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Echinococcus Disease of the Kidney
THE JouR:>L~L OF UROLOGY
Vol. 68, No. 2, August 1952 Printed in U.S.A.
ECHINOCOCCUS DISEASE OF THE KIDNEY WILLIAM BAURYS From The Guthrie Clinic, Sayre, Pa.
Renal hydatid is a rare disease in the United States. Although Rolnick's textbook recorded 245 cases from the world's literature, only 35 have been reported in this country. In pastoral countries like South America, Australia, Iceland and Asia, it is of not infrequent occurrence. In Beyrouth, Syria, for instance, Haddad and Khairallah stated that 0.75 per cent of hospital admissions during a recent 10year survey were patients with echinococcus cysts. Although numerous instances of this infestation have been found invading other organs and tissues among American inhabitants, only four were in natives. Of 46 cases treated at the Mayo Clinic among admissions until 1940, one involved the kidney. At the Guthrie Clinic and Robert Packer Hospital, the case herein reported is the only one of renal involvement among 240,000 hospital admissions. Because of its definite scarcity in this country, detailed information must necessarily come from foreign writers with extensive experience in wool-growing localities. ETIOLOGY
Careless ingestion of food contaminated ·with echinococcus tapeworm ova is responsible for the disease in humans. This cestode is a parasitic inhabitant of the infested dog's intestines. Ova excreted with feces find their way into the alimentary tract of sheep or human and there develop into intermediate larval forms (scolices) encased in the cyst. Sheep consume the embryos while grazing in pastures where dog excreta have been deposited. When the infested animals are slaughtered and the entrails which contain scolices are carelessly left lying around, dogs devour them. The ingested scolices develop into mature forms in the canine's intestines and the cycle is complete. The human gastro-intestinal tract serves the same type of refuge in the cycle as that of sheep. The Australian authority, Dew, contends the cyst in adults is almost as old as the individual harboring it. In his opinion, the patient, in childhood, becomes infested by careless fondling of dogs. Since so few early cases have been found beyond the fourth decade, it is generally believed the adult develops an immunity. PATHOLOGY
When ova are ingested, the chitinous covering is dissolved by gastric digestion and the embryo released. Were it not that most ova are destroyed by natural body defenses and gastric secretions, the disease would be much more widely prevalent and multiple cysts more common. 441
442
WILLIAM BAURYS
Parasites escaping these hazards, pierce the stomach mucosa or upper intestinal tract, filter into the portal circulation and usually become embedded in the liver. A small number bypass the portal circulation and enter the lungs. Some few escape the pulmonary venous plexus, become dispersed and finally arrested in various body tissues. Approximately 77 per cent of cysts form in the liver and about 10 per cent in the lungs. The remaining 13 per cent are deposited in other portions of the body. About 2.5 per cent reach the kidney; here the embryo embeds itself in cortical tissue and within a few hours forms a small blister-like cyst and in years attains mature size. At maturity, the cyst is composed of an adventitious capsule inside of which is a laminated nutritive layer lined by a germinal membrane. From this endocystal germinal membrane, brood capsules develop. At least part of the cyst surface is covered by renal capsule. The cyst has no blood supply. Nutrition is supplied by selective osmosis through the laminated covering. This layer is impervious to noxious substances and for this reason destructive medications cannot reach the interior. As the original hydatid enlarges, it reproduces within itself daughter cysts whose construction is a replica of the parent. The mother cyst wall expands to accommodate the multiplication of offspring and the increased amount of nutritive fluid. While it grows, the mass encroaches on the pelvis and parenchymal renal tissue obliterating some of its blood supply and destroying function. As a result of pressure necrosis, rupture into the renal pelvis can occur and cyst contents expelled into the urinary tract. In such an event, microscopic examination of the urine will show fragments of cyst wall, scolices, hooklets. Invariably, following this outcome, infection develops, involving the renal pelvis and surgical treatment of urosepsis becomes necessary. On the other hand, if pressure is exerted on the peritoneal side with resultant rupture, the contents are expelled intraperitoneally. Following such a complication, the patient experiences abdominal distress and severe anaphylactic shock. The host is sensitized to the cyst fluid and the shock may be severe enough to cause death. The contents may gravitate down to the pelvis and start new areas. If a new cyst forms in the retrovesical space, it may occasion bladder neck obstruction requiring operation. In about 20 per cent, the wall undergoes calcification preventing the entrance of nutritive substances and degeneration results. A pathologic picture simulating tuberculous caseation follows. In such a termination, the cyst becomes an innocuous mass, which does not trouble the host and usually requires no treatment. SYMPTOMATOLOGY
Twenty to thirty years of development are required for the cyst to cause symptoms. The growth acts as a foreign body and causes distress by pressure. The patient complains of flank discomfort and may also note a mass in the area. If the cyst ruptures into the pelvis of the kidney, colicy pains are experienced when the small daughter cysts pass down the ureter.
ECHINOCOCCUS DISEASE OF KIDNEY
443
The anaphylactic reaction following rupture into the peritoneum has already been mentioned. Ordinarily, the unruptured, modest sized cyst is asymptomatic. The patient's nutrition is normal and his health is not obviously interfered with. DIAGNOSIS
In countries where the disease is prevalent, the diagnosis is frequently made preoperatively because it is always suspected, but in the United States, since so few cases are encountered, it is rarely detected until after exploratory operation . .Preoperative diagnosis was made in only four of 17 cases reviewed by Kretschmer.
Frn. 1. Retrograde pyelogram
In three of these daughter cysts were found in the urine. It is most often mistaken for renal malignancy or simple cyst. When the kidney has been severely compressed, the function is inhibited and excretory urography fails on the involved side. Retrograde study shows a cup shaped deformity referred to as the "goblet" sign. The pyelographic appearance of an upper pole cyst is not unlike that of a champagne glass with the ureter serving as the stem (fig. I). An eosinophilia is present almost invariably. vVhen cysts rupture into the pelvis, urinary findings have been listed previously and the diagnosis is apparent. Physical examination reveals a nontender mass associated with the kidney. With the exception of urinary findings, in cases of rupture into the pelvis, no
444
WILLIAM BAURYS
signs could be considered definitive. Intradermal tests and compliment fixation studies have been developed to aid in detecting the presence of the disease. PROGNOSIS
If untreated, it may end fatally. About 20 per cent develop calcification of the
cyst wall with autodestruction of contents. In most instances, the involved kidney is sacrificed. In some cases, the hydatid has been successfully resected from renal tissue.
Fm. 2. Gross specimen TREATMENT
Nephrectomy appears essential. Because the laminated membranes are impervious, therapeutic medication is of no value. Marsupialization and treatment with formaldehyde are advocated by some. If the patient has no other organs involved, nephrectomy results in a cure. Dew claims that 60 per cent of patients have multiple cysts. Bilateral renal involvement is rare. PROPHYLAXIS
It had been predicted that the disease will become more prevalent in this country with increase in sheep raising; however, this has not occurred. In spite
ECHINOCOCCUS DISEASE OF KIDNEY
445
of our enlarged, wool-growing industry the disease remains rare. On the other hand, it has become less frequent in those countries adopting modern American hygienic supervision of abbatoirs.
Fm. 3. Cyst opened showing daughter cysts
Fm. 4. Low power photomicrograph showing brood capsule with scolices and hooklets. CASE REPORT
A white 24-year old war bride, native of vV ales, who had been in this country for 3 years, had been conscious of a moderate amount of distress in her right flank and a palpable mass in the same area for at least 2 years. There were no associated urinary symptoms and she considered herself in vigorous health. She
446
WILLIAM BAURYS
had gone through two pregnancies during the preceding three years without unusual difficulty. Until her marriage, she was never outside of her native country. Her parents were chicken raisers in a wool-growing country district. As far back as she could recall, a pet dog was always around the home. She had no knowledge of the prevalence of echinococcus disease in her native community. Her parents, brothers and sisters were all living and well. Cardiorespiratory and gastro-intestinal system studies showed nothing remarkable. In the right renal area, a regular, slightly tender, rounded mass was easily palpated. The upper border extended above the costal margin. Excretory urography showed a normal pyelogram on the left side but no dye was excreted on the right after 1 hour. The enlarged kidney shadow was distinct and appeared to be about three times normal size. Retrograde study showed an extreme degree of compression deformity on the involved side. Specimens of urine were negative on microscopic examination. Indigo carmine appeared within normal time limits from the left but only a faint trace after a prolonged time was obtained from the right side. Exploratory operation with possible nephrectomy was'"recommended and the patient submitted. The kidney was approached through a flank incision. Mobilization was rather difficult because of adhesions. Rough handling of the mass on the lower pole did not result in rupture. The mass was firm yellowish in color, and fluctuation was not observed. Our diagnosis was hypernephroma and nephrectomy was performed. The specimen was about three times the size of a normal kidney. About one-fourth was renal tissue and the rest was the attached mass (fig. 2). The incision was treated in the usual manner and closed without drain. On section, the thick capsule of the mass retracted and numerous spherical cysts rolled out (fig. 3). They varied from the size of a match head to that of a pigeon's egg (fig. 3). Dozens of these were enclosed in the large mother cyst and were surrounded by a colorless fluid. These were the daughter cysts in various stages of development. They were filled with a clear fluid and were a miniature replica of the larger cyst. The renal tissue was compressed and distorted by the attached mass. On microscopic section (fig. 4) numerous hooklets, brood capsules and scolices were identified. The patient made an uneventful recovery and no evidence was found of any other cysts. CONCLUSION
Echinococcus disease is rare in the United States. The kidney is involved in about 2.5 per cent of instances. The life cycle of the parasite is described. The symptomatology, pathology and treatment as reported by foreign writers are reviewed. An uncomplicated case treated by nephrectomy is presented. REFERENCES DEw, H. R.: Hydatid Disease. Australian Medical Pub. Co., 1928. HADDAD, S. I. AND KHAIRALLAH, A. A.: Ann. Surg., 111: 597, 1940. KRETSCHMER, H. L.: Surg., Gynec. & Obst., 36: 196, 1923.
Vol. 68, No. 2, August 1952 Printed in U.S.A.
ECHINOCOCCUS DISEASE OF THE KIDNEY WILLIAM BAURYS From The Guthrie Clinic, Sayre, Pa.
Renal hydatid is a rare disease in the United States. Although Rolnick's textbook recorded 245 cases from the world's literature, only 35 have been reported in this country. In pastoral countries like South America, Australia, Iceland and Asia, it is of not infrequent occurrence. In Beyrouth, Syria, for instance, Haddad and Khairallah stated that 0.75 per cent of hospital admissions during a recent 10year survey were patients with echinococcus cysts. Although numerous instances of this infestation have been found invading other organs and tissues among American inhabitants, only four were in natives. Of 46 cases treated at the Mayo Clinic among admissions until 1940, one involved the kidney. At the Guthrie Clinic and Robert Packer Hospital, the case herein reported is the only one of renal involvement among 240,000 hospital admissions. Because of its definite scarcity in this country, detailed information must necessarily come from foreign writers with extensive experience in wool-growing localities. ETIOLOGY
Careless ingestion of food contaminated ·with echinococcus tapeworm ova is responsible for the disease in humans. This cestode is a parasitic inhabitant of the infested dog's intestines. Ova excreted with feces find their way into the alimentary tract of sheep or human and there develop into intermediate larval forms (scolices) encased in the cyst. Sheep consume the embryos while grazing in pastures where dog excreta have been deposited. When the infested animals are slaughtered and the entrails which contain scolices are carelessly left lying around, dogs devour them. The ingested scolices develop into mature forms in the canine's intestines and the cycle is complete. The human gastro-intestinal tract serves the same type of refuge in the cycle as that of sheep. The Australian authority, Dew, contends the cyst in adults is almost as old as the individual harboring it. In his opinion, the patient, in childhood, becomes infested by careless fondling of dogs. Since so few early cases have been found beyond the fourth decade, it is generally believed the adult develops an immunity. PATHOLOGY
When ova are ingested, the chitinous covering is dissolved by gastric digestion and the embryo released. Were it not that most ova are destroyed by natural body defenses and gastric secretions, the disease would be much more widely prevalent and multiple cysts more common. 441
442
WILLIAM BAURYS
Parasites escaping these hazards, pierce the stomach mucosa or upper intestinal tract, filter into the portal circulation and usually become embedded in the liver. A small number bypass the portal circulation and enter the lungs. Some few escape the pulmonary venous plexus, become dispersed and finally arrested in various body tissues. Approximately 77 per cent of cysts form in the liver and about 10 per cent in the lungs. The remaining 13 per cent are deposited in other portions of the body. About 2.5 per cent reach the kidney; here the embryo embeds itself in cortical tissue and within a few hours forms a small blister-like cyst and in years attains mature size. At maturity, the cyst is composed of an adventitious capsule inside of which is a laminated nutritive layer lined by a germinal membrane. From this endocystal germinal membrane, brood capsules develop. At least part of the cyst surface is covered by renal capsule. The cyst has no blood supply. Nutrition is supplied by selective osmosis through the laminated covering. This layer is impervious to noxious substances and for this reason destructive medications cannot reach the interior. As the original hydatid enlarges, it reproduces within itself daughter cysts whose construction is a replica of the parent. The mother cyst wall expands to accommodate the multiplication of offspring and the increased amount of nutritive fluid. While it grows, the mass encroaches on the pelvis and parenchymal renal tissue obliterating some of its blood supply and destroying function. As a result of pressure necrosis, rupture into the renal pelvis can occur and cyst contents expelled into the urinary tract. In such an event, microscopic examination of the urine will show fragments of cyst wall, scolices, hooklets. Invariably, following this outcome, infection develops, involving the renal pelvis and surgical treatment of urosepsis becomes necessary. On the other hand, if pressure is exerted on the peritoneal side with resultant rupture, the contents are expelled intraperitoneally. Following such a complication, the patient experiences abdominal distress and severe anaphylactic shock. The host is sensitized to the cyst fluid and the shock may be severe enough to cause death. The contents may gravitate down to the pelvis and start new areas. If a new cyst forms in the retrovesical space, it may occasion bladder neck obstruction requiring operation. In about 20 per cent, the wall undergoes calcification preventing the entrance of nutritive substances and degeneration results. A pathologic picture simulating tuberculous caseation follows. In such a termination, the cyst becomes an innocuous mass, which does not trouble the host and usually requires no treatment. SYMPTOMATOLOGY
Twenty to thirty years of development are required for the cyst to cause symptoms. The growth acts as a foreign body and causes distress by pressure. The patient complains of flank discomfort and may also note a mass in the area. If the cyst ruptures into the pelvis of the kidney, colicy pains are experienced when the small daughter cysts pass down the ureter.
ECHINOCOCCUS DISEASE OF KIDNEY
443
The anaphylactic reaction following rupture into the peritoneum has already been mentioned. Ordinarily, the unruptured, modest sized cyst is asymptomatic. The patient's nutrition is normal and his health is not obviously interfered with. DIAGNOSIS
In countries where the disease is prevalent, the diagnosis is frequently made preoperatively because it is always suspected, but in the United States, since so few cases are encountered, it is rarely detected until after exploratory operation . .Preoperative diagnosis was made in only four of 17 cases reviewed by Kretschmer.
Frn. 1. Retrograde pyelogram
In three of these daughter cysts were found in the urine. It is most often mistaken for renal malignancy or simple cyst. When the kidney has been severely compressed, the function is inhibited and excretory urography fails on the involved side. Retrograde study shows a cup shaped deformity referred to as the "goblet" sign. The pyelographic appearance of an upper pole cyst is not unlike that of a champagne glass with the ureter serving as the stem (fig. I). An eosinophilia is present almost invariably. vVhen cysts rupture into the pelvis, urinary findings have been listed previously and the diagnosis is apparent. Physical examination reveals a nontender mass associated with the kidney. With the exception of urinary findings, in cases of rupture into the pelvis, no
444
WILLIAM BAURYS
signs could be considered definitive. Intradermal tests and compliment fixation studies have been developed to aid in detecting the presence of the disease. PROGNOSIS
If untreated, it may end fatally. About 20 per cent develop calcification of the
cyst wall with autodestruction of contents. In most instances, the involved kidney is sacrificed. In some cases, the hydatid has been successfully resected from renal tissue.
Fm. 2. Gross specimen TREATMENT
Nephrectomy appears essential. Because the laminated membranes are impervious, therapeutic medication is of no value. Marsupialization and treatment with formaldehyde are advocated by some. If the patient has no other organs involved, nephrectomy results in a cure. Dew claims that 60 per cent of patients have multiple cysts. Bilateral renal involvement is rare. PROPHYLAXIS
It had been predicted that the disease will become more prevalent in this country with increase in sheep raising; however, this has not occurred. In spite
ECHINOCOCCUS DISEASE OF KIDNEY
445
of our enlarged, wool-growing industry the disease remains rare. On the other hand, it has become less frequent in those countries adopting modern American hygienic supervision of abbatoirs.
Fm. 3. Cyst opened showing daughter cysts
Fm. 4. Low power photomicrograph showing brood capsule with scolices and hooklets. CASE REPORT
A white 24-year old war bride, native of vV ales, who had been in this country for 3 years, had been conscious of a moderate amount of distress in her right flank and a palpable mass in the same area for at least 2 years. There were no associated urinary symptoms and she considered herself in vigorous health. She
446
WILLIAM BAURYS
had gone through two pregnancies during the preceding three years without unusual difficulty. Until her marriage, she was never outside of her native country. Her parents were chicken raisers in a wool-growing country district. As far back as she could recall, a pet dog was always around the home. She had no knowledge of the prevalence of echinococcus disease in her native community. Her parents, brothers and sisters were all living and well. Cardiorespiratory and gastro-intestinal system studies showed nothing remarkable. In the right renal area, a regular, slightly tender, rounded mass was easily palpated. The upper border extended above the costal margin. Excretory urography showed a normal pyelogram on the left side but no dye was excreted on the right after 1 hour. The enlarged kidney shadow was distinct and appeared to be about three times normal size. Retrograde study showed an extreme degree of compression deformity on the involved side. Specimens of urine were negative on microscopic examination. Indigo carmine appeared within normal time limits from the left but only a faint trace after a prolonged time was obtained from the right side. Exploratory operation with possible nephrectomy was'"recommended and the patient submitted. The kidney was approached through a flank incision. Mobilization was rather difficult because of adhesions. Rough handling of the mass on the lower pole did not result in rupture. The mass was firm yellowish in color, and fluctuation was not observed. Our diagnosis was hypernephroma and nephrectomy was performed. The specimen was about three times the size of a normal kidney. About one-fourth was renal tissue and the rest was the attached mass (fig. 2). The incision was treated in the usual manner and closed without drain. On section, the thick capsule of the mass retracted and numerous spherical cysts rolled out (fig. 3). They varied from the size of a match head to that of a pigeon's egg (fig. 3). Dozens of these were enclosed in the large mother cyst and were surrounded by a colorless fluid. These were the daughter cysts in various stages of development. They were filled with a clear fluid and were a miniature replica of the larger cyst. The renal tissue was compressed and distorted by the attached mass. On microscopic section (fig. 4) numerous hooklets, brood capsules and scolices were identified. The patient made an uneventful recovery and no evidence was found of any other cysts. CONCLUSION
Echinococcus disease is rare in the United States. The kidney is involved in about 2.5 per cent of instances. The life cycle of the parasite is described. The symptomatology, pathology and treatment as reported by foreign writers are reviewed. An uncomplicated case treated by nephrectomy is presented. REFERENCES DEw, H. R.: Hydatid Disease. Australian Medical Pub. Co., 1928. HADDAD, S. I. AND KHAIRALLAH, A. A.: Ann. Surg., 111: 597, 1940. KRETSCHMER, H. L.: Surg., Gynec. & Obst., 36: 196, 1923.