Cranial Nerve Injury
Cranial nerve injury can result from hyperextension, traction, and overstretching with simultaneous rotation. Neurapraxia will resolve swiftly but complete nerve or cord transection is a much more serious matter.
Consequences of cranial nerve injury:
- Central damage to the facial and vagus nerves cause an asymmetrical face on crying with swelling and smoothness of the affected side and drooping of the side of the mouth.
- Peripheral damage from a cranial nerve injury causes paralysis to the eye, forehead or mouth only.
- In most cases children affected soon start to recover but full recovery may take months.
- The eye must be protected with a covering and synthetic tears.
- If there is no improvement after 7 to 10 days, investigation is required. Phrenic nerve damage can cause paralysis of half of diaphragm leading to breathing difficulties with significant mortality. Ultrasound or X-ray shows an elevated hemidiaphragm but this may be absent in the early stages. Screening may show immobility.
- 80% of phrenic nerve palsies are on the right side, 10% on the left side and 10% are bilateral.
- With a cranial birth injury there is a mortality rate of 10 to 15% for unilateral lesions rising to 50% for bilateral ones.