From the Guidelines
Lateral rectus palsy in a 14-year-old is most likely caused by trauma, infection, or neoplasm.
Common Causes
- Trauma: Head injury, basilar skull fracture, or acute rise in intracranial pressure from an intracranial bleed 1
- Infection: Postviral sixth nerve palsy, Lyme disease, or syphilis 1
- Neoplasm: Intracranial neoplasm, such as clival chordoma, or meningeal process 1
Other Possible Causes
- Demyelinating diseases: Multiple sclerosis, which can cause isolated cranial nerve VI palsy or other neurologic findings 1
- Increased intracranial pressure: Papilledema, bilateral sixth nerve palsy, or meningeal signs (stiff neck with headache) 1 It is essential to evaluate the patient for other neurologic changes, such as facial and extremity motor weakness, third- and fourth-cranial nerve involvement, visual field defect, and central acuity loss from optic nerve involvement, IOP, and proptosis to determine the underlying cause of the lateral rectus palsy 1. Neuroimaging, such as MRI of the brain with and without contrast, may be indicated to rule out underlying pathology, especially if there is no compelling vasculopathic risk factor or if the patient is young 1.
From the Research
Causes of Lateral Rectus Palsy
The causes of lateral rectus palsy in a 14-year-old can be attributed to various factors, including:
- Head trauma, which is one of the most common causes of abducens nerve palsy, as the abducens nerve has a tortuous course and is vulnerable to injury, especially as it passes into Dorello's canal or through the cavernous sinus 2
- Orbital and/or facial injuries, which can affect the lateral rectus muscle directly or the orbital course of the abducens nerve, leading to palsy 2
- Mechanical trauma to the orbit, which can cause impingement of the lateral rectus muscle, resulting in a complete loss of abduction 2
- Congenital conditions, such as congenital third-nerve palsy, which can be associated with accessory lateral rectus muscle 3
- Orbital trauma, which can result in isolated orbital "roof blow" in fracture, impingement on the superior rectus muscle, and potentially affect the lateral rectus muscle as well 4
- Surgical complications, such as delayed lateral rectus palsy following resection of a pineal cyst in sitting position, which can be caused by direct or indirect compressive phenomenon 5
- Idiopathic causes, such as recurrent idiopathic lateral rectus muscle palsy, which can occur in adults and adolescents, characterized by ipsilateral recurrence, lack of pain, spontaneous recovery within six months, and no clear cause 6