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Neurology

Question
8 out of 25
 

After a minor head injury a young patient was unable to close his left eye and had drooling of saliva from left angle of mouth. He is suffering from: (AIIMS May 09)



A VIIth nerve injury

B Vth nerve injury

C IIIrd nerve injury

D Combined VIIth and IIIrd nerve injury

Ans. A

VIIth nerve injury

VII cranial nerve (Facial nerve)

ANATOMY – Upper half of the face has a B/L representation whereas the lower half of face has a unilateral representation.

Table: Functional components of the facial nerve

Component

Connections

Function / Supply

Somatic motor

VII nucleus in pons: facial nerve

Muscles of facial expression + stapedius

Visceral efferent parasympathetic

Superior salivary nucleus: nervus intermedius

Lacrimal gland, submandibular and sublingual salivary glands

Special afferent (taste)

Lingual nerve, Chorda tympani, geniculate ganglion, nervus intermedius, tractus solitarius

Taste sensation on anterior 2/3 of tongue

Somatic afferent

Geniculate ganglion

Cutaneous sensation to external ear

Fig:Lesion of right facial nerve or nucleus (Lower motor neurons)

Fig:Lesion of left precentral area or pyramidal tract (Upper motor neurone)

LOCALISATION OF LESION –

Site

Lesion

Clinical features

1). Cortex (supranuclear)

cerebral infract-

C/L facial weakness (upper part of face spared)

2). Pons

Infract- /Hemg.

LMN type of face weakness often VI nerve

a. also affected C/L hemiparesis Milan Gubler syndrome

3). Cerebellopontine angle

Acoustic neuroma

LMN type of I/L facial weakness tinnitus.

a. Ophth div of V nerve also affected

4). Facial canal (Petrous bone)

Bell’s palsy

Herpes zoster

(Ramsay Hunt syndrome)

LMN type of weakness loss of taste, salivation & lacrimation

(proximal to chordee)

Hyperacusis (Proxi ton. to stapedius)

Common causes of VII nerve palsy

UNILATERAL

BILATERAL

1). UMN type

1). UMN type

a. Vascular

a. Multi infract dementia

b. Cerebral tumour

b. Motor neuron disease

c. Multiple sclerosis

2). LMN type

2). LMN type

a. Bell’s palsy

a. Guillain – Barre syndrome

b. Parotid tumour

b. Sarcoidosis

c. Diabetes

c. Leprosy

Feature

B/L UMN palsy

B/L LMN palsy

1). Bell’s phenomenon –

Absent

Present

2). Emotional fibres –

Spared

Affected

3). Long track Signs –

Present

Absent

4). Jaw jerk –

Exaggerated

Normal

5). Corneal reflex –

Present

Absent

Bell’s Palsy – (Ref. Hari-18th ed., pg- 3363)

1). Acute onset non – suppurative inflammation of the facial nerve with in the facial canal above the stylomastoid foramen.

2). Pathophysiology (Ref. Hari-18th ed., pg- 3362)

a. In acute Bell's palsy there is inflammation of the facial nerve with mononuclear cells, consistent with an infectious or immune cause.

b. Herpes simplex virus (Ref. HariSV) type 1 DNA was frequently detected in endoneurial fluid and posterior auricular muscle, suggesting that a reactivation of this virus in the geniculate ganglion may be responsible for most cases.

3). Risk factors – Diabetes, Hypertension, herpesvirus type 1

Poor prognostic factors –

1. Age > 60yrs.

2). Diabetes, Hypertension

3). Decrease Lacrimation

4). Total paralysis at the onset

5). Hyperacusis

Complications –

1). Incomplete recovery

2). Contracture

3). Crocodile tears

4). Cross innervation

Neurology Flashcard List

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