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Hemorrhagic endovasculitis of the placenta and fetomaternal hemorrhage: A relationship?
860
Seplellll...,1' 1992 Am.J Ob.. el GYllcml
Letters
Englund Journal of Medicine, Benacerraf et al.' found 3% of fetuses in their population to have this level of renal prominence (~4 mm). With this estimate and considering that there is a false-positive rate of approximately 50%, the true-positive rate yields an incidence of 1.5% or 1 in 66 in the general population. This represents a fivefold increase in the authors' incidence (I in 330, from an unpublished and unreferenced source). How would the authors explain this difference? Certainly the discussion surrounding the management of the fetus with mild renal prominence is timely. With present high-resolution ultrasonographic equipment. subtle abnormalities are being detected at everincreasing rates. However, the significance of these abnormalities remains undetermined. WaVlle Persutte, BS, RDMS, and Roger R. Lenke. MD Departm'ent oj Obltetrin and Gynecology. University oj Colorado lIealth Soma Center, Denver. CO 80262
REFERENCE I. Bcnacerraf SR, ~andell J, Estroff JA, et al. Fetal pyelectasis: a possible correlation with Down syndrome. Obstet Gynecol I 990:76:.'l8-60.
Reply To the Editors: We appreciate the interest shown in our work and would like to respond to the following points. Fig. 1 in the letter of Persutte and Lenke demonstrates pyelectasis, not calicectasis. The anechoic space (d~ noted by arrows) represents the fluid-filled renal pelVIS and not the renal sinus as suggested in the letter. The renal sinus is a potential space containing vessels, as well as fat, in adults. Fig. 2 illustrates prominence of the extrarenal pelvis. This is considered a normal anatomic variant and should not be mistaken for ureteropelvic junction obstruction. 1n some fetuses both the intrarenal and extrarenal pelves may appear prominent. The possibility of clinically significant obstruction or reflux is greater in this situation. Accordingly, follow-up studies would be appropriate. Neither Fig. 3 nor Fig. 4 represents clinically significant dilatation of the renal pelvis in our experience. Electronic calipers were apparently not used in Fig. 4; however, hand-held calipers yield an anteroposterior pelvic diameter of 2 to 3 mm. This would be considered within normal limits and below our lowest threshold of 4 mm for fetuses <33 weeks' gestation. With respect to our Table III the false-positive rate for each prescribed threshold does indeed decrease with advancing gestational age. This may reflect the relative growth rates of the developing renal parenchYma, renal pelvis, and ureteropelvic junction. Spontaneous resolution of mildly dilated renal pelves may therefore occur as fetal age advances. The probability of spontaneous resolution would be expected to decrease as the scan-to-delivery interval shortens (i.e., persistent renal pelvic dilatation during the third trimester
is more likely to represent a clinically significant problem, thereby reducing the observed false-positive rate). As acknowledged in our article, the study population included all cases in which hydronephrosis was suspected by gross ultrasonographic appearance. This entry criterion was nebulous by necessity because the quantitative criteria for defining significant renal pyelectasis had not been previously established. Finally, the incidence of congenital hydronephrosis will vary, depending on the method of ascertainment. The incidence of 1 in 330 referenced in the introduction of our article was derived from a population of low-risk patients. In our own high-risk referral population, 1 in every 45 fetuses is found to have an aIlleroposterior renal pelvic diameter that exceeds the thresholds advocated in our article. The incidence of hydronephrosis as confirmed by postnatal evaluation is approximately 1 in 66. In summary. we believe that the standards established by our study enhance diagnostic accuracy and provide sound guidelines for the management of this common ultrasonographic finding. Jane E. Cortevilll', MD Genetics DWlSion, Departmmt of Obstetrics and Gynecology, Washington Univl'T.lity School oj Medicine, 216 S. Kmg,lhighway, St. Louis. 1'>1063110
Hemorrhagic endovasculltls of the placenta and fetomaternal hemorrhage: A relationship? To the Editors: Novak et al. (Novak PM, Sander M, Yang SS, von Oeyen PT. Report of fourteen cases of nonimmune hydrops fetalis in association with hemorrhagic endovasculitis of the placenta. AM.J OBSTET Gyi':ECOL 1991; 165:945-50) reported a series of \4 cases of llonimmune hydrops fetalis associated with hemorrhagic endovasculitis of the placenta. In 1989 we reported a series of 66 cases of fetal death, three of which were determined to be associated with a massive fetomaternal hemorrhage.' While a placental pathologic examination was available in only two of these three cases, one showed hemorrhagic endovasculitis. The relationship between fetomaternal hemorrhage and nonimmune hydrops fetal is has been well established. and it has been suggested that a fetal cell stain be performed as part of the evaluation of nonimmune hydrops.2 Therefore we are inquiring as to whether any of these patients with nonimmune hydrops and hemorrhagic endovasculitis had experienced a significant fetomalernal hemorrhage? John OWf1l, MD J)epU1tmmt oj Obstetncs and Gynecolol{l', Unil'e1.\/tv oj Alabama at Binmnghllm, L'AB Station, Binningham. AL 35233-7333
REFERENCES I. Owen./, Stedman eM, Tucker '1'1.. Comparison of predelivery versus postdelivery Klcihauer-Betke staiIlS ill cases of fetal death. AM.I OBSTH GY!':ECOL 1989: 161 :663-6. 2. Warsof SL, :'I:icolaides KII, Rodeck C. Immune and nonimmune hydrops. C1in Obstet Gynecol 19H6:29:533-42.
Seplellll...,1' 1992 Am.J Ob.. el GYllcml
Letters
Englund Journal of Medicine, Benacerraf et al.' found 3% of fetuses in their population to have this level of renal prominence (~4 mm). With this estimate and considering that there is a false-positive rate of approximately 50%, the true-positive rate yields an incidence of 1.5% or 1 in 66 in the general population. This represents a fivefold increase in the authors' incidence (I in 330, from an unpublished and unreferenced source). How would the authors explain this difference? Certainly the discussion surrounding the management of the fetus with mild renal prominence is timely. With present high-resolution ultrasonographic equipment. subtle abnormalities are being detected at everincreasing rates. However, the significance of these abnormalities remains undetermined. WaVlle Persutte, BS, RDMS, and Roger R. Lenke. MD Departm'ent oj Obltetrin and Gynecology. University oj Colorado lIealth Soma Center, Denver. CO 80262
REFERENCE I. Bcnacerraf SR, ~andell J, Estroff JA, et al. Fetal pyelectasis: a possible correlation with Down syndrome. Obstet Gynecol I 990:76:.'l8-60.
Reply To the Editors: We appreciate the interest shown in our work and would like to respond to the following points. Fig. 1 in the letter of Persutte and Lenke demonstrates pyelectasis, not calicectasis. The anechoic space (d~ noted by arrows) represents the fluid-filled renal pelVIS and not the renal sinus as suggested in the letter. The renal sinus is a potential space containing vessels, as well as fat, in adults. Fig. 2 illustrates prominence of the extrarenal pelvis. This is considered a normal anatomic variant and should not be mistaken for ureteropelvic junction obstruction. 1n some fetuses both the intrarenal and extrarenal pelves may appear prominent. The possibility of clinically significant obstruction or reflux is greater in this situation. Accordingly, follow-up studies would be appropriate. Neither Fig. 3 nor Fig. 4 represents clinically significant dilatation of the renal pelvis in our experience. Electronic calipers were apparently not used in Fig. 4; however, hand-held calipers yield an anteroposterior pelvic diameter of 2 to 3 mm. This would be considered within normal limits and below our lowest threshold of 4 mm for fetuses <33 weeks' gestation. With respect to our Table III the false-positive rate for each prescribed threshold does indeed decrease with advancing gestational age. This may reflect the relative growth rates of the developing renal parenchYma, renal pelvis, and ureteropelvic junction. Spontaneous resolution of mildly dilated renal pelves may therefore occur as fetal age advances. The probability of spontaneous resolution would be expected to decrease as the scan-to-delivery interval shortens (i.e., persistent renal pelvic dilatation during the third trimester
is more likely to represent a clinically significant problem, thereby reducing the observed false-positive rate). As acknowledged in our article, the study population included all cases in which hydronephrosis was suspected by gross ultrasonographic appearance. This entry criterion was nebulous by necessity because the quantitative criteria for defining significant renal pyelectasis had not been previously established. Finally, the incidence of congenital hydronephrosis will vary, depending on the method of ascertainment. The incidence of 1 in 330 referenced in the introduction of our article was derived from a population of low-risk patients. In our own high-risk referral population, 1 in every 45 fetuses is found to have an aIlleroposterior renal pelvic diameter that exceeds the thresholds advocated in our article. The incidence of hydronephrosis as confirmed by postnatal evaluation is approximately 1 in 66. In summary. we believe that the standards established by our study enhance diagnostic accuracy and provide sound guidelines for the management of this common ultrasonographic finding. Jane E. Cortevilll', MD Genetics DWlSion, Departmmt of Obstetrics and Gynecology, Washington Univl'T.lity School oj Medicine, 216 S. Kmg,lhighway, St. Louis. 1'>1063110
Hemorrhagic endovasculltls of the placenta and fetomaternal hemorrhage: A relationship? To the Editors: Novak et al. (Novak PM, Sander M, Yang SS, von Oeyen PT. Report of fourteen cases of nonimmune hydrops fetalis in association with hemorrhagic endovasculitis of the placenta. AM.J OBSTET Gyi':ECOL 1991; 165:945-50) reported a series of \4 cases of llonimmune hydrops fetalis associated with hemorrhagic endovasculitis of the placenta. In 1989 we reported a series of 66 cases of fetal death, three of which were determined to be associated with a massive fetomaternal hemorrhage.' While a placental pathologic examination was available in only two of these three cases, one showed hemorrhagic endovasculitis. The relationship between fetomaternal hemorrhage and nonimmune hydrops fetal is has been well established. and it has been suggested that a fetal cell stain be performed as part of the evaluation of nonimmune hydrops.2 Therefore we are inquiring as to whether any of these patients with nonimmune hydrops and hemorrhagic endovasculitis had experienced a significant fetomalernal hemorrhage? John OWf1l, MD J)epU1tmmt oj Obstetncs and Gynecolol{l', Unil'e1.\/tv oj Alabama at Binmnghllm, L'AB Station, Binningham. AL 35233-7333
REFERENCES I. Owen./, Stedman eM, Tucker '1'1.. Comparison of predelivery versus postdelivery Klcihauer-Betke staiIlS ill cases of fetal death. AM.I OBSTH GY!':ECOL 1989: 161 :663-6. 2. Warsof SL, :'I:icolaides KII, Rodeck C. Immune and nonimmune hydrops. C1in Obstet Gynecol 19H6:29:533-42.