Flaccid paralysis
Flaccid paralysis is a clinical manifestation characterized by weakness or paralysis and reduced muscle tone without other obvious cause (e.g., trauma). This abnormal condition may be caused by disease or by trauma affecting the nerves associated with the involved muscles. For example, if the somatic nerves to a skeletal muscle are severed, then the muscle will exhibit flaccid paralysis. When muscles enter this state, they become limp and cannot contract. This condition can become fatal if it affects the respiratory muscles, posing the threat of suffocation.
Causes
Polio and other viruses
The term acute flaccid paralysis (AFP) is often used to describe a sudden onset, as might be found with polio.
AFP is the most common sign of acute polio, and used for surveillance during polio outbreaks. AFP is also associated with a number of other pathogenic agents including enteroviruses, echoviruses, West Nile virus, and adenoviruses, among others.
Botulism
The Clostridium botulinum bacteria are the cause of botulism. Vegetative cells of C. botulinum may be ingested. Introduction of the bacteria may also occur via endospores in a wound. When the bacteria are in vivo, they induce flaccid paralysis. This happens because C. botulinum produces a toxin which blocks the release of acetylcholine. Botulism toxin blocks the exocytosis of presynaptic vesicles containing Acetylcholine (ACh). When this occurs, the muscles are unable to contract. Other symptoms associated with infection from this neurotoxin include double vision, blurred vision, drooping eyelids, slurred speech, difficulty swallowing, dry mouth, and muscle weakness. Botulism prevents muscle contraction by blocking the release of ACh, thereby halting postsynaptic activity of the neuromuscular junction. If its effects reach the respiratory muscles, then it can cause respiratory failure, leading to death.
