Renal Cell Carcinoma: This is a common cause of spontaneous renal hemorrhage in adults, especially in the absence of trauma. The risk increases with age, and postmenopausal women are within a higher risk demographic.

Angiomyolipoma (AML) with Rupture: AMLs are benign tumors of the kidney that can rupture and cause bleeding, especially in women. While they can occur at any age, the risk of rupture may increase over time.
Arteriovenous Malformation (AVM) or Arteriovenous Fistula (AVF): These vascular anomalies can cause bleeding due to the abnormal connection between arteries and veins within the kidney.
Nephrolithiasis (Kidney Stones): Large stones can cause obstruction and subsequent bleeding, though this is less common without associated symptoms like pain.

Papillary Necrosis: Often associated with diabetes, analgesic abuse, or sickle cell disease, it can cause sloughing of renal papillae leading to bleeding. Although less common, missing this diagnosis could lead to significant morbidity.
Vasculitis (e.g., Polyarteritis Nodosa): Systemic vasculitis can affect renal vessels, leading to aneurysm formation and rupture. This condition, though rare, has a high morbidity and mortality if not promptly treated.
Renal Vein Thrombosis: More common in patients with nephrotic syndrome or dehydration, it can cause renal infarction and bleeding. This condition requires urgent diagnosis and treatment to preserve renal function.

Renal Metastasis: Metastatic disease to the kidney from other primary cancers can cause bleeding, though this is less common than primary renal tumors.
Tuberculosis or Other Infections: Certain infections can cause caseous necrosis and bleeding within the kidney, though these are relatively rare in the context of a bleeding kidney without other symptoms.
Sickle Cell Disease: In patients with sickle cell trait or disease, sickling within the renal medulla can lead to infarction and bleeding, especially under conditions of dehydration or acidosis.