Diseases Of The Nervous System Question And Answers

Diseases Of The Nervous System Important Notes

  1. Nerve injuries
    • Neuropraxia
      • It is temporary physiological paralysis of nerve conduction
      • Recovery is complete
      • There is no reaction of degeneration
    • Axonotmesis
      • It is the division of nerve fibers or axons with intact nerve sheath
      • There is the reaction of degeneration distal with near-complete recovery
      • Features – sensory loss. Paralysis of muscles or causalgia
    • Neurotmesis
      • Complete division of nerve fibers with sheath occurs
      • Degeneration occurs proximal upto first node of Ranvier
      • Recovery is incomplete
  2. Tinel’s sign
    • Used to assess the level of regeneration
    • Done by tapping over the course of the nerve from distal to the proximal end to elicit a sensation
    • ResultDiseases Of The Nervous System Tinel's Sign
  3. Commonly used tendon grafts are
    • Palmaris tendon in the forearm
    • Plantaris tendon in leg
  4. Trigeminal Neuralgia
    • It is a sudden, severe, brief, stabbing, recurrent pain along the distribution of the trigeminal nerve
    • Trigeminal Neuralgia Etiology:
      • Pathological
      • Dental pathosis
      • Traction on division of trigeminal nerve
      • Ischaemia
      • Aneurysm of internal carotid artery
    • Trigeminal Neuralgia Environmental
      • Allergic
      • Irritation to the ganglion
      • Secondary lesions

Read And Learn More: General Surgery Question and Answers

    • Trigeminal Neuralgia Trigger zones
      • Vermillion border of lip
      • Around eyes
      • Ala of nose
    • Trigeminal Neuralgia Management
      • Medical
        • Carbamazepine – 100 mg twice daily
        • Dilantin – 300-400 mg
        • Gabapentin – 11200 -3600 mg/day
        • Baclofen – 10 mg T1D
      • Surgical
        • Injection of alcohol in gasserian ganglion
        • Nerve avulsion
        • Electrocoagulation of gasserian ganglion

Diseases Of The Nervous System Short Essays

Question 1. Bell’s Palsy

Bell’s Palsy

Idiopathic paralysis of the facial nerve of sudden onset

Bell’s Palsy Etiology:

  • 5 Hypothesis:
  • Rheumatic
  • Cold
  • Ischaemia
  • Immunological
  • Viral

Bell’s Palsy Clinical Features:

  • Pain in post auricular region
  • Sudden onset
  • Unilateral loss of function
  • Loss of facial expression
  • Absence of wrinkling
  • Inability to close the eve
  • Watering of eve
  • Inability to blow the cheek
  • Obliteration of nasolabial fold
  • Loss of taste sensation
  • Hyperacusis
  • Slurring of speech

Bell’s Palsy Management:

  • Physiotherapy:
    • Facial exercises
    • Massaging
    • Electrical stimulation
  • Protection to eye
    • Covering of eye with bandage
  • Medical management
    • Prednisolone – 60-80 mg per day
      • 3 tablets for 1st 4 days
      • 2 tablets for 2nd 4 days
      • 1 tablet for 3rd 4 days
    • Surgical treatment
      • Nerve decompression
      • Nerve grafting

Diseases Of The Nervous System Nervous System

Question 2. Trigeminal Neuralgia

Trigeminal Neuralgia Definition: It is a sudden, severe, brief, stabbing, recurrent pain along the distribution of the trigeminal nerve

Trigeminal Neuralgia Etiology

Diseases Of The Nervous System Trigeminal Neuralgia

Trigeminal Neuralgia Clinical Features:

  • Age: Around 35 years
  • Sex: Common in female
  • Site: Right lower portion of the face, usually unilateral
  • Duration: a few seconds to a few minutes
    • As time passes duration between the cycles decreases
  • Nature: stabbing or lancinating
  • Aggravating factors: activation of Trigger Zones
    • These are the vermillion border of the lip, around the eyes, and the nose
  • Interference with other activities:
    • The patient avoids shaving, washing face, chewing, and brushing, as these may aggravate pain
    • These lead to a poor lifestyle
  • Extreme cases: leads to “Frozen Or Mask Like Face”

Trigeminal Neuralgia Management:

  1. Medical:
    • Carbamazepine: initial dose: 100mg twice daily until relief is achieved
    • Dilantin: 300-400mg in single or divided doses
    • Gabapentin: 11200-3600 mg/day TID/QID
    • Baclofen: 10 mg TID
    • Amitryptaline: 25-75 mg/ day QID
    • Combination therapy: dilantin + carbamazepine
  2. Surgical
    • Injection of alcohol in gasserian ganglion
    • Nerve avulsion: performed on lingual, buccal, or mental
      • nerve
      • Part of the nerve is sectioned
    • Electrocoagulation of gasserian ganglion: diathermy is done

Question 3. Electrocoagulation of Trigeminal ganglion

Electrocoagulation of Trigeminal ganglion

  • Electrocoagulation of the Trigeminal ganglion refers to percutaneous heat ablation of the Gasserian ganglion at the base of the skull
  • It is performed by placing a needle into the ganglion through which an electrical current passes, heating the probe and producing a thermal lesion in the ganglion

Electrocoagulation of Trigeminal ganglion Side Effects:

  • Facial numbness- mild to severe
  • It may be temporary

Electrocoagulation of Trigeminal ganglion Complications:

  • Unintended nerve damage
  • Failure to access the Trigeminal nerve or Gasserian ganglion
  • Bleeding from the puncture site
  • Apnoea

Question 4. Nerve grafting


Nerve grafting

Nerve grafting is defined as the replacement of a damaged nerve with a section of a healthy nerve that has been removed from another part of the body

Nerve grafting Indication: When nerve suturing is impossible or undesirable

Nerve grafting Ideal Requirements:

  • Should be immunologically acceptable
  • Should undergo Wallerian degeneration
  • Should contain active nerve cells
  • Should become vascularised after being placed in a favorable nourished bed

Nerve grafting Donor Sites:

  • The saphenous nerve of the thigh
  • The sural nerve of the leg
  • The medial cutaneous nerve of the forearm

Question 5. Neuropraxia


Neuropraxia is the mildest type of peripheral nerve injury

Neuropraxia Features

  • No organic damage
  • Endoneurium, perineurium, and epineurium are intact a Temporary physiological paralysis of conduction through the intact nerve fibers
  • No Wallerian degeneration
  • There may be sensory loss or weakness of muscle groups
  • Recovery is complete and requires hours to a few weeks
  • EMG shows a lack of fibrillation

Question 6. Neurotmesis


  • In Neurotmesis there is partial or complete division of the nerve fibers as well as their sheaths
  • Partial lesion produces lateral neuroma while complete division produces terminal neuroma.

Neurotmesis Clinical Features:

  • In the proximal segment of the divided nerve:
    • Retrograde degeneration up to the first node of Ranvier
    • Distal ends of the axons move downwards
    • The gap between the divided nerve ends gets replaced by organic clots and fibrous tissue
  • In the distal segment of the divided nerve:
    • Wallerian degeneration of axons occurs
    • Schwan cells proliferate to form small bulb-like projection

Neurotmesis Treatment:

  • Primary nerve repair
  • Done in clean incised wounds when presented within 6 hours of injury
  • It is immediate suturing of the nerve
  • Secondary nerve repair
  • Done in untidy contaminated wounds presented after 6 hours of injury
  • In it, suturing is delayed for 3-4 hours

Question 7. Axonotmesis


In axonotmesis, there is a rupture of nerve fibers or axons within intact sheaths

Axonotmesis Features:

  • Wallerian degeneration occurs in the distal portion of the broken axons
  • Loss of sensation, tone, and power of the muscles
  • There is no nerve conduction distal to the site of injury
  • EMG shows fibrillation potential and positive sharp waves
  • Area of anesthesia and paralysis of muscles will be restricted to those structures which are supplied by the damaged nerve
  • Secondary effects
    • Impaired circulation due to disuse
    • The affected portion is cold and blue
    • Trophic changes occur
    • Affected muscles no longer respond to stimulation

Axonotmesis Treatment:

  • Maintain good nutrition
  • Exercise of the paralyzed muscles
  • Encouragement of the patients
  • Axonal regeneration occurs without any surgical treatment.

Question 8. Types of nerve injuries

Seddon’s Classification:

  1. Neuropraxia:
    • Results from mild insult to nerve
    • No axon degeneration occurs
    • Mild paraesthesia present
  2. Axonotmesis
    • Severe injury
    • Degeneration of afferent fibers
    • Severe paraesthesia present
  3. Neurotmesis
    • Most severe injury of nerve
    • Complete destruction of nerve structure

Sunderland’s Classification:

  1. First-degree injury
    • Type 1
      • Mild compression of the nerve trunk
      • Results in ischemia and conduction block
      • No axonal degeneration
      • Recovery within a day
    • Type 2
      • Moderate compression
      • Results in edema and conduction block
      • Recovery within 1-2 days
    • Type 3
      • Severe compression
      • Disruption of myelin sheath
      • Sensory loss
      • Recovery in 1-2 months
  2. Second-degree nerve injury
    • Synonymous to Seddon’saxonotmesis
    • Axonal damage occurs
    • Epineurium, perineurium and endoneu- rium is intact
    • Paraesthesia and anaesthesia present
    • Spontaneous recovery
  3. Third-degree nerve injury
    • Synonymous to Seddon’s axonotmesis
    • Axonal damage
    • Damage to epineurium
    • Paraesthesia and anaesthesia present
    • Regeneration of axon is blocked
    • Incomplete sensory recovery
    • Surgical repair needed
  4. Fourth-degree nerve injury
    • Synonymous to Seddon’saxonotmesis
    • Damage to epineurium, endoneurium and axons
    • Intact epineurium
    • Sensory impairment
    • Poor recovery
    • Surgical intervention needed
  5. Fifth-degree nerve injury
    • No conduction of impulses
    • Even epineurium is destroyed
    • Poor prognosis

Question 9. Facial nerve palsy

Facial Nerve Palsy Etiology:

  • Congenital
  • Traumatic
  • Infections
  • Inflammation
  • Neoplastic
  • Idiopathic

Facial Nerve Palsy Clinical Features:

  • Unable to raise eyebrows
  • Unable to blow cheeks
  • Expressionless face
  • Absence of wrinkling and Absence of function of the mandibular nerve
  • Lack of movement of the upper lip
  • Unable to close one eye
  • Absence of nasolabial fold
  • Absence of taste sensation
  • Drooling of the lower lip on the affected side

Question 10. Frey’s syndrome


Frey’s syndrome

This is auriculotemporal nerve syndrom

Frey’s syndrome Causes: Iatrogenic causes- followed by parotidectomy

Frey’s syndrome Features:

  • Pain in auriculotemporal nerve distribution
  • Gustatory sweating
  • Flushing on affected side

Frey’s syndrome Diagnosis: Positive starch iodine test

Frey’s syndrome Treatment:

  • Topical application of anticholinergic
  • Radiation therapy
  • Surgical procedures
    • Skin excision
    • Nerve section
    • Tympanic neurectomy

Question 11. Horner’s syndrome


Horner’s syndrome

Homer’s syndrome is a clinical syndrome caused by damage to the sympathetic nervous system

Horner’s syndrome Clinical Features:

  • The affected part of the face shows:
  • Ptosis
  • Anhydrosis
  • Dilation lag
  • Enophthalmos
  • Loss of ciliospinal reflex
  • Bloodshot conjunctiva

Horner’s syndrome Diagnosis:

  1. Cocaine drop test
    • Cocaine eyedrops block tire reuptake of noradrenaline resulting in the dilation of a normal pupil
    • In Horner’s syndrome, the pupil fail to dilate
  2. Paredrine test
    • Helps to localize the cause of miosis
  3. Dilation lag test

Question 12. Branches of facial nerve


Branches of facial nerve

  1. Within the facial canal
    • Greater petrosal nerve
    • Nerve to stapedius
    • Chorda tympani nerve
  2. At its exit from stylomastoid foramen
    • Posterior auricular
    • Digastric
    • Stylohyoid
  3. Terminal branches
    • Temporal
    • Zygomatic
    • Buccal
    • Marginal mandibular
    • Cervical
  4. Communicating branches with adjacent cranial and spinal nerve

Diseases Of The Nervous System Viva Voce

  1. Tinel’s sign is used to assess level of regeneration
  2. Cut the end of nerve forms neuroma proximally and glioma distally
  3. Causalgia is burning sensation in the distribution of a peripheral nerve
  4. Carpel tunnel syndrome is the compression neuropathy of the median nerve in the carpus
  5. Tendon is the continuity of muscle

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