|Year : 2019 | Volume
| Issue : 4 | Page : 148-151
Sonographic diagnosis of fetal meningomyelocele in an obese patient: Report of a case
Ernest Ruto Upeh1, Olaolopin Ijasan2, Cletus Uche Eze3
1 Department of Radiology, Ave Maria Hospital, Victoria Island, Lagos, Nigeria
2 Department of Obstetrics and Gynaecology, Ave Maria Hospital, Victoria Island, Lagos, Nigeria
3 Department of Radiography, Faculty of Clinical Sciences, College of Medicine of The University of Lagos, Yaba Campus, Lagos, Nigeria
|Date of Web Publication||22-Oct-2019|
Mr. Ernest Ruto Upeh
Department of Radiology, Ave Maria Hospital, Victoria Island, Lagos
Source of Support: None, Conflict of Interest: None
Meningomyelocele and meningocele are common neural tube defects in developing countries. Risk factors include poor sensitization of intending mothers on preconception folic acid use, maternal obesity, hyperthermia from malaria, and high pollution levels. Some of the problems associated with this condition include lack of dedicated spinal bifida clinics, expensive treatment, the social stigma associated with the condition, and poor awareness about the condition among local physicians. This has led to poor management outcomes. A multidisciplinary approach involving neonatologists/pediatricians, obstetricians, neurosurgeons, radiologists, psychologists, and physiotherapists is necessary to optimize patient outcome.
Keywords: Meningomyelocele, neural tube defect, obesity, spina bifida
|How to cite this article:|
Upeh ER, Ijasan O, Eze CU. Sonographic diagnosis of fetal meningomyelocele in an obese patient: Report of a case. J Clin Sci 2019;16:148-51
| Introduction|| |
Myelomeningocele is the most common type of neural tube defects (NTDs) in Nigeria, and incidence rates of 2.75–7/1000 births have been reported. It is known to account for 5.7% of neurosurgical admissions in Nigeria. Screening methods employed in identifying NTDs include second-trimester maternal serum alpha-fetoprotein levels, amniocentesis, and fetal ultrasonographic evaluations. Immediately an NTD is detected, families are counseled on the various management options available including possible termination of pregnancy, an in utero surgery, and referral to a dedicated or tertiary facility for proper management and delivery. Therefore, optimal care of the obstetric patient and fetus is based on the understanding of the practicing obstetrician in employing the complex diagnostic and management options available.
There are two types of NTDs: closed or open defects. In closed NTDs, there is an incomplete closure of the spinal column due to a bony vertebral defect; nerve tissue is covered by the skin and not exposed outside the body. In contrast, open NTDs involve neural tube exposure through spinal cord or skull defects, and present as a meningocele or meningomyelocele (MMC). The meningocele involves the protrusion of a fluid-filled sac containing the meninges only. On the other hand, the spinal cord contents and its meninges are seen within a sac filled with cerebrospinal fluid protruding through a gap in the vertebral arches in MMC. It has been reported that MMC is the most common NTD and the severest birth defect compatible with long-term survival.
Several studies have identified maternal obesity as one of the leading risk factors for congenital heart and NTDs. Mechanisms postulated for this include changes in maternal hormone levels, altered gene expression, fetal epigenetic modification, undiagnosed gestational diabetic mellitus, and defective folic acid metabolism., Other maternal and environmental risk factors include maternal alcohol use; caffeine use; elevated glycemic index; low levels of zinc, Vitamin C, Vitamin B12, and choline; smoking; low socioeconomic status; infections; and stress. Environmental factors postulated to contribute to increased risk include air pollution, disinfectant by-products in drinking water, exposure to organic solvents, pesticides, nitrate-related compounds, and polycyclic aromatic hydrocarbons.
Over the years, MMC has led to a lifelong and devastating physical disability. In patients with a lumbosacral spina bifida, problems include motor and sensory dysfunction in the lower extremities, anorectal and urinary bladder malfunctions, sexual dysfunction, various skeletal deformations, endocrine disorders, and orthopedic issues such as clubfoot.,, Until a decade ago, the treatment of MMC consisted of surgical closure of the spinal canal at birth and lifelong supportive care. Recent reports of in utero mid-trimester fetal repair suggest that this novel approach may improve neurologic function and reduce morbidity from hydrocephalus and Arnold–Chiari II malformation. Children who have undergone fetal MMC closure before 26 weeks of gestation may preserve neuromotor function, reverse hindbrain herniation, and reduce the need for ventriculoperitoneal shunting. Intermittent catheterization is often essential for individuals with a myelomeningocele and neurogenic bladder.
| Case Report|| |
We report the case of a 27-year-old primigravida who presented to our center at an estimated gestational age of 29 weeks for routine antenatal care. There was a background history of chronic hypertension. She was on antihypertensive medications and routine antenatal supplements. On presentation, her weight was 157 kg, with a body mass index (BMI) of 56 kg/m 2. Her prepregnancy weight was said to be 135 kg. She was deemed high risk on account of our assessment of chronic hypertension in pregnancy and morbid obesity. Previous scans including anomaly review done in another center before presentation to us were said to have been within normal limits. However, transabdominal scan done at our center was suggestive of lumbosacral myelomeningocele and ventriculomegaly [Figure 1]a, [Figure 1]b, [Figure 1]c and [Figure 2]a, [Figure 2]b. The sonogram showed evidence of an open NTD with splayed echogenic posterior elements. The lateral ventricles were dilated and measured 20 mm in diameter. She was appropriately counseled about her findings and suggested a plan of management. An oral glucose tolerance test done to rule out gestational diabetes mellitus was within normal limits.
|Figure 1: (a) Sonogram showing transverse section through the meningomyelocele at the level of the femur. (b) Sonogram showing transverse section through the meningomyelocele at the level of the kidneys with evidence of echogenic splayed posterior elements. (c) Sonogram showing a sagittal section through the meningomyelocele with visualization of the spine|
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|Figure 2: (a and b) Sonograms of the head circumference showing dilated lateral ventricles|
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The rest of the antenatal period was uneventful. She had an elective cesarean section at 38 weeks and was delivered of a live female neonate, with birth weight of 3.2 kg, with an 8 cm × 6 cm MMC [Figure 3]a and [Figure 3]b. No other abnormalities were detected. Chest X-ray and abdominal scans of the neonate were unremarkable. She had an MMC repair [Figure 3]c done by the neurosurgeon on the 5th day of life. She also had a ventriculoperitoneal shunt inserted a week after because of increasing occipitofrontal circumference. Subsequent neonatal scans showed increasing ventriculomegaly (30 mm in anteroposterior diameter) at 15 days of life [Figure 4]a and [Figure 4]b.
|Figure 3: (a) Neonate with meningomyelocele immediately after birth. (b) Neonate with meningomyelocele 2 h after birth, meningomyelocele was observed to be distended with cerebrospinal fluid. (c) Meningomyelocele repair done by the neurosurgeon on the 5th day of life|
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|Figure 4: (a) Sonogram showing sagittal section showing neonatal dilated lateral ventricles at day 15. (b) Sonogram showing coronal section showing neonatal dilated lateral ventricles at day 15|
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| Discussion|| |
The critical period of neural tube formation is the first 4 weeks of gestational life, which is why it is suggested that intending mothers should be on 400 μg daily folic acid regimen 3 months before conception and till at least the 12th week of pregnancy. Women who have had previous babies with NTDs or that are on anti-epileptic medications should be on a 5-mg daily regimen of folic acid. In a developing country like ours, a policy of routine folic acid supplementation as outlined above would be even more difficult to implement due to high poverty levels, poor health-care infrastructure, and high prevalence of unplanned pregnancies. While our patient did not take folic acid before conception, she was on daily folic acid regimen throughout pregnancy, but we are of the view that the overall dose of folic acid was probably not enough for uneventful outcome in the case being reported.
Obese pregnant women are at an increased risk for an array of maternal and perinatal complications, and the risks are amplified if maternal obesity increases as pregnancy advances. The adverse effect of excessive weight gain is so notorious that it has been estimated that one-quarter of pregnancy complications are attributable to maternal overweight/obesity and almost one-third of large-for-gestational age infants are attributable to excessive gestational weight gain. To reduce its effect, it has been suggested that women of childbearing age with a BMI 30 kg/m 2 or greater at booking should receive information and advice about the risks of obesity during pregnancy and childbirth and should be supported to lose weight before conception. A comprehensive meta-analysis has shown that obese pregnant women are at an increased risk of a range of structural anomalies including NTDs and spinal bifida. Mechanisms postulated for this include changes in maternal hormone levels, altered gene expression, fetal epigenetic modification, undiagnosed gestational diabetic mellitus, and defective folic acid metabolism. Screening and diagnostic test for structural anomalies should be offered to all pregnant obese women., In view of this, it is plausible to suggest that excessive maternal weight could have been a major contributing factor to the case being reported. This assertion is supported by the fact that the patient in the present report was morbidly obese (on presentation, her weight was 157 kg and BMI was 56 kg/m 2).
Worldwide, studies have shown a female preponderance in neonates with spina bifida, with the most common location of the lesion being the lumbosacral area. These descriptions aptly fit into the case being reported. It is pertinent to point out that the incidence of spinal defects is more common in women residing in urban areas than in rural dwellers. In fact, the fear that urbanization with its attendant pollution in Lagos, Nigeria, could predispose neonates to an increased risk of congenital malformations has been expressed. It is, therefore, likely that the cause of spinal defect being reported could include poor living conditions associated with urbanization and its attendant problems.
In patients with a congenital spinal defect, the most common neonatal findings are lower limb paralysis, sphincter dysfunction, and hydrocephalus., This was observed in the present case. The aim of treatment of MMC is, therefore, to aid patients with maximum mobility and social continence that is possible through multidisciplinary care. In a developing country where support system for these patients and parents is weak, experience has shown that for an MMC baby to have any chance of living a fruitful life, dedicated medical services must be available. In fact, the importance of the availability of dedicated medical services was amply exemplified in the present report by the synergy between the sonographer, the obstetrician/gynecologist, and the neurosurgeon.
| Conclusion|| |
The management of NTDs can be improved with the prompt intervention of medical professionals involving synergy between sonographers, obstetricians/gynecologists, and neurosurgeons in the prenatal and postnatal management of the abnormality. Maternal factors such as obesity and environmental factors appear to be major contributors to the development of NTDs. Good antenatal care including routine screening for structural anomalies, losing weight before conception and after delivery, as well as compliance with recommended daily intake of folic acid should be encouraged.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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