Sarin attack happened in Tokyo Subway in March 20, 1995. It is famous that metro in tokyo is extremely crowded in rush hour, during which the terror happened. 13 people died and 6,300 people were injured.

Tokyo Sarin Terror Incident

Medical relation: (pharmacology) Sarin is an organophosphate, an Acetylcholine(Ach) Esterase Inhibitor. Different from other AchE-I, an organophosphate is irreversible AchE-I. Organophosphate is typically used as insecticides by farmers, who are usually intoxicated by organophosphates. But organophosphates are very toxiic to insects but not very so for humans. But some organophosphates are very toxic to humans, which are called nerve gas. Sarin is one of them.

Pathomechanism: Ach level increases in Neuro Musculor Junction(NMJ), which causes twitches and spasms. The Ach Receptor Nm, which can be found in NMJ, is known that it is desensitized quickly. If Ach level is kept high, then muscle can not be moved any more. The person dies due to suffocation once the paralysis reaches the diaphragm.

It is, so called, a choline crisis, which is different from myathenia crisis, which happens lack of Ach. Again pathomechanism of sarin toxicity is too much Ach which desensitizes the Nm Receptor. Myathenia crisis can be helped by cholinomimetics, but choline cirisis can not be. Not only that, the patients get worse if you give more Ach because it desensitize the Recepter further.

Treatment:

1. Muscuranic Antagonist, such as atropin, help relieve other symptoms known as DUMBBELLS; diarrhea, urination, miosis, bradycardia, lacrimiation, salivation, sweating. Because these symptoms are caused by Muscuranic recepters.
   
   miosis

2. Atropin does not decrease the symptoms of suffocation which kills patients. This is because skeletal muscle paralysis is caused by another recepter, muscular nicotinic recepter Nm.
3. Also The problem is irreversibly bound sarin to the AchE. It is PAM which can remove the sarin from AchE. AchE released from the nerve gas can work again and decrease the level of Ach.

In St. Luke's International Hospital on the terror day: It accepted more than 100 patients from the terror attack. The common symptoms were sever miosis. It is typically seen in case of organophophate toxicity, which is commonly used as insecticides. Dr. Ishimatsu used atropine, but it did not work well enough to the direct cause of the death, suffocation(see above).

St. Luke's International Hospital.

Many patients complained that they can not see, they can not breathe. Some patients are put into mechanical ventilation. Dr. Ishimatsu did not understand what causes these symptoms.

One year back, there was a sarin incidence in Matsumoto city. All members of a family died. Dr. Yanagisawa did autopsy of the victims and he found sarin. It is later found that this case was also done by the same occult organization. Dr. Yanagisawa called Dr. Ishimatsu to tell him the symptoms are similar to the previous case in Matsumoto.

PAM

There are a few amount of PAM in the hospital. He used the drug in the severely ill patient. They became better after the drug administration. He was convinced. but there are not so many ampules of such drug. The hospital called many drug companies to find addtional amples. Finally they got the drugs for 230 patients. Many patients was rescured by the drug.

Reference

• Tokyo Metro sarin attack
• http://www5a.biglobe.ne.jp/~t-senoo/Ningen/tikatetu_sarin/tikatetu_sarin.htm
• https://ja.wikipedia.org/wiki/%E5%9C%B0%E4%B8%8B%E9%89%84%E3%82%B5%E3%83%AA%E3%83%B3%E4%BA%8B%E4%BB%B6
• Pathomechanism: Kaplan USMLE Step1 Pharmacology.