HANDS-ON COURSE BEDSIDE URINARY MICROSCOPY

GIOVANNI BATTISTA FOGAZZI LECTURES SERIES

URINARY SEDIMENT: Part 1: Methods G.B. Fogazzi, Milan, Italy

  

Dr G.B Fogazzi Research Laboratory on Urine, Unità Operativa di Nefrologia

Fondazione IRCCS, Ospedale Maggiore Policlinico, Mangiagalli e Regina ElenaMilan, Italy

 

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Prof Fogazzi: This is the outline of the course. After a brief introduction, I will speak about the main methodological aspects concerning the urinary sediment; the particles of the urinary sediment of nephrological importance with their clinical implications; the urinary sediment in the clinical practice and, finally, I will draw some conclusions.

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From the historical point of view, we know that the urinary sediment was introduced into clinical practice in the late 1830s in Paris at La Charité hospital by François Rayer and his pupil Eugène Napoléon Vigla. By the end of the 19th century, all the main particles had been identified and the main urine profiles had been described. However, in the subsequent century, the 20th century, the urinary sediment examination knew only a progressive decline with only very few exceptions. One was the original and important work of Thomas Addis in the 1920s and the other was the publication, in 1982, of a paper by Fairley and Birch on the utility of urinary erythrocyte morphology evaluation by phase contrast microscopy in patients with hematuria.

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What is the situation today? In most instances, urinary sediments are examined in central laboratories far from bedside and without the correct equipment and knowledge, and with the dream to entrust the whole task to automated instruments. These are already on the market, one being UF 100, which is based on flow cytometry, and the other iQ200, which is based on images obtained by a video camera. Last but not least, too often the urinary sediment examination is neglected even by nephrologists.

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In our unit at the Ospedale Maggiore of Milan, we examine urine sediments ourselves. We examine about 2,300 samples per year, most of which contain abnormalities. Most of our sediments come from our ward and clinic.

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Methodological aspects are very important for urine sediment. The main methodological aspects include: a correct urine collection; a standardised method for the handling of the urine; the use of a proper microscope and the use of a proper report to describe the findings. All these aspects are described in detail in the document published by the European Urinalysis Group 5 years ago as a supplement of the Scandinavian Journal of Clinical and Laboratory Investigation (2000; Vol 60, Suppl 231) as well as in our book (Fogazzi GB, Ponticelli C, Ritz E. The Urinary Sediment. An Integrated View 2nd Edition. Oxford , Oxford University Press, 1999).

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As to urine collection, it’s important to give the patient written and simple instructions. According to the strategy of the single lab, we can ask the patient to supply the first or the second urine of the morning. In our lab, we ask for the second urine, since overnight urine, due to its prolonged permanence in the bladder can favour the lysis of particles. We suggest the patient to avoid strenuous physical effort in the hours preceding the test, since this may influence in various ways the findings (for instance by causing haematuria and/or cylindruria). We advise the patient to clean the external genitalia in an ordinary way. In this respect, we do not suggest special procedures since the more the procedures suggested are complicated, the less the patient is compliant. In order to avoid contamination, the male has to uncover the glans and female to spread the labia of the vagina. For the same reason, we always suggest to collect midstream urine. It’s important to remember that urine collection during menstruation must be avoided because of the high probability of blood contamination. It is also important to use a proper urine container (with a capacity of at least 50 to 100 mL, an opening of at least of 5 cm to allow easy collection of urine for both men and women, a wide base to avoid accidental spillage, a cap to avoid leakage, a label for patient identification). It is no more time for the patient to collect the urine into jugs, bottles, cans, etc.

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What about a standardized method for the handling of urine? Why is standardization of the handling of the urine important? It is important because only with a standardized method we can obtain quantitative reproducible results. The slide shows the method that we use in our lab. We ask the patient to supply the second urine of the morning produced over a period of 2 hours; then, we centrifuge a 10 mL aliquot of urine for 10 minutes at 400 G , which correspond to 2,000rpm with our centrifuge. Then, we remove with a pump a fixed volume of supernatant urine, which is 9.5 mL. Then, with a Pasteur pipette, we gently but thoroughly re-suspend the sediment in the remaining 0.5 mL of urine. Then, with a precision pipette, we transfer 50 mL of resuspended urine to a glass slide, which is covered with a coverslip of a fixed surface, namely 32 x 24 mm . Then, we examine the samples at low and high magnification (160x and 400x) within 3 hours from urine collection. For routine practice, we express the particles as lowest/highest number seen by microscopic field. When we want to produce scientific results, we count the number of the cells found over 20 high power field, as we will see in the last part of my speech (see “The urinary sediment findings in proliferative and non proliferativer glomerular diseases”). With this method we were able to obtain reproducible results, which in addition correlated significantly with the number of particles found by the counting chamber.

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And now the microscope. The microscope must be of good quality, must be equipped with a low and high magnification, and must, and I want to stress must, be equipped with phase contrast and polarized light.

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This is the microscope we use in our lab. Why phase contrast?

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It’s very simple to explain. On the right you see bright-field, and on the left you see phase contrast. You see that with phase contrast the particles are much better seen against the background than with bright-field, and this without the use of stains! I want to stress that the European Guidelines strongly recommends the use of phase contrast microscopy.

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And why polarized light? Polarized light is extremely useful to correctly recognize the crystals. For example, you see uric acid crystals as seen by phase contrast microscopy (slide 15), and what happens when we use polarized light (slide 16). Under polarized light, uric acid crystals assume a typical polychromatic appearance, which is useful to identify them.

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Polarized light is also important to correctly identify lipid particles,

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which under polarized light appear as “Maltese crosses” which is, “shining” particles containing a “black cross” whose arms are regular and symmetrical. This feature allows the identification of lipid particles, especially when they come with an atypical appearance.

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Now, the urinary sediment report. This is the report we use in our lab. After the patient details, we have pH, density (or specific gravity), haemoglobin and leukocyte esterase as detected by dipstick. Then the particles: erythrocytes (with their morphological classification; see below), leukocytes, tubular cells, transitional cells (from the deep and superficial layers of the uroepithelium), squamous cells, casts, lipids, crystals, bacteria, and yeasts. We also have a space for a brief conclusive comment. I want to stress the importance of having in the report the findings obtained by dipstick. Why this?

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Let me give you an example. You see in this slide a sample with a pH of 6.0, a density of 1.006,  a +++ haemoglobin and +++ leukocyte esterase by dipstick. However, by microscopy we find a low number of erythrocytes and leukocytes, which is in contrast with +++ haemoglobin and +++ leukocytes esterase. Is there any explanation for this discrepancy? Yes there is. The discrepancy is due to the fact that low density causes the lysis of erythrocytes and leukocytes, which therefore cannot be seen by microscopy. In contrast, in other instances we may have negative haemoglobin and many erythrocytes by microscopy. This may be due, for example, to the presence of large concentrations of Vitamin C in the urine, which reduces the sensitivity of dipstick for haemoglobin. Therefore, it is always important to match the findings obtained by dipstick with those obtained with microscopy and to try to explain them. Thus, our comment for the sample shown in the slide is: ” Mild erythrocyturia and leucocyturia. Please note the discrepancy between dipstick for haemoglobin and leukocyte esterase and microscopy. This is probably due to cell lysis caused by low density.”  The final message on this point is that examining the urine only by dipsticks or only by microscopy exposes to the risk of false results. This risk is reduced when both methods are used on the same sample.

PART II

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And now the particles of the urinary sediment of nephrological importance with their clinical meaning. In the urine sediment we can find cells, lipids, casts, crystals and microorganisms.

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What about cells? We have two groups of cells in the urinary sediment: the cells deriving from blood and the cells of epithelial origin. The cells deriving from blood include: erythrocytes, leukocytes, and macrophages. The epithelial cells include:

renal tubular cells, transitional cells, and squamous cells. For the lack of time, today I will not speak about transitional and squamous cells.

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What about erythrocytes? In our lab, they are a frequent finding, being observed in 53% of the samples. Since the early 1980s we know that in the urine we can find two main types of erythrocytes: the so-called glomerular (or dysmorphic) erythrocytes and the so-called non-glomerular (or isomorphic) erythrocytes.

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The slide shows a good example of glomerular or dysmorphic erythrocytes. These are cells with irregular shape, size, and cell membrane, which differ remarkably from the image of erythrocytes we have stored in our mind.

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While this slide shows a nice example of non glomerular or isomorphic erythrocytes i.e., erythrocytes with a spherical shape and regular contours, containing (green-bluish cells) or not (colourless cells) haemoglobin.

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What is the clinical implication of distinguishing glomerular from non glomerular erythrocytes? In 1982 Fairley and Birch from Australia published this important and seminal paper in Kidney International.

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That paper showed that glomerular or dysmorphic erythrocytes were found in patients with haematuria caused by a glomerular disease, while non glomerular or isomorphic erythrocytes were found only in patients with hematuria of urological origin. Thus, it was concluded that the evaluation of urinary erythrocyte morphology could be used to identify the source of hematuria.

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In the same year, Fassett and co-workers, again from Australia, published a paper in Lancet in which, besides confirming the results of Fairley and Birch, established that a haematuria is of glomerular origin when it contains >80% dysmporhic erythrocytes, while it is of non glomerular origin when >80% of erythrocytes are isomorphic.

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Using this criterion, they obtained a correct diagnosis in 115/120 patients with a glomerular disease and in 100/105 patients with a urological disorder. The same criterion was adopted by other investigators such as Dr De Santo from Naples and Dr Rath from London, UK, and if we put all the results together we see that a correct diagnosis could be obtained in 93-94% of cases.

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However, the evaluation of the urinary erythrocyte morphology is associated with some drawbacks. First of all it requires experience. Then, it is exposed to the risk of a low inter-observer reproducibility. Finally, even after more than 20 years from the publication of the paper in Kidney International by Fairley and Birch we still do not have univocal criteria for the classification of the haematuria. In fact, there are investigators who consider a haematuria as glomerular when 2 erythrocyte subtypes are present, others who say that there must be at least 3 subtypes of erythrocytes, while others as we have just seen use a >80% cut-off, others use other cut-offs, etc.

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Thus, put in this way the whole matter could seem a little complicated and not very useful in clinical practice. However, some years ago Köhler and co-workers published an important paper, which overtook some of the problems mentioned above.

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In their paper, Köhler and co-workers showed that there is a subtype of dysmorphic erythrocyte, which they called “acanthocyte”, which can be easily (and less subjectively) identified due to its shape of a ring from which one or more blebs protrude (slide 33 shows an acanthocyte as seen by scanning electron microscopy) and which they found to be a marker of glomerular bleeding.

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In this slide you can see how easily the acanthocytes can be identified by phase contrast.

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And here you see a diagram of the main types of acanthocytes.

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The paper of Köhler and co-workers stimulated other groups to investigate the utility of the search of acanthocytes in the urine. The main studies published so far have shown that by using a cut-off for acanthocytes of ³5% a glomerular bleeding could be identified with a 52-100% sensitivity and a 96-100% specificity. In addition, Köhler and co-workers subsequently showed that if the patient supplies a second urine sample, sensitivity goes up to 72%, and to 84% if supplies a fourth urine sample. Thus, my advice is to start the evaluation of erythrocyte morphology by the search of acanthocytes. If they are not present, we proceed with the search of the other dysmorphic red cells.

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What is the main indication for the evaluation of urinary erythrocyte morphology in clinical practice? It’s persistent isolated microscopic haematuria of unknown origin (see below slides 109-117). In this condition, the evaluation of red cell morphology helps in deciding whether the patient has to be submitted to a nephrological work-up rather than to a urological one. This saves to the patient inappropriate investigation such as cystoscopy for a patient with haematuria due to a glomerular disease.

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Now leukocytes. In most instances, leukocyturia is due to polymorphonuclear leukocytes, much less frequently to eosinophils or lymphocytes. Polymorphonuclear leukocytes may derive from any segment of the urinary tract, without forgetting genital contamination, which occurs especially in women with vaginitis or leukorrhoea of whatever cause. The clinical meaning is of leukocyturia is inflammation of whatever cause, including immunological disorders such as glomerular diseases.

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This is an example of polymorphonuclear leukocytes as seen by phase contrast microscopy. You can easily see their lobulated nucleus and their granular cytoplasm.

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These are eosinophils, which can be identified only after staining (in this case May-Grünwald-Giemsa). Eosinophiluria has been considered as a marker of acute interstitial nephritis.

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Is this belief still true today? I don’t think so. Why?

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After the publication in the New England Journal of Medicine in 1986 of this paper by Nolan and colleagues we know that eosinophiluria can be found in a wide range of conditions, not only in acute interstitial nephritis.

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In fact, by using a specific stain for eosinophils which is, Hansel stain, it was found that these cells were present not only in acute interstitial nephritis, but also in rapidly progressive glomerulonephritis, and acute prostatitis. In addition, subsequent studies demonstrated that eosinophiluria can also be found in acute renal failure caused by a cholesterol embolism, urinary schistosomiasis, Schönlein-Henoch purpura nephritis, etc. Therefore, I believe that eosinophiluria cannot be longer considered as a specific marker of acute interstitial nephritis. For this reason in our lab we have abandoned the search of urinary eosinophils.

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What about urinary lymphocytes?

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The utility of the search of lymphocytes in the urine sediment has been largely investigated in the 1980s and early 1990s. Most studies have demonstrated that they are an early marker of acute cellular rejection of renal allograft, with a 80-90% sensitivity. However, stains and cytological techniques are needed to identify lymphocytes, and these techniques are usually available only in specialized labs.

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Now renal tubular cells. If you remember slide 23, among the cells deriving from blood I also mentioned macrophages. I will speak about these cells in the last part of the course (see slides 163-171).

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As you can see in the slide, there are different morphological types of renal tubular cells, which derive from different tubular segments, from the proximal convoluted tubule to the collecting duct.

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This is an example of a proximal tubular cell, with a large nucleus surrounded by a large granular cytoplasm.

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This is an example of a distal tubular cell, which is smaller than the previous one, and has a smaller cytoplasm.

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And this is an example of a collecting duct cell. Compared to the two previous ones, it has a columnar aspect and a basal nucleus. Renal tubular cells can be recognised by phase contrast microscopy without difficulty, even though some experience is needed. They can be confused with transitional cells of the deep layers of the

uroepithelium. However, while tubular cells are seen in a nephrological context, the transitional cells are seen in patients with urological disorders.

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What is the clinical meaning of tubular cells in the urine? They always indicate a renal tubular damage. Therefore, they are a marker of acute tubular necrosis. Moreover, they can be found in acute interstitial nephritis, in acute cellular rejection of renal allograft etc. However, they can also be found in glomerular diseases especially of proliferative type, as we will see later on.

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Now, lipids. Lipids can be found in the urine as: fatty droplets, in clusters or isolated; “oval fat bodies”, a definition which goes back to the 19th century; fatty casts, and cholesterol crystals. In most instances, they are the consequence of lipid ultrafiltration due to an impairment of glomerular basement membrane (GBM) permeability. Therefore, they are a marker of GBM damage, as it occurs in glomerular diseases. However, rarely, lipiduria can be due to lipid storage diseases, such as Fabry disease.

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This is an example of lipid droplets, both in clusters and isolated.

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These are lipid particles within the cytoplasm of a proximal renal tubular cell after they have been ultrafiltered at glomerular level and reabsorbed by the tubular cells and organised into lysosomes.

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This is a typical “oval fat body”. Today we know that they are nothing but macrophages or renal tubular cells gorged with lipid particles.

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And here, a typical fatty cast. As already mentioned above (see slides 17 and 18), under polarized light lipid particles show the typical appearance of “Maltese crosses”.

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And here a typical cholesterol crystal, which instead does not polarize light.

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What is the clinical meaning of urinary lipids? They are a typical marker of heavy proteinuria as it is found in nephrotic syndrome. However, this is only a general rule, because lipiduria has been described also in patients with mild to moderate proteinuria, and in patients with nonglomerular disorders such as polycystic kidney disease (Kirk et al. Urinary lipid bodies in polycystic kidney disease. Am J Kidney Dis 1985; 5: 49-53). Another situation in which lipiduria can be found is Fabry disease.

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Fabry disease is due to the hereditary deficiency of the enzyme α-galactosidase A. It is characterised by the accumulation of globotriaosylceramide (GL-3) in several organs such as the heart, the brain, the skin and the kidneys. In the kidneys, GL-3 accumulates in glomerular visceral epithelial cells, distal convoluted tubular cells, and the cells of Henle’s loop.

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What are the urinary sediment findings in Fabry disease? By phase contrast, we see cells laden with lipids as well as free fatty particles. By polarising light, we see the so-called "Maltese crosses", and by electron microscopy we find lysosomal inclusions, which appear as “myelin figures “ or “myelin bodies”.

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To show some images of lipiduria as found in Fabry disease, I have to turn to the work “A Colour Atlas of Urine Microscopy” written by Birch DF, Fairley KF, Becker GJ, and Kincaid-Smith P, and published by Chapman & Hall (London) in 1984. Here there is a fatty particle under phase contrast microscopy,

 

and here the same particle under polarized light. You can see very well the “Maltese cross”.

   

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Here, you see the lysosomal accumulation of GL-3 by transmission electron microscopy, with its typical “myelin body ” structure. All this is interesting and

useful, because it is possible to diagnose and follow the course of the disease also by examining the urinary sediment. Of course not necessarily with the electron microscope, but just with phase contrast and filters for polarized light.

 

 

PART III

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Now casts. I will not speak about the whole spectrum of casts we can find but only the most important ones. Casts are elements, which form in the distal tubules and collecting ducts of the kidney. They have a matrix, which is Tamm-Horsfall glycoprotein, which is produced by the thick ascending segment of the loop of Henle. There are different types of casts with different clinical meanings.

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What about the clinical meaning of casts? One cause that I think is important, whatever particle is contained in the cast, this particle comes from the kidneys.

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Thus if we have an erythrocyte cast, we must know, we must remember that this means that the red cells come from the kidneys. With a sensitivity however, which seems to be low.

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Several investigators have looked for erythrocyte casts in patients with various types of glomerulonephritis and you see here the percentage of patients which have been found is rather low from 22 to 38% even though a more recent paper published by the group of Doctor Köhler has shown that if they are found in a very extensive way, the percentage goes up to 86%. I will tell you later on what is our experience in 100 patients with glomerulonephritis.

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Leukocyte casts. Again they tell us that the leukocytes come from the kidney which may happen both in patients with glomerulonephritis and in patients with for instance renal infection, pyelonephritis.

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Epithelial casts, which contain tubular cells these casts are typically seen in patients with acute tubular necrosis but they are also seen in patients with glomerular nephritis and again I’ll show you later on our findings.

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Bacterial casts, extremely rare but again these tell us that the bacteria comes from the kidney.

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We can even have yeast casts but in this case this is a candial cast, again infection comes from the kidneys.

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Now the big chapter of urinary crystals. We can very arbitrarily distinguish 3 groups of crystals, the so-called common crystals, the pathological crystals and crystals due to drugs.

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Common crystals first, uric acid crystals, which we always find in acidic urine.

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Calciumoxylate monohydrated which is found in this range of urinary pH,

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and calcium oxalate dehydrated.

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Calcium phosphate crystals, alkaline pH

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and triple phosphate crystals, alkaline pH.

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What is the clinical meaning of these common crystals? In most instances, 99.99% of cases, uric acid calcium oxalate and calcium phosphate crystals are simply due to a transient super saturation of the urine which is caused by foods, dehydration or changes of urine pH and/or temperature upon stenting. However, especially when they are persistent in the same patient they may be associated with a metabolic disorder such as hypercalcuria, hyperoxaluria or hyperuricosuria.

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So they suggest that there is a metabolic disorder in these cases and very rarely they can be associated with acute renal failure due to intrarenal precipitation of crystals, which happens in 2 very well-known clinical situations which are acute urate nephropathy which is associated with an intratubular precipitation of uric acid crystals and the other situation is the poisoning entrained by ethylene glycol ingestion which is associated with intratubular precipitation of calcium oxalate crystals, which then appear in the urine.

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What about pathological crystals? We have cholesterol crystals; we have already seen them, cysteine crystals, urocine, tyrosine and 2, 8 dihydroxy adenine crystals. We speak about cholesterol, cysteine and this one not about these ones very rare.

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Cholesterol again as you can see it is a marker of heavy proteinuria.

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Cysteine crystals they are a typical marker of patients with cysteinuria. The more the urine is acidic, the higher is the possibility to find these crystals in the urine.

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Now 2,8 dihydroxy adenine crystals. These crystals are similar, maybe similar to uric acid crystals at least for their colour, which is an amber colour, brownish, yellowish colour. They have spherical particles with irradiations which have origin in the centre of the crystal and then spread towards the edge of the crystals.

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These are crystals seen by phase, by bright-field microscopy and under polarised light they appear as maltese crosses very similar to lipid particles.

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Are these crystals important? The answer is yes. These crystals are due to the hereditary deficiency of adenine phosphoribosyl transferase enzyme. APRT is an enzyme which catalyses the transformation of adenine into adenosine monophosphate. If there is a deficiency of this enzyme, adenine is transformed by

the xanthine oxidase into 2, 8 dihydroxy adenine, which is a molecule, which is highly insoluble at any pH, which means that it goes, it precipitates always in the urine present.

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We know that there are 2 types of APRT deficiency, which is a condition, which is inherited in an autosomal recessive manner. Type 1 which is seen in Caucasian people is associated with a virtually absent enzyme activity while type 2 APRT deficiency is seen in Japanese and is associated with a low but however, some activity of the enzyme.

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From the clinical point of view this condition has been well studied in Iceland where the condition is endemic and you see here that any age can be affected by the disease with a ratio male-female which is 1:1 and 65% of patients may have recurrent radiolucent stone disease which is often confused with uric acid stone disease. There will be 26% of patients with acute renal failure due to intratubular precipitation of the substance, 17% of patients with chronic renal failure probably due to chronic interstitial nephritis and 96% of patients may have crystalluria.

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This is an example of acute renal failure due to the intratubular precipitation of 2, 8 ATHA which occurred in Rome at the Policlinico and Gemelli. It was a patient in which after biopsy it was found that there was a precipitation of crystals in the tubules, which were then identified as 2, 8-dehydroxy adenine. This is a PAH pen and this is a phase polarised light.

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You see here these are the lumina of the tubules they are completely obstructed by precipitated crystals while here crystals are probably within the cytoplasm of cells. It is important to recognise this condition because after the renal biopsy the patient at the time was on dialysis, after the identification of the crystals allopurinol had been given and the patient was able to recover from acute renal failure.

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The diagnosis of the deficiency of APRT. We can measure the level of the residual enzyme activity in erythrocyte lisate. We can measure the urine to dehydroxy adenine by high performance liquid chromatography, we can perform ultraviolet and infrared spectrophotometry of stones and we can finally examine the urine sediment.

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What is the role of urine sediment examination in this condition? It is well written here, this statement of Doctor Alderperson an expert of this condition, skilful and let

me add motivated urinary microscopy is the single most important diagnostic procedure because urinary 2 8-dehydroxy-adenine crystals are usually abundant in untreated patients. So with a simple test we can do very important clinical things.

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Now the main types of crystals due to drugs. A number of drugs can cause crystalluria. For instance sulphadiazine and acyclovir, the antiretroviral agent indinavir, piridoxylate which is used in some European countries as a coronary dilator.

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Primidone, which is a barbiturate. Naftidrofuryl oxalate, which is used again as a vasodilator, vitamin C, amoxycillin all these drugs can cause crystalluria.

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This is an example of sulphadiazine under polarised light,

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an example of amoxycillin under bright-field microscopy,

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the nature of which here was confirmed by spectroscopy which was performed in Paris by our colleague and friend Professor Daudon in indinavir crystal and in acyclovir crystals.

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What are the factors, which favour the precipitation of drugs in kidneys? First of all is a drug overdose, dehydration, hypoalbuminemia which causes the presence of a high percentage, proportion of unbound drug in the blood and urine pH, some drugs precipitate at acidic pH for instance, amoxycillin while neutral pH or alkaline pH is necessary for the precipitation of ciprofloxacin crystals.

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What are the clinical manifestations of drug crystalluria? One is isolated and asymptomatic crystalluria, the most frequent one then they can cause hematuria, microscopic or gross hematuria with or without leucocyturia. Crystals are very frequently associated with stones, which can cause obstructive uropathy and they can even cause acute renal failure due to intratubular precipitation of crystals with the same mechanisms I’ve just described for 2,8 dihdyroxiadenine.

Slide 101

General rules to follow when we think that there is a crystalluria due to drugs in the urine. First think of a drug whenever you come across crystals with unusual appearance. Second, if you have this feeling, this impression ask the patient if and which drugs she/he is taking, then check the renal function because acute renal failure may be a consequence of crystalluria and then hydrate the patient and reduce and discontinuate the drug to prevent acute renal failure.

Slide 102

Microorganisms. We know here everybody knows that in the urine we can find bacteria, yeast protozoa and parasites. Bacteria can be present in the urine as a marker of infection or of contamination of the urine. Candida most of the time comes from contamination from the genital secretion as well as Trichomonas vaginalis. Enterobius vermicularis is very rare and it can be seen as a result of the contamination of the urine from faeces especially in children. A true infection is always caused by schistosoma haematobium. Urinary sediment plays an important role in the diagnosis of schistosoma haematobium. Urinary schistosomiasis may not be a problem in our countries, in Europe, in the United States but is a very important clinical problem in a number of developing countries.

Slide 103

The urine sediment shows in patients with urinary schistosomiasis the presence of the eggs of the schistosoma hematobium which are very easily recognised because they are very big first of all 120-50 micrometers, a typical shape and this spine which is a terminal spine which allows us to differentiate schistosoma haematobium from schistosoma mansoni which has a spine which is lateral but which is not found in the urine but is found in faeces.

Slide 104

Urinary schistosomiasis as I told you is endemic in many geographic areas, look here in many areas of Africa going from areas North of the Sahara and in many sub Saharan Africa, it is also present in the Middle East and here you see this is Iraq. This is responsible for a recurrent bouts of gross hematuria, which are recurrent and cyclic, and in many areas of sub-Saharan rural Africa it is also known as the agent causative of "male menstruation". It can cause obstructive uropathy, bladder carcinoma and glomerulonephritis.

Slide 105

What is the role of urinary sediment? The diagnosis of urinary schistosomiasis is largely based on the examination of the urinary sediment, which shows first of all the eggs. To increase the egg yield and then sensitivity, the urinary sediment is examined after a physical effort for example, a run and between 10 A.M. and 2 P.M. and then the quantification of the eggs is usually used to estimate the severity of the infection.

Slide 106

This is the experience we measured in a hospital of Republic of Benin, which is a small country of West Africa. We found over the years 50 subjects with urinary schistosomiasis and besides the eggs we found erythrocytes in 100% of cases, glucocytes in 92% of cases, transitional uroepithelial cells in 28% of cases and moderate to severe albuminuria in 14% of cases. You see from this data that we can arrive to define a urine profile in urinary schistosomiasis.