THE FOLLOWING ARTICLE APPEARED IN THE

JANUARY 2000 ISSUE

THE POISON SLEUTHS

DEATH BY SUCCINYLCHOLINE

-Dr. Anil Aggrawal

"Good morning doctor. Oh, my God, what are you doing today? You have the dead body of a young boy today. What happened to him? Please tell me.”

“Good morning Tarun. The name of this 26 year old young boy is Subodh, and he was a post-graduate medical student in a leading medical college of this city. For the last few months, he was in love with a fellow medical student Rita. Recently she had ditched him and had got married to someone else. This had hurt him very much. Actually a few days before her marriage, he had got a hint that she was going to ditch him. So he had gone to her to plead his case. At that time she was reportedly sitting with his fiancée Suresh, who literally pushed him out. There was a minor scuffle too, and Suresh had threatened to kill him, if he ever troubled Rita again. Today morning Subodh did not report at the O.P.D. his fellow doctors got suspicious, and went to his hostel room. There they found his dead body.”

“Oh, that is indeed very unfortunate. So do you think that Suresh has carried out his threat?”

“Let us get all the facts straight, before we can say anything. The body of Subodh was lying on his charpoy (a charpoy is a popular hand woven bed used in India mostly by villagers). A syringe was inserted in his leg vein. And there were two empty vials of Anectine lying on the floor beside him.”

“What is Anectine doctor?”

“Tarun, Anectine is the trade name of a very useful drug in medical practice. Its chemical name is succinylcholine, and it is a very useful drug for surgical operations.”

“Oh, so obviously Subodh has not died of Succinylcholine. How has he actually died doctor? And do you think he has committed suicide?”

“Why can’t he die of succinylcholine Tarun?”

“How can a useful drug kill a person doctor? He must have died of something else.”

“This is a mistake Tarun. All drugs are poisons in large doses, and many poisons may act as useful drugs in extremely small doses. Some time back I told you the story of a death by Digitalis (See Science Reporter Death By Digitalis (August 1999, Pages 22-24). Now Digitalis as you know is a very useful drug in several heart ailments, and yet it killed when given in more than the required dose. So it is incorrect for you to think that a useful drug can not kill. Now to your other questions. No one knows how he has actually died, and that is indeed why the police has handed over his dead body to me. As far as your conjecture concerning suicide is concerned, he might indeed have committed suicide. The scene certainly appears as if he has committed suicide. Had the room been locked from inside, and a suicide note found, we would have very strongly thought that he has committed a suicide. But neither was the room locked from inside, nor was any suicide note found. The police knows that Suresh had threatened to kill him some days back. Suresh - like Subodh - is a medical student and knows about drugs like succinylcholine. So it is quite clear that Suresh is the prime suspect with police. In fact, Subodh’s parents have lodged an FIR with the police, naming Suresh as the possible killer.”

“Doctor, is succinylcholine very commonly used as a homicidal poison?”

“No, not at all. In fact, I am aware of only one instance, when a person has been convicted of murder by succinylcholine. In 1983, a Texas-licensed vocational nurse Genene Jones was tried on a single charge of murder, even though those who had worked with her believed she had been responsible for the deaths of more than a dozen children under her care. In her first 31 days of work for a child specialist, nine incidents of respiratory failure involving eight patients occurred before Jones was finally arrested. She was finally sentenced to 99 years for the murder of one patient and 60 years for the attempted murder of a second. So succinylcholine can definitely be used for homicide, although its use is very rare. But before we come to any conclusions, we have to first prove that Subodh indeed died of succinylcholine poisoning.”

“How are you going to prove that doctor?”

“Tarun, to do that you must know a little bit about succinylcholine and how it actually kills. Succinylcholine actually mimics a natural chemical within the body, acetylcholine. The function of acetylcholine is to make a muscle contract. Whenever we make any muscular movement- be it walking, running, climbing, even laughing and crying - some muscle has to contract, and in most of the cases, it is the acetylcholine, which makes the muscle contract. First of all, a nerve impulse goes from the brain to the required muscle. Then a tiny amount of acetylcholine is liberated at neuro-muscular junction..”

“Doctor, what is neuro-muscular junction?”

“Tarun, it is technical name of the junction of that nerve with the muscle. It is also known as the myoneural junction. So I was telling you about acetylcholine, being released at the neuro-muscular junction. This small amount of acetylcholine starts a train of physical and chemical events at that junction, which ultimately leads to contraction of that muscle. Whole of this procedure takes a fraction of a second only. Of course, once acetylcholine has succeeded in making the muscle contract, it must be removed from the junction. For if it is not removed, the muscle would remain in a contracted position. And this can be very disastrous indeed. For instance, when the heart contracts, it is due to acetylcholine making the heart muscle contract. But if this acetylcholine could not be removed, the heart muscle would remain in a contracted state, and no useful purpose would be served. In fact, the person would die within minutes.”

“Oh, I see. How does the body remove this acetylcholine then doctor?”

“There is another chemical at the junction- acetyl cholinesterase. It destroys the acetylcholine, after it has done its work. Succinylcholine may be regarded as a sister chemical to acetylcholine. Earlier I was telling you that succinylcholine is widely used in surgery. Now you can understand why. In most abdominal operations, the doctors want that the abdominal muscles remain in a relaxed state. If the muscle is relaxed, doctors can make incisions easily, and make several manipulations in the abdomen easily. Succinylcholine is used to relax the abdominal muscles….”

“Just a minute doctor. You said that acetylcholine makes the muscles contract, and also that succinylcholine is a sister chemical to acetylcholine. Doesn’t it mean that succinylcholine should also contract the abdominal muscles?”

“That is an interesting question, Tarun. Actually succinylcholine belongs to a class of muscle relaxants, known as depolarizers. Let me first tell you the meaning of this new term. Earlier I told you that acetylcholine starts a train of physical and chemical events at the neuro-muscular junction, which ultimately leads to contraction of muscle. One of these events is the reversal of the electric charge normally found on the muscle fibres. In other words, the muscle is depolarized. Since succinylcholine depolarizes the muscle, it is known as a depolarizer or a depolarizing agent. There are several other depolarizing agents. One of these is decamethonium. It also acts very much like succinylcholine. All depolarizing agents, including succinylcholine, initially do act much like acetylcholine, i.e. they cause the muscle to contract. But since doctors give succinylcholine continuously in an intravenous drip, it keeps contracting the muscles. Finally a stage comes, when the muscle is exhausted, i.e. it can no more work. In other words it gets paralyzed. That is why despite acting very much like acetylcholine, succinylcholine paralyses the muscles, while acetylcholine makes the muscles contract. When an animal is injected with succinylcholine, the animal indeed shows repeated contractual movements of the muscles. These repetitive muscular movements have been given the name fasciculations. After a few minutes of fasciculations, the muscles get tired, and paralysis sets in.”

“Doctor, is succinylcholine easily available in the market?”

“Oh, yes. Succinylcholine is available as injections of Anectine. It is marketed also as a sterile powder. Injections are available in three different concentrations- 20 mg/ml, 50 mg/ml and 100 mg/ml. Now that you have understood some basic facts about succinylcholine, I can tell you, how this drug kills. It repeatedly stimulates and finally paralyses, respiratory muscles. This causes respiratory failure and death. The usual dose in surgical operations is 20 mg, but more can be given too. It is interesting to note that this succinylcholine not only relaxes abdominal muscles, but also respiratory muscles, so the anesthetists maintain the respiration of the patient artificially throughout the operation. If however the same dose is injected by a person for suicidal purposes, or by someone with homicidal intentions, it would easily kill, because there is no one to support the respiration artificially. In other words, the same dose helps a surgeon in operation, and the very same dose would kill a person, if it were given with homicidal intentions.”

“Doctor how are we going to prove that Subodh indeed died of succinylcholine poisoning?”

“Tarun, in the body, succinylcholine is broken down by enzymes in human plasma, especially by one known as pseudocholinesterase, into succinic acid and nitrogen containing choline. Both of these are normal components of human tissues. That is why it is indeed difficult to say by chemical examination of Subodh’s viscera alone that he died of succinylcholine poisoning. However, I have found the lungs to be swollen and loaded with water. In technical terms we say that the lungs are oedematous. This is a sign that Subodh’s respiration was compromised just before his death. If we couple this finding with other findings at the scene of his death, it becomes very plain and simple that Subodh has died of succinylcholine poisoning. Regarding the manner of death, I do not think, Suresh has injected this drug into Subodh’s body. Subodh would simply not allowed him to do that. It appears that Subodh has committed suicide because of failure in love.”

“Doctor, had someone caught him during the act, or just after it, could he have been saved? In other words, what is the antidote of succinylcholine?”

“Tarun, unfortunately there is no antidote to succinylcholine. The only thing one could have done is to give artificial respiration as the respiration is compromised in succinylcholine poisoning.”

"This was a most interesting discussion doctor. Tell me what are you going to tell me the next time?"

"Tarun, next time, I would tell you about a very interesting poison - Gold."