Final answer:
The principal diagnosis for a patient with AIDS admitted to the hospital for treatment of Pneumocystis carinii pneumonia would be Pneumocystis pneumonia.
Step-by-step explanation:
The principal diagnosis for a patient with AIDS admitted to the hospital for treatment of Pneumocystis carinii pneumonia would be Pneumocystis pneumonia. Pneumocystis pneumonia is a type of pneumonia caused by the fungus Pneumocystis jirovecii. It is commonly seen in patients with AIDS and other immunocompromised individuals. The best treatment for Pneumocystis pneumonia is the combination drug trimethoprim-sulfamethoxazole (TMP/SMZ).