History and exam
Key diagnostic factors
common
presence of risk factors
Key risk factors include history of self-harm or recent interpersonal conflict, mental illness, alcohol or drug abuse, and pesticide availability and ease of access.
increased secretions
One of the main clinical signs of cholinergic excess. Patients may present with bronchorrhoea, excessive lacrimation, and salivation.
fasciculations
These are much more noticeable early on and are diagnostic. They usually occur in peri-orbital, chest, or leg muscles.
pinpoint pupils
These are almost universally present in severe cases and do not respond to naloxone (an opioid receptor antagonist used in the treatment of opioid overdose). Naloxone is not recommended for administration in organophosphate poisoning; however, it is often given by clinicians in response to pinpoint pupils and an assumption of opiate poisoning.
distinctive odour
Distinctive odour of solvent can often be detected on a patient.
chest crackles and rhonchi
Widespread wheezes and crackles indicate bronchospasm and pulmonary oedema.
semi-conscious/coma
Patient may be semi-conscious at presentation; coma indicates a worse prognosis.
Other diagnostic factors
common
visual disturbances
Patient may report blurred vision.
vomiting
Nausea and vomiting are common muscarinic symptoms of organophosphate poisoning.
influenza-like syndrome
Exposure, even dermal, may result in an influenza-like syndrome (e.g., fatigue, runny nose, headache, dizziness, anorexia, sweating, diarrhoea, and muscle weakness).
urinary or faecal incontinence
Patient may report incontinence, or it may be a sign on presentation if a patient is semi-conscious or confused.
proximal muscle weakness
This may occur early on, or after other signs are resolving.
abnormal deep tendon reflexes
Frequently increased early on, and decreased or absent later.
abnormal heart rate
Extreme bradycardia or tachycardia may be seen.
abnormal blood pressure
Hypertension may be seen. Refractory hypotension is a far more concerning sign, indicating a grave prognosis.
decreased respiration
Oxygen saturation is usually low. Respiratory failure is more common with severe poisoning.
hypothermia
Mild to moderate hypothermia is often present on admission if atropine treatment has not been given.
uncommon
seizures
Seizures are more common with severe poisoning.
delayed-onset central nervous system and peripheral (predominantly motor) neuropathy
Onset is 1 to 5 weeks. The neuropathy may be severe and can lead to permanent disability. It may also have upper motor neuron disease features.
Risk factors
strong
pesticide availability
A major factor determining the frequency with which fatal and non-fatal acute pesticide poisoning occurs in various countries.[7]
history of self-harm or recent interpersonal conflict
mental illness
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