AN inquest jury has returned a second open verdict into the death of a teenager who died ten months after he was punched once in a nightclub toilet.

Kristian Thompson, who was 18 at the time, suffered a severe brain injury after hitting his head on piping, but medical experts said it was not possible to conclude the attack caused his death.

A hearing at County Durham Coroners’ Court in Crook heard the cause of death was "unascertained".

Consultant neuropathologist Daniel Du Plessis said it was possible he could have suffered a seizure, but it was also possible he could have suffered from an unidentified heart abnormality.

Mr Thompson, of Garesfield Gardens, Burnopfield, died at St Nicholas Hospital in Northampton in July 2011, ten months after he was attacked in K2 nightclub in Consett.

The jury was told he was diagnosed with a personality disorder in the months after the attack and was sectioned under the mental health act.

Dr Du Plessis said there was a one in three chance of him developing epilepsy and he could have suffered from Sudden Unexplained Death through epilepsy, but added: “I cannot favour a cause of death based on speculation, however tempting it is. It is very plausible. I have to be satisfied on the balance of probability. I have to rely on clinical evidence.”

The jury heard Mr Thompson had not suffered seizures prior to his death, although he had become incontinent of urine.

Home Office Dr Mark Egan who said he could find no evidence of a heart abnormality either.

He said: “Possible causes are that this was a first fit and it has switched his heart off or this was one of the cases where a young person whose heart has stopped. “There is no way of determining either of these causes.”

The first inquest, in 2012, led by Senior Assistant Coroner Crispin Oliver, also returned an open verdict, which was quashed by two judges sitting at the High Court in London, paving the way for the second hearing today. (Monday August 8)

County Durham Coroner Andrew Tweddle directed the jury to return a second open verdict.

Kristian’s mother, Maxine Thompson-Curl, who launched the One Punch Can Kill campaign to warn others of the dangers of becoming involved in violent situations, said justice had not been done.

She said: “Common sense yet again has not been taken into consideration.

“We are gutted to be honest. It is extremely frustrating.”