The Urinary System Flashcards
The urinary system in girls
Kidneys - produces urinE
Ureter- transports urine toward the urinary bladder
Urinary bladder- temporarily stores urine prior to elimination
Urethra- conducts urine to exterior
Function of the urinary system
To collect, transport, store and expel urin periodically in a highly corrdinated fashion
The urinary tract enables the elimination of metabolic products and toxic wastes in urine produced by the kidneys
The ability of the urn art tract to defend against microbial infections relies on its normal anatomic archietecture and a functional physiological state
Micturition
Inner action of the bladder neck
For storage of urine, contract bladder neck and relaxed detrusor
For voiding urine, relaxation of the bladder neck and contraction of the detrusor
Keeping the urinary tract sterile
Under normal circumstances, the urinary system is sterile except for the distal urethra
Closed system for drainage of urine from the kidneys with a unidirectional flow of urine
- constant flow in the upper urinary tract and
- intermittent elimination from the lower urinary tract
Host defenders mechanisms exist to prevent invasion and establishment of bacterial infection which includes the lining of the tract by a specialised epithelium known as urothelium
Anatomical anomalies
Duplicate ureters
Multicystic kidneys
Horseshoe kidneys
Anatomy Michal anomalies
Obstructive nephropathy
Pelviureteric junction obstruction - kidney
Vesicoureteric junction obstruction - bladder
Posterior urethral valve - urethra
Neurogenic bladders e.g spina bifida
Renal function in the first 2 years
Neonatal urine is more dilute - the ability to concentrate urine begins to develop during the first mouth of life
The ability to concentrate continues to mature through 2 years of age and Th ere after the system is fully functional
Young infants therefore
- produce more urine to excrete a given solute load and
- are vulnerable to fluid overload
Urinalysis tract infections
Uti in children
Infection usually bacterial can affect any part of the urinary tract
Common infection in infancy and childhood ~ 5% of febrile children have a UTI
Highest incidence in the first year of life
- highest in preterm neonates : 3-10% in babies <2.5kg
- 3 to 8 fold increases in boys more than girls in the neonatal period
- thereafter UTI occurs in approx 8.4% of girls and 1.7% of boys
- recurrence in both boys and girls following a first infection is about 1/3 and 86% of these were within 6 months of the first UTI
uTI in children
Protective factors normal anatomy and function of the urinary tract
Optimal hydration and nutrition
Frequent nappy area care and good hygiene
Complete bladder emptying
Anti microbial properties of the bladder urothelium
Male circumcision reduces incidence of UTI in boys less than 1 year of age
UTI in children
Susceptibility factors
Reduced immuno-competence in young children
Suboptimal nappy Carr
Colonised anterior urethra with bacteria from the large intestine and vagina
Anatomical or functional anomalies
Invasive procedure eg catheterisation
UTI in children
Features of bacterial in UTIs
80 90% of 1st UTIs uropathogenic E. coli
Most urrothelial cells have galactose-containing proteins which have high binding affinity for some Encoli, increasing the risk of UTI
Some uropathogenic E. coli have flagellae which means that they are motile and can work their way upstream in the urinary tract
Depending on location the infection leads to cystitis (local symptoms) or acute pyelonephritis (systemic symptoms)
UTIs in children
Clinical manifestations in neonates are mainly systemic
Non specific symptoms
Hypothermia
Lethargy; jaundice
Irritability
Poor feeding
Failure to thrive
Diarrhoea and vomiting
UTIs in children
Clinical manifestations in older infants and children
Systemic effects
• malaise
•lethargy
•pyrexia
Local effects •loin pain or tenderness •pain on micturition •dysprosium, polyuria •foul/smelling, cloudy urine
UTIs in children
UTI must be treated to avoid damage to the kidneys, risk of hypertension and risk of sepsis
Treatment for a first UTI
- Lowe tract=> trimethoprim
- upper tract=> co amoxiclav
Recurrent UTI must be investigated in case of underlying pathology which can damage the kidneys permanently
Investigative procedures
Urinalysis of clean voided urine
Ultrasound scan
Functional scanning, static or dynamic:
DMSA- radioisotope injected into blood and clearance image at it courses through kidney (used to identify any scaring of the kidneys)
MCUG- micturating cystourethrography: filling the bladder with contrast and observing the urinary system when passing urine (looking for ureteric reflux)
