NEUROMUSCULAR DISORDERS.

By PATIENCE MONDE

A number of relatively uncommon but significantly neuromuscular conditions may affect dental treatment, particularly elderly patients

Inability to carry out proper oral hygiene may result in an increased caries rate and greater incidence and severity of periodontal disease, causing these patients to seek dental care for chronic and acute disorders.

PARKINSON’S DISEASEAlso known” as shaking palsy”

A progresssive neurodegenerative disorder of neurons that produce dopamine

Caused by death and depletion of doparminergic neurons, wch are manufactured in the substantia nigra and released in the caudate nucleus and putamen (the niagrostriatal pathway)

MANIFESTATIONS Chronic progressive combinations of resting

tremor Cogwheel rigidity Bradykinesia( slownesss of voluntary

movement) Facial impassiveness Falls Mood disturbances Insomia Fatigue

POTENTIAL MEDICAL PROBLEM RELATED TO DENTAL CARE Patients may be unable to perform oral

procedures Patients may have severe tremor or may be

unable to coperate during dental treatment

ORAL MANIFESTATIONS Excessive salivation and drooling Muscle rigidity and repetitive muscle

movements contribute to poor oral hygiene Antiparkinson’s drugs may cause xerostomia,

nausea, tardive dykinesia

PREVENTION OF PROBLEMS Provide frequent dental recall and specialized

toothbrushes (e.g. Collis curve toothbrush, mechanical brushes) to maintain adequate oral hygiene

Salivary substitutes and topical fluoride are beneficial

Personal care providers should be educated about their role in assisting and maintaining the oral hygiene if these patients.

TREATMENT PLAN MODIFICTIONS Sedation may be required to overcome

muscle rigidity

MULTIPLE SCLEROSIS Most common autoimmune disease of the

nervous system Characterized by chronic and continuous

demyelination of the cortico-spinal tract of the brain and spinal cord

Affects the white matter in the cns and spares the pns with the exception of the optic nerve

MS is a Demyelinating Disease

Myelin – provides insulation to nerve processes (axons)

Blood vessel

Blood vessel

Blood vessel

Inflammation

Inflammation

Inflammation

Myelin – provides insulation to nerve processes (axons)

Blood vessel

Blood vessel

Blood vessel

Blood vessel

Blood vessel

Blood vessel

Inflammation

Inflammation

Inflammation

Inflammation

Inflammation

Inflammation

CLINICAL MANIFESTATIONS Disturbances in visual function Abnormal eye movements(nystagmus and

double vision) Incordination Spaticity Difficulty in walking Loss of balance Vertigo Tremor or paralysis of the limbs

ORAL COMPLICATIONS AND MANIFESTATIONS Dysarthria produces slow , irregular speech

with unusual separation of words referred to as scanning speech

Facial Parethesia Numbness of orofacial structures Trigeminal neuralgia wch can be relieved by

carbamezapine, clonazepam or amitripytline or surgery

TREATMENT PLANNING MODIFICATIONS Patients with stable disease and little motor

spasticity or weakness can receive routine dental care

With more advanced disease may require help in transferring to and from the dental chair, may have difficulty maintaining oral hygiene, and may be poor candidates for reconstructive and prosthetic procedures

Short morning are advised because fatigue is often worse in the afternoon

MYSTHENIA GRAVIS

MG Uncommon

Chronic

Autoimmune

Women tend to get it earlier (20 – 40)

Men get it later (70 – 80)

PATHOPHYSIOLOGY Normally impulses travel along the nerve to the ending and

release the neurotransmitter substance acetylcholine

Acetylcholine travels through the neuromuscular junction and binds to acetylcholine receptors, which are activated, and generate a muscle contraction

In myasthenia gravis, person’s own antibodies block, alter, or destroy the receptors for acetylcholine at the neuromuscular junction, preventing muscle contraction

S & S'S

In most cases, the first noticeable symptom is weakness of the eye muscles

Diplopia (blurred or double vision)Ptosis (drooping of one or both eyelids)

ALSO COMMON …

Majority also have weakness of face and throat muscles

Dysphagia (difficulty in swallowing)

Dysarthria (slurred speech)

Dysphonia (voice impairment )

Therefore, RISK of choking + aspiration

ALWAYS A B CS …

The degree of muscle weakness involved in MG varies greatly among patients

Within a year of onset, approximately 85–90% will develop Generalized myasthenia gravis, which is characterized by weakness in the trunk, arms, and legs

May lose muscle strength for breathing and need ventilator

DENTAL IMPLICATIONS Crisis rarely occurs suddenly and patients with

crisis do not present for dental treatment For routine dental care, awareness of

immunosuppressive medications and the potential for increased respiratory and oral secretions is mandatory

May antibiotics may worsen MG e.g. imipenem, fluoroquinolones

Ester local anesthetics may be toxic because they are hydrolyzed more slowly

Patients are very sensitive to non depolarizing muscle relaxants

MUSCULAR DYSTROPHY

WHAT IS MUSCULAR DYSTROPHY?

Genetic disease affecting skeletal muscles

Characterized by progressive muscle weakness and wasting, and loss of motor skills

X-linked recessive most common: Duchenne and Becker

More than 1 in 3500 males born Onset age from infancy to adulthood Most end up wheelchair-bound

DUCHENNE MUSCULAR DYSTROPHY

Most common type: 1 in 3500 Early onset: signs appear before 6

years of age Delayed development of motor skills Weakness/fatigue Difficulty in keeping balance Pseudohypertrophy Contractures Wheelchair dependent by ~12 years of

age

DMD - GOWER MANEUVER

BECKER MUSCULAR DYSTROPHY

Milder form of Duchenne 1 in 18,518 males Onset age: 5 to 15 years of age Loss of muscle mass and motor skills Weakness/fatigue Pseudohypertrophy Contractures Wheelchair dependent by 25-30

OTHER CONDITIONS CAUSED Scoliosis

Curvature due to contractures and muscle weakness

Cardiac Dilated cardiomyopathy Arrhythmia Shortness of breath and fatigue

Respiratory Progressive weakening of the diaphragm

Cognitive (non-progressive)

DENTAL CONSIDERATIONS Patients can often have conventional care in a

dental office that is wheelchair accessible Increased risk of toxicity to LA Slower onset of drug actions Increased duration of drug actions Poor candidates for intramuscular sedation Caution with nitrous oxide if respiration is

impaired May not tolerate supine position Consider steroid supplementation exogenous

prednisone