Source, mechanism of poisoning, clinical signs, diagnosis, treatment, and differential diagnosis of nux-vomica poisoning.

1. Poisoning of Nux-vomica

2. source of poisoning
• seeds of ripe fruits of the plant Strychnos nux vomica

4. Mechanism of action
Ingestion of nuxvomica
Blocks the inhibitory pathway exerted by Renshaw cells over the motor
cells in the spinal cord
Lowers the threshold for stimulation of spinal reflexes
Any slight stimulus (noise, light, breeze) cause reflex action producing
general contraction of the muscles
Convulsion

5. Clinical signs
• Stiffness of muscle
• Opisthotonus condition
• Emprosthotonus and Pleurosthotonus(sometimes)
• Cyanosis
• Blood stained froth from mouth
• Crease in and around the eyelid (Risus Sardonicus)
• Dilated pupils
• Loss of consciousness
• Asphyxia due to the spasm of diaphragm and thoracic muscle
• Hypoxia causing medullary paralysis and death

6. Diagnosis
a. On the basis of sign and symptoms
b. On the basis of postmortem changes
• Rigor mortis appear early but is not necessarily prolonged.
• Occasional rupture of stretched muscles.
• Hemorrhage under peritoneal coat of stomach.
c. Lab diagnosis
• Collection of sample: brain, spinal cord and blood
• Chemical analysis

7. Treatment
• The patient is kept in dark, noiseless room so as to minimize stimulation.
• Diazepam at the rate 0.1-0.5 mg/kg body weight is given IV initially and then
phenobarbital IV.
• General anaesthetic ( Curare, gallamine or pancuronium bromide).
• Short acting barbiturates like phenobarbital sodium or sodium amytal at the rate
0.3- o.6 gm/kg body weight IV.
• Stomach wash with dil. Solution of potassium permanganate/ tannic acid
• Activated charcoal
• Acidification of urine Increases excretion of strychnine.

8. Differential diagnosis
• Tetanus