Volume 29 | Issue 3 Article 2

1967 Crystalline Obstruction of the male Feline Urethra John J. Andrews Iowa State University

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Recommended Citation Andrews, John J. (1967) "Crystalline Obstruction of the male Feline Urethra," Iowa State University Veterinarian: Vol. 29 : Iss. 3 , Article 2. Available at: https://lib.dr.iastate.edu/iowastate_veterinarian/vol29/iss3/2

This Article is brought to you for free and open access by the Journals at Iowa State University Digital Repository. It has been accepted for inclusion in Iowa State University Veterinarian by an authorized editor of Iowa State University Digital Repository. For more information, please contact [email protected]. Crystalline Obstruction of the Male Feline Urethra

by John J. Andrews

Obstructive urolithiasis, or more cor­ cent experiments have not supported this rectly phosphocrystalluria (since calculi claim. Likewise, hypovitaminosis A has rarely occur in the feline kidney or ureter), not been supported as a cause by research occurs quite often in the male domestic experiments. cat. The female cat seems to escape this The material which forms the urethral problem because her urethra is wider and obstruction in nearly all the cases of fe­ more expansible. The male cat, however, line urolithiasis is "struvite" crystal con­ has a relatively narrow penile urethra and glomerations. Struvite (NH4MgPO,,-6H20 fine urinary crystals may obstruct and -ammonium magnesium phosphate hex­ pack this urethral canal. If this condition ahydrate) is found in three forms in the is left untreated death is the usual result. feline urinary tract: 1) sabulous or mu­ Even if treatment is initiated, permanent cus-like plugs of fine struvite crystals urinary tract damage may have already mixed with some cellular debris; 2) "sand" occurred or the condition may reoccur and or granular material of larger struvite plague both the pet owner and the pet for crystals many in small clumps; and the rest of the cat's life. 3) "calculi," larger aglomerations of stru­ vite crystals up to several millimeters in ETIOLOGY diameter. These can usually be easily The cause of obstructive urolithiasis crushed into smaller ·granules. seems to be any factor that affects the There are two physical-chemical proper­ urine concentration of phosphate ions, the ties of these crystals that are very impor­ pH of the urine, the diameter of the ure­ tant. One, these struvite crystals have a thra or the integrity of the epithelial lining very regular rhomboid shape with perfect of the urethra. Some proposed specific sharp edges. Therefore, the usual feline causes thus include: 1) inadequate fluid calculi is not a smooth rounded stone as intake; 2) infection of the urinary tract, you might find in the dog, but rather it is especially by Proteus or Pseudomonas spp. an irregular conglomeration of regular since these organisms split urea to yield crystals which displays sharp jagged edges ammonia which increases the urine pH; around its circumference. And two, in 3) urinary stasis such as occurs in the nearly ninety percent of the normal fe­ house-broken cat; 4) castration of the im­ line urine samples that had a pH reaction mature male; and 5) trauma of the ure­ above 6.8, struvite crystals were found.8 thral lining. The normal pH of feline urine varies from Too much dietary ash has long been con­ 6.0 to 7.4; not only in different cats, but sidered to be a cause of urolithiasis but re- also in the same cat at different times. The median urine pH was 6.4. Thus we can • Mr. Andrews is a senior in .the pollege of Veter· Inary Medicine. Iowa State UniversIty. see that the probability of a male cat hav-

Issue, No.3, 1967 111 ing struvite crystals in his urine sometime increases the renal tubular secretion is se­ during his life is quite high. verely reduced. Congestion and engorge­ ment of the vessels in the bladder wall be­ CLINICAL SIGNS comes marked as the urinary bladder The usual clinical picture of urethral distends beyond its normal distended size. obstruction is a severely depressed cat that This congestion gives the wall a thickened has been straining for a period of hours to impression upon palpation. The vessels in days. A frequent comment by the owner the renal parenchyma also become con­ is that the cat appears constipated because gested. Copious amounts of blood and tis­ he has been sitting in his ''kitty pan" sue debris appear in the urine arising from straining, but no feces have been passed. this engorgement and hemorrhage in the There may also be some vomiting in the renal parenchyma, the degeneration of the severely affected cat. The eyes are usually renal papillae and later from degeneration dull and the mucous membranes may be and hemorrhage in the lower urinary pale to "muddy." Palpation of the abdo­ tract.3 Blood in the urine is therefore a men will easily reveal a tense thick walled poor prognostic sign. bladder. Unless the cat is very depressed The blood-urea-nitrogen level is in­ pain may be elicted upon palpation of the creased by the decreased tubular function. abdomen. In many cases the penis is pro­ Also a certain amount of the retained truded and the penile tip may be a pur­ urine seeps into surrounding tissues and plish color. is picked up by the capillaries and lym­ phatics, thus causing the B.U.N. to rise DIAGNOSIS even more. This should be taken into ac­ The history of straining and the palpa­ count when the B.U.N. is being used as a tion of the distended bladder are usually prognostic tool. sufficient for a diagnosis. This condition Gross pathological changes include demands immediate treatment and there­ swollen bluish kidneys, a thickened se­ fore there is little time to differentiate ob­ verely congested bladder wall that may ex­ structive urolithiasis from other condi­ hibit numerous hemorrhagic areas and tions. presence of "sand" or "calculi" in the blad­ . Other conditions that might later be der and urethra. considered in differentiation are a stenosis Glycosuria has also been reported due of the urethra or a neoplasm impinging to tubular damage. upon the urethra. A radiograph of the pel­ vic area might be helpful in differentiating TREATl'l.BNT these conditions, however, crystal obstruc­ The treatment of fehne urethral block­ tion is so common this is probably not war­ age can be divided into three areas: ranted. 1) immediate relief, 2) aftercare, and A blood-urea-nitrogen test could be uti­ 3) surgical treatment. lized as a prognostic test to determine the amount of kidney damage caused by the IMMEDIATE TREATMENT increased pressures in the urinary tract. Since the diameter of the penile urethra I would like to emphasize that immedi­ from the prostate caudally is only one-half ate relief of the urinary stasis is more im­ the diameter of the preprostatic urethra, portant than attempting to confirm the nearly all calculi lodge in the penile por­ specific diagnosis. Proceed as if it were tion with many lodging within one-half crystalline obstruction and you will be cor­ inch of the orifice. A parenteral smooth rect in a great majority of the cases. muscle relaxant can be given as soon as a diagnosis has been made. Its usefulness PATHOLOGY is questioned because of the slight amount After crystals have lodged in and ob­ of smooth muscle surrounding the penile structed the urethra, the intravesicular portion of the feline urethra. lIS Probably pressure begins to rise. As this pressure the only urethral relaxation obtained is in

112 Iowa State University Veterinarian the preprostatic portion where smooth prove to be too traumatic. muscle is more abundant. This may be of Careful flushing should attempt to benefit if back-flushing of the urethra is break down and/or force the obstruction used. back into the bladder. If this proceedure Next a gentle digital manipulation of doesn't succeed a 32g. stainless steel wire the penis should be attempted; lightly roll­ loop can be used. This can be made by ing the penis between the forefinger and twisting the wire upon itself and leaving a thumb, trying to dislodge or break-up the small loop at one end. This loop is then obstruction. Care must be taken so that inserted into the urethra and a further at­ further damage to the urethral mucosa is tempt to disintegrate the obstruction is not caused. Even though many of these tried. struvite calculi are quite easily crushed If all else fails, puncture of the bladder many veterinarians choose not to attempt through the abdominal wall should be this manipulation because of the possibil­ done. This is a "last resort" solution for ity of causing further trauma. If the ob­ two reasons: 1) it does not solve the pri­ struction does not dislodge immediately mary problem, the obstruction (although upon digital manipulation (or if you the obstruction may now be easier to back­ choose not to use it) back-flushing of the flush because of the release of the intra­ urethra should be attempted. vesicular pressure) and 2) there is a dan­ Many of these affected cats are so de­ ger of contaminating the peritoneum with pressed that manipulation and even back­ pathogenic bacteria leaking through the flushing can be done without an anes­ needle hole in the urinary bladder wall. A thetic. In fact because the kidneys are one-inch 22g. (or smaller diameter) needle practically non-functional, long acting is the safest size to use. As much urine as barbituate anesthetics or any other anes­ possible should be withdrawn. Once the thetics that are detoxified mainly by the bladder has been emptied another attempt kidneys are contraindicated. If chemical to dislodge the obstruction should be restraint is needed, a tranquilizer such as made. meperidine or trifluomeprazine usually When the obstruction has finally been gives adequate results. If an anesthetic is dislodged, the bladder should be flushed still needed, give an ultra-short barbituate out thoroughly. If the bladder does not to effect or give one of the inhalents such contract spontaneously (and this is often as methoxyflurane. These anesthetics and the case in cases of several days' duration) tranquilizers also give needed skeletal gentle pressure through the abdominal muscle relaxation; thus some penile ure­ wall may be needed to empty the bladder. thral muscle relaxation is obtained. Renacidin (Guardian Labs.) or another Back-flushing of the urethra may be at­ weak acid solution should then be flushed tempted using either a three-quarter inch into the bladder. Infuse about SOc.c., let 20g. blunt tip needle or a three-quarter it stay a few minutes, then express it. Re­ inch silver lacrimal cannula (B.D. #43 peat this about four times and leave the LC) and a ten c.c. syringe filled with sa­ last flush in the bladder overnight. This line. An acid solution such as weak sul­ hopefully will rid the urinary bladder of furic acid, citric acid or the commercial the majority of the struvite crystals. buffered (to pH 4.0) citric acid product If the cat is still "open" the next morn­ Renacidin (Guardian Labs.) could be used ing but still has no bladder tone, 1.2Smg. as a flush. These would have an added of bethanechol chloride (a smooth muscle dissolving power saline lacks. Some vet­ stimulant) may be given orally. Make ex­ erinarians like to use a solution containing tra sure that the obstruction has not re­ a topical anesthetic such as tetracaine. curred, then express the bladder manually. This gives pain relief in the urethra and After the acid has been exp~essed it is therefore usually yields a more manage­ useful to infuse the bladder with 10 cc. of able patient. Large cannulas such as a penicillin or chloramphenicol. "tom cat catheter" may be used but may Because cystitis often exists in these

Issue, No.3, 1967 113 cases it is a good idea to culture and sensi­ have been used with variable success. As­ tivity-test the urine that is first removed pirin and other salicylates (1 Y2gr. bj.d.) from the bladder after the obstruction has have also been used since salicylates are been relieved. Later cultures may also be excreted in the urine as glucuronides and desirable. theoretically increase the stability of the urine phosphates in solution. A urinary MEDICAL AFTERCARE antiseptic (or antibiotic), an antispas­ modic and a salicylate are often combined Once the urethral obstruction has been in one tablet. Some of these useful prod­ removed the battle is just beginning. An ucts include Urised (Chicago Pharm.), Ur­ intensive aftercare program is needed to iad (Haver-Lockhart), and Renachek (Dia­ prevent a recurrence of the problem. This mond Labs.). Renachek does not contain care should probably be performed in the a salicylate but does contain a urine acidi­ home as much as possible since many cats fier, ammonium chloride (80 mg. per will not urinate in a hospital cage, es­ tablet). By using a suitable combination pecially the house-broken cats. product struvite crystal obstruction of the This program should include: urethra may be controlled with one tablet 1) diet-A high protein diet with a high bj.d. in a great many of these cases. level of vitamins and a low mineral con­ tent is preferred. A high level of protein SURGICAL TREATMENT tends to acidify the urine. Salt (sodium chloride) should be sprinkled on the food If a medical program does not seem to to increase the fluid intake. Plenty of give satisfactory results surgery may be fresh water or milk should, of course, be attempted. Surgery, however, should not available at all times. be attempted until the medical condition 2) urine acidifiers-These are used to of the patient is satisfactory. prevent the formation of more struvite Many different surgical approaches crystals; oral tablets of ethylene-diamine have been done and the most satisfactory dihydrochloride, 3gr. bj.d. (Chlor-Etha­ seems to be the perineal urethrostomy.5 mine, Pitman-Moore) should be dispensed. This involves amputation of the penis just Ammonium chloride (5gr. bj.d.) or methi­ anterior to the bulbourethral glands and onine (Methischol, U.S. Vitamins) can also suturing the remaining urethra to the skin be used to control the urine pH. Which­ surrounding a surgical· incision just below ever one is used, it should be used for at the anus. When the hair grows back after least two to three weeks follOWing the re­ surgery the "new" orifice present a good lief of the obstruction. Paper colormetric appearance and client satisfaction seems pH indicators (pHydrion Papers, Micro Es­ to be excellent. About the only problem sential Labs., Inc.) may be dispensed also with this technique is constriction of the so the owner may periodically check the scar tissue at the suture line around the urine pH and use the acidifiers as needed. orifice. This constriction may be stretched 3) antibiotics-If a cystitis exists a ten­ daily with a fine mosquito forceps for sev­ day regimen of antibiotics will usually eral days and a permanent constriction clear up the problem. Penicillin and chlor­ may be avoided. amphenicol seem to be the most useful but Other procedures that have been tried sulfisoxisole, furadantin, nitrofuradantoin, with some success have been: 1) scraping sulfadimethoxine and tetracyclines have the bladder epithelium to remove all been used with success. Corticosteroid "sand";19 2) preputial urethrostomY,9 am­ products have also been used to lessen the putating the penis and then using the chance of a urethral stenosis due to scar prepuce to gUide the urine to the exterior formation. (cystitis and urine scalds are frequent 4) combination products-Besides the problems); 3) ureterocolostomy,2 suturing fore-mentioned medications, antispasmod­ the ureters to the colon wall (ascending ics, antiseptics, intravesical injections of kidney infections and loose watery stools hyaluronidase, and indwelling catheters are frequent problems); 4) urethrocolos-

114 Iowa State University Veterinarian 2. Beamer, R, J •• Ureterocolostomy for the relief of tomy,lO.23 suturing the pelvic urethra to urinary stenosis in the domestic cat. J.A.V.M.A., the colon wall (cystitis and soft stools are 134:201-204 1959. 3. Campbell, M. F., Urology. Sunders Co., Philadel· frequent problems); 5) antepublic ure­ phia, Penn. 1962. 4. Catcott, E. J. (editor), Feline Medicine and Surg· throstomy,22 suturing the pelvic urethra to ery. A.V.P. Inc., Santa Barbara, Calif. 1964. 5. Carbone. M. G., A modified technique for perin. the ventral abdominal wall (urine scald eal urethrostomy in the male cat. J.A.V.M.A .• 151 (3):301-305 1967. and dribbling incontinence are frequent 6. Carbone, M. G., Perineal urethrostomy to relieve urethral obstruction in the male cat. J.A.V.M.A., problems); 6) permanent indwelling cath­ 143:34-39 1963. eter19 (urine incontinence and cystitis are 7. Carbone, M. G., Perineal urethrostomy in male cat, A report of twenty cases, J.A.V.M.A., 146: frequent problems); and 7) bladder proth­ 843-853, 1965. 8. Carbone, M. G., Phosphocrystalluria and urethral esis,l3 similar to having a drain plug in obstruction in the cat. J.A.V.M.A., 147:1195- 1200,1965. the bladder to use when needed. 9. Christensen, N. R., Preputial Urethrostomy in the male cat. J.A.V.M.A., 145:903-908, 1964. 10. Gale, V. G., Anastomosis of bladder to colon for urethral obstruction. Vet. Rec., 74(45):1228-1229. SUMMARY 1962. 11. Holzworth, J.1. Disorders of the urinary system. Cornell Vet., ;,3(1):157-159, 1963. In summary one should remember these 12. Lauerman, L. H.. Occurrence of urolithiasis in cats. Western Vet. 7:30-34, 1960. important features of the treatment of fe­ 13. Manziano, C. F. and Manziano, J. R. A bladder prothesis to relieve urethral blockage hi the male line urethral obstruction by struvite crystal cat. J.A.V.M.A., 151(2):218-222, 1967. 14. McCully. R. M .• Antepubic urethrostomy for the copglomerations: 1) the need for a quick relief of recurrent urethral obstruction in the male cat. J.A.V.M.A .• 149:1312-1316, 1965. diagnosis and immediate relief of urinary 15. McCully, R. M. and Lieberman, L .• Histopathol· bladder distention, 2) the need for an ogy of feline urolithiasis. Can. Vet. J .• 2(2):52- 60,1961. aftercare program best performed in the 16. Meier. F. W.. Urethral obstruction and stenosis in the male cat. J.A.V.M.A., 137(1):67-70. 1960. patient's home, including diet, antibiotics, 17. Povar. R. and Povar. M. L .. Use of Renacidin in treatment of urinary calculi. Veterinarian 6(2): urine acidfiers and combination products 8-17,1961. 18. Schlaafl'. S., Hyaluronidase for urinary calculi. (antispasmodic, antiseptic, salicylate, Berl. Munch. tierarztl. Wschr. 72:121-126, abs. Vet. Bull. 30:90. 1960. and/or acidifier combinations); and 3) the 19. Stansbury, R.. Feline urolithiasis. Mod. Vet. usefulness of surgical intervention in Prac.. 40(13):55. 1959. 20. Udall. R. H.. Studies On urolithiasis. III. The problem cases. control by force feeding sodium chloride. Am . .T. Vet. Res .• 20:423-425, 1959. 21. Vice, T., Urethral blockage. Sm. An. Clin.• 2(3): 125-128. 1962. BIBLIOGRAPHY 22. Whitehead, .J. E.. Feline urolithiasis. Sm. An. Clin. 1(10):307-319, 1961. 23. Whittick. W. H. and Bonar. C. J .• Surgical cor· 1. Barnes. J. W. and Bone, J. K., Urethrocolostomy rection of urinary retention. Can. Vet. Jour. 2(1): of the cat. Sm. An. Clin., 3:31-32, 1963. 39-42, 1961.

Do Dogs Watch TV?

Dogs may watch television, but they from the set. Auto horns, doorbells, don't see what we see, according to experts knocks, dogs, or high pitched electronic at the Gaines Dog Research Center, New noises are all attention getters for canines. York .. , which mayor may not make Even some human voices can produce them luckier than mere humans. howls or "singing" from dogs whose par­ There are many opinions on the subject ticular sensitivity to sound has been of whether or not dogs "view" t.v., but touched. most agree that the dog does not see com­ Many people claim that their dog has a plete images on the screen. His eyes catch particular favorite among television pro­ the moving black and white patterns, how­ grams or that their dog "watches Rin Tin ever it is very doubtful that he sees any­ Tin." Again, according to what is cur­ thing more than blurry movement. rently known, this can be explained by the The sound from a television set, on the other hand, does catch the dog's attention dog's attraction to the sounds and rather if it is of a particular kind. The same blurred movements of shadowy figures. In sounds which make Towser bark normally this sense, the medium really is the mes­ may make him bark when he hears them sage.

Issue, No.3, 1967 115