Clinical Spectrum, Management and Short-Term Outcomes of Congenital Central Nervous System Anomalies in Children: A Four-Year Retrospective Study from South-West Nigeria

1. Introduction

Congenital central nervous system (CNS) anomalies are structural abnormalities of the brain, spinal cord and related structures that arise during embryogenesis and remain important causes of childhood neurological disability, morbidity and mortality. Common lesions include hydrocephalus, neural tube defects such as myelomeningocele and meningocele, encephalocele, anencephaly, Dandy–Walker malformation and agenesis of the corpus callosum.(Eke et al., 2016; Ogunleye et al., 2023)

The burden of congenital CNS anomalies is particularly important in low- and middle-income settings, where limited prenatal diagnosis, inadequate specialist services and incomplete birth-defect surveillance may contribute to delayed recognition and under-reporting.(Eke et al., 2016; Ogunleye et al., 2023) Neural tube defects remain an important public health concern despite evidence that adequate periconceptional folic acid supplementation reduces their occurrence.(Adeleye and Olowookere, 2009)

Previous Nigerian reports have described hydrocephalus and neural tube defects among the predominant congenital neurosurgical conditions encountered in children.(Eke et al., 2016; Joel-Medewase and Adeleye, 2015; Obu et al., 2012; Adeyemo et al., 1994; Alatise et al., 2006; Ohaegbulam and Saddeqi, 1979) Clinical presentation varies according to the anomaly and may include progressive head enlargement, developmental delay, seizures, cranial or spinal swellings and neurological deficits.(Eke et al., 2016; Joel-Medewase and Adeleye, 2015; Obu et al., 2012)

Late presentation and barriers to specialist care remain important challenges in many resource-limited settings. Financial constraints, inadequate antenatal care, delayed referral, poor access to diagnostic services and social factors may influence when affected children reach specialist centres.(Komolafe et al., 2008; Bankole et al., 2012)

Although congenital CNS anomalies have been described in several Nigerian centres, published data from Ekiti State remain limited. Local data are important for describing the spectrum of disease managed at a tertiary referral centre and for informing preventive counselling, antenatal services, early recognition and paediatric neurosurgical planning. This study therefore evaluated the clinical spectrum, pattern, management and short-term outcomes of congenital CNS anomalies among children managed at EKSUTH over a four-year period.

2. Methods

2.1 Study design and setting

This was a retrospective descriptive hospital-based study of children with congenital CNS anomalies managed at Ekiti State University Teaching Hospital (EKSUTH), Ado-Ekiti, South-West Nigeria. EKSUTH is a tertiary healthcare institution providing neurosurgical, paediatric, neonatal and obstetric services and serving patients from Ekiti State and neighbouring areas.

2.2 Study period

The records reviewed covered the four-year period from January 2022 to December 2025. Data extraction and record review were undertaken over four months, from April to July 2026.

2.3 Study population and case identification

The study population comprised children aged 0–18 years with documented congenital CNS anomalies who were managed at EKSUTH during the review period. Eligible cases were identified retrospectively from neurosurgical, paediatric, neonatal, ward admission, theatre and medical records. All consecutive patients meeting the eligibility criteria and having sufficiently complete records for the variables analysed were included. A total of 51 eligible patients were identified.

2.4 Eligibility criteria

Children aged 0–18 years with a documented congenital CNS anomaly and available clinical records were eligible. Patients with acquired neurological disorders, uncertain diagnoses or records insufficient to establish the diagnosis or major clinical variables were excluded.

2.5 Diagnostic classification

For analysis, congenital CNS diagnoses were treated as mutually exclusive principal diagnostic categories as recorded in the clinical records. Congenital hydrocephalus, myelomeningocele, hydrocephalus associated with myelomeningocele, encephalocele, meningocele, Dandy–Walker malformation and agenesis of the corpus callosum were reported as separate categories. The combined hydrocephalus–myelomeningocele category was therefore not counted again within the separate hydrocephalus or myelomeningocele categories.

2.6 Data collection

Data were extracted using a structured data-extraction proforma from case notes, admission records, operative records, radiological reports and discharge summaries. Variables included age, sex, residence, maternal and perinatal characteristics, clinical presentation, congenital CNS diagnosis, treatment, postoperative complications and documented discharge outcome. Maternal characteristics were analysed descriptively because the study did not include a comparison group and therefore could not estimate relative risks for congenital CNS anomalies.

2.7 Outcome definitions

The principal short-term outcome was clinical status at discharge as documented by the treating team. Patients were classified according to the documented discharge outcome as improved, died in hospital, or discharged against medical advice. Where the discharge outcome could not be established from the available records, it was classified as not documented. Subsequent loss to follow-up was treated as a separate post-discharge observation and was not considered a mutually exclusive discharge outcome. Postoperative complications were recorded when documented in the medical record.

2.8 Statistical analysis

Data were entered into and analysed using IBM SPSS Statistics version 25.0 (IBM Corp., Armonk, NY, USA). Categorical variables were summarised using frequencies and percentages. Associations between principal anomaly category and selected clinical presentations were assessed using the chi-square test or Fisher’s exact test, as appropriate. Because the sample was small and the study was descriptive, no multivariable modelling was undertaken. Statistical significance was set at p < 0.05.

2.9 Ethical considerations

Ethical approval was obtained from the Research and Ethics Committee of Ekiti State University Teaching Hospital, Ado-Ekiti. The study used existing medical records and involved no direct patient intervention. Extracted data were anonymised and personal identifiers were excluded from the analytical dataset. The study was conducted in accordance with applicable institutional ethical requirements.

3. Results

3.1 Demographic characteristics

A total of 51 children with congenital CNS anomalies were included. Twenty-seven (52.9%) were neonates and 15 (29.4%) were aged 1–12 months. Seven (13.7%) were aged 1–5 years and two (3.9%) were older than five years. There was a male predominance, with 31 (60.8%) males and 20 (39.2%) females. Thirty-three children (64.7%) lived in urban areas and 18 (35.3%) lived in rural communities.

3.2 Spectrum of congenital CNS anomalies

Congenital hydrocephalus was the most frequently recorded principal diagnostic category, occurring in 22 (43.1%) children. Myelomeningocele accounted for 13 (25.5%) cases, while hydrocephalus associated with myelomeningocele was recorded in seven (13.7%). Encephalocele occurred in five (9.8%), meningocele in two (3.9%), and Dandy–Walker malformation and agenesis of the corpus callosum in one (2.0%) child each. The categories were mutually exclusive for the purpose of Table 2.

3.3 Clinical presentation

Progressive head enlargement was the most frequent presenting feature, occurring in 30 (58.8%) children. Swelling over the spine or skull occurred in 19 (37.3%), while developmental delay was documented in 16 (31.4%). Lower-limb weakness or paralysis occurred in 13 (25.5%) children, seizures in 10 (19.6%), feeding difficulty in eight (15.7%), urinary or faecal incontinence in seven (13.7%), and visual impairment in five (9.8%). Presentations were not mutually exclusive.

Values are presented as frequency (percentage). Clinical presentations were not mutually exclusive; therefore, percentages do not necessarily sum to 100%.

3.4 Maternal and perinatal characteristics

Among the mothers of affected children, 44 (86.3%) had no documented preconception folic acid use and 35 (68.6%) commenced folic acid late. No documented antenatal care attendance was recorded for 29 (56.9%) mothers. Low socioeconomic status was documented in 33 (64.7%) families, while maternal febrile illness during pregnancy and herbal medication exposure were documented in 14 (27.5%) and 11 (21.6%) cases, respectively. Sixteen (31.4%) children were delivered at home or by a traditional birth attendant. These variables are reported descriptively and should not be interpreted as independently established risk factors because the study had no unaffected comparison group.

Values are presented as frequency (percentage). Characteristics were not mutually exclusive and were derived from available medical records.

3.5 Relationship between principal anomaly category and clinical presentation

Progressive head enlargement was strongly associated with the principal anomaly category and occurred in 20 (90.9%) children in the congenital hydrocephalus group (p < 0.001). Swelling over the spine or skull was significantly associated with anomaly category and was present in 12 (92.3%) children with myelomeningocele and all five children with encephalocele (p < 0.001). Lower-limb weakness or paralysis occurred in 11 (84.6%) children with myelomeningocele (p < 0.001). Developmental delay also varied significantly across anomaly categories (p = 0.041), whereas seizure occurrence did not (p = 0.182). For this analysis, the seven children with hydrocephalus associated with myelomeningocele were included in the 'Others' category to preserve mutually exclusive diagnostic groups.

Values are frequency (percentage within each diagnostic category). P-values were obtained using the chi-square test or Fisher’s exact test, as appropriate. The 'Others' category comprised hydrocephalus with myelomeningocele, meningocele, Dandy–Walker malformation and agenesis of the corpus callosum.

3.6 Management, complications and short-term outcomes

Surgical intervention was performed in 40 (78.4%) children. Ventriculoperitoneal shunt insertion was recorded in 22 (43.1%) and neural tube defect repair in 14 (27.5%). Conservative management was documented in 11 (21.6%) children. These management categories were not mutually exclusive because some children underwent more than one intervention or had conservative care during part of their clinical course. Postoperative complications occurred in nine (17.6%) children, including wound infection in four (7.8%) and cerebrospinal fluid leakage in three (5.9%). At discharge, 37 (72.5%) children were documented to have improved, six (11.8%) died and three (5.9%) were discharged against medical advice. The discharge outcome was not documented sufficiently to classify five (9.8%) children into these three categories. Separately, eight (15.7%) children were subsequently documented as lost to follow-up; this was treated as a post-discharge observation rather than a discharge outcome.

Management categories and postoperative complications were not mutually exclusive. CSF, cerebrospinal fluid. Loss to follow-up was assessed separately from discharge outcome.

4. Discussion

This four-year retrospective study describes the clinical spectrum, management and short-term outcomes of children with congenital CNS anomalies managed at a tertiary hospital in South-West Nigeria. The principal findings were the predominance of congenital hydrocephalus and neural tube defects, a high proportion of neonatal and infant presentations, frequent presentation with progressive head enlargement or craniospinal swelling, a substantial requirement for surgery, and appreciable short-term mortality. The study also identified a high frequency of documented gaps in periconceptional folic acid use and antenatal care among mothers of affected children.

The predominance of hydrocephalus and neural tube defects is consistent with previous reports in our environment describing these conditions among the common congenital neurosurgical disorders encountered in children.(Eke et al., 2016; Joel-Medewase and Adeleye, 2015; Obu et al., 2012; Adeyemo et al., 1994; Alatise et al., 2006; Ohaegbulam and Saddeqi, 1979) Differences in the relative proportions reported between centres may reflect differences in referral patterns, case ascertainment, diagnostic capacity and the organisation of paediatric neurosurgical services. Because this was a tertiary-centre study, the distribution should be interpreted as the spectrum of cases reaching EKSUTH rather than as an estimate of population prevalence.

More than half of the children presented during the neonatal period, and nearly one-third were infants. This age distribution is clinically plausible because several congenital CNS anomalies produce visible or progressive abnormalities early in life. Progressive head enlargement was the commonest presenting feature and was strongly associated with the congenital hydrocephalus category. Similarly, craniospinal swelling was strongly associated with myelomeningocele and encephalocele, while lower-limb weakness or paralysis was particularly common among children with myelomeningocele. These findings reflect the characteristic clinical manifestations of the principal diagnostic groups and support the value of early recognition by caregivers and frontline healthcare workers.

A male predominance was observed in this series. Similar male predominance has been described in some Nigerian studies, although the biological basis for sex differences in the occurrence or presentation of congenital CNS anomalies remains uncertain.(Joel-Medewase and Adeleye, 2015; Obu et al., 2012) The small sample and referral-centre design make it inappropriate to draw firm conclusions regarding sex-specific susceptibility from the present study.

A high proportion of mothers had no documented preconception folic acid use or had commenced supplementation late, and more than half had no documented antenatal care. These findings are important from a preventive health perspective because periconceptional folic acid supplementation and appropriate antenatal care are established components of maternal and fetal health programmes.(Adeleye and Olowookere, 2009; Ekanem et al., 2008) However, the present study cannot establish that these characteristics caused the congenital anomalies because there was no unaffected comparison group. They should therefore be regarded as descriptive findings that warrant further investigation rather than as quantified risk factors.

The study also documented low socioeconomic status, maternal febrile illness and herbal medication exposure in a proportion of mothers. These findings may be relevant to future research, but their interpretation requires caution because retrospective medical records may contain incomplete or inconsistent documentation, and information about timing, dose and duration of exposures may be unavailable. Prospective case-control or population-based studies would be more appropriate for evaluating their independent contribution to congenital CNS anomalies.

Most children underwent surgical intervention, reflecting the substantial operative burden associated with congenital hydrocephalus and neural tube defects. Ventriculoperitoneal shunting was the most frequently documented procedure, while neural tube defect repair was also common. The postoperative complication rate of 17.6% and in-hospital mortality of 11.8% indicate that these patients remain clinically vulnerable despite access to surgical treatment. Previous Nigerian reports have also documented significant morbidity and mortality in children with congenital neurosurgical conditions.(Joel-Medewase and Adeleye, 2015; Obu et al., 2012; Adeyemo et al., 1994; Alatise et al., 2006; Ohaegbulam and Saddeqi, 1979)

Loss to follow-up was documented in 15.7% of children after discharge. In a setting where long-term neurological and developmental outcomes are important, incomplete follow-up limits the ability to determine the functional consequences of congenital CNS anomalies and the durability of treatment. Financial constraints, transportation difficulties, caregiver burden and access to specialist services may contribute, although these factors were not directly measured in the present study. Future studies should incorporate structured follow-up and objective developmental and neurological outcome measures.

The findings have practical implications for both prevention and service delivery. Strengthening maternal health education, ensuring access to periconceptional folic acid, improving antenatal attendance and prenatal ultrasound services, and establishing efficient referral pathways may facilitate earlier recognition of congenital anomalies. At the tertiary level, sustained access to paediatric neurosurgical, neonatal, anaesthetic and postoperative support is essential for timely management. These recommendations should be regarded as health-service implications of the observed pattern rather than causal conclusions from this retrospective series.

4.1 Strengths and limitations

A strength of this study is that it provides local data from a tertiary hospital in a region where published information on congenital CNS anomalies is limited. The four-year review period captured a range of congenital CNS diagnoses and included information on presentation, management and short-term outcomes. The analysis of relationships between principal anomaly categories and selected clinical presentations also adds clinical context to the descriptive findings.

The study has several limitations. Its retrospective design limited the analysis to information documented in existing medical records and therefore introduced the possibility of missing or inconsistently recorded variables. The sample was small and derived from a single tertiary referral centre, limiting generalisability and creating potential referral and selection bias. The study cannot estimate the population prevalence or incidence of congenital CNS anomalies. Maternal characteristics were descriptive because there was no unaffected comparison group, and causal inferences regarding folic acid use, antenatal care, socioeconomic status or other exposures cannot be made. Detailed environmental, genetic, nutritional and exposure data were not consistently available. Finally, long-term neurological and developmental outcomes could not be reliably assessed because follow-up was incomplete.

5. Conclusion

Congenital CNS anomalies remain an important cause of paediatric neurosurgical morbidity at EKSUTH. Congenital hydrocephalus, myelomeningocele and related neural tube defects constituted the principal diagnostic categories, while progressive head enlargement, craniospinal swelling, developmental delay and lower-limb neurological deficits were prominent clinical manifestations. Most children required surgical treatment, but postoperative complications and in-hospital mortality remained substantial, and a proportion were subsequently lost to follow-up.

The high frequency of absent or late periconceptional folic acid use and inadequate antenatal care documented among mothers of affected children highlights important opportunities for preventive and antenatal health interventions, although these observations should not be interpreted as causal risk estimates. Strengthened preconception counselling, access to folic acid, antenatal care, prenatal detection, timely referral and comprehensive paediatric neurosurgical services may improve care. Prospective multicentre studies with appropriate comparison groups and structured long-term follow-up are needed to define population-level risk factors and functional outcomes.

Declarations

Authors' contributions

All authors contributed to the conception and design of the study, interpretation of the data, drafting or critical revision of the manuscript, and approval of the final version.

Acknowledgements

The authors acknowledge the support of the medical, nursing and records staff of the Children Emergency Department, Paediatric Ward, Neonatal Intensive Care Unit and Neurosurgical Outpatient Clinic of Ekiti State University Teaching Hospital, Ado-Ekiti, Ekiti State.

Ethical approval

Ethical approval was obtained from the Research and Ethics Committee of Ekiti State University Teaching Hospital, Ado-Ekiti, Nigeria. Patient confidentiality was maintained by anonymising extracted data and excluding personal identifiers from the analytical dataset.

Consent for publication

Not applicable. The study was based on retrospective review of anonymised medical records.

Competing interests

The authors declare no competing interests.

Funding

This research received no external funding.

Data availability

The datasets generated and analysed during the study are available from the corresponding author on reasonable request, subject to institutional confidentiality requirements.