Pin point pupil poisoning and Oxalic acid poisoning

Introduction:

• Poisoning causing myosis  (constriction of pupil):  Carbolic  acid  (phenol),  chloralhydrate,  chloroform,barbiturates  (slightly contracted  and  reacting  to  light),  organophosphates,
• opioids  (morphine),mushroom  poisoning, nitrobenzene  (first  contracted,  later  dilated),  early nicotine poisoning  (later  dilated),  and  pontine hemorrhage.
• Pin  point  pupil  can  be  caused  by:  Opioids  (morphine). organophosphates, phenothiazines,  clonidine,  mushroom  poisoning,  chloral  hydrate, carbolic  acid  and  pontine hemorrhage.
• Hippus reaction :  It  is  alternate  constriction  and  dilatation  of pupil. It  is  seen  in  poisoning  with  aconite  and barbiturates.
• Poisoning  causing  mydriasis  (dilatation  of  pupil) : Dhatura,atropine,or belladona),   aconite,  nux  vomica,  ether,  viper  venom,  cyanide,  cocaine,  chloroform,  calatropis,  pethidine  and  barium carbonate

OXALIC  ACID POISONING:

• It  is  also  known as  salt  of sorrel  or acid  of sugar.It  is  used  to  erase  writing as bleaching  agent  and  in calico printing.  It occurs  in  leaves  of rhubarb.
• Local  effects  :  Oxalic acid  rarely  damages  the  skin but  readily  corrode the  mucus  membrane of digestive  tract.
• Systemic effects: Shock:  Large  doses  can  cause  death  from  shock;
• Hypocalcemia  :  Oxalic acid readily  combines with calcium  to  cause  hypocalcemia,  which  may  present  as tingling,  numbness,  twitching,  tetany  and  convulsions, 
• Renal damage:  It is  due to  oxaluria  which  may cause  tubular  necrosis
•  Antidote:  Any  calcium  preparation  (e.g.  calcium  gluconate/chloride,  lime  water, suspension  of  chalk)  which  converts poison  into  insoluble  calcium  oxalate is  an  antidote  for  oxalate poisoning

Don’t Forget to Solve all the previous Year Question asked on Pin point pupil poisoning and Oxalic acid poisoning