Differential Diagnosis for Pneumonia with Renal Failure
Single Most Likely Diagnosis
- Sepsis: This is the most likely diagnosis, as pneumonia can lead to sepsis, which in turn can cause renal failure due to hypoperfusion and direct effects of inflammatory mediators on the kidneys.
Other Likely Diagnoses
- Acute Tubular Necrosis (ATN): Pneumonia can lead to hypoxia and hypoperfusion, causing ATN, which is a common cause of renal failure in critically ill patients.
- Prerenal Acute Kidney Injury (AKI): Dehydration, hypovolemia, or heart failure can occur in the context of pneumonia, leading to prerenal AKI.
- Postrenal AKI: While less common, obstruction of the urinary tract (e.g., due to kidney stones or bladder outlet obstruction) can occur in patients with pneumonia, especially if they are bedridden or have neurogenic bladder.
Do Not Miss Diagnoses
- Pulmonary-renal syndromes (e.g., Goodpasture's syndrome, ANCA-associated vasculitis): These conditions can present with both pneumonia and renal failure, and are potentially treatable with immunosuppressive therapy.
- Endocarditis: Infective endocarditis can cause both pneumonia (due to septic emboli) and renal failure (due to emboli or immune complex deposition).
- Leptospirosis: This zoonotic infection can cause both pneumonia and renal failure, and is often underdiagnosed.
Rare Diagnoses
- Hantavirus pulmonary syndrome: A rare viral infection that can cause severe pneumonia and renal failure.
- Mycoplasma pneumoniae-induced renal failure: While M. pneumoniae is a common cause of pneumonia, it is a rare cause of renal failure.
- Legionnaires' disease with renal failure: Legionella pneumonia can occasionally cause renal failure, especially in immunocompromised patients.