CNS Examination Format for Left Pontine Syndrome

Anatomical Localization

The combination of left 6th nerve palsy, left LMN facial palsy, right hemiparesis, and left horizontal gaze palsy localizes to a left pontine lesion, most likely affecting the left facial colliculus and adjacent corticospinal tract, requiring urgent neuroimaging to identify the underlying cause, according to the American Academy of Ophthalmology 1, 2, 3
Left 6th nerve nucleus involvement produces both the left 6th nerve palsy and the left horizontal gaze palsy, since the abducens nucleus contains not only motor neurons for the lateral rectus but also interneurons that coordinate conjugate horizontal gaze, as stated by the American Academy of Ophthalmology 1, 2, 3
Left 7th nerve fascicle involvement causes the ipsilateral LMN facial palsy, as noted by the American Academy of Ophthalmology 1, 3
Left corticospinal tract involvement produces the contralateral right hemiparesis, according to the American Academy of Ophthalmology 1, 2, 3

Level of consciousness should be assessed, with the patient being alert, oriented to person/place/time, or any alteration, as recommended by the American Academy of Ophthalmology 1
Speech and language should be evaluated for dysarthria or aphasia, which may suggest additional cortical involvement, according to the American Academy of Ophthalmology 1
Cognitive screening for attention, memory, and executive function should be performed if clinically indicated, as stated by the American Academy of Ophthalmology 1

Visual acuity should be assessed in each eye to screen for optic nerve involvement, as recommended by the American Academy of Ophthalmology 1, 4
Pupillary examination should check for afferent pupillary defect, pupil size, and reactivity, according to the American Academy of Ophthalmology 1, 4
Fundoscopy should look specifically for papilledema or optic atrophy, as noted by the American Academy of Ophthalmology 1, 4, 5
Visual fields should be assessed using confrontation testing to exclude additional pathology, as recommended by the American Academy of Ophthalmology 1

Voluntary gaze should be documented, with an inability to move both eyes to the left, indicating left horizontal gaze palsy, according to the American Academy of Ophthalmology 1, 2, 3
Vestibulo-ocular reflex should be assessed to distinguish between nuclear and supranuclear gaze palsy, as stated by the American Academy of Ophthalmology 6
Optokinetic nystagmus should be evaluated, with absent or reduced response when targets move toward the affected side, according to the American Academy of Ophthalmology 6

Tone should be assessed for spasticity, rigidity, or flaccidity in the right arm, as recommended by the American Academy of Ophthalmology 1
Strength should be tested in the right arm, with grading from 0 to 5/5, according to the American Academy of Ophthalmology 1
Pronator drift should be evaluated, with the right arm drifting downward and pronating, as noted by the American Academy of Ophthalmology 1

Deep tendon reflexes should be assessed, with grading from 0 to 4+, and compared between the right and left sides, according to the American Academy of Ophthalmology 1
Babinski sign should be evaluated, with an extensor plantar response on the right side indicating corticospinal tract involvement, as stated by the American Academy of Ophthalmology 1

MRI brain with and without contrast is the gold standard to identify pontine infarct, hemorrhage, tumor, or demyelinating plaque, as recommended by the American Academy of Ophthalmology 1, 4, 5
CT head without contrast may be used if MRI is unavailable or contraindicated, though it is less sensitive for posterior fossa, according to the American Academy of Ophthalmology 1, 5

Blood pressure should be assessed, as hypertension is a major risk factor for vasculopathic 6th nerve palsy and pontine stroke, as noted by the American Academy of Ophthalmology 1, 2, 3, 4
Heart rate and rhythm should be evaluated, with atrial fibrillation increasing stroke risk, according to the American Academy of Ophthalmology 1
Temperature should be assessed, with fever suggesting infectious or inflammatory etiology, as recommended by the American Academy of Ophthalmology 1