Agency for Toxic Substances and Disease Registry
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Learning Objectives |
Upon completion of this section, you should be able to:
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Introduction |
The cholinergic toxidrome represents the acute phase of cholinesterase inhibitor poisoning. It results from the accumulation of excessive levels of acetylcholine in the synapses, glands, smooth muscles, and motor end plates where cholinergic receptors are found. Thus, the pathology of the cholinergic toxidrome (and the clinical picture that results) can best be understood with knowledge of the types of acetylcholine receptors, where they are located, and what physiological processes they modulate. |
Types of Cholinergic Receptors |
There are 2 main types of cholinergic receptors, nicotinic and muscarinic, so named because their effects are similar to those of nicotine and muscarine. The nicotinic and muscarinic receptors:
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Mixed Nicotinic and Muscarinic Effects |
In any given case, the patient's signs and symptoms may vary depending on the balance between sometimes apposing nicotinic and muscarinic effects. |
Summary Diagram of Signs and Symptoms |
Signs and symptoms of acetyl cholinesterase inhibitors --- and their relationship to nicotinic and muscarinic receptors --- are summarized in Figure 5 below. (Gershon and Shaw 1961; du Toit, Muller et al. 1981; Lotti 1992; Okumura, Takasu et al. 1996; Sidell 1997; Yokoyama, Araki et al. 1998; Reigart and Roberts 1999; Tareg, B et al. 2001; Erdman 2004) It is provided here, so that the reader can refer back to this figure as the topic is covered in further detail. Figure 5. Summary diagram showing where nicotinic and muscarinic receptors are found. Refer back to this when reading the following sections. |
Nicotinic vs. Muscarinic Effects | The exact signs and symptoms found in any given individual with cholinesterase toxicity vary depending on the balance of nicotinic and muscarinic stimulation. |
Key Points |
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Progress Check |