- Email: [email protected]
Nonsurgical pneumoperitoneum
Nonsurgical Pneumoperitoneum C. Bernard Gantt, Jr, MD,’ Birmingham, Alabama William W. Daniel, MD, Birmingham, Alabama George A. Hallenbeck, MD, La Jolla, California
Pneumoperitoneum, especially when associated with significant abdominal pain, is often caused by perforation of a viscus that contains gas and commonly requires surgical treatment. Less frequently considered is pneumoperitoneum that results from causes that do not require surgical treatment. The radiologist is often the first to recognize free intraperitoneal gas; therefore, it is of paramount importance that he or she be acutely aware of the many nonsurgical causes of pneumoperitoneum. The radiologist may play the decisive role in preventing needless emergency laparotomy. Case Report A thirty-one year old, 2-gravida, 2-para housewife was admitted to the hospital for elective cholecystectomy. She was free of symptoms at the time of admission, and physical examination revealed no abnormalities. A routine chest roentgenogram (Figure I) revealed a large amount of free subdiaphragmatic gas. The surgeon, notified immediately by the radiologist, reexamined the patient and after reviewing the chest roentgenogram, performed immediate exploratory laparotomy, suspecting a perforated viscus; however, perforated viscus was not revealed. The patient underwent cholecystectomy and had an uneventful postoperative course. Several days later, after discussing the case with a gynecologist, the surgeon questioned the patient further and found that on the night prior to her admission, she had engaged in sexual activity with her husband who had, during orogenital contact, blown forcefully into her vagina. The patient recalled that at the time she noticed From the Department of Diagnostic Radiology, University of Alabama School of Medicine, Birmingham. Alabama, and the Department of Surgery, Scripps Clinic Medical Center, Inc., La Jolla, California. Reprint requests should be addressed to William W. Daniels, MD, Department of Diagnostic Radiology, Universityof Alabama School of Medicine. 619 South 19th Street, Birmingham, Alabama 35233. * Present address: Lee County Hospital, 106 Hill Crest Drive, Sanford, North Carolina 27330.
Volume 134, September 1977
an increase in her abdominal pain.
girth but experienced
no
Comments
The case described herein of pneumoperitoneum after orogenital insufflation emphasizes the importance of accurate diagnosis of the cause of pneumoperitoneum. Pneumoperitoneum from nonsurgical causes may be either symptomatic or asymptomatic. When the disease is symptomatic, pain referred to the shoulder is often present. Asymptomatic, nonsurgically caused pneumoperitoneum may result in unnecessary exploratory surgery, as would have occurred with our patient had it not been for the presence of cholelithiasis. The literature contains examples of patients subjected to surgery because asymptomatic pneumoperitoneum was attributed to a perforated viscus. Unfortunately, the diagnosis was never established in some of these patients and one can only speculate as to the real cause [1,2]. The nonsurgical causes of pneumoperitoneum may be classified according to the source of the gas. Three anatomic sites of origin are (1) intrathoracic, (2) abdominal, and (3) gynecologic. A fourth classification, iatrogenic, should present no difficulty when history is available. lntrathoraclc Causes of Pneumoperitoneum
Intrathoracic causes of pneumoperitoneum have been widely reported [3-71. When the disease is associated with pneumomediastinum, the cause is thought to be dissection into the abdominal cavity via transdiaphragmatic routes. When tuberculosis or pneumonia is present and presumed to be causal, the mechanism of entry is less clear, but entry into the abdominal cavity is almost certainly by a similar pathway. A recent case of this type was reported after
411
Gantt, Daniel, and Hallenbeck
a tooth extraction [7]. Jash [S] reported a case of pneumothorax and pneumoperitoneum after tonsillectomy, and Atcheson, Peterson, and Fred [3] reported a case of pneumoperitoneum after closed chest cardiac massage. Pneumoperitoneum in infancy may present a difficult diagnostic problem, especially in newborns treated with ventilatory assistance. Here the problem is compounded by the fact that some newborns treated with ventilation have a perforated abdominal viscus and some do not. Leonidas et al (51, in an excellent review of this subject, described several criteria that may be of value in deciding whether or not to operate on ventilated newborns with pneumoperitoneum. Pneumoperitoneum without evidence of extraalveolar air on the chest roentgenogram is evidence in favor of abdominal perforation, but the reverse may or may not be true. One case illustrated the danger of assuming that extraalveolar air in the chest indicates that an accompanying pneumoperitoneum is from the same cause. A second helpful sign is the presence of a peritoneal air-fluid level, which can sometimes be seen on upright films and is indicative of peritonitis. A third consideration, according to Leonidas et al [5], is the possibility of using water-soluble contrast agents to demonstrate per-
foration. Finally, abdominal roentgenograms may disclose the presence of necrotizing enterocolitis, and this would favor visceral perforation. Kirkpatrick, Felman, and Eitzman [4], addressing the same problem, also found water-soluble contrast media in the gut useful if time permitted, and observed that rapid increase of fluid and air in the peritoneal cavity over a short period of time is suggestive of a ruptured viscus. These authors also found paraspinal air present in two patients and interpreted this as a sign of dissection of air from the chest into the peritoneal cavity. Abdomlnal Causes of Pneumoperitoneum
The rare disease, pneumatosis cystoides intestinalis (also called cystic lymphopneumatosis, gas cysts, intestinal emphysema, and enteromesenteric emphysema), in which multiple gas-filled cysts are present in the walls of the gastrointestinal tract, may result in pneumoperitoneum without surgical indications [9]. The cause of these cysts is not known; they are commonly thought to begin as dilated lymphatics into which gas passed through a break in mucosal continuity. Usually other diseases are present and the pneumatosis intestinalis is an incidental finding that appears to be producing no
Figure 7. Posteroanterior ( feff) and lateral chesf roenfgenogram (r/ghf ) demonsfrafing a large amount of stbdlaphragmafic gas.
412
The American Journal of Surgery
Nonsurgical Pneumoperitoneum
symptoms. It has been reported in association with gastric or duodenal ulcers often with pyloric obstruction, esophageal strictures, diaphragmatic hernia, bowel obstruction due to a variety of causes, and inflammatory bowel disease, according to Wolloch, Dintsman, and Weiss [9]. It is especially common in debilitated patients. The cysts occasionally rupture and cause pneumoperitoneum that is commonly asymptomatic and sometimes thought to be caused by a coexisting disease. Any surgical treatment found necessary would be for the associated disease. Papp and Sullivan [IO] reported a case of spontaneous pneumoperitoneum due to aerophagia. They discussed other causes of pneumoperitoneum including gastroscopy and surgical procedures about the mouth and neck. Hovelius [II] reported a case of pneumoperitoneum in a patient with emphysematous cholecystitis or “pneumocholecystitis.” Although no perforation could be found in the gallbladder wall, this is analogous to those cases of pneumatosis cystoides intestinalis with pneumoperitoneum in which no perforation of the bowel wall could be found. GynecologlcCauses 01 Pneumoperitoneum
Gynecologic causes of pneumoperitoneum, as in the case presented herein, have received less attention in the literature and are not as well known as abdominal, intrathoracic, and iatrogenic causes. Thus, gynecologic causes are likely to lead to diagnostic problems and unnecessary exploratory laparotomy, especially when the patient is symptomatic. Ours is not the first report of pneumoperitoneum after orogenital insufflation. Freeman [12] reported a similar case in which the gynecologic history was decisive in avoiding surgery. Orogenital insufflation has been reported more often as a cause of air embolism during pregnancy [13-151. No accurate statistics are available concerning the frequency of this practice; it may be more common during pregnancy. One report [14] included a patient who practiced orogenital sex after she was advised by her physician not to have sexual intercourse late in her pregnancy. Aronson and Nelson [13] reviewed five cases of fatal air embolism in pregnancy and reported two additional cases of their own with autopsies. In all seven cases, sexual partners admitted blowing into the vagina of the deceased immediately prior to death.
Other gynecologic causes of pneumoperitoneum have been reported, such as knee-chest exercises in the postpartum period [16] and pelvic examination
Vdume134.september1977
in the postpartum period [17]. In addition, pneumoperitoneum was reported in one patient who, four weeks post partum, bent over and picked up a table, and there have been radiographically proved cases of pneumoperitoneum after vaginal douching [18]. Fredrikson [19] reported on a thirty-nine year old female, 3-gravida, 3-para, who had five episodes of pneumoperitoneum. Although its source was never definitely established, the disease did not recur after bilateral salpingectomy. Tabrisky, MaIlin, and Smith [20] reported a case of pneumoperitoneum after coitus as a complication of uterine tube prolapse after vaginal hysterectomy. latrogenlc Causes of PneumoperHoneum
Iatrogenic pneumoperitoneum is usually asymptomatic and often follows laparotomy. Pneumoperitoneum occurs rarely after repairs of inguinal hernias and variably after appendectomy; it usually occurs after operations on the gallbladder, stomach, and intestines which require larger incisions [21]. It may be detectable radiologically for up to three weeks but is usually undectable after one week or less [22-251. Other examples of iatrogenic causes of pneumoperitoneum include perforation during endoscopic procedures, tubal insufflation to determine patency, and the old and seldom used technic of pneumoperitoneum for treatment of tuberculosis or to enlarge the abdomen before surgical repair of a large hernia. Iatrogenic pneumoperitoneum should present no diagnostic problem, assuming a correct patient history is available. Conclusions
The main danger when pneumoperitoneum is due to causes other than visceral perforation is that it may be mistakenly attributed to visceral perforation and result in needless exploratory laparotomy. In addition, there may be a delay in the discovery of other pathologic conditions which a careful history might have elicited and which could require treatment. When the history is well known to the clinician, such as in postoperative or other iatrogenic causes of pneumoperitoneum, there is little likelihood of unnecessary operation. Additionally, other associated radiologic findings may be helpful in detecting nonsurgical causes of pneumoperitoneum, such as finding of pneumomediastinum on a chest roentgenogram or the typical finding of pneumatosis cystoides intestinalis on an abdominal film. However, when the finding of free abdominal air is incidental and symptoms are absent or minimal, it is important that
413
Garth, Daniel,
and Hallenbeck
the female patient be questioned thoroughly about sexual habits to prevent unnecessary surgery. Summary
Free intraperitoneal air is not necessarily caused perforated viscus. The present study reviews the causes of pneumoperitoneum that do not necessitate laparotomy, and emphasizes the importance of obtaining a complete clinical history. by a
References 1. Mason JM, Mason EM, Kesmodel KF: Spontaneous pneumoperitoneum without peritonitis and without demonstrable cause. South Med J 39: 620, 1946. 2. Side1 N, Wolbarsht A: Spontaneous pneumoperitoneum from an unknown cause. N Engl J Med 231: 450, 1944. 3. Atcheson SG, Peterson GV. Fred HL: Ill-effects of cardiac resuscitation: report of two unusual cases. Chest 67: 615, 1975. 4. Kirkpatrick BV, Felman AH, Eitzman DV: Complications of ventilator therapy in respiratory distress syndrome. Am J Ois Child 128: 496, 1974. 5. Leonidas JC, Hall RT, Holder TM, Amoury RA: Pneumoperitoneum associated with chronic respiratory disease in the newborn. Pediatrics 51: 933, 1973. 6. Leonidas JC, Hall RT, Rhodes PG, Armoury RA: Pneumoperitoneum in ventilated newborns. Am J Dis Child 128: 677, 1974. .-. 7. Sandler CM, Libshitz HI, Marks G: Pneumoperitoneum, pneumomediastinum. and pneumopericardium following dental extraction. Radiology 115: 539, 1975. 8. Jash DK: An unusual complication during adeno-tonsillectomy. JLaryngolOtol87: 191, 1973.
414
9. Wolloch Y, Dintsman M, Weiss A: Pneumatosis cystoides intestinalis of adulthood. Arch Surg 105: 723. 1972. 10. Papp JP, Sullivan BH: Spontaneous pneumoperitoneum without peritonitis. Clev C/in Q 32: 149, 1965. 11. Hovelius L: Pneumocholecystitis: an uncommon cause of pneumoperitoneum. Acta Chir Stand 139: 410, 1973. 12. Freeman RK: Pneumoperitoneum from oral-genital insufflation. Obstet Gynecol36: 162, 1970. 13. Aronson ME, Nelson PK: Fatal air embolism in pregnancy resulting from an unusual sexual act. Obstet Gynecol30: 127, 1967. 14. Aronson ME: Fatal air embolism caused by bizarre sexual behavior during pregnancy. Med Aspects Human Sexuality 3: 33, 1969. 15. Nelson PK: Pulmonary gas embolism in pregnancy and the puerperium. Obstet Gynecol Surv 15: 449, 1960. 16. Lozman H, Newman AJ: Spontaneous pneumoperitoneum occurring during post partum exercises in the knee-chest position. Am J Obstet Gynecol72: 903, 1956. 17. Cass LJ, Dow E, Brooks KR: Pneumoperitoneum following pelvic examination. Am J Gastfoenterol45: 209, 1966. 18. Walker MA: Pneumoperitoneum following a douche. J Kans Med sot 43: 55, 1942. 19. Fredrikson H: A case of pneumoperitoneum. Acta Obstet Gynecol Stand 35: 568, 1956. 20.. Tabrisky J, Mallin LP, Smith JA: Pneumoperitoneum after coitus. Obstet Gynecol40: 218, 1972. 21. Gerwig WH: Appendicitis; study of over 500 cases observed during present emergency in army hospitals. Wit Surg 95: 291.1944. 22. Harrison I, Litwer H. Gerwig WH: Studies on the incidence and duration of postoperative pneumoperitoneum. Ann Surg 145: 591.1957. 23. von Keiser D. Lemmertz K: uber die dauer des oostooerativen pneumoperitoneums. Der Chirurg 17;18: 260, 1947. 24. Bannen JE: Post-operative pneumoperitoneum. 6f J Radio/ 17: 119,1944. 25. Bannen JE: Investigation of free gas in the peritoneal cavity. Br J Radio1 18: 390, 1945.
The American Journal of Surgery
Pneumoperitoneum, especially when associated with significant abdominal pain, is often caused by perforation of a viscus that contains gas and commonly requires surgical treatment. Less frequently considered is pneumoperitoneum that results from causes that do not require surgical treatment. The radiologist is often the first to recognize free intraperitoneal gas; therefore, it is of paramount importance that he or she be acutely aware of the many nonsurgical causes of pneumoperitoneum. The radiologist may play the decisive role in preventing needless emergency laparotomy. Case Report A thirty-one year old, 2-gravida, 2-para housewife was admitted to the hospital for elective cholecystectomy. She was free of symptoms at the time of admission, and physical examination revealed no abnormalities. A routine chest roentgenogram (Figure I) revealed a large amount of free subdiaphragmatic gas. The surgeon, notified immediately by the radiologist, reexamined the patient and after reviewing the chest roentgenogram, performed immediate exploratory laparotomy, suspecting a perforated viscus; however, perforated viscus was not revealed. The patient underwent cholecystectomy and had an uneventful postoperative course. Several days later, after discussing the case with a gynecologist, the surgeon questioned the patient further and found that on the night prior to her admission, she had engaged in sexual activity with her husband who had, during orogenital contact, blown forcefully into her vagina. The patient recalled that at the time she noticed From the Department of Diagnostic Radiology, University of Alabama School of Medicine, Birmingham. Alabama, and the Department of Surgery, Scripps Clinic Medical Center, Inc., La Jolla, California. Reprint requests should be addressed to William W. Daniels, MD, Department of Diagnostic Radiology, Universityof Alabama School of Medicine. 619 South 19th Street, Birmingham, Alabama 35233. * Present address: Lee County Hospital, 106 Hill Crest Drive, Sanford, North Carolina 27330.
Volume 134, September 1977
an increase in her abdominal pain.
girth but experienced
no
Comments
The case described herein of pneumoperitoneum after orogenital insufflation emphasizes the importance of accurate diagnosis of the cause of pneumoperitoneum. Pneumoperitoneum from nonsurgical causes may be either symptomatic or asymptomatic. When the disease is symptomatic, pain referred to the shoulder is often present. Asymptomatic, nonsurgically caused pneumoperitoneum may result in unnecessary exploratory surgery, as would have occurred with our patient had it not been for the presence of cholelithiasis. The literature contains examples of patients subjected to surgery because asymptomatic pneumoperitoneum was attributed to a perforated viscus. Unfortunately, the diagnosis was never established in some of these patients and one can only speculate as to the real cause [1,2]. The nonsurgical causes of pneumoperitoneum may be classified according to the source of the gas. Three anatomic sites of origin are (1) intrathoracic, (2) abdominal, and (3) gynecologic. A fourth classification, iatrogenic, should present no difficulty when history is available. lntrathoraclc Causes of Pneumoperitoneum
Intrathoracic causes of pneumoperitoneum have been widely reported [3-71. When the disease is associated with pneumomediastinum, the cause is thought to be dissection into the abdominal cavity via transdiaphragmatic routes. When tuberculosis or pneumonia is present and presumed to be causal, the mechanism of entry is less clear, but entry into the abdominal cavity is almost certainly by a similar pathway. A recent case of this type was reported after
411
Gantt, Daniel, and Hallenbeck
a tooth extraction [7]. Jash [S] reported a case of pneumothorax and pneumoperitoneum after tonsillectomy, and Atcheson, Peterson, and Fred [3] reported a case of pneumoperitoneum after closed chest cardiac massage. Pneumoperitoneum in infancy may present a difficult diagnostic problem, especially in newborns treated with ventilatory assistance. Here the problem is compounded by the fact that some newborns treated with ventilation have a perforated abdominal viscus and some do not. Leonidas et al (51, in an excellent review of this subject, described several criteria that may be of value in deciding whether or not to operate on ventilated newborns with pneumoperitoneum. Pneumoperitoneum without evidence of extraalveolar air on the chest roentgenogram is evidence in favor of abdominal perforation, but the reverse may or may not be true. One case illustrated the danger of assuming that extraalveolar air in the chest indicates that an accompanying pneumoperitoneum is from the same cause. A second helpful sign is the presence of a peritoneal air-fluid level, which can sometimes be seen on upright films and is indicative of peritonitis. A third consideration, according to Leonidas et al [5], is the possibility of using water-soluble contrast agents to demonstrate per-
foration. Finally, abdominal roentgenograms may disclose the presence of necrotizing enterocolitis, and this would favor visceral perforation. Kirkpatrick, Felman, and Eitzman [4], addressing the same problem, also found water-soluble contrast media in the gut useful if time permitted, and observed that rapid increase of fluid and air in the peritoneal cavity over a short period of time is suggestive of a ruptured viscus. These authors also found paraspinal air present in two patients and interpreted this as a sign of dissection of air from the chest into the peritoneal cavity. Abdomlnal Causes of Pneumoperitoneum
The rare disease, pneumatosis cystoides intestinalis (also called cystic lymphopneumatosis, gas cysts, intestinal emphysema, and enteromesenteric emphysema), in which multiple gas-filled cysts are present in the walls of the gastrointestinal tract, may result in pneumoperitoneum without surgical indications [9]. The cause of these cysts is not known; they are commonly thought to begin as dilated lymphatics into which gas passed through a break in mucosal continuity. Usually other diseases are present and the pneumatosis intestinalis is an incidental finding that appears to be producing no
Figure 7. Posteroanterior ( feff) and lateral chesf roenfgenogram (r/ghf ) demonsfrafing a large amount of stbdlaphragmafic gas.
412
The American Journal of Surgery
Nonsurgical Pneumoperitoneum
symptoms. It has been reported in association with gastric or duodenal ulcers often with pyloric obstruction, esophageal strictures, diaphragmatic hernia, bowel obstruction due to a variety of causes, and inflammatory bowel disease, according to Wolloch, Dintsman, and Weiss [9]. It is especially common in debilitated patients. The cysts occasionally rupture and cause pneumoperitoneum that is commonly asymptomatic and sometimes thought to be caused by a coexisting disease. Any surgical treatment found necessary would be for the associated disease. Papp and Sullivan [IO] reported a case of spontaneous pneumoperitoneum due to aerophagia. They discussed other causes of pneumoperitoneum including gastroscopy and surgical procedures about the mouth and neck. Hovelius [II] reported a case of pneumoperitoneum in a patient with emphysematous cholecystitis or “pneumocholecystitis.” Although no perforation could be found in the gallbladder wall, this is analogous to those cases of pneumatosis cystoides intestinalis with pneumoperitoneum in which no perforation of the bowel wall could be found. GynecologlcCauses 01 Pneumoperitoneum
Gynecologic causes of pneumoperitoneum, as in the case presented herein, have received less attention in the literature and are not as well known as abdominal, intrathoracic, and iatrogenic causes. Thus, gynecologic causes are likely to lead to diagnostic problems and unnecessary exploratory laparotomy, especially when the patient is symptomatic. Ours is not the first report of pneumoperitoneum after orogenital insufflation. Freeman [12] reported a similar case in which the gynecologic history was decisive in avoiding surgery. Orogenital insufflation has been reported more often as a cause of air embolism during pregnancy [13-151. No accurate statistics are available concerning the frequency of this practice; it may be more common during pregnancy. One report [14] included a patient who practiced orogenital sex after she was advised by her physician not to have sexual intercourse late in her pregnancy. Aronson and Nelson [13] reviewed five cases of fatal air embolism in pregnancy and reported two additional cases of their own with autopsies. In all seven cases, sexual partners admitted blowing into the vagina of the deceased immediately prior to death.
Other gynecologic causes of pneumoperitoneum have been reported, such as knee-chest exercises in the postpartum period [16] and pelvic examination
Vdume134.september1977
in the postpartum period [17]. In addition, pneumoperitoneum was reported in one patient who, four weeks post partum, bent over and picked up a table, and there have been radiographically proved cases of pneumoperitoneum after vaginal douching [18]. Fredrikson [19] reported on a thirty-nine year old female, 3-gravida, 3-para, who had five episodes of pneumoperitoneum. Although its source was never definitely established, the disease did not recur after bilateral salpingectomy. Tabrisky, MaIlin, and Smith [20] reported a case of pneumoperitoneum after coitus as a complication of uterine tube prolapse after vaginal hysterectomy. latrogenlc Causes of PneumoperHoneum
Iatrogenic pneumoperitoneum is usually asymptomatic and often follows laparotomy. Pneumoperitoneum occurs rarely after repairs of inguinal hernias and variably after appendectomy; it usually occurs after operations on the gallbladder, stomach, and intestines which require larger incisions [21]. It may be detectable radiologically for up to three weeks but is usually undectable after one week or less [22-251. Other examples of iatrogenic causes of pneumoperitoneum include perforation during endoscopic procedures, tubal insufflation to determine patency, and the old and seldom used technic of pneumoperitoneum for treatment of tuberculosis or to enlarge the abdomen before surgical repair of a large hernia. Iatrogenic pneumoperitoneum should present no diagnostic problem, assuming a correct patient history is available. Conclusions
The main danger when pneumoperitoneum is due to causes other than visceral perforation is that it may be mistakenly attributed to visceral perforation and result in needless exploratory laparotomy. In addition, there may be a delay in the discovery of other pathologic conditions which a careful history might have elicited and which could require treatment. When the history is well known to the clinician, such as in postoperative or other iatrogenic causes of pneumoperitoneum, there is little likelihood of unnecessary operation. Additionally, other associated radiologic findings may be helpful in detecting nonsurgical causes of pneumoperitoneum, such as finding of pneumomediastinum on a chest roentgenogram or the typical finding of pneumatosis cystoides intestinalis on an abdominal film. However, when the finding of free abdominal air is incidental and symptoms are absent or minimal, it is important that
413
Garth, Daniel,
and Hallenbeck
the female patient be questioned thoroughly about sexual habits to prevent unnecessary surgery. Summary
Free intraperitoneal air is not necessarily caused perforated viscus. The present study reviews the causes of pneumoperitoneum that do not necessitate laparotomy, and emphasizes the importance of obtaining a complete clinical history. by a
References 1. Mason JM, Mason EM, Kesmodel KF: Spontaneous pneumoperitoneum without peritonitis and without demonstrable cause. South Med J 39: 620, 1946. 2. Side1 N, Wolbarsht A: Spontaneous pneumoperitoneum from an unknown cause. N Engl J Med 231: 450, 1944. 3. Atcheson SG, Peterson GV. Fred HL: Ill-effects of cardiac resuscitation: report of two unusual cases. Chest 67: 615, 1975. 4. Kirkpatrick BV, Felman AH, Eitzman DV: Complications of ventilator therapy in respiratory distress syndrome. Am J Ois Child 128: 496, 1974. 5. Leonidas JC, Hall RT, Holder TM, Amoury RA: Pneumoperitoneum associated with chronic respiratory disease in the newborn. Pediatrics 51: 933, 1973. 6. Leonidas JC, Hall RT, Rhodes PG, Armoury RA: Pneumoperitoneum in ventilated newborns. Am J Dis Child 128: 677, 1974. .-. 7. Sandler CM, Libshitz HI, Marks G: Pneumoperitoneum, pneumomediastinum. and pneumopericardium following dental extraction. Radiology 115: 539, 1975. 8. Jash DK: An unusual complication during adeno-tonsillectomy. JLaryngolOtol87: 191, 1973.
414
9. Wolloch Y, Dintsman M, Weiss A: Pneumatosis cystoides intestinalis of adulthood. Arch Surg 105: 723. 1972. 10. Papp JP, Sullivan BH: Spontaneous pneumoperitoneum without peritonitis. Clev C/in Q 32: 149, 1965. 11. Hovelius L: Pneumocholecystitis: an uncommon cause of pneumoperitoneum. Acta Chir Stand 139: 410, 1973. 12. Freeman RK: Pneumoperitoneum from oral-genital insufflation. Obstet Gynecol36: 162, 1970. 13. Aronson ME, Nelson PK: Fatal air embolism in pregnancy resulting from an unusual sexual act. Obstet Gynecol30: 127, 1967. 14. Aronson ME: Fatal air embolism caused by bizarre sexual behavior during pregnancy. Med Aspects Human Sexuality 3: 33, 1969. 15. Nelson PK: Pulmonary gas embolism in pregnancy and the puerperium. Obstet Gynecol Surv 15: 449, 1960. 16. Lozman H, Newman AJ: Spontaneous pneumoperitoneum occurring during post partum exercises in the knee-chest position. Am J Obstet Gynecol72: 903, 1956. 17. Cass LJ, Dow E, Brooks KR: Pneumoperitoneum following pelvic examination. Am J Gastfoenterol45: 209, 1966. 18. Walker MA: Pneumoperitoneum following a douche. J Kans Med sot 43: 55, 1942. 19. Fredrikson H: A case of pneumoperitoneum. Acta Obstet Gynecol Stand 35: 568, 1956. 20.. Tabrisky J, Mallin LP, Smith JA: Pneumoperitoneum after coitus. Obstet Gynecol40: 218, 1972. 21. Gerwig WH: Appendicitis; study of over 500 cases observed during present emergency in army hospitals. Wit Surg 95: 291.1944. 22. Harrison I, Litwer H. Gerwig WH: Studies on the incidence and duration of postoperative pneumoperitoneum. Ann Surg 145: 591.1957. 23. von Keiser D. Lemmertz K: uber die dauer des oostooerativen pneumoperitoneums. Der Chirurg 17;18: 260, 1947. 24. Bannen JE: Post-operative pneumoperitoneum. 6f J Radio/ 17: 119,1944. 25. Bannen JE: Investigation of free gas in the peritoneal cavity. Br J Radio1 18: 390, 1945.
The American Journal of Surgery