Brainstem Lesions Part 1

Question 1

Describe alternating hypoglossal hemiplegia and destruction of contralateral corticospinal tract (A12H+CST)

Answer 1

Destruction of hypoglossal nerve results in ipsilateral paralysis and atrophy of tongue muscles
Destruction of ipsilateral corticospinal tract results in contralateral spastic hemiplegia
Partial destruction of contralateral corticospinal tract results in some degree of ipsilateral spastic paralysis

Question 2

Describe alternating hypoglossal hemiplegia and destruction of ipsilateral medial lemniscus (A12H+ML)

Answer 2

Destruction of of ipsilateral hypoglossal nerve and corticalspinal tract (contralateral hemiplegia)
Destruction of ipsilateral medial lemniscus results in contralateral loss of proprioception, 2pt tactile discrimination, and vibratory sensations from body

Question 3

Describe alternating abducens hemiplegia (A6H)

Answer 3

Destruction of abducens nerve results in ipsilateral paralysis of lateral gaze and/or internal strabismus
Destruction of corticospinal tract at this level results in contralateral spastic hemiplegia

Question 4

Describe Millard-Gubler’s syndrome (A6H+7)

Answer 4

Includes signs of alternating abducens hemiplegia plus a lesion of VII nerve
Destruction of facial. Nerve results in ipsilateral facial palsy, loss of taste sensations from anterior 2/3 of tongue, decreased lacrimation, and hyperacusis

Question 5

Describe Syndrome of Foville (A6H+ML)

Answer 5

Includes signs of alternating abducens hemiplegia plus additional signs due to dorsal extension of lesion:
Destruction of medial lemniscus results in contralateral loss of proprioception, 2-pt tactile discrimination, and vibratory sensations from body
Destruction of medial longitudinal fasciculus results in internuclear ophthalmoplegia
Facial nerve may also be involved
Destruction of crossed corticobulbar fibers results in denervation of ipsilateral nucleus ambiguus and hypoglossal nucleus

Question 6

Describe alternating trigeminal hemiplegia (A5H)

Answer 6

Destruction of trigeminal nerve results in ipsilateral loss of all sensations from half of face and scalp as well as ipsilateral muscles of mastication
Destruction of corticospinal tract results in contralateral spastic hemiplegia

Question 7

Describe alternating trigeminal hemiplegia with a dorsal expansion (A5H+ML)

Answer 7

Signs of A5H plus deficits assoicated with involvement of dorsally located structures
Destruction of medial lemniscus results in contralateral loss of proprioception and 2-pt tactile discrimination from body and limbs
Destruction of uncrossed corticobulbar fibers results in denervation of contralateral cranial nerve nuclei:
-abducens nerve
-1/2 of facial nucleus results in paralysis of mimetic muscles on lower half of face (supranuclear facial palsy)
-hypoglossal nucleus
-nucleus ambiguus

Question 8

Describe Weber’s syndrome (alternating oculomotor hemiplegia A3H)

Answer 8

Destruction of oculomotor nerve results in external strabismus, pupillary dilation, and complete ptosis
Destruction of corticospinal tract results in contralateral spastic hemiplegia
Destruction of substantia nigra may result in contralateral resting tremor
Destruction of uncrossed corticobulbar tract contralateral brainstem motor nuclear palsies, including supranuclear facial palsy

Question 9

Describe alternating hypoglossal hemiplegia (A12H)

Answer 9

Destruction of hypoglossal nerve results in ipsilateral paralysis of muscles of tongue and atrophy of ipsilateral muscles of tongue
Destruction of corticospinal tract at this level results in contralateral spastic hemiplegia