Ultrasound Diagnosis of Anencephaly

A Case Report

Introduction

Anencephaly is a severe neural tube defect (NTD) characterized by the absence of the fetal cranial vault (calvarium) and cerebral hemispheres, with exposed brain tissue. It is a fatal condition, and most affected pregnancies result in stillbirth or neonatal death shortly after delivery. Early detection through ultrasound is crucial for appropriate counseling and management.

This case report describes a 28-year-old female, gravida 2 para 1+0, at approximately 20 weeks of gestation, who was referred for a routine fetal anatomical scan. The ultrasound findings were consistent with anencephaly, leading to a structured management plan.

Case Presentation

Patient History

• Age: 28 years

• Obstetric History: G2P1+0

• Gestational Age: ~20 weeks

• Presenting Complaint: Routine second antenatal visit, reported fetal movements

• General Condition: Good, afebrile, no signs of anemia, jaundice, or edema

• Vital Signs:

  • BP: 115/83 mmHg

  • Pulse: 97 bpm

  • Respiratory Rate: 18 breaths/min

  • SpO₂: 98% (room air)

• Abdominal Examination:

  • Fundal height: 20/40

  • Soft, non-tender, no organomegaly

Ultrasound Findings

• Fetal Presentation: Oblique

• Fetal Heart Rate (FHR): 157 bpm

• Estimated Fetal Weight (EFW): 381.4g (±61.03g)

• Gestational Age (AGA): 20 weeks 5 days

• Placenta: Fundal, intact with uterine wall

• Amniotic Fluid: Adequate (DVP: 7.56 cm)

• Key Abnormal Findings:

  • Absent calvarium (missing skull bones)

  • Exposed brain tissue (partially destroyed due to amniotic fluid exposure)

  • Frog-like facial appearance (due to absent forehead and prominent orbits)

Laboratory Findings

• Blood Group: A+

• Complete Blood Count (CBC):

  • Hemoglobin (Hb): 10.4 g/dL

  • Platelets: 113 x10³/µL

  • White Blood Cells (WBC): 3.8 x10³/µL

• Bleeding Time: 2 minutes 34 seconds

• Clotting Time: 7 minutes 45 seconds

Ultrasound Report & Conclusion

Report:

• Single live intrauterine fetus in oblique presentation.

• Absent calvarium with exposed brain tissue (anencephaly).

• Frog-like facies noted (characteristic of anencephaly).

• Normal cardiac activity (FHR: 157 bpm).

• Placenta: Fundal, no evidence of abruption.

• Amniotic fluid volume: Normal (DVP: 7.56 cm).

• No other structural abnormalities detected.

Conclusion:

The ultrasound findings are diagnostic of anencephaly, a lethal congenital anomaly. Given the poor prognosis, counseling regarding termination of pregnancy was provided.

Management Plan

1. Counseling: Detailed discussion with the couple regarding the diagnosis, prognosis, and options.

2. Admission: Admitted to the gynecology ward for further management.

3. Termination of Pregnancy (TOP):

   • Cervical ripening: Dinoprostone 2mg vaginal insert.

   • Antibiotic prophylaxis: Flucamox (Amoxicillin) 500mg + Metronidazole 400mg TDS for 5 days.

4. Follow-up: Post-procedure monitoring and psychological support.

Discussion

Anencephaly is a fatal condition with no chance of survival postnatally. Early detection via ultrasound allows for timely intervention, reducing maternal physical and emotional distress. The absence of the calvarium and exposed brain tissue are pathognomonic findings.

Key Takeaways:

• Prenatal ultrasound is diagnostic.

• Termination is often recommended due to the poor prognosis.

• Genetic counseling should be offered for future pregnancies, including folic acid supplementation to reduce recurrence risk.

Final Thoughts

This case highlights the importance of detailed mid-trimester anomaly scans in detecting severe fetal malformations. Early diagnosis enables informed decision-making, ensuring optimal maternal care and psychological support.

Disclaimer:

This case report is for educational purposes only. Management should always be tailored to individual patient needs under medical supervision.