Rashtriya Janata Dal (RJD) leader Lalu Prasad, who was brought to AIIMS here on Tuesday, was kept under observation overnight in the emergency department before being discharged at around 3 am, official sources said.

The former Bihar chief minister, 73, was brought to AIIMS here at around 9 pm on Tuesday after being referred by a medical board of the Rajendra Institute of Medical Sciences (RIMS), Ranchi, as his health condition deteriorated there.

"Prasad was kept under observation in the Emergency department overnight. He was evaluated and was discharged at around 3 am," a source here said.

Prasad was sentenced by a special CBI court to five years imprisonment and slapped with a fine of Rs 60 lakh on February 21 after being convicted in the embezzlement of Rs 139 crore from Doranda treasury in the fodder scam.

The court had convicted Prasad on February 15 and pronounced the quantum of the sentence after hearing the arguments virtually.

The incarcerated politician suffers from multiple ailments, including renal problems.

"Prasad's creatinine level has increased to 4.6, which was earlier at 3.5. Blood sugar and blood pressure have been fluctuating. The sugar level is hovering between 150 and 200 mg/dl," Dr Vidyapati, who heads the seven-member team of doctors formed by RIMS to treat Prasad, had said Tuesday.

"His kidney is functioning at 15-20 per cent capacity," he had said.