Abnormal composition of urine

1. Abnormal composition of urine mirka.rovenska@lfmotol.cuni.cz

2. Urine examination • Physical – volume, density, colour, odour, turbidity • Chemical • Examination of urine sediment

3. Routine: pH proteins ketone bodies glucose blood in the urine nitrites leukocytes Targeted: bilirubin, urobilinogen amino acid metabolites hormones (cortisol, sex hormones, somatotropin) Chemical examination of urine

4. pH of urine • Usual range: 5,5 – 7,0 (maximal range: 4,5 – 7,5) • Aciduria – pH < 5,4 • Cause: • diet high in meat products (sulphur and phosphorus are metabolized to sulphates and phosphates) • compensation of metabolic / respiratory acidosis • along with ketonuria can be predictive of starving/lack of saccha-rides; if glucosuria is also present, the combination can indicate decompensated DM • Alkaluria (alkalinuria) – pH > 6,5 • Cause: • lacto vegetarian diet • urinary tract infection (bacterial urease) • compensation of respiratory / metabolic alkalosis at its onset

5. Proteins in urine • Proteinuria = excessive excretion of proteins into the urine: >150 mg/d • Cause: • physiological: physical effort • pathological: • renal disease – according to the origin: • glomerular proteinuria • tubular proteinuria • glomerular and tubular proteinuria • post-renal proteinuria –either bleeding into the urinary tract, or local secretion of immunoglobulin • pre-renal proteinuria – due to an increased plasma concentration of low-molecular proteins ( increased excretion into the urine)

6. Ketone bodies • Acetone, acetoacetate, -hydroxybutyrate • Synthesis: from acetyl-CoA, produced by -oxidation of fatty acids • Starvation, physical effort, stress   lipolysis and -oxidation of FA; acetyl-CoA is used preferentially for the synthesis of ketone bodies

7. Ketonuria •  level of ketone bodies in the urine (normally – very low) • Causes: • severe DM • long-term starvation, marked reduction of saccharides in diet • tenacious vomiting • Test strips: acetoacetate (not -HB!) reacts with nitroprusside (in the presence of alkali), producing purple-coloured complexes (Legal reaction)

8. Glucose in urine • Physiological range: 0,1 – 1,4 mmol/l • Test strips: glucose is oxidized by glucose oxidase; H2O2 is formed that converts a colourless substrate to a coloured complex • Glucosuria (glycosuria) = increased amount of glucose in the urine; causes: • hyperglycaemia > 10 mmol/l (DM, acute pancreatitis…) • renal glycosuria (glucose is abnormally excreted by the kidney) • increased intestinal reabsorption

9. Blood in urine • A) hematuria (erythrocyturia) – causes: • renal disease (glomerulonephritis, tumours) • other diseases of the urinary tract • haemorrhagic diathesis (e.g. thrombocytopathy,haemophilia) • B) hemoglobinuria – excessive intravascular haemolysis (haemolytic anaemia, e.g. hereditary or after non-compatible transfusion) • Test: • i)test strip detecting hemoglobin:Hb catalyzes oxidation of the substrate with peroxide to a coloured product (pseudoperoxidase activity) • ii) erythrocytes in the urinary sediment

10. Nitrites in urine • Nitrates in the urine can by reduced by some pathogenic bacteria to nitrites that can thus serve as indicators of the infection in the urinary tract • These bacteria include: E. Coli, Klebsiella, Salmonella, Proteus, Aerobacter, Citrobacter, some strains of Enterococcus, Staphylococcus, Pseudomonas

11. Leukocytes in urine • Increased amount of leukocytes (> 20/µl) – pyuria – is a sign of inflammation in the urinary tract • Test: granulocyte esterase activity • Causes: • infection of the urinary tract • tumours

12. heme→ biliverdin → bilirubin transport to the liver (albumin) conjugation with glucuronate  bilirubin diglucuronide secreted into the bile bacteria in the small intestine release bilirubin from diglucuronide and convert it to colourless urobilinogens a small fraction is reabsorbed and re-excreted through theliver into the bile a small fraction is excreted into the urine by the kidney most of them are oxidi-zed to pigments and excreted in the faeces (urobilin, stercobilin) Urobilinogen and bilirubin in urine

13. Causes of icterus • Icterus (jaundice): bilirubin in the blood exceeds 10 mg/l (hyperbilirubine-mia)  bilirubin diffuses into tissues, which become yellow • Pre-hepatic: haemolysis  overproduction of bilirubin that exceeds the liver's capacity for handling bilirubin (haemolytic anaemia, neonatal jaundice)  unconjugated bilirubin in blood and urobilinogen in urine • Hepatic: liver damage (hepatitis, cirrhosis)   capacity for handling bilirubin (uptake, conjugation, excretion)   conj. as well as unconj. bilirubin in blood, urobilinogen in urine can  if microobstruction is present, otherwise it rises (impaired enterohepatic cycle) • Post-hepatic– obstructive: obstruction of the biliary tree (concretions, tumours)  conj. birubin regurgitates into the hepatic veins and lymphatics   conj. bilirubin in blood, no urobilinogen in urine

14. Urobilinogen in urine • Abnormal values: ≥10 mg/l • Causes: • increased degradation of hemoglobin (heavy bleeding, haemolytic jaundice) • liver disease interfering with the enterohepatic urobilinogen cycle (hepatitis, tumours) • Causes of the absence of urobilinogen in the urine: • obstruction in the biliary tree • failure of bile production in the liver • absence of intestinal flora

15. Direct and indirect bilirubin • Conjugated bilirubin = direct bilirubin x unconjugated = indirect • Normally, only conjugated bilirubin can appear in the urine the level is increased when the plasma concentration of conjugated bilirubin rises • On the other hand, only unconjugated bilirubin can cross BBB (neonatal jaundice  encephalopathy can occur)

16.  conj. bilirubin in blood  bilirubin is in the urine: liver damage, microobstruction (hepatitis, cirrhosis) Dubin-Johnson Syndrome: defect in the hepatic secretion of conjugated bilirubin into the bile obstructive jaundice  unconj. bilirubin in blood  bilirubin is NOT in the urine: hemolytic anaemia neonatal jaundice: accelerated haemolysis and immature hepatic system for bilirubin metabolism (low activity of UDP-glucuronosyltransferase) Crigler-Najjar Syndrome: decreased activity of bilirubin UDP-glucuronosyltransferase Bilirubin in blood and urine

17. Clinical parameters in 3 different causes of jaundice

18. Phenylketonuria • Defect in phenylalanine hydroxylase  Phe cannot be converted to Tyr, accumulates, and is metabolized to phenylacetate, phenyllactate, and phenylacetylglutamine. Urinary level of phenylpyruvateis elevated. • If leftuntreated, it leads to mental retardation • Prevention: low-Phe diet • Screening: plasma Phe → genetic test

19. Urolithiasis • Urinary calculi (concretions) are formed in the urinary tract • 80-90% = renal concretions made of calcium salts (oxalate, phosphate) • Factors that predispose to calculi formation: • highly concentrated urine (e.g. dehydration) • increased urinary excretion of: • phosphates, calcium (e.g. increased breakdown of bones) • oxalates • uric acid (hyperuricosuria) • cystine (cystinuria – maybe due to impaired resorption in the kidney) • urine alkalization (in case of excretion of Ca2+, phosphates, oxalates) • urine acidification (pH<5,5) in case of excretion of uric acid

20. Hyperuricosuria • Excretion of >700-800 mg of uric acid into the urine/24h; serum uric acid rises, too (hyperuricemia) • Causes: • gout • cancer, especially if treated with cytostatic drugs or radiation therapy (increased cell death and thus also increased NA degradation) • renal disease • high intake of purines in the diet • dehydration

21. Revision: purinecatabolism

22. Gout • Enzyme defect in PRPP-synthase or HGPRTase  overproduction of purines, and thereby also of uric acid  crystallization of urates in soft tissues and joints  inflammation (arthritis). • Therapy: allopurinol – converted by xanthine oxidase to alloxanthine that inhibits the enzyme   synthesis of uric acid, more soluble xanthine and hypoxanthine are excreted

23. PRPPS and HGPRT in purine metabolism (first step) („salvage pathway“)

24. Urine sediment • Urine sediment: • substances discharged from organs • crystals (oxalates, urates, phosphates) • Examination detects the presence of: • blood – erythrocyturia (>5 ery/µl); causes: impaired permeability of glomerular membrane, infection, urolithiasis… • leukocytes – pyuria (>10 leuko/µl); causes: infection of the urinary tract • casts – formed in the kidney (the matrix is made of the protein produced by tubules, other components: plasma proteins, lipid droplets)  casts can indicate a renal disease (different types of casts indicate different types of damage) • epithelial cells • microorganisms

25. macrophage hyaline cast erythrocytes a…granulocyte; b…bacteria

26. hyaline cast cuboidal epithelial cell a…tubular epithelial cell (inside a cast) b…2 cells of a transitional epithelium

27. granular cast waxy cast (with the cells of tubularepithelium inside)

28. fatty cast granulocyte yeast yeast