Oral Medicine Lec 7

7/27/2019 Oral Medicine Lec 7

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Neuromuscular Disorder

Tetany( Decrease in Calcium ions):Decrease of calcium ions in serum lead to(hypocalcaemia Tetany), which cause

heightened neuromuscular excitabilitytogether with minor disorder of sensationsuch as paresthesia of the lip, twitching ofthe facial muscles, tingling in the hand and

feet and around the mouth, spasm of thevocal cord resulting high pitcheddistressing or laryngeal stridor and epilepticseizures


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Increase in the excitability of theperipheral nerve could also be due toalkalosis in which the proportion of serum

calcium in the ionized form is decreasedalthough the total amount of calciumconcentration is still constant. (alkalosistetany)

.*Causes of tetany due to hypocalcaemia- Malabsorption- Osteomalacia characterized by increasing

bone turn over with failure of bonemineralization due to vitamin D deficiency.

- Hypoparathyroidism- Acute pancreatits- Chronic renal failure


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Muscular dystrophy :

Is the main crippling disease of childhood.It is a genetic disease characterized bymuscle atrophy that causes severe

progressive weakness and it is frequentlyassociated with cardiomyopathy andrespiratory impairment.General anesthesia is dangerous in thepresence of cardiac disease or respiratoryimpairment.


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- The clinical manifestations of MS(disturbance of sensation) depend on the

sites of lesions in brain and the mostaffected sites ( optic chiasm, brain stem ,cerebellum and spinal cord)

-- Diagnosis depend on the presence of

multiple deficits , particularly defects ofvision, weakness of the limbs and sensorylosses.

-- MRI demonstrates characteristicabnormalities in 95% of patients.

- High doses of intravenous corticosteroidsmay arrest the progress of MS.


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It begins with myalgia or paresthesia of thelower limbs, followed by weakness, which

often ascends to involve abdominal ,thoracic,and upper-limb muscles.

Involvement of the autonomic nervoussystem by the disease process may inducechanges in blood pressure and pulse rates.Impaired swallowing or paresthesia of the

mouth and face may be early signs of thedisease. Bilateral facial weakness iscommon. Dysarthria ,dysphagia and diplopiamay develop in severe cases.


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discussed in previousRamsy Hunt syndrome :lecture.

Cerebral PalsyGroup of disorders with motormanifestations due to non progressive brain

damage occurring before or after birth.- Anoxia and ischemia during labor havebeen implicated, but congenital infectionsthat transmitted through placenta to fetus

during 1st trimester of pregnancy such astoxoplasmosis, rubella, Cytomegalovirusdisease, herpes simplex, syphilis andinfluenza have also been associated with

cerebral palsy.


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The clinical manifestation of cerebral palsyinclude:spastic leg, dyskinesia (athetosis), ataxic or

a combination.- Spasticity causes fixed contraction of the

affected muscles and general stiffness.Hemiplegia is the most common type in

such cases , mental retardation isuncommon but other neurologicaldisorders, such as epilepsy are frequent.

Quardriplegia by contrast are frequentlymentally retarded but less often epileptic.

- Athetosis refers to involuntary jerkingmovement ,often of a wriggling character,

sometimes accompanied by grimacing.


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- Ataxia is characterized by lack of balance,unsteady gait and poor control overvoluntary movements.

With improved perinatal care, both anoxiaand perinatal infections have been markedlyreduced, thus leading to a reduction in theincidence of CP. Many children with CP havenormal intelligence and should not bepenalized because of dysarthria orinvoluntary movements. If the patient

suffers from seizures, appropriate drugtherapy is instituted.Children with CP show an increasedincidence of enamel defects, the cause of

which is not clear.


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A much more bothersome finding is thesialorrhea and drooling experienced by CPpatients.

Dental aspects:a/ increase incidence of caries and

periodontal disease due to inability tomaintain oral hygiene.

b/ sedation in case of anxiety or evengeneral anesthesia to prevent dental

trauma.c/ bruxism and massetric hypertrophy.d/ delayed eruption.e/ drooling of saliva.

f/ malocclusion.

Th


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Therapy:1/ increase care to improve pre and post

natal assessment and decrease the

chance of anoxia and infections orvaccination.2/ physiotherapy as early as possible.3/ psychotherapy to adjust emotionally to

their handicapping.4/ anticonvulsant drugs (L-dopa).

pontic angle tumor-CerebroMany cranial nerves pass at this areaincluding 5,6,7,8 and 9 cranial nerve. Sotumor in this area lead to pain and other

problems such as hearing problems, facialweakness .etc


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Parkinsonism (Parkinson's disease)Is an idiopathic neurodegenerative disorderthat mainly affects adult in middle or latelife.It is due to dopamine depletion in thebrainstem lead to an imbalance of dopamine

and acytelcholine (neurotransmitters thatare normally present in the corpus striatum.The cardinal features of parkinsonisminclude: tremor, rigidity, bradykinesia and

postural instability. The most disablingsymptoms are due to bradykinesia,manifested as a slowness of voluntarymovement such as the swinging of arms

while walking.


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-- Symptoms similar to Parkinsonismdisease may induced by drugs that cause a

reduction of dopamine in the brain, themost common of these drugs is(phenothiazine derivatives).

Dental Consideration in Parkinsonismdisease:1/ Reassurance before treatment.2/ Premedication to control anxiety to

prevent muscular rigidity and tremor.3/ Avoidance of postural changes of patient

on dental chair to prevent posturalhypotension.


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Treatment:at present there is no cure for parkinsonism

disease , but a variety of medications andprocedures provide dramatic relief from thesymptoms. The most commonpharmacological treatment is dopaminereplacement therapy using (Levodopa).

Myasthenia Gravis

Is a chronic disabling autoimmune diseasecharacterized by progressive muscularweakness and rapid fatigue of voluntarymuscles.


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In patient with MG, autoantibodies combinewith and may destroy the acetylcholine

receptor sites at the neuromuscular junctionpreventing the transmission of nerveimpulses to the muscle. The origin of theautoantibodies is unknown.

The disease occur more frequently inwomen than in men ,particularly during thethird and fourth decades of life.

Patient present with ptosis, diplopia ,difficulty in chewing or swallowing,respiratory difficulties ,limb weakness orsome combination of these problems.


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MG follows an unpredictable course ,andexacerbations and remissions occur

frequently. In severe advanced casesrespiratory difficulty arises.

Avoid prescribing drugs that may affect the

neuromuscular junction such as narcotics,tranquilizers and barbiturates. Certainantibiotics including tetracycline,

streptomycin, sulfonamides and clindamycinmay reduce neuromuscular activity andshould be avoided.


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Diagnosis:

is confirmed by serologic evidence ofautoantibodies to acetylcholine receptor.

Treatment:

Anticholinesterase drugs such asneostigmine and pyridostigmine bromideincrease acetylcholine availability andreceptor binding and provide symptomatic

benefit without influencing the course of thedisease.


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Facial PalsyAn upper motor neuron (UMN) has a cellbody in the brain and an axon that extendsinto the spinal cord, where it ends in thesynapses, it is entirely within the CNS.A lower motor neuron (LMN) has a cell body

in the spinal cord or brainstem and an axonthat extends outwards in a cranial or spinalmotor nerve to reach an effector.The UMN lesion affects the lower part of

face while LMN lesion affects the whole theface in the same side.Facial palsy include both UMN and LMNlesions, the causes are divided into extra

and intracranial causes:

E t i l


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Extra cranial causes:1/ Bell's palsy2/ Malignant parotid neoplasms

3/ Parotid surgery4/ Sarcoidosis (Heefordt's syndrome)5/ Misplaced local anesthesia6/ Melkersson-Rosenthal syndrome

Intra cranial causes :1/ Stroke (cerebrovascular accident)2/ Cerebral tumors

3/ Multiple sclerosis4/ HIV infection5/ Lyme disease6/ Ramsy Hunt syndrome7/ Trauma to the base of the skull.


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Bell's PalsyIs a common cause of facial paralysis. It

probably results from compression of thefacial nerve in it's canal as a result ofinflammation and swelling. A viral infection,particularly herpes simplex, is suspected

the cause.

Bell's Palsy begins with slight pain aroundone ear, followed by an abrupt paralysis ofthe muscles on that side of the face.The eye on the affected side stays opens,the corner of the mouth drops, and there is

drooling.


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As a result of masseter weakness, food isretained in both the upper and lower buccal

and labial folds. The facial expressionchanges remarkably ,and the creases of theforehead are flattened.Corneal ulcerations from foreign bodies canoccur.

Systemic corticosteroid within the first few

days after the onset of paralysis ,but thistherapy should be avoided if Lyme diseaseis suspected.


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Combining steroid with antiherpetic drugssuch as acyclovir may decrease the severityand length of paralysis.

It is also helpful to protect the eye withlubricating drops or ointment and a patch ifeye closure is not possible.

Rosenthal syndrome-MelkerssonUnilateral recurrent facial paralysis ,whichmay become permanent .Recurrent ,soft ,painless facial swelling is

more common ,but may become persistentdue to progressive fibrosis.The buccal mucosa may have a cobblestonepattern, and histologically , granulomas are

found. There is no specific treatment.


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Lyme diseaseCaused by spirochete bacteria Borrelia

burgdorferi and transmitted by animal ticks.Facial palsy or cervical lymphadenopathy issometimes prominent but arthritis is thechief effect.

Heerfordt's syndromeCombination of facial palsy ,uveitis and

parotid swelling caused by sarcoidosis ofcranial nerve and salivary glands.


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Cerebovascular accident (CVA)

Is a common complication of hypertensionin the elderly.Unilateral paralysis (hemiplegia) and often

loss of speech (aphasia) are frequent .Unilateral facial palsy is common but differsfrom Bell's palsy in that the lower part ofthe face is affected.

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Oral Medicine Lec 7