Collier's sign

Collier's sign, also known as the posterior fossa stare or tucked lid sign, is a clinical sign that indicates a dysfunction in the midbrain, particularly involving the structures responsible for vertical gaze. This sign is characterized by bilateral eyelid retraction, giving the appearance of a fixed and wide-eyed stare. It is often associated with lesions in the dorsal midbrain and can be a hallmark of Parinaud's syndrome, a condition that affects the ability of the eyes to move properly, especially in the vertical direction.

Etiology

Collier's sign can be caused by various conditions that affect the midbrain, including stroke, tumors, multiple sclerosis, and hydrocephalus. The midbrain contains crucial structures for vertical eye movement, and damage to these areas can lead to the characteristic eyelid retraction seen in Collier's sign.

Pathophysiology

The pathophysiology of Collier's sign involves disruption of the neural pathways in the midbrain that control eyelid position and eye movement. The rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF) and the interstitial nucleus of Cajal (INC) are particularly important in this regard. These nuclei coordinate vertical eye movements and eyelid opening. Lesions in these areas can lead to a loss of coordination between the movements of the eyes and the eyelids, resulting in the retracted eyelids characteristic of Collier's sign.

Clinical Presentation

Patients with Collier's sign may present with a variety of symptoms related to impaired vertical gaze, including difficulty looking up or down, double vision (diplopia), and the distinctive eyelid retraction. This sign is often observed alongside other signs of Parinaud's syndrome, such as convergence-retraction nystagmus and light-near dissociation of the pupils.

Diagnosis

The diagnosis of Collier's sign is primarily clinical, based on the observation of the characteristic eyelid retraction and associated symptoms. Neuroimaging, such as MRI or CT scan, may be used to identify the underlying cause of the midbrain dysfunction, such as a tumor or stroke.

Treatment

Treatment of Collier's sign focuses on addressing the underlying cause of the midbrain dysfunction. This may involve surgical intervention for tumors, management of hydrocephalus, or treatment of other conditions like multiple sclerosis. Symptomatic treatment may also be provided to help manage the effects of impaired vertical gaze.

Prognosis

The prognosis for patients with Collier's sign depends on the underlying cause of the midbrain dysfunction. Early detection and treatment of the cause can improve outcomes, but some patients may have persistent difficulties with vertical gaze and eyelid position.

See Also

• Parinaud's syndrome
• Midbrain
• Vertical gaze palsy
• Neuro-ophthalmology