When you see community acquired pneumonia and the ICU intern mentions that there was a lot of blood during the intubation your mind needs to starting thinking about pulmonary-renal syndromes. Ask the family about a history of sinusitis, pay extra-attention to the red cells on the U/A, fire off that ANCA and anti-GBM ab. It is the job of the nephrologist to consider this diagnosis, if you don',t no one will and a week later when the ICU and ID teams begin scratching their collective heads on why this patient is not behaving like a typical pneumonia you will have the reason and prevent a low yield and dangerous bronchoscopy because you will have the serologic evidence you need to get the renal biopsy for the win.
The cryptic case of acute kidney injury starts off just like the banal case of acute renal failure, a rise in creatinine. If you open your eyes to the faint threads that don't quite fit the standard narrative you will be more receptive to seeing the clues you need to make that rare diagnosis.
Stay vigilant and stay hungry