Horner's Syndrome

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | References

Definition

Horner's syndrome is a rare condition characterised by a combination of signs and symptoms caused by the disruption of the sympathetic nerves supplying the eye and surrounding facial muscles. It results in ptosis (drooping of the upper eyelid), miosis (constriction of the pupil), and anhidrosis (loss of sweating) on the affected side of the face.

Aetiology

Horner's syndrome can result from various underlying causes that affect the sympathetic pathway, including:

• Stroke or brainstem lesions
• Spinal cord injury or tumours
• Neck trauma or surgery
• Carotid artery dissection
• Lung cancer (particularly Pancoast tumour)
• Cluster headaches

Pathophysiology

The sympathetic pathway to the eye involves three neurons:

• First-order neurons originate in the hypothalamus and descend to the spinal cord.
• Second-order neurons exit the spinal cord and ascend through the sympathetic chain to the superior cervical ganglion.
• Third-order neurons travel along the internal carotid artery to the eye and surrounding facial structures.

Risk Factors

• History of neck or chest trauma
• Known malignancies, especially lung cancer
• Vascular conditions such as carotid artery dissection
• Neurological conditions that affect the brainstem or spinal cord

Signs and Symptoms

Common signs and symptoms of Horner's syndrome include:

• Ptosis (drooping of the upper eyelid)
• Miosis (constriction of the pupil)
• Anhidrosis (loss of sweating) on the affected side of the face
• Enophthalmos (sunken appearance of the eye)

Investigations

• Clinical history and physical examination
• Pharmacological tests:
  • Cocaine test to confirm Horner's syndrome (affected pupil does not dilate)
  • Apraclonidine test to confirm Horner's syndrome (affected pupil dilates)
• Imaging studies:
  • MRI or CT scan of the brain, neck, and chest to identify the underlying cause
  • Carotid ultrasound if carotid artery dissection is suspected

Management

Primary Care Management

• Referral to a specialist: Immediate referral to a neurologist or ophthalmologist for further evaluation and management

Specialist Management

• Treatment of underlying cause: Management is focused on addressing the underlying condition causing Horner's syndrome (e.g., surgery for tumours, anticoagulation for carotid artery dissection)
• Regular follow-up to monitor the condition and manage any complications

References

1. Patient.info. (2024). Horner's Syndrome. Retrieved from Patient.info
2. NHS. (2023). Horner's Syndrome. Retrieved from NHS
3. British Medical Journal (BMJ). (2022). Horner's Syndrome: Diagnosis and Management. Retrieved from BMJ
4. American Academy of Ophthalmology (AAO). (2021). Clinical Practice Guidelines: Horner's Syndrome. Retrieved from AAO

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