Motor Neurone Disease Flashcards
pathophysiology of MND
This is a degenerative condition that affects motor neurons, namely the anterior horn cells of the spinal cord and the motor cranial nuclei. It causes lower motor neurone (LMN) and upper motor neurone (UMN) dysfunction, leading to a mixed UMN/LMN picture of muscular paralysis, usually with LMN signs predominating
types of MND
Amyotrophic Lateral Sclerosis
Progressive Bulbar Palsy - 9, 10, 11, 12
Progressive Muscular Atrophy - rare
Progressive lateral sclerosis – rare
progressive muscular atrophy
LMN signs fasciculation, wasting, weakness TENDON reflexes are preserved flexor plantar repsonses
begin asymmetrically in the small muscles f the hadn or feet or spread
primary lateral sclerosis
UMN signs typically initially in the legs before progressing to involve arms and bulbar muscles
Slower progression and better prognosis
Genetic component of MND
SOD1
autosomal dominant
symptoms of MND
1) Limb weakness - usually affects the upper limbs:
- drop objects or loss of dexterity
- Wrist drop, stiffness, weakness or cramping of the hands may also occur.
- wasting of muscles
- Fasciculations of the muscles.
2) Foot drop (early).
- Gait disorder.
- A sensation of heaviness of one or both legs.
- A tendency to trip.
- Difficulty in rising from low chairs and climbing stairs.
- Excessive fatigue when walking.
3) Bulbar onset
- slurred speech
- Wasting and fasciculation of the tongue.
- dysphagia
- mouth issues - dribbling, dysphonia
4) Resp onset
- dyspnoea and orthopnoea
- hypoventiliation overnight
pseudobulbar effect - wrong emotions at the inappropriate times
weight loss
signs of MND
LMN - weakness
atrophy
fasciculations - thigh hyporeflexia.
UMN - weakness hypertonia hyper-reflexia plantar responses bulbar muscles - spasticity - exaggerated jaw jerk
DD mimicking MND
Benign cramp fasciculation syndrome:
Fasciculation or cramps usually affecting large muscles (for example, calves).
The fasciculation is more common after exercise or with lack of sleep.
Cervical radiculomyelopathy - LMN wasting and weakness and UMN brisk reflexes and spasticity signs.
GBS
myasthenia gravis
ALS
cervical spondylotic radiculomyelopathy
spinal tumours
hyperthyroidism
diagnostic test for MND
EMG - Records electrical activity of muscle
Mx treatment for MND
prolong life
muscle cramps
too much saliva
breathlessness
anxiety induced breathlessness
ineffective cough
non-pharm
- nutrition
- psychosocial support
- physiotherapy
- exercise programmes
- use of special equipment or mobility aids.
Mx of symptoms -> MUSCLE CRAMPS 1. quinine - muscle cramps 2. baclofen 3rd gabapentin/dantrolene sodium/tizadine
-> for muscle stiffness, spasticity or increased tone Mx with the last 2 Mx
SALIVA
too much saliva - anitmuscarinic
Cognitive Impairment - glycopyrronium bromide
botulinum toxin type A
THICK TENACIOUS SALIVA
- Humidification, nebulisers and carbocisteine
RESP Sx
opioids for SOB
benzos for anxiety
respiratory impairment -> NIV
ALS to extend life and time to mechanical ventilation
- Riluzole
ineffective cough -> manual assisted cough/unassisted breath stacking
- exercise progeamme
- maintain joint range of movement
- prevent contractures
- reduce stiffness and discomfort
- optimise function and quality of life.
Type 1 resp failure
damage to lung tissue which prevents adequate oxygenation of the blood. However, the remaining normal lung is still sufficient to excrete carbon dioxide.
low O2 and normal or low CO2
Type 2 resp failure
alveolar ventilation is insufficient to excrete the carbon dioxide being produced. Inadequate ventilation is due to reduced ventilatory effort or inability to overcome increased resistance to ventilation.
hypercapnia
what type of resp failure does MND cause
Type 2 resp failure
causes of type 1 resp failure
ulmonary oedema, pneumonia, COPD, asthma, acute respiratory distress syndrome, chronic pulmonary fibrosis, pneumothorax, pulmonary embolism, pulmonary hypertension.
causes of type 2 resp failure
CNS depression
