antistreptolysin O titer and other blood tests detect streptococcal exoenzymes

• x-ray of kidney, ureters, bladder (KUB) to evaluate kidney size and rule out other causes

• ESR to detect general inflammatory response

• BUN/creatinine

• urine, creatinine

• electrolytes

• urinalysis

glomerulonephritis management

• APIGN, penicillin type antibiotic drugs to kill streptococcal bacteria

• corticosteroids to decrease inflammation and edema

• antihypertensives if child presents with HTN due to decrease kidney function (not common in children)

• diuretics to treat edema (use with caution in children due to higher risk of dehydration)

• teach parent/caregiver that this infection is self limiting and usually resolves in about 1-2 weeks, hematuria/cola colored urine

• avoid foods high in sodium and potassium

• preventing subsequent infections

The glomerular filtration rate of a newborn is ______ than that of an adult, placing the newborn at risk for _______.

a. higher, dehydration

b. lower, fluid volume overload

c. higher, fluid volume overload

d. lower, hypothermia

B. newborn kidneys are immature and have a lower GFR than adults, they cannot excrete excess fluid quickly, making them more prone to fluid volume overload, not dehydration in this case

Which are limitations of newborn kidneys compared to adults? SATA

a. short and narrow tubules

b. limited ability to dilate urine

c. increased ability to concentrate urine

d. full ability to regulate electrolytes

e. immature gfr

A, B, E

Newborns have short/narrow tubules, immature GFR, and limited ability to dilute/concentrate urine. Electrolyte regulation is limited, not complete.

With aging, the bladder wall becomes more fibrous and pelvic muscles weaken, leading to ______ and increased risk for ________.

a. retention, infection

b. incontinence, hypovolemia

c. increased capacity, polyuria

d. stronger contractions, dehydrations

A. fibrosis + weal pelvic floor = retention and UTI risk

Place the following developmental milestones in the correct sequence:

1. meconium passage (first stool)

2. kidneys double in size

3. decline in renal function with aging

4. urinary continence and daytime control

5. nighttime continence

1. newborns pass meconium within 8-24 hours

4. daytime urinary control occurs around 2-5 years

5. nighttime continence develops after daytime

2. kidneys double in size between 5-10 years

3. renal function declines after 45 years

Which contribute to constipation in older adults? SATA

a. medication side effects

b. decreased activity

c. high fiber diet

d. muscle weakness

e. high fluid intake

A, B, D

constipation is common due to low activity, meds, and weak muscles, not high fiber/fluid intake

Which interrelated concepts influence elimination more in children than adults? SATA

a. development

b. cognition

c. nutrition

d. perfusion

e. infection

A, B, C

for children, development, cognition, and nutrition play a larger role due to immaturity of organs and developmental milestones like potty training