Cape Town - The mystery illness that struck down ex-All Blacks flank Adam Thomson has been diagnosed as lumbar discitis, a painful infection of the spine.
According to the Stuff website, Thomson, 35, has been in hospital in Tokyo for over a week with doctors struggling to identify the problem that has given him "excruciating pain" in the lower back in particular.
The 29-Test All Black was rushed to the A&E department in the middle of the night.
Discitis is inflammation amid the discs of the spine, leading to pain and is relatively uncommon.
A spokesperson for Thomson said he was expected to make a full recovery and there were no plans for him to return to New Zealand "at this moment, the team there is handling it well".
Thomson played almost a century of Super Rugby matches for the Highlanders, Reds and Rebels and first played in Tokyo in 2013.
Thomson's partner, Jessie Gurunathan, said the illness gave her the "biggest fright in the 6 years we've been doing life together."