Severely poisoned patients may develop seizures, skeletal-muscle paralysis, cardiac arrhythmias and respiratory failure, or may become comatose.
[wwwn.cdc.gov]
Complications include severe bronchorrhea, seizures, weakness, and neuropathy. Respiratory failure is the most common cause of death.
[emedicine.medscape.com]
Symptoms of parathion poisoning can include headache, nausea, vomiting, abdominal cramps, diarrhea, generalized muscle weakness and twitching, slurred speech, pinpoint pupils
[wwwn.cdc.gov]