Final answer:
The most likely diagnosis in a young male with a recent URI or GI infection that presents with nephritis is pyelonephritis.
Step-by-step explanation:
The most likely diagnosis in a young male with a recent URI or GI infection that presents with nephritis is pyelonephritis.
Pyelonephritis is an infection of the kidneys that is often caused by bacteria that travel from infections in the urinary tract.
Common signs and symptoms include fever, chills, lower back pain, and frequent painful urination.