1992, The British Journal of Radiology, 65, 868-870
Pelvic phleboliths: is there an association with diverticulitis? By E. H. de Vries, M D , A. Z. Ginai, M D , PhD, S. G. F. Robben, M D and *W. C. J . Hop, MSc Departments of Radiology and 'Epidemiology and Biostatistics, University Hospital Dijkzigt and Erasmus University Rotterdam, The Netherlands (Received 2 January 1992 and accepted 6 May 1992) Keywords: Pelvic phleboliths, Diverticulitis, Diverticulosis Abstract. Pelvic phleboliths are familiar structures to radiologists although their pathogenesis is not fully understood. The literature suggests a relationship between the prevalence of phleboliths and diverticular disease, and with a low-fibre diet. Phleboliths are said to be seen more frequently in women and on the left side in the pelvis. Their number seems to increase with advancing age. We have attempted to establish relations of phleboliths with diverticulitis, diverticulosis, sex, age and pelvic location. In this study the only statistically significant relation was an increase of the number of phleboliths with advancing age.
Pelvic phleboliths, which represent calcified thrombi in pelvic veins, are by no means rare and are a common finding on plain abdominal radiographs. Phleboliths are not normally found in other parts of the body, except when associated with arteriovenous malformations and certain other vascular lesions. Very little is known about the aetiology of pelvic phleboliths, or why phleboliths are present in some people and not in others. It has been suggested that some relationship exists between a low-fibre diet, diverticulosis and phleboliths (Hunter et al, 1984). The reason for a higher prevalence of thrombosis of pelvic veins in the case of diverticulosis is thought to be due to thrombosis at the site of damaged intima as a result of excessive straining at stools. Another cause for thombosis in general is slow blood flow. Decrease of venous flow may result from many causes, one of which is venous compression in oedematous inflammed tissues such as in peri-diverticulitis. To investigate the possible role of diverticulitis in the causation of phleboliths it was decided to define the number, location and prevalence of phleboliths in a group of patients with proven diverticulitis. The findings in this group were compared with two randomly selected groups of patients: one with diverticulosis (without any history of diverticulitis) and another group without any colon abnormality on barium enema examination.
The three groups of patients studied were: Group I (diverticulitis): 89 patients, 48 male, 41 female, mean age 65 years (range 27-86 years). Group II (diverticulosis): 58 patients, 28 male, 30 female, mean age 66 years (range 33-88 years). Group III (normal colon): 71 patients, 31 male, 40 female, mean age 54 years (range 18-86 years). The plain abdominal radiographs were independently scored for the number and location (R, L) of pelvic phleboliths by three radiologists. Two of the radiologists were unaware of the barium enema results at the time of scoring. In a small number of cases where differences existed in the scoring for the number of phleboliths, a consensus was reached by examining the abdominal radiographs together. Statistical methods Numbers of phleboliths on the left and right side were compared using Wilcoxon's test. The prevalence of phleboliths on both sides was compared using McNemar's test. Differences in numbers of phleboliths between groups were evaluated using the Kruskal-Wallis test. Correlation coefficients given are Spearman's; P-values given are two-sided; 0.05 was considered to be the limit of significance.
Materials and methods
Results
The plain abdominal radiographs from barium enemas of patients with a proven diagnosis of diverticulitis (Group I) were studied for the prevalence, number and location of pelvic phleboliths. For comparison, two groups were randomly chosen from barium enema examinations, one with diverticulosis but without any history of diverticulitis (Group II) and another group with no abnormality in the colon (Group III).
The percentages of patients with phleboliths present for the diverticulitis, diverticulosis and control groups were, respectively, 66% (59/89), 76% (44/58) and 52% (37/71). The prevalence of phleboliths appeared to be greater on the left side compared with the right side in diverticulitis and controls (Table I). The number of phleboliths was also statistically significantly larger on the left side for the latter groups. The differences, however, were generally small. In each group there was a significant correlation between the numbers of phleboliths on the left and right side of patients (controls: r = 0.63, p < 0.001); diverticulosis: r = 0.55, p < 0.001; diverticulitis: r = 0.59, p < 0.001).
*Address correspondence to E. H. de Vries, MD, Department of Radiology, University Hospital Rotterdam-Dijkzigt, Dr Molewaterplein 40, 3015 GD Rotterdam, The Netherlands. 868
The British Journal of Radiology, October 1992
Pelvic phleboliths
Table I. Percentages of cases with phleboliths present according to patient group
30 -i
Side
Controls
20-
Left Right
48% (34/71)* 64% (37/58) 30% (21/71)* 57% (33/58)
Diverticulosis Diverticulitis 57% (51/89)** 44% (39/89)**
Controls n=71 r=0.46(p 65 years). No loose connective tissue, become distended by the high significant differences between the three patient groups intraluminal pressure, which may damage the intima were present for any age range. The same applied when with the formation of a protective thrombus. the left and right side were analysed separately. Why the thrombi in the pelvic veins become calcified Although females tended to have more phleboliths has never been explained. Clots in this situation apparthan males, the differences were not significant. ently remain localized and exhibit dystrophic calcification. Of the many theories for dystrophic calcification, Discussion that of a locally high concentration of phosphatase in Pelvic phleboliths are calcified thrombi in pelvic veins the perivascular soft tissues would best explain the (Shemilt, 1972). Their cause, and pathological and formation of phleboliths (Robison, 1923). clinical significance are obscure. Rokitansky described Several studies by Burkitt show that phleboliths and one anatomically in 1856 (cited in Culligan, 1926), and diverticular disease are very rare in developing countries Wydler in 1911 concluded, on microscopical grounds, (Burkitt et al, 1977, 1985). They are virtually never seen that they were due to calcification of non-organized in Black Africans. As pelvic phleboliths are as common thrombi (Culligan, 1926). The radiological features of in black Americans as in white Americans, they are phleboliths were not recognized until 1908 by Clark probably related to environmental rather than genetic (cited in Culligan, 1926). causes. Phleboliths originate as thrombi in the pelvic veins Burkitt's studies suggest there is a relation between a and are the result of injury to the vein wall. Although in low-fibre diet and the prevalence of diverticular disease J
Vol. 65, No. 778
869
E. H. de Vries, A. Z. Ginai, S. G. F. Robben and W. C. J. Hop
and pelvic phleboliths. Pelvic phleboliths are thought to originate as a result of injured vein walls, caused by raised intra-abdominal pressure during evacuation of firm stools, and an increased clotting tendency, as seen with low-fibre diets (Burkitt et al, 1985). Besides these possible aetiological factors, decreased venous blood flow is likely to be important in the pathogenesis of thrombosis in pelvic veins, with phleboliths as a consequence. Venous blood flow decreases as intraabdominal pressure rises during evacuation of a lowbulk stool. Another reason for decrease of venous blood flow is venous compression in inflammed, oedematous peri-diverticular tissue in peri-diverticulitis. As diverticulitis is usually on the left, a study was performed to investigate if phleboliths existed more frequently on the left in patients who had a history of diverticulitis on the left. An attempt was also made to define if age and sex have any influence on the number and prevalence of pelvic phleboliths (Burkitt et al, 1977; Marquis, 1977; Dubrisay et al, 1978; Mattson, 1980). Our study showed that there were more phleboliths on the left side than on the right in the diverticulitis group and in the control group, but not in the diverticulosis group. No specific correlation of phleboliths with diverticular disease has been shown. There were also no statistically significant difference in the number of phleboliths between males and females in all three groups. However, the relationship between the amount of phleboliths and age is interesting. There is an increasing number of phleboliths with advancing age in all groups except in the diverticulitis group. To gain a better understanding of the relationship with age, each group was arbitrarily divided into three subgroups, i.e. < 45, 46-65, > 65 years. This showed no significant differences between the three patient groups for all three age ranges. The same applied when the left and right side were analysed separately.
diverticulosis/itis. This does not necessarily rule out diverticular disease as an aetiological factor. This study shows no relation to sex or preference for the increased prevalence of left-sided phleboliths. An increase in the number of pelvic phleboliths with advancing age has been shown. Other factors such as straining at stools due to causes other than diverticular disease and conditions that give rise to persistent or repeated increase in intra-abdominal pressure may be considered as aetiological factors. Inflammatory conditions in the pelvis other than diverticulitis may play a role. The pathogenesis of pelvic phleboliths is multifactorial and complex. References BURKITT, D. P., LATTO, C , JANVRIN, S. B., MAYOU, B., 1977.
Pelvic phleboliths. Epidemiology and postulated etiology. Medical Intelligence, 296, 1387-1389. BURKITT, D. P., CLEMENTS, J. R. & EATON, S. B., 1985.
Prevalence of diverticular disease, hiatus hernia and pelvic phleboliths in black and white Americans. Lancet, 19, 880-881. CULLIGAN, J. M., 1926. Phleboliths. Journal of Urology, 15, 175-188. DUBRISAY, J., DANAN, G. & PATRI, B., 1978. Association
diverticulose colique et phlebolithes pelviens. La Nouvelle Presse Medicale, 7, 3049. HUNTER, T. B., MERKLEY, R. & PITT, M. J., 1984. Relation
between pelvic phleboliths and diverticular disease of the colon. American Journal of Roentgenology, 143, 105-107. MARQUIS, J. R., 1977. The incidence of pelvic phleboliths in pediatric patients. Pediatric Radiology, 5, 211-212. MATTSON, T., 1980. Frequency and location of pelvic phleboliths. Clinical Radiology, 31, 115-118. ROBINSON, F., 1923. The possible significance of Hexosephosphoric esters in ossification. Biochemical Journal, 17, 286. SHEMILT, P., 1972. The origin of phleboliths. British Journal of Surgery, 59, 695-700.
Conclusion
In this study, we could not establish a significant relationship between the prevalence of phleboliths and
870
The British Journal of Radiology, October 1992
Pelvic phleboliths: is there an association with diverticulitis? By E. H. de Vries, M D , A. Z. Ginai, M D , PhD, S. G. F. Robben, M D and *W. C. J . Hop, MSc Departments of Radiology and 'Epidemiology and Biostatistics, University Hospital Dijkzigt and Erasmus University Rotterdam, The Netherlands (Received 2 January 1992 and accepted 6 May 1992) Keywords: Pelvic phleboliths, Diverticulitis, Diverticulosis Abstract. Pelvic phleboliths are familiar structures to radiologists although their pathogenesis is not fully understood. The literature suggests a relationship between the prevalence of phleboliths and diverticular disease, and with a low-fibre diet. Phleboliths are said to be seen more frequently in women and on the left side in the pelvis. Their number seems to increase with advancing age. We have attempted to establish relations of phleboliths with diverticulitis, diverticulosis, sex, age and pelvic location. In this study the only statistically significant relation was an increase of the number of phleboliths with advancing age.
Pelvic phleboliths, which represent calcified thrombi in pelvic veins, are by no means rare and are a common finding on plain abdominal radiographs. Phleboliths are not normally found in other parts of the body, except when associated with arteriovenous malformations and certain other vascular lesions. Very little is known about the aetiology of pelvic phleboliths, or why phleboliths are present in some people and not in others. It has been suggested that some relationship exists between a low-fibre diet, diverticulosis and phleboliths (Hunter et al, 1984). The reason for a higher prevalence of thrombosis of pelvic veins in the case of diverticulosis is thought to be due to thrombosis at the site of damaged intima as a result of excessive straining at stools. Another cause for thombosis in general is slow blood flow. Decrease of venous flow may result from many causes, one of which is venous compression in oedematous inflammed tissues such as in peri-diverticulitis. To investigate the possible role of diverticulitis in the causation of phleboliths it was decided to define the number, location and prevalence of phleboliths in a group of patients with proven diverticulitis. The findings in this group were compared with two randomly selected groups of patients: one with diverticulosis (without any history of diverticulitis) and another group without any colon abnormality on barium enema examination.
The three groups of patients studied were: Group I (diverticulitis): 89 patients, 48 male, 41 female, mean age 65 years (range 27-86 years). Group II (diverticulosis): 58 patients, 28 male, 30 female, mean age 66 years (range 33-88 years). Group III (normal colon): 71 patients, 31 male, 40 female, mean age 54 years (range 18-86 years). The plain abdominal radiographs were independently scored for the number and location (R, L) of pelvic phleboliths by three radiologists. Two of the radiologists were unaware of the barium enema results at the time of scoring. In a small number of cases where differences existed in the scoring for the number of phleboliths, a consensus was reached by examining the abdominal radiographs together. Statistical methods Numbers of phleboliths on the left and right side were compared using Wilcoxon's test. The prevalence of phleboliths on both sides was compared using McNemar's test. Differences in numbers of phleboliths between groups were evaluated using the Kruskal-Wallis test. Correlation coefficients given are Spearman's; P-values given are two-sided; 0.05 was considered to be the limit of significance.
Materials and methods
Results
The plain abdominal radiographs from barium enemas of patients with a proven diagnosis of diverticulitis (Group I) were studied for the prevalence, number and location of pelvic phleboliths. For comparison, two groups were randomly chosen from barium enema examinations, one with diverticulosis but without any history of diverticulitis (Group II) and another group with no abnormality in the colon (Group III).
The percentages of patients with phleboliths present for the diverticulitis, diverticulosis and control groups were, respectively, 66% (59/89), 76% (44/58) and 52% (37/71). The prevalence of phleboliths appeared to be greater on the left side compared with the right side in diverticulitis and controls (Table I). The number of phleboliths was also statistically significantly larger on the left side for the latter groups. The differences, however, were generally small. In each group there was a significant correlation between the numbers of phleboliths on the left and right side of patients (controls: r = 0.63, p < 0.001); diverticulosis: r = 0.55, p < 0.001; diverticulitis: r = 0.59, p < 0.001).
*Address correspondence to E. H. de Vries, MD, Department of Radiology, University Hospital Rotterdam-Dijkzigt, Dr Molewaterplein 40, 3015 GD Rotterdam, The Netherlands. 868
The British Journal of Radiology, October 1992
Pelvic phleboliths
Table I. Percentages of cases with phleboliths present according to patient group
30 -i
Side
Controls
20-
Left Right
48% (34/71)* 64% (37/58) 30% (21/71)* 57% (33/58)
Diverticulosis Diverticulitis 57% (51/89)** 44% (39/89)**
Controls n=71 r=0.46(p 65 years). No loose connective tissue, become distended by the high significant differences between the three patient groups intraluminal pressure, which may damage the intima were present for any age range. The same applied when with the formation of a protective thrombus. the left and right side were analysed separately. Why the thrombi in the pelvic veins become calcified Although females tended to have more phleboliths has never been explained. Clots in this situation apparthan males, the differences were not significant. ently remain localized and exhibit dystrophic calcification. Of the many theories for dystrophic calcification, Discussion that of a locally high concentration of phosphatase in Pelvic phleboliths are calcified thrombi in pelvic veins the perivascular soft tissues would best explain the (Shemilt, 1972). Their cause, and pathological and formation of phleboliths (Robison, 1923). clinical significance are obscure. Rokitansky described Several studies by Burkitt show that phleboliths and one anatomically in 1856 (cited in Culligan, 1926), and diverticular disease are very rare in developing countries Wydler in 1911 concluded, on microscopical grounds, (Burkitt et al, 1977, 1985). They are virtually never seen that they were due to calcification of non-organized in Black Africans. As pelvic phleboliths are as common thrombi (Culligan, 1926). The radiological features of in black Americans as in white Americans, they are phleboliths were not recognized until 1908 by Clark probably related to environmental rather than genetic (cited in Culligan, 1926). causes. Phleboliths originate as thrombi in the pelvic veins Burkitt's studies suggest there is a relation between a and are the result of injury to the vein wall. Although in low-fibre diet and the prevalence of diverticular disease J
Vol. 65, No. 778
869
E. H. de Vries, A. Z. Ginai, S. G. F. Robben and W. C. J. Hop
and pelvic phleboliths. Pelvic phleboliths are thought to originate as a result of injured vein walls, caused by raised intra-abdominal pressure during evacuation of firm stools, and an increased clotting tendency, as seen with low-fibre diets (Burkitt et al, 1985). Besides these possible aetiological factors, decreased venous blood flow is likely to be important in the pathogenesis of thrombosis in pelvic veins, with phleboliths as a consequence. Venous blood flow decreases as intraabdominal pressure rises during evacuation of a lowbulk stool. Another reason for decrease of venous blood flow is venous compression in inflammed, oedematous peri-diverticular tissue in peri-diverticulitis. As diverticulitis is usually on the left, a study was performed to investigate if phleboliths existed more frequently on the left in patients who had a history of diverticulitis on the left. An attempt was also made to define if age and sex have any influence on the number and prevalence of pelvic phleboliths (Burkitt et al, 1977; Marquis, 1977; Dubrisay et al, 1978; Mattson, 1980). Our study showed that there were more phleboliths on the left side than on the right in the diverticulitis group and in the control group, but not in the diverticulosis group. No specific correlation of phleboliths with diverticular disease has been shown. There were also no statistically significant difference in the number of phleboliths between males and females in all three groups. However, the relationship between the amount of phleboliths and age is interesting. There is an increasing number of phleboliths with advancing age in all groups except in the diverticulitis group. To gain a better understanding of the relationship with age, each group was arbitrarily divided into three subgroups, i.e. < 45, 46-65, > 65 years. This showed no significant differences between the three patient groups for all three age ranges. The same applied when the left and right side were analysed separately.
diverticulosis/itis. This does not necessarily rule out diverticular disease as an aetiological factor. This study shows no relation to sex or preference for the increased prevalence of left-sided phleboliths. An increase in the number of pelvic phleboliths with advancing age has been shown. Other factors such as straining at stools due to causes other than diverticular disease and conditions that give rise to persistent or repeated increase in intra-abdominal pressure may be considered as aetiological factors. Inflammatory conditions in the pelvis other than diverticulitis may play a role. The pathogenesis of pelvic phleboliths is multifactorial and complex. References BURKITT, D. P., LATTO, C , JANVRIN, S. B., MAYOU, B., 1977.
Pelvic phleboliths. Epidemiology and postulated etiology. Medical Intelligence, 296, 1387-1389. BURKITT, D. P., CLEMENTS, J. R. & EATON, S. B., 1985.
Prevalence of diverticular disease, hiatus hernia and pelvic phleboliths in black and white Americans. Lancet, 19, 880-881. CULLIGAN, J. M., 1926. Phleboliths. Journal of Urology, 15, 175-188. DUBRISAY, J., DANAN, G. & PATRI, B., 1978. Association
diverticulose colique et phlebolithes pelviens. La Nouvelle Presse Medicale, 7, 3049. HUNTER, T. B., MERKLEY, R. & PITT, M. J., 1984. Relation
between pelvic phleboliths and diverticular disease of the colon. American Journal of Roentgenology, 143, 105-107. MARQUIS, J. R., 1977. The incidence of pelvic phleboliths in pediatric patients. Pediatric Radiology, 5, 211-212. MATTSON, T., 1980. Frequency and location of pelvic phleboliths. Clinical Radiology, 31, 115-118. ROBINSON, F., 1923. The possible significance of Hexosephosphoric esters in ossification. Biochemical Journal, 17, 286. SHEMILT, P., 1972. The origin of phleboliths. British Journal of Surgery, 59, 695-700.
Conclusion
In this study, we could not establish a significant relationship between the prevalence of phleboliths and
870
The British Journal of Radiology, October 1992
