Case 4 Presentation: A 15-year old male patient was admitted to the ER because a

Question

Case 4

Presentation: A 15-year old male patient was admitted to the ER because an inability to swallow his breakfast. He had been discharged from the hospital 36-hours prior following two weeks of recovery from a motor vehicle accident that resulted in a compound tib-fib fracture, as well as other broken bones.

Neurological Exam: Touch discrimination of the left forehead is impaired and mild temperature sensation in the right hand is absent. Gag reflex is not present upon tactile stimulation of the soft palate. No other motor, sensory, or behavioral findings were present in the neurological exam.

History: The patient had been previously diagnosed (at 12 years of age) with an atrial septal defect (ASD) of the heart. No family history is of consequence to this case.

Case 4 Question 1:  Based on the neurological exam results in this case, match the symptoms with the involved cranial nerve and central fiber tracts. 1. sensory discrimination in forehead 2. gag reflex 3. temperature sensitivity in right hand;

A. CN III - Oculomotor nerve, B. CN IX - Glossopharyngeal nerve, C. Lateral corticospinal tract, D. CN I - Olfactory nerve, E. Lateral Spinothalamic tract, F. CN VI - Abducens nerve, G. CN V - Trigeminal nerve, H. Dorsal Columns, I. CV XI - Spinal Accessory nerve, J. CN VIII - Vestibulocochlear nerve, K. CN II - Optic nerve, L. CN VII - Facial nerve, M. CN IV - Trochlear nerve, N. CN XII - Hypoglossal nerve

Case 4 Question 2: Where in the brainstem are nuclei associated with the affected cranial nerves located? Where are they found closest to each other and to the fiber tract involved?

Case 4 Question 3: What is the most likely cause of these deficits considering that they presented two weeks after the original accident, are limited in scope, and improved with therapy?

Case 4 Question 4: Given your answer to the above question, how does the patient’s history suggest a cause for this episode (especially considering his age)?

Explanation / Answer

Ans: Glossopharyngeal: CN IX- Injury to nerve produces loss of gag reflex, difficulty in swallowing (dysphagia), loss of taste on posterior third of tongue (not noticed by patient unless tested), loss of sensation on affected side of soft palate, decrease in salivation.

Gag reflex: the gag or cough reflex tests the somatic motor responses of cranial nerves IX and X. The reflex is initiated by holding the tongue down with a tongue depressor, and then touching the mucosa alternately on each side of the uvula. The mucosa of the posterior pharyngeal walls should rise equally and evenly simultaneously on both sides. The gag reflex is important in preventing solid material to pass into our airways.

Sensory cranial nerves: olfactory nerve (I), optic nerve (II) and the vestibulocochlear nerve (VIII)

Motor cranial nerves: oculomotor nerve (III), trochlear nerve (IV), abducens nerve (VI), spinal nerve (XI) and the hypoglossal nerve (XII)

Mixed (sensory and motor) cranial nerves: trigeminal nerve (V), facial nerve (VII), glossopharyngeal nerve (IX) and the vagus nerve (X)

CN I. Olfactory. Function: Smell. Disorder: Anosmia - Inability to smell

CN II. Optic Function: Vision. Disorder:ipsilateral blindness, loss of pupillary light reflex

CN III. Oculomotor. Function: Contol of eyelid muscles and inferior rectus/oblique muscles of eyeball. Disorder: Ptosis: drooping of the eyelid, Diplopia: double vision, ipsilateral eye looks outward and down, deficits moving ipsilateral eye medially, downward and upward, loss of pupillary reflex (optic nerve is afferent and oculomotor is efferent), loss of constriction of lens in response to focusing on a near object

CN IV. Trochlear. Function involves the activation and control of superior oblique muscle of eyeball. Disorder: double vision, difficulty reading, visual problems when descending stairs)

CN V. Trigeminal. Function: Innervates muscles of mastigation and Sensory to Ipsilatera.Disorder: Geminal Neuralgia: severe sharp, stabbing pain on facial. Pain occurs when eating, talking, touching face, lasts less than 2 mins

CN VI. Abducens

Function: Control of lateral Rectus Muscles
Disorder: Eye looks inward (paralysis of lateral rectus muscle). Unable to voluntarily abduct eye, double vision

CN VII. Facial Nerve

Function: Innervates ipsilateral facial muscles and sensory to anterior of the tongue
Disorder: (1) Bell palsy - paralysis or paresis of ipsilateral muscles of facial
expression.

CN VIII. Vestibulocochlear

Function: Gaze fixation, to carry information of head movement and position to the
brain, hearing information translation
Disorder: 1. Conductive deafness - transmission of vibrations prevented
2. Sensorineural deafness - damage of receptor cells or cochlear nerve

CN IX. Glossopharyngeal

Function: Sensory to posterior of the tongue and gag reflex, innervates pharyngeal muscles
Disorder: Glossopharyngeal Neuroglia - induce pain or brachycardia

CN X. Vagus

Function: Motor to gag reflex and speech production and sensory to parasympethatic control

CN XI. Spinal Accessory

Function: Innervates sternocleido mustoid muscles and trapezius muscles
Disorder: paralysis of ipsilateral sternocleidomastoid and trapezius (complete lesion)

CN XII. Hypoglossal

Function:Innervates tongue muscles

Disorder: Atrophy of ipsilateral tongue difficulty speaking/swallowing.

2:Difficulty in swallowing affect the the lower cranial nerves – CN V (trigeminal), VII (facial), IX (glossopharyngeal), X (vagus), XI (accessory) and XII (hypoglossal). The hypoglossal nucleus (XII) is located in the midline of the rostral medulla and supplies musculature of the tongue. The nerve fibers exit anterior to the inferior olive (in the pre-olivary sulcus). Damage to these LMNs produces deviation of the tongue on protrusion. When the nucleus or nerve fibers are damaged (LMNs), the ipsilateral muscles of the tongue are paralyzed and thus the tongue will protrude toward the side where the muscles are weak, which in the case of LMN lesions is also toward the side of the lesion.

3: Difficulty in swallowing affect the the lower cranial nerves – CN V (trigeminal), VII (facial), IX (glossopharyngeal), X (vagus), XI (accessory) and XII (hypoglossal).

Anticholinergic drugs can reduce the problems with excess saliva and drooling which occur in patients with neurological dysphagia and a portable suction apparatus is helpful. Difficulty in clearing secretions from the throat may be helped by the administration of a mucolytic agent such as carbocisteine or provision of a cough assist device.

4: Dysphagia or the swallowing difficulty is a growing health concern with the aging population. Age-related changes in swallowing physiology as well as age-related diseases are predisposing factors for dysphagia in the elderly. Older adults are more at risk due to general wear and tear on the body over time. Also, certain diseases of old age can cause dysphagia like Parkinson disease and also the nervous system disorders make dysphagia more likely.

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