The first signs of poisoning by canned fish, meat or vegetables can most often occur 12-36 hours after the botulinum toxin enters the body (although the manifestation time can vary from 4-5 hours to 6-8 days).
Patients have symptoms in the form of general weakness and dizziness, dry mouth, decreased vision and diplopia (double vision). If the BoNT E serotype is affected, gastrointestinal symptoms (repeated vomiting, diarrhea, bloating and cramping) can occur at the initial stage.
Further distribution of neurotoxin leads to the development of:
- ptosis (prolapse of both upper eyelids), strabismus (squint) and anisocoria (asymmetric change in pupil size) due to bilateral paresis of the oculomotor muscles
- dysphagia (difficulty swallowing) and dysarthria (slurred speech);
- loss of mobility of facial muscles;
- difficulty breathing due to a decrease in the tone of the diaphragmatic and intercostal muscles.
In severe poisoning with neurotoxin C. Botulinum (ingestion of it in large quantities), there are observed: progressive descending paralysis of the lower extremities in the proximal-distal direction with loss of muscle function (leading to ataxia and loss of ability to move independently); reduction or disappearance of tendon reflexes; constipation - due to paralytic ileus; urinary retention or urinary incontinence (due to impaired detrusor muscle contraction).
Dysfunction of the respiratory muscles causes acute respiratory failure, fraught with a complete stop of breathing.
According to infectious disease specialists, foodborne botulism in case of canned food poisoning can vary from a mild form to a lightning lesion, which ends in death within 24 hours. Although a different combination of symptoms is possible, acute respiratory failure may occur before ophthalmopathy and other signs appear.