Cholinergic Crisis
What is Cholinergic Crisis?
The crisis in myasthenia gravis which is a type of neuromuscular disease is divided into two main types: cholinergic crisis and myasthenic crisis. Cholinergic crisis rarely happens and is caused by an excess of acetylcholine resulting to inactivity or the decrease of the AChE enzyme, which usually breaks down acetylcholine.
Cholinergic crisis can also be a result of some types of nerve exposures. In medicine, cholinergic crisis is seen in individuals who suffer from myasthenia gravis with an inconsistent weakening of the medications who uses a high dose of anticholinesterase drugs.
When cholinergic crisis takes place, the muscles cannot anymore react to the inflow of acetylcholine so the symptoms usually follow.
Cholinergic crisis is also sub-divided into:
- Nicotinic crisis – The muscle weakens and twitches involuntarily, dysphagia or the difficulty of swallowing, and cramping.
- Muscarinic crisis – Vision becomes blurry, pain in the abdomen can be felt, vomiting, diarrhea, nausea, discharge and secretion of tears, and too much secretion of the bronchial passages.
What are the Signs and Symptoms?
Since the muscles stop reacting to the acetylcholine, symptoms may occur. These include:
- Salivation
- Failure of the respiratory system due to the insufficient gas exchange
- Flaccid paralysis wherein the muscle tone is decreased by paralysis or enfeeblement that might be caused by a disease or trauma
- Too much sweating
- Bronchial secretions together with miosis
Cholinergic crisis can be concealed together by an accompanied usage of atropine which is a type of medication alongside which cholinesterase inhibitor so that the side effects can be prevented.
Flaccid paralysis is one of the symptoms of cholinergic crisis which can be prominent from myasthenia gravis by using a drug called Tensilon, which strengthens the muscles for myasthenia gravis but aggravate the paralysis brought about by cholinergic crisis.
What are the Treatments for Cholinergic Crisis?
A diagnosis will be done first by the physician by the use of edrophonium drug to determine which crisis is present. Individuals who have myasthenia gravis will be given this drug and if the paralysis becomes worse, a true cholinergic crisis is there.
Otherwise it is myasthenic crisis if the patient’s muscle strength is increased after the drug intake. As the diagnosis is done knowing that the patient is really positive with cholinergic crisis, a standard course of treatment comes after. There are a number of cholinergic crisis elements and some can be treated with atropine which is an antimuscarinic drug.
The most essential element cannot be treated by antimuscarinic drugs which is respiratory arrest, wherein a failure in the lungs occurs causing the normal breathing to cease. The brain communicates with the muscles at the neuromuscular junction and the activation of nicotinic acetycholine receptors functions due to the acetycholine.
This later on results to the contraction of muscles. Since atropine obstructs another set of receptors which are acetycholine receptors, atropine will not help the patient with cholinergic crisis refine the capacity to breath and improve muscle strength.
The patient will then be required to use mechanical ventilation by way of endotracheal intubation as a support to help the breathing until the crisis settles on its own. The damage in the respiratory system due to cholinergic crisis has still no therapy or pharmacologic solutions.
Myasthenic Vs Cholinergic Crisis
As compared to myasthenic crisis, cholinergic crisis predisposes a greater threat since it mainly weakens the respiratory and pharyngeal muscles, and with a wavering course in a more severe cases.
The symptoms of cholinergic crisis and myasthenic crisis may be similar but the way they are treated is different. The results of the Tensilon test are also different since the body has its dissimilar reactions with the two crises.
Cholinergic crisis happens when too much cholinergic medications are taken and if not treated accordingly, respiratory failure and hypotension might happen. While myasthenic crisis requires the application of more anticholesterase drugs, cholinergic crisis must not use these along with atropine in order to enhance and maintain respiration.
References
- http://www.wisegeek.com/what-is-a-cholinergic-crisis.htm
- http://www.uptodate.com/contents/myasthenic-crisis#H107469123
- http://www.cram.com/flashcards/135-e2-cholinergic-drugs-3001171
- Marx, John A. Marx (2014). Rosen’s emergency medicine : concepts and clinical practice (8th ed.). Philadelphia, PA: Elsevier/Saunders. pp. 1441–1444.
- Kandel E, Schwartz J, Jessel T, Siegelbaum S, Hudspeth A (2012). Principles of Neural Science (5 ed.). pp. 318–19.
- Kaminski, Henry J. (2009-03-02). Myasthenia Gravis and Related Disorders. Springer Science & Business Media. ISBN 9781597451567.