Thai king recovering after lung inflammation

A well-wisher holds a portrait of Thailand's King Bhumibol Adulyadej at Siriraj Hospital in Bangkok September 21, 2009.

BANGKOK (Reuters) - Tests on Thailand's 81-year-old King Bhumibol Adulyadej show inflammation in his lungs, the Royal Household Bureau said on Monday, adding he was responding well to treatment during his longest hospitalisation in two years.

The king is regarded by his people as a semi-divine source of unity and stability in a country beset by four years of political turmoil that has been marked by several changes in government and frequent mass street protests.

The world's longest-reigning monarch was being given antibiotics intravenously to treat fever after an x-ray late on Sunday detected a lung problem, a bureau statement said.

"His fever has lessened since this morning. His general condition is good," the statement said.

The king was admitted to Bangkok's Siriraj hospital on Sept. 19 with fever, fatigue and loss of appetite, three days after a routine check-up. It is his longest hospital stay since October 2007.

On Thursday, the bureau said he was receiving physical therapy to help him regain strength after the fever subsided and tests showed no signs of bacteria or virus.

Last month, the king called for unity in Thailand in a rare comment on the country's political crisis, which has triggered credit rating downgrades and unsettled investors in Southeast Asia's second-biggest economy.

(Reporting by Kittipong Soonprasert; Writing by Martin Petty; Editing by Jason Szep and Dean Yates)