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Classification of congenital muscular dystrophy
16 6
Editorial correspondence
use of duplex Doppler equipment may improve the accuracy of the method, but we used this type of equipment to compare the results of cardiac output measured by means of thermodilution and Doppler ultrasound in rabbits weighing between 2.2 and 3.3 kg, and obtained remarkably similar results. Correlation coefficients ranged from 0.68 to 0.88. The discrepancy appeared higher for increasing values of cardiac output, and this was confirmed by an analysis of the difference between the paired results compared with their means, as suggested by Bland and Altman. 1 There was a significantly increasing difference for increasing values of cardiac output. The 95% confidence intervals for our results were _+55 ml; for a cardiac output of between 200 and 325 ml/kg/min in neonates of similar size, 2 this error is probably unacceptable. The rapid heart rate of the rabbit (200 to 250 beats/rain) may have explained the increasing discrepancy with higher values, because the sampling rate of the Doppler analysis software was 25 Hz, meaning that more of the peak velocities may have been missed at higher heart rates. The estimation of aortic size was done with M-mode echocardiograpby, which at best is capable of a degree of resolution of the order of 0.5 to 1 ram. Thus an error of 20% in measurement of the area of a vessel 5 mm in diameter is unavoidable. Moreover, the difference between the systolic diameter and the diastolic diameter of the aorta in small babies and children can only be guessed at; it is likely to be higher than the 11% suggested for adults. Thermodilution has its own sources of inaccuracy, but until we can produce better results, we also would counsel against reliance on Doppler estimation of cardiac output in neonatal and pediatric intensive care units.
Janet Rennie, MD, MRCP, DCH Richard Barnes, PhD, MB, ChB Departments of Paediatrics and Physiology University of Cambridge Cambridge CB2 2QQ, England REFERENCES
1. Bland JM, Altman D. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986;1:307-10. 2. Walther F J, Siassi B, Ramadan NA, et al. Pulsed Doppler determinations of cardiac output in neonates: normal standards for clinical use. Pediatrics 1985;76:829-33.
Classification of congenital muscular dystrophy
The Journal of Pediatrics July 1990
cases of typical CMD with normal or borderline intelligence without neurologic abnormality. 1 This finding suggests a considerable amount of overlapping in clinical presentations. 2 An intermediate form between type 1 CMD ("pure" form) and type 2 CMD (Fukuyama) with early hypotonia, preserved intelligence, and white matter hypodensity on CT scan has recently been suggested to be named as "Occidental-type cerebromuscular dystrophy" because this form appears to be prevalent in the W e s t ) We recently reported one case of this particular type, 4 and have data for seven more. These patients invariably have facial involvement, macrocephalic appearance, amy0trophy , and joint contractures. They may have dysmorphic features such as long and thin face, abnormalities of jaw articulations, and high-arched palate. The CT scans show cortical atrophy or marked white matter hyperlucency, or both, usually without ventricular dilation. O n l y one reported patient has been subjected to necropsy. 5 Lesions consisted of degeneration of the myelin sheath, cerebellar hypoplasia, and cortical areas of micropolygyria, cerebral neural loss, and heterotopic nerve cells. We believe that these patients, with their distinct features, should be regarded within the CMD nosology as a separate subgroup.
Haluk Topalo~lu, MD Yavuz Renda, MD Kalbiye Yalaz, MD Kivilcim Giicfiyener, MD Melda ~a~lar, MD Safiye G~fi~, MD Gfilsev Kale, MD Hacettepe University Children's Hospital Ankara, Turkey REFERENCES
1. Echenne B, Arthuis M, Billard C, et al. Congenital muscular dystrophy and cerebral CT scan anomalies. J Neurol Sei 1986; 75:7-22. 2. Yoshioka M, Kuroki S, Mizue H. Congenital muscular dystrophy of non-Fukuyama type with characteristic CT images. Brain Dev 1987;9:316-8. 3. Castro-Gago M, Pena-Guitian J. Congenital Muscular dystrophy of non-Fukuyama type with characteristic CT images [Letter]. Brain Dev 1988;! 0:60. 4. Topalo~lu H, Yalaz K, Kale G, Ergln M. Congenital muscular dystrophy: report of a case of "Occidental-type eerebromuscular dystrophy." Neuropediatrics 1990;21:53-4. 5. Egger J, Kendall BE, Erdohazi M, Lake BD, Wilson J, Brett EM. Involvement of the central nervous system in congenital muscular dystrophies. Dev Med Child Neurol 1983;25:32-42.
To the Editor." Leyten et al., in their article "Congenital Muscular Dystrophy" (J PEDIATR 1989;l 15:214-21 ), suggest that there are two types of congenital muscular dystrophy (CMD) with CNS involvement: (1) the Fukuyama type and (2) "muscle, eye, and brain disease" or "cerebro-ocular dysplasia-muscular dystrophy syndrome." They conclude by classfying patients with CMD as having "pure" CMD, Fukuyama-CMD, or muscle, eye, and brain disease. However, we have evidence for further modification of the CMD nosology. Cerebral CT scan abnormalities have been seen in some
Reply To the Editor." Topalo~lu et al. suggest an intermediate form between the "pure" form of congenital muscular dystrophy (CMD) and the Fukuyarna type of CMD. Their suggestion is based on clinical characteristics and on white matter hypodensities on CT scan. They
Editorial correspondence
use of duplex Doppler equipment may improve the accuracy of the method, but we used this type of equipment to compare the results of cardiac output measured by means of thermodilution and Doppler ultrasound in rabbits weighing between 2.2 and 3.3 kg, and obtained remarkably similar results. Correlation coefficients ranged from 0.68 to 0.88. The discrepancy appeared higher for increasing values of cardiac output, and this was confirmed by an analysis of the difference between the paired results compared with their means, as suggested by Bland and Altman. 1 There was a significantly increasing difference for increasing values of cardiac output. The 95% confidence intervals for our results were _+55 ml; for a cardiac output of between 200 and 325 ml/kg/min in neonates of similar size, 2 this error is probably unacceptable. The rapid heart rate of the rabbit (200 to 250 beats/rain) may have explained the increasing discrepancy with higher values, because the sampling rate of the Doppler analysis software was 25 Hz, meaning that more of the peak velocities may have been missed at higher heart rates. The estimation of aortic size was done with M-mode echocardiograpby, which at best is capable of a degree of resolution of the order of 0.5 to 1 ram. Thus an error of 20% in measurement of the area of a vessel 5 mm in diameter is unavoidable. Moreover, the difference between the systolic diameter and the diastolic diameter of the aorta in small babies and children can only be guessed at; it is likely to be higher than the 11% suggested for adults. Thermodilution has its own sources of inaccuracy, but until we can produce better results, we also would counsel against reliance on Doppler estimation of cardiac output in neonatal and pediatric intensive care units.
Janet Rennie, MD, MRCP, DCH Richard Barnes, PhD, MB, ChB Departments of Paediatrics and Physiology University of Cambridge Cambridge CB2 2QQ, England REFERENCES
1. Bland JM, Altman D. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986;1:307-10. 2. Walther F J, Siassi B, Ramadan NA, et al. Pulsed Doppler determinations of cardiac output in neonates: normal standards for clinical use. Pediatrics 1985;76:829-33.
Classification of congenital muscular dystrophy
The Journal of Pediatrics July 1990
cases of typical CMD with normal or borderline intelligence without neurologic abnormality. 1 This finding suggests a considerable amount of overlapping in clinical presentations. 2 An intermediate form between type 1 CMD ("pure" form) and type 2 CMD (Fukuyama) with early hypotonia, preserved intelligence, and white matter hypodensity on CT scan has recently been suggested to be named as "Occidental-type cerebromuscular dystrophy" because this form appears to be prevalent in the W e s t ) We recently reported one case of this particular type, 4 and have data for seven more. These patients invariably have facial involvement, macrocephalic appearance, amy0trophy , and joint contractures. They may have dysmorphic features such as long and thin face, abnormalities of jaw articulations, and high-arched palate. The CT scans show cortical atrophy or marked white matter hyperlucency, or both, usually without ventricular dilation. O n l y one reported patient has been subjected to necropsy. 5 Lesions consisted of degeneration of the myelin sheath, cerebellar hypoplasia, and cortical areas of micropolygyria, cerebral neural loss, and heterotopic nerve cells. We believe that these patients, with their distinct features, should be regarded within the CMD nosology as a separate subgroup.
Haluk Topalo~lu, MD Yavuz Renda, MD Kalbiye Yalaz, MD Kivilcim Giicfiyener, MD Melda ~a~lar, MD Safiye G~fi~, MD Gfilsev Kale, MD Hacettepe University Children's Hospital Ankara, Turkey REFERENCES
1. Echenne B, Arthuis M, Billard C, et al. Congenital muscular dystrophy and cerebral CT scan anomalies. J Neurol Sei 1986; 75:7-22. 2. Yoshioka M, Kuroki S, Mizue H. Congenital muscular dystrophy of non-Fukuyama type with characteristic CT images. Brain Dev 1987;9:316-8. 3. Castro-Gago M, Pena-Guitian J. Congenital Muscular dystrophy of non-Fukuyama type with characteristic CT images [Letter]. Brain Dev 1988;! 0:60. 4. Topalo~lu H, Yalaz K, Kale G, Ergln M. Congenital muscular dystrophy: report of a case of "Occidental-type eerebromuscular dystrophy." Neuropediatrics 1990;21:53-4. 5. Egger J, Kendall BE, Erdohazi M, Lake BD, Wilson J, Brett EM. Involvement of the central nervous system in congenital muscular dystrophies. Dev Med Child Neurol 1983;25:32-42.
To the Editor." Leyten et al., in their article "Congenital Muscular Dystrophy" (J PEDIATR 1989;l 15:214-21 ), suggest that there are two types of congenital muscular dystrophy (CMD) with CNS involvement: (1) the Fukuyama type and (2) "muscle, eye, and brain disease" or "cerebro-ocular dysplasia-muscular dystrophy syndrome." They conclude by classfying patients with CMD as having "pure" CMD, Fukuyama-CMD, or muscle, eye, and brain disease. However, we have evidence for further modification of the CMD nosology. Cerebral CT scan abnormalities have been seen in some
Reply To the Editor." Topalo~lu et al. suggest an intermediate form between the "pure" form of congenital muscular dystrophy (CMD) and the Fukuyarna type of CMD. Their suggestion is based on clinical characteristics and on white matter hypodensities on CT scan. They