User:Jbrtn44/Horizontal gaze palsy

Overview
A horizontal gaze palsy is a subtype of gaze palsy in which conjugate, horizontal eye movements are limited by neurologic deficits.

(original) Horizontal gaze palsy typically results from an ipsilateral pontine lesion or a contralateral frontal lesion. (DELETE ALL AFTER THIS)The palsy is often quite severe. That is, it is quite challenging to move the eyes past the midline to the other side. Less severe cases may cause difficulty focusing on one thing for extended periods of time. Moreover, they might have nystagmus. (An eye that flutters repeatedly in one direction and then slowly drifts slowly in the opposite direction is known as nystagmus.

Clinical features
(original)

Individuals suffering from complete horizontal gaze palsy (usually!!delete) cannot move one eye past the midline in any(CHANGE TO !ONE!) direction. The eyes of patients with pontine lesions involving the sixth nerve nucleus or PPRF may stray from the lesion's side. Therefore, patients with a left pontine lesion will be unable to look to their left, and may have their eyes deviated to the right at baseline. If there is only partial damage to the pontine structures, patients may exhibit partial horizontal gaze movement. Patients with horizontal gaze palsy may have to turn their heads toward the affected side to focus on an object that is directly in front of them because their eyes are constantly shifted to the opposite side.

Lesions in the frontal lobe can hinder ipsilateral horizontal smooth pursuit, while lesions in the parietal-occipital-temporal region or posterior parietal cortex reduce the amplitude and speed of smooth pursuit eye movements in the direction of the lesion

Anatomy
Eye movements are controlled by supranucelar communication, infranuclear communication, and ocular motor nuclei. Horizontal gaze specifically also involves the Abducens nerve and the Paramedian pontine reticular formation. Horizontal gaze involves synchronous activation of the abducens muscle of one eye and the medial rectus muscle of the other, via communication through the Medial longitudinal fasciculus. Horizontal gaze palsies can be caused by a lesion affecting any structure in these pathways. Lesions to abducens nucleus or PPRF typically create an ipsilateral gaze palsy where neither eye is able to look towards the side of the lesion. Lesions to MLF typically cause Internuclear ophthalmoplegia, a type of horizontal gaze palsy in which a single affected eye cannot adduct in conjugation with the contralateral eye during horizontal gaze, but convergence is preserved. Lesions to both PPRF and MLF can result in a rare condition known as One and a half syndrome, where a patient will have complete loss of lateral movement in one eye as well as a unilateral horizontal gaze palsy.

Causes
The most common cause of horizontal gaze palsies are strokes. Horizontal gaze palsies have also been described in certain genetic conditions involving heterozygous mutations of the ROBO3 gene, resulting in the rare disease known as "Horizontal gaze palsy and progressive scoliosis." Other rare causes include inflammation, encephalitis, and tumors affecting the midbrain.

org: (Add- "A common cause of horizontal gaze palsies are strokes to pontine structures or abducens nerve. They are also commonly due to strokes of the motor cortex. .) (add "Less commonly, )Horizontal gaze palsy has been reported in cases of metastasis, hemorrhage, neuromyelitis optica spectrum disorder, and multiple sclerosis.

Rarely is horizontal gaze palsy reported in isolation; it may be classified as type III Duane syndrome. Mobius syndrome is characterized by facial weakness and horizontal gaze palsy. (ADD THIS SENTENCE-->) Horizontal gaze palsies have also been described in certain genetic conditions involving heterozygous mutations of the ROBO3 gene, resulting in the rare condition known as "Horizontal gaze palsy and progressive scoliosis."

(DELETE ENTIRE SENTENCE) --> Congenital horizontal gaze palsy only(DELETE "only") occurs in a consistent form when it co-occurs with progressive scoliosis

Diagnosis
(original)

Pontine lesions can typically be distinguished from supranuclear lesions in the frontal lobe at the bedside (delete- medical jargon) based on (clinical ) neurologic findings. The doll's eye or oculocephalic maneuver is useful. Gaze palsies (brought on) (CHANGE TO "secondary to") frontal lobe lesions can be (treated- CHANGE TO "temporarily relieved by") (delete---with) passive horizontal head rotation, which also directly stimulates the sixth nerve nucleus through the vestibuloocular reflex. However, gaze palsies (brought on--> change to "secondary to" delete by) pontine nuclear and intranuclear lesions cannot be clinically relieved.

The dorsal pons should be carefully considered when conducting neuroimaging studies. MRIs, or magnetic resonance imaging, are typically the preferred method. Computed tomography (CT) is a suitable substitute for magnetic resonance imaging (MRI) in certain situations, such as acute patients, patients with altered consciousness, or patients for whom MRI is contraindicated (such as pacemaker patients).

When a patient exhibits intermittent conjugate gaze deviation or clinical seizure activity or is comatose or obtunded, an electroencephalogram (EEG) should be performed to rule out a seizure disorder.

Treatments and Prognosis
Horizontal gaze palsies caused by damage to pontine structures have a poor prognosis with minimal recovery expected. (reference) Palsies due to frontal lobe/ motor cortex have a better prognosis,

See also section- delete. out of place and redundant.