Due to the death of these motor neurons, the muscle fibres that are supplied by them undergo atrophic change. This Neuro degeneration can occur in lower and upper parts of the motor neuron systems. The primary theory behind Motor neurone disease is that, neurotransmitter glutamate causes cell injury to nerve cells by over excitation of these cells. Other possible causes of moto neurone disease include, free radical damage, oxidative stress and autoimmune diseases. There have been several risk factors identified with Motor neurone disease however the cause was yet unknown (Gal, Kilty, …show more content…
One of the uttermost important nursing diagnosis of Motor neurone disease is ineffective airway clearance related to respiratory muscle weakness evidenced by dyspnoea, weakened cough, orthopnoea, hypoxia, headaches and general tiredness. This diagnosis found to be critical as most deaths from MND occur due to respiratory failure (Miller, 2009).
Patients with MND have decreased number of motor units in respiratory muscles, which causes the force produced by respiratory muscles to be weaker than usual, therefore the capacity to overcome the respiratory load is less. As the upper motor neurone input is interrupted in MND, voluntary control of breathing can be impaired. Respiratory dysfunction can also be contributed by the abnormal central respiratory drive. During sleep, hypotonia of intercostal muscles, weakened diaphragm and depressed central respiratory drive causes hypoventilation as not enough pressure can be generated to overcome respiratory load. Early manifestation of respiratory dysfunction is sleep-disordered breathing. This decrease in respiratory muscle strength is reflected by Forced vital capacity (Oliver, 2008). The ability to produce an effective cough is also supressed by respiratory muscle weakness. Producing an effective cough is important, as it is one of the body’s defence mechanisms. Excessive secretion and airborne particle clearance and aspiration prevention is done through coughing.