The sensory system and pain syndromes

1
The sensory system and pain syndromes

• Vth year, dentistry, 30.09.2008
• Department of Neurology
• Semmelweis University

2
Sensory system

• Receptors
• - specialised (smell, vision, hearing, taste
• - visceral (viscera, smooth muscle -
  unconscious or autonomic)
• - somatic (skin, striated muscle, joints)

3
Cutaneous receptors
Muscle, tendon receptors
4
The sensory system

• Spinothalamic system (tractus spinothalamicus)
  exteroceptive sensation) pain
• temperature
• light touch
• Dorsal column pathway ( lemniscus medialis)
  conscious proprioception joint position
• vibration
• deep pressure
• two point discrimination
• graphaesthesia ! stereoaesthesia
  !
• Dorsal and ventral spinocerebellar pathway
  unconscious proprioception

5
Pain
Nociceptors -Unimodal mechanoreceptors, thinly
myelinated fiber -Bimodal cold
mechanoreceptors, thinly myelinated and
unmyelinated fibers warmmechanoreceptors
-Polymodalwarm-mechano-chemical receptors,
unmyelinated fibers
6
Spinothalamic system
Pain perception C fibers thin, unmyelinated A
delta thinly myelinated Temperature A delta
thinly myelinated
7
origin of pain - manifestations

• Peripheral
• Postherpetic neuralgia
• Trigeminal neuralgia
• Polyneuropathy in diabetes mell.
• Posttraumatic neuropathy
• Central
• Poststroke pain
• Description2
• Burning
• Tickling, itching,pins and needles
• Hypersensitivity to touch/cold

• Low back pain with radiculopathy
• Cervical pain with radiculopathy
• Cancer pain
• Carpal tunnel syndrome

• inflammation
• fractures
• osteoarthritis.
• Postoperativ visceral pain
• Description2
• smarting
• Sharp
• Pulsating, throbbing

1. International Association for the Study of
Pain. IASP Pain Terminology. 2. Raja et al. in
Wall PD, Melzack R (Eds). Textbook of pain. 4th
Ed. 1999.11-57
8
Dorsal column pathway/lemniscus medialis

• Proprioceptiv modalities pressure,
• vibration,
• joint positiontwo points discrimination,
• graphaesthesia !
• stereoaesthesia !
• Type of fibers thick, myelinated
  fibers (Aa, I, II)

9
Somatotopia in the cortex
10
Segmental innervation (dermatomes)Peripheral
innervation
11
Sensory disturbances

• Positive symptoms
• Pain
• Hyperaesthesiaincreased sensitivity to any
  stimulus
• Hyperalgesia increased sensitivity to a painful
  stimulus
• Hyperpathia increased sensitivity with
  increasing
• pain threshold to repetitive stimulation
• Paraesthesiapins and needles sensation,
• burning feeling
• Dysaesthesia inappropriate sensation to a
  stimulus
• Allodynia pain provoked by a non-painful stimulus

12
Sensory disturbances

• Negative symptoms
• Hypoalgesia reduced sensitivity to a painful
• stimulus
• Hypoesthesia reduced sensitivity to any
• stimulus
• Analgesia absent sensitivity to a painful
• stimulus
• Anaesthesia absent sensitivity to any stimulus

13
Examination of the sensory system 1.

• Special standpoints
• Subjective examination
• Requires good cooperation on the patients side.
• Allows accurate localisation of the pathology.
• Preliminary diagnosis is needed. Examine
  according to the expected damage !
• Most often we compare different parts of the
  body.
• Do not tell the patient what should be felt !
• The patient should not see the examined part of
  the body !
• Subjective sensory disturbance ( pain,
  paraesthesia ) is not necessarily accompanied by
  objective sensory disturbance (hypaesthesia,
  anaesthesia )

14
Examination of the sensory system 2.

• Pain pin prick, tooth picks
• Light touch use a wisp of cotton wool !
• Temperatureuse cold (5-10 0C)/or hot (40-45 0C)
  test tubes !
• -Instruct the patient to reply Tell me if you
  feel the stimulus !
• Name the area stimulated ! Is it equal on
  both sides?
• -Map out the extent of abnormality by moving
  from the
• abnormal to the normal area (Tell me if
  sensation changes!)
• Joint position / motion
• -Hold the sides of the patients finger !
  Move it up and down at
• random ! Ask to specify the direction of
  movement !
• Vibration
• -Place a vibrating tuning fork on a bony
  prominence ( ankle,
• knee, processus spinosus, processus
  styloideus radii et
• ulnae, elbow, clavicula)

15
Examination of the sensory system 3.

• Two point discrimination
• -The ability to discriminate two blunt points
  when applied simultaneously. (3-5 mm on the
  finger, 4-7 cm on the trunk)
• Sensory inattention (perceptual rivalry)
• -The ability to detect sensory stimuli applied
  simultaneously on both limbs.
• -Subdominant parietal lobe, associative areas
• Stereoaesthesia
• - An object is placed in the patients hand.
• - Ask patient to describe its size, shape,
  surface, material !
• - Stereoanaesthesiadisturbance of the sensory
  afferent tracts.

16
Examination of the sensory system 4.

• Astereognosis.
• -Inability to identify an object by palpation
• -The primary sense data being intact
• -Lesion of the opposite hemisphere,
  postcentral gyrus
• Tactile agnosia
• -The patient is unable to recognize an object
  by touch in both
• hands
• -Disorder of perception of symbols.
• -Lesion of the dominant parietal lobe,
  associative areas
• Graphaesthesia
• - The ability to recognize numbers or letters
  traced out
• on the palm.

17
Examination of the sensory system

• Nerve conduction studies
• sensory antidrom neurography
• median nerve, ulnar nerve
• Somatosensory evoked potentials (SEP)
• median nerve, tibial nerve

18
Peripheral nerve, Polyneuropathies

• Peripheral nerve according to the
• distribution area of the affected nerve
• Polyneuropathies symmetrical
• sensory disturbance in stocking/glove
• like distribution, more pronounced
• distally
• Sensory disturbance usually starts on
• the toes, gradually spreads higher,
• rarely above the knee later on the
• hands

19
Spinal ganglion
segmental, localised to dermatomes
20
Root damage

• Sensory disturbance and pain according to the
  dermatome (variability!)
• Anaesthesia does not develop because of
  overlapping dermatomes

C7
S1
21
Syringomyelia

• spinothalamic fibers crossing at cervical level
  are affected first
• dissociated sensory loss temperature, pain
  disturbance on both hands

22
Cranial structures - pain

• skull
• cervical spine
• eyes
• ears
• nose, sinuses
• teeth
• temporomandibular joint

23
HeadachePathways
PAGperiaqueductal gray matter LC locus
ceruleus TGtrigeminal ganglion DRGdorsal root
ganglion
24
Taking a headache history

• Age of onset ?
• Duration of complaint ?
• Time pattern
• Continuous or transient ? Frequency and
  duration of each headache ?
• Site ?
• Intensity, quality ?
• Associated phenomena ?
• Aggravating and relieving factors ?

25
Headache - duration - frequency
26
Headache - danger signals

• Danger signals
• sudden onset of new, severe headache
• onset of headache after exertion, straining,
  coughing or sexual activity
• progressively worsening headache
• any abnormality on neurological examination
• systemic features fever, arthralgia
• onset of first headache after the age of 50 years
• Refer to specialist
• Cooperating patient ineffective treatment
• Chronic daily headache drug abuse, dependency
• Severe anxiety , depression
• Severe comorbid diseases

27
International classification of headache disorders
Primary headaches 1. Migraine 2. Tension-type
headache 3. Cluster headache and other
trigeminal autonomic headaches 4. Other primary
headaches
Secondary headaches 5. Posttraumatic (head/neck
trauma) 6. Vascular disorder (cranial/cervical) 7
. Non vascular intracranial disorder 8.
Substance abuse/ withdrawal 9. Infection 10
Disorder of homeostasis 11.Disorder of
facial/cranial structures 12.psychiatric disorder
Cranial neuralgias, central and primary facial
pain 13.Cranial neuralgias and central causes
of facial pain 14.Other headache
International Headache Society. ICHD-II.
Cephalalgia 2004 vol 24 suppl 1.
28
Migraine without aura
A) n ? 5 B) 4 - 72 h C) 1. 2. 3.
/ 4. ? D) 1. ? 2.
E) normal
2/4
/?
1/2
29
Phases of migraine
Blau, Lancet, 1992
30
Migraine and spreading depression
31
Trigemino - vascular system
Lancet Neurology 20021251-257.
32
migraine - treatment

• Acute
• - Non specific analgesics, NSAID, antiemetics
• - Specific ergotamine,
  dihydroergotamine, triptans
• Preventive (prophylactic)
• - Episodic if there is a trigger for a limited
  time ( menses)
• - Chronic decrease the frequency independently
  of triggers
• Migrén gyógyszeres kezelésének protokollja,
• Magyar Fejfájás Társaság, 2003

33
Tension type headache criteria
A. n gt 10 B. 30 min lt duration of painlt 7
nap C. 2/4 / D.
2/2 E. normal
/ ?
34
Convergence and sensitisation in the trigeminal
nuclei
Thalamus
DRN, LC
pia / dura vessels
art. temp.
Trigeminus nucleus caudalis
masticatory muscle
Brainstem and spinal cord
35
Tension type headache - treatment
Acute treatment analgesics NSAID
antiemetics, coffein Preventive
treatment tricyclic AD SSRI valproat
(?) Complex treatment pharmacological
treatment psychotherapy relaxation physio
therapiy (Not massage!)
36
Cluster headache criteria
A) n ? 5 B) 30-180 min
D) Frequency 1/2 -gt50 E) normal
C)
1/4
37
Cluster headache treatment
Acute treatment oxygen (7 l/min, 10
perc) sumatriptan sc. inj. ergotamine in
domethacin supp.
Preventive treatment verapamil (360
mg/day) valproate (600-1500 mg
/day) infiltration of occipital nerve
? methysergide, pizotifen ? lithium
(chronic cluster!) corticosteroids/dihydroergo
tamine Surgical ?
38
International classification of headache disorders
Secondary headaches 5. Posttraumatic (head/neck
trauma) 6. Vascular disorder (cranial/cervical) 7
. Non vascular intracranial disorder 8.
Substance abuse/ withdrawal 9. Infection 10
Disorder of homeostasis 11.Disorder of
facial/cranial structures 12.psychiatric disorder
Primary headaches 1. Migraine 2. Tension-type
headache 3. Cluster headache and other
trigeminal autonomic headaches 4. Other primary
headaches
Cranial neuralgias, central and primary facial
pain 13.Cranial neuralgias and central causes
of facial pain 14.Other headache
International Headache Society. ICHD-II.
Cephalalgia 2004 vol 24 suppl 1.
39
Trigeminal neuralgia
V/1
V/2
V/1
V/1
V/3
V/3
C2/3
40
Trigeminal neuralgia

• Prevalence 10-20 / 100 000 population
• female/male 1.6
• age of onset gt 50 years (90)
• site most frequently V/2,3 lt 5
  V/1 division 10
  all the three division 5
  bilateral
• Features
• placebo effect 0 -1 !
• trigger zone 90
• refracter phase
• spontanous remission 50 , lt 6 months
• pretrigeminal neuralgia

41
Trigeminal neuralgia

• Classical/Idiopathic
• duration lt 2 minutes
• affecting one/more divisions
• sudden onset
• severe, sharp,stabbing pain
• precipitated from trigger areas
• patiens is pain free between paroxysm
• no neurological deficit
• no causative lesion

• Symptomatic
• pain as described before
• persistence of aching between paroxysm
• sensory impairment or other neurological
  deficit
• causative lesion , other than vascular
  compression

42
Trigeminal neuralgia
mouth -ear zone, 60
nose - orbit zone, 30
43
Peripheral aetiology -central pathogenesis

• chronic irritation of trigeminal nerve division
• focal demyelinisation
• ectopic action potentials decrease of
  segmental inhibition
• paroxysmal discharge of LTM interneurons of
  nucleus oralis n.V
• paroxysmal discharge of WDR neurons of nucleus
  caudalis n.V
• attack of trigeminal neuralgia

44
sites of trigeminal nerve damage
45
Trigeminal neuralgia

• differential diagnosis
• examinations anamnesis physical
  examination Rtg otology dental
  surgery ophthalmology brain
  MR trigeminal SEP psychology dia
  gnostic blockade

46
Trigeminal neuralgia

• If it is possible determine causative lesion,
  treat it
• Pharmacological treatment
• - antiepileptics
• - muscle relaxants
• - tranquillants
• TENS?
• surgery

47
Trigeminal neuralgia-pharmacological treatment

• Carbamazepine 400-1200 mg/day
• Phenytoin 300-600 mg/day
• Valproate 500-2000 mg/day
• L baclofen 40-80 mg/day
• Clonazepam 2-8 mg/day
• Pimozide 4-12 mg/day
• Tiapridal 300-600 mg/day
• Gabapentin up to 3600 mg/day
• Pregabalin ?

48
Trigeminal neuralgia - phamacological treatment

• start with small dose, increase gradually
• prefer combination
• blood counts, hepatic, renal function tests are
  needed
• monitoring of complaints is important
• timing of discontinuation (after pain free for 8
  weeks)
• gradual tapering is necessary
• 30 of patients fail to respont to medical
  therapy

49
Trigeminal neuralgia surgical management

• Peripheral nerve blockade
• Percutanous radiofrequency trigeminal
  thermocoagulation (Sweet, Wespic, 1974)
• Retrogasserian Glycerol injection
  (Hakansson, 1981)
• Radiosurgery - gamma knife
• Microvascular decompression (Gardner 1966,
  Janetta 1967, MéreiFT 1973) Janetta 85
  vascular compression a. cerebelli superior
  V/2,3 a. cerebelli inferior anterior
  V/1 pain free 80,
• mortality 0.5

50
neuralgias

• Glossopharyngeal neuralgia classical/symptomatic
• - pain in the tonque, tonsillar fossa, angle of
  the jaw, ear
• - peritonsillar abscess, oropharyngeal carcinoma
  !
• Nervus intermedius neuralgia
• - posterior wall of the auditory canal
• - herpes zoster oticus !
• Superior laryngeal neuralgia
• Nasociliary neuralgia
• Supraorbital neuralgia
• Occipital neuralgia
• - greater or lesser occipital nerves
• - cervical spine !

51
Central causes of facial pain

• Anaesthesia dolorosa
• - lesion of the relevant nerve/ after trauma
  (surgical?)
• - diminished sensation to pin prick over the
  affected area(hypalgesia)
• - spontaneous, persistent pain and dysaesthesia
  (allodynia)
• Central post stroke pain
• Persistent idiopathic (atypical) facial pain
• - persisting pain without features of neuralgia
• - on a limited area of the face, poorly
  localised
• - no sensory deficit, investigations exclude
  relevant abnormality

52
Chronic postherpetic neuralgia

• herpes zoster trigeminal ggl. 15 (V/1
  80) ggl. Geniculi (VII, Ramsay-Hunt)
• pain gt 3 months
• indicence lt40years5 , gt60years50 ,
  gt70years75
• lymphoma patients with lymphoma 10-25
• treatment capsaicin cream, vincristin
  iontoforesis
  amitryptilin carbam
  azepine, valproat neuroleptics amantad
  in gabapentin
• prognosis 56 remission gt 3 years

53
Symptomatic headaches

• Giant cell arteritis
• - incidence 3-9 / 100 000, 133 / 100 000(gt50
  years), 843 / 100 000 (gt80 years)
• - headache (70-90 ) permanent or transient,
  unilateral or bilateral
• - swollen tender scalp artery, decreased
  pulsation (60 )
• - blindness (50 -13 ) amaurosis fugax, AION
  transient / permanent
• - diplopia (15 )
• - jaw claudication (25- 40 )
• - polymyalgia rheumatica (25 )
• - neurological signs stroke, hearing loss,
  myelopathy, neuropathy
• - elevated ESR and/or CRP (41 gt 100 mm/h, 89
  gt 31 mm/h) biopsy
• - treatment 60- 80 mg methylprednisolon (
  gradually decrease in every third day,
• to 30 mg, then decrease weekly with 5 mg to 10
  mg) 3 months, We ?
• - headache relief within 3 days after the start
  of steroid treatment
• Costen syndroma