1. 1 Alterations of Renal and Urinary Tract Function in Children Chapter 37

2. Mosby items and derived items © 2006 by Mosby, Inc. 2 Development of the Urinary Renal System  Pronephros  Mesonephros  Metanephros Ureteric bud Metanephrogenic blastema  Urine formation and excretion begin by the third month of gestation

3. Mosby items and derived items © 2006 by Mosby, Inc. 3 Development of the Urinary Renal System

4. Mosby items and derived items © 2006 by Mosby, Inc. 4 Fluid and Electrolyte Balance  Blood flow to the kidney in a newborn is primarily to the medullary nephrons  Due to the short loops of Henle in the medullary nephrons, an infant produces more dilute urine  Infants are in a high anabolic state, so their urea excretion is low Urea is required to establish the concentration gradient in the medulla

5. Mosby items and derived items © 2006 by Mosby, Inc. 5 Fluid and Electrolyte Balance  Infants have a narrow chemical safety margin due to high hydrogen ion concentration, low osmotic pressure, and limited ability to regulate their internal environment  Diarrhea, infection, fasting, and poor feeding can rapidly lead to severe acidosis and fluid imbalance

6. Mosby items and derived items © 2006 by Mosby, Inc. 6 Structural Abnormalities  Ectopic kidneys  Horseshoe kidneys  Hypospadias Chordee  Epispadias  Exstrophy of the bladder

7. Mosby items and derived items © 2006 by Mosby, Inc. 7 Structural Abnormalities  Ureteropelvic junction obstruction  Bladder outlet obstruction  Hypoplastic or dysplastic kidneys  Renal agenesis  Polycystic kidney disease

8. Mosby items and derived items © 2006 by Mosby, Inc. 8 Glomerulonephritis  Acute poststreptococcal glomerulonephritis (PSGN) PSGN occurs after a throat or skin infection with certain strains of group A α-hemolytic streptococci The patient experiences a sudden onset of hematuria, edema, hypertension, and renal insufficiency Antigen-antibody complexes and complement are deposited in the glomerulus The immune complexes initiate inflammation and glomerular injury

9. Mosby items and derived items © 2006 by Mosby, Inc. 9 Glomerulonephritis  Immunoglobulin A nephropathy IgA nephropathy is characterized by the deposition of mostly IgA but some IgM antibodies and complement in the mesangium of the glomerular capillaries.  Henoch-Schönlein purpura nephritis Also referred to as anaphylactoid purpura IgA nephropathy that causes inflammation and damage to the glomerular blood vessels

10. Mosby items and derived items © 2006 by Mosby, Inc. 10 Hemolytic-Uremic Syndrome (HUS)  HUS is the most common cause of acute renal failure in children  There is an association of HUS with bacterial and viral agents Escherichia coli O157:H7  The bacterial toxin from E. coli damages red cells and endothelial cells  The endothelial lining of the glomerulus becomes swollen and occluded with fibrin clots

11. Mosby items and derived items © 2006 by Mosby, Inc. 11 Hemolytic-Uremic Syndrome (HUS)  HUS causes a decreased glomerular filtration rate with hematuria and proteinuria  The swollen vessels damage red cells as they pass  The damaged red cells are removed from the circulation by the spleen, causing acute hemolytic anemia  The microcirculation develops numerous thrombi

12. Mosby items and derived items © 2006 by Mosby, Inc. 12 Nephrotic Syndrome  Nephrotic syndrome describes a group of symptoms characterized by proteinuria, hypoproteinemia, hyperlipidemia, and edema Minimal change nephropathy (MCN) Focal segmental glomerulosclerosis (FSGS) Mesangial proliferation  Nephrotic syndrome can develop as part of numerous renal diseases

13. Mosby items and derived items © 2006 by Mosby, Inc. 13 Urinary Tract Infections (UTI)  UTIs are common 7- to 13-year-old girls  E. coli, the most common pathogen, ascends the urethra in cystitis or the ureter in pyelonephritis  Cystitis  Acute pyelonephritis

14. Mosby items and derived items © 2006 by Mosby, Inc. 14 Vesicoureteral Reflux (VUR)  Retrograde flow of urine from the bladder into the ureters  Reflux encourages infected urine from the bladder to be swept up into the kidneys  Leads to frequent pyelonephritis  Caused by a congenital abnormality or ectopic insertion of the ureter into the bladder  Diagnosed by a voiding cystourethrogram (VCUG) and an intravenous pyelogram (IVP)

15. Mosby items and derived items © 2006 by Mosby, Inc. 15 Vesicoureteral Reflux (VUR)

16. Mosby items and derived items © 2006 by Mosby, Inc. 16 Vesicoureteral Reflux (VUR)

17. Mosby items and derived items © 2006 by Mosby, Inc. 17 Wilms Tumor  Wilms tumor is an embryonal tumor of the kidney  Wilms tumor arises from the proliferation of abnormal renal stem cells (metanephric blastema)  Three cellular components: Stromal, epithelial, and blastemic  Inherited and sporadic forms

18. Mosby items and derived items © 2006 by Mosby, Inc. 18 Enuresis  Involuntary passage of urine by a child who is beyond the age when voluntary bladder control should have been acquired 4 to 5 years old  Primary enuresis The child has never been continent  Secondary enuresis Diurnal, nocturnal, or both

19. Mosby items and derived items © 2006 by Mosby, Inc. 19 Enuresis  Theories Organic causes Maturational lag Genetic factors Sleep patterns Psychosocial theories