Sepsis: The presentation of fever, chills, rigors, and elevated lactic acid is highly suggestive of sepsis. The elevated CK and troponin could indicate muscle and cardiac involvement, which can occur in severe sepsis. Full body tremors could be due to the systemic inflammatory response.

Meningitis: Although the patient has preserved awareness, meningitis can present with fever, chills, and rigors. The full body tremors could be a manifestation of the infection affecting the central nervous system.
Pneumonia: Community-acquired or hospital-acquired pneumonia could explain the fever, chills, and rigors. Elevated lactic acid and CK could be seen in severe pneumonia with associated muscle injury.
Endocarditis: The presence of fever, chills, and elevated troponin could suggest endocarditis, especially if the patient has a history of valvular heart disease. Full body tremors could be a manifestation of embolic phenomena.

Neuroleptic Malignant Syndrome (NMS): Although less likely, NMS is a life-threatening condition that can present with fever, rigors, and muscle rigidity. The elevated CK and full body tremors could be consistent with NMS.
Thyroid Storm: This is a life-threatening condition that can present with fever, chills, and tremors. The elevated troponin and CK could be seen in thyroid storm due to the hypermetabolic state.
Malignant Hyperthermia: This is a rare but life-threatening condition that can occur in response to certain anesthetics or other triggers. The presentation of fever, rigors, and elevated CK is consistent with malignant hyperthermia.

Streptococcal Toxic Shock Syndrome: This is a rare but life-threatening condition that can present with fever, chills, and rigors. The elevated lactic acid and CK could be seen in this condition.
Rhabdomyolysis: Although the patient has elevated CK, rhabdomyolysis is a rare condition that can present with muscle weakness and elevated CK. The full body tremors could be a manifestation of the underlying condition leading to rhabdomyolysis.