Slide on Urine analysis and urine microscopy

Slide on urine analysis including microscopy and urinalysis

1. Urinalysis

2. Outline Introduction Urine composition Urine collection Physical examination Chemical examination Microscopic examination

3. Introduction Urine can be used to screen for and aid in diagnosis of some conditions . The indications for urinalysis include : S u s p e c t e d renal disease like glomerulonephritis , pyelonephritis , nephrotic syndrome and renal failure D e t e c t i o n of urinary tract infection D e t e c t i o n and management of meta b o l i c disorder like diabetes mellitus Diagnosis of pregnancy

4. Composition of normal urine Volume : 6 -200ml Specific gravity : 1 . 3 -1 . 3 Osmolality : 5 - 1 2 0mosm / kg PH : 4 . 6 - 8 Glucose : < . 5 g Protein : < 1 5 m g Urobilinogen : . 5 -4 . mg Na : 4 -220mEq K : 2 5 -125mEq Cl : 1 1 -250mEq red cells , WBC , epithelial cells : < 1 -2 / hpf

5. Urine collection First morning midstream urine : preferred for routine urine examination Random midstream urine : routine urine collection 2 4 hour urine collection : quantitative estimation of protein or hormones

6. Changes that occur with standing urine at room temperature Increse in PH due to production of ammonia from urea by urease producing bacteria D i s i n t e g r a t i o n of colour elements especially in alkaline urine F o r m a t i o n of Crystal's due to precipitation of phosphate and calcium B a c t e r i a l proliferation Oxidation of urobilinogen to urob i l i n causing false negative result for urobilinogen

7. Preservation of urine sample Urine sample should be examined in the laboratory within 2 -3hrs of collection to get accurate result Refrigeration ( 4 -6c ) is the best method of preserving urine sample for up to 8 hrs Some preservatives can be added to a 24hr urine sample for preservation . Eg inclides : boric acid , thymol , hydrochloric acid

8. Urine Examination Physical examination Chemical examination Microscopic examonation

9. Physical examination Volume Average 2 4 hr urinary output in adult is 6 -200 ml Abnormalities of urinary volume are as follows polyuria means urinary vol > 3 00ml it can be seen in conditions like diabetes mellitus , diabetes insipidus , diuretic therapy - Oliguria means urinary vol < 400ml / 2 4 hr It can be seen in acute glomerulonephritis , dehydration , congestive cardiac failure - Anuria means u r i n a r y output < 100ml / 24hr It o c c u r s in complete urinary tract obstruction , acute tubular necrosis eg shock , acute glomerulonephritis

10. Physical examination Colour Normal urine colour in fresh state is pale yellow or amber

11. Physical examination Appearance Normal freshly avoided urine is clear in appearance Foamy urine occurs in the presence of excess protein Cloudy urine occurs due to the presence of bacteria , leukocytes or epithelial cells in urine Varying degrees of t u r b i d i t y can a l s o occur following the presence of l i p i d in urine

12. Physical examination Odour Freshly avoided urine has a typical aromatic odour S o m e abnormal odour with associated conditions include :

13. Chemical Analysis Specific gravity Specific gravity refers to the weight of a solution , with respect to an equal weight of distilled water . Normal SG of urine is 1.003 - 1 . 3 Hypersthenuria : seen in DM , glycosuria , dehydration , fever hyposthenuria : DI , diuretics Isosthenuria ; T h e SG becomes l ow and fixed at 1 . 1 . It occurs due to loss of concentrating ability of the tubules seen in end stage renal failire

14. Protein Urinary protein excretion should not exceed 150mg / day , of which less than 20mg is albumin . The daily physiological proteinuria consists of mucoprotein ( Tamm horsfall glycoprotein , 70mg ) , blood group related substance ( 35mg ) , albumin ( 16mg ) , immunoglobulin ( 6 mg ) , mucopolysaccharide ( 16mg ) , very small amount of other proteins such as hormones , enzymes

15. Microalbuminuria

16. Glucose All of the glucose filtered by the glomeruli is reabsorbed by the proximal renal tubules Glycosuria occurs if the filtered glucose load exceeds the capacity of renal tubular absorption ( plasma level of > 10mmol / l ) Renal glycosuria occurs when tubular renal.injury leads to a failure to reabsorbed filtered glucose

17. Causes of glycosuria include : Endocrine diseases such as DM , Cushing's syndrome , acromegaly , hyperthyroidism Drugs : thiazides , corticosteroids

18. Ketones Ketonuria is the excretion of ketone bodies in urine Ketones are breakdown of fatty acids and their p3esence in urine is indicative of excessive fatty acid metabolism to produce energy Causes include : Decrease utilisation of CHO eg DKA , glycogen storage disease decrease availability of CHO in diet eg starvation , increase metabolic needs eg Fever , severe vomiting

19. Bilirubin Presence of bilirubin in urine indicates hepatic or chloestatic disease

20. Blood Hematuria is defined as presence of 2 RBC / hpf in sp u n urine Causes includes : Glomerular diseases : GN , L u p u s hepatitis , Berger's diseas e N o n glomerular disease : tumor , calculus , pyelonephritis , tuberculosis , polycystic kidney disease , diseases of the prostate H e m a t o l o g i c a l disorders eg coagulation disorder , SCD

21. Nitrite / leukocytes estetase

22. Microscopic examination Normal urine microscopy contains few epithelial cells , few crystals and occasional RBC

23. Casts Casts are plugs of Tamm-Hodsfall mucoprotein that form in the renal tubules They can be classified as cellular and non cellular casts

24. Cellular casts includes Red cell casts which is suggestive of intra renal inflammation . It is seen in GN , allergic interstitial nephritis , pyelonephritis White cell casts seen in acute pyelonephritis Epithelial casts are s l oughed epithelial cells embedded in mucoprotein . It can be seen in ATN , GN Fattycast : contain lipid filled epithelial cells or lipid globular . Seen in nephrotic syndrome

25. Non cellular casts includes hyaline cast which can seen in concentrated urine , CCF , after exercise or administration of diuretics Granular casts consists of degenerated tubular cells and strongly suggests renal pathology . Can be seen in CKD , ATN broad or waxy casts can be seen in advanced CKD

26. Cells in urine RBC which can be isomorphoc or dysmorphic . Isomorphoc cell is seen in non glomerular hematuria from genitourinary source while dysmorphic cells are from glomerular bleeding Neutrophils : leucocyte are prominent feature of UTI but may also be present in inflammatory renal condition like GN , TIN lymphocyte s : may be seen in chronic tubulointerstitial disease Eosinophils may be seen in TIN , prostatitis ,

27. Transisitional cells are seen in cystitis Renal tubular cells are present in normal urine but increases in tubular damage ( TIN , ATN )

28. Crystals Crystal's are detected by examining urine under polarised light . Examples include ; calcium oxalate : a few may be normal but can denote hypercalciuria , hyperoxaluria Uric acid : may form several types of Crystal's in patients with uric acid nephrolithaisis , tumor lysine syndrome , hyperuricosuria Calcium phosphate : : might be a risk factor for calcium stone formation Cystine : a marker of cystinurai

29. Cholesterol crytals : occurs with heavy proteinuria Magnesium ammonium phosphate : if present exclude a proteus UTI Drug induced crytalluria seen with drugs like antibiotics : amoxicillin methotrexate antiviral agents eg acyclovir , famciclovor , valaciclovir vitamin C Triamterene

30. Conclusion Urinalysis is very vital in the management of patients as it aids in diagnosis and follow up of patients

31. Reference Harrison T R, Petersdorf R G;Harrison’s Principles of Internal Medicine 19th Ed. MC Graw Hill Education N e i l Turner , Nobert La m e i r e , David Goldsmith ; Oxford Textbook of Clinical Nephrology Murray L, Lan B W, Edward H D, alexander F, Ahmad R M; Oxford Handbook of Clinical Medicine 9th Ed.

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