Kaya Chikitsa = Agni Chikitsa by Dr. Murthy

die Lehre von der Behandlung (Chikitsa) der Krankheiten, die den ganzen Körper (Kaya) betreffen = innere Medizin.

As we all know Agni is responsible for conversion of food into the body elements. Diseases emerge due to malfunctioning of the Agni in the body and hence if the Agni is set right again, then the patients get cured. Therefore the whole treatment in Ayurveda is based on the concept of Agni.
Dr. Murthy, director of Ayuwave said: "Kaya" means body and kaya chikitsa means internal medicine, but symbolical it means also Agni.

Conclusion: Therefore Kaya Chikitsa is in fact Agni Chikitsa.