Muscles of our body are controlled via motor nerves that are stimulating their contraction. If this nervous transmission is interrupted by nerve or muscle disease then weakness of the involved muscles will result. The two common causes of severe neuromuscular weakness are myasthenia gravis and the Guillain-Barré syndrome.
It causes weakness that fluctuates from hour to hour and day to day. The muscles usually affected by this weakness control the eyes, face, neck, and throat. In half of patients weakness affects the arms or legs as well. The disease results from an auto-immune attack of the patient's immune system against receptors that stimulate muscle contraction.
What are the symptoms of myasthenia gravis?
Weakness of the eye muscles and eyelid resulting in double vision and drooping of the eyelids.
Weakness of the lips, mouth, tongue and throat can lead to slurred speech and difficulty in swallowing. Aspiration of food into the wind-pipe and lungs can lead to pneumonia, which can in turn precipitate respiratory failure.
some myasthenia patients experience an attack of weakness so severe that the muscles of breathing fail, necessitating placement on a respirator. This condition is called myasthenic crisis.
What is myasthenic crisis?
Myasthenic crisis occurs when myasthenic weakness affects the respiratory muscles and breathing is dangerously impaired leading to respiratory failure requiring intubation and mechanical ventilation. Crisis can be produced by infection or can occur spontaneously. Other causes of myasthenic crisis include aspiration, pregnancy, medications, and surgery. A high percentage of those who had a crisis will develop another one within a month.
How to treat mysthenic crisis?
With proper ventilatory support. The treatment is plasma phoresis involves the process of removing blood from the body and "cleansing" if of antibodies directed against acetylcholine receptors. It results in short-term improvement in 75% of patients, and can reduce the duration of intubation and mechanical ventilation. Intravenous immunoglobulin (IVIG) is another treatment option.
It results from a rapid attack of the immunologic system against the nerves that control muscle activity, leading to rapidly progressive paralysis. It is usually precipitated by an immune response to an antecedent viral infection (flu, cold, Zika virus or gastroenteritis).
They usually start with burning or tingling sensations in the distal extremities. This is followed by a rapidly progressive and symmetrical paralysis or weakness which begins in the legs and ascends to the head. The disease can progress to affect the muscles of swallowing and respiration. In this situation the volume of air in the lung decreases. Some patients with Guillain-Barré syndrome experience respiratory failure in which intubation and mechanical ventilation are required. It is in these patients that the treatment offered by a neuro-ICU is particularly helpful.
How is Guillain-Barré syndrome treated in a neuro-ICU?
There are two specific treatment approaches employed to combat Guillain-Barré syndrome:
Plasmaphroresis "cleansing" the blood of antibodies directed against the myelin sheaths of peripheral nerves. IVIG: This treatment involves the administration of high doses of intravenous immunoglobulin.
Complications associated with Guillain-Barré syndrome:
Disturbances in autonomic function associated with the condition can cause rapid heart rate and high blood pressure.
The experience if Guillaine-Barré is extremely stressful, and can lead to severe depression. This may require treatment.