Urinary Tract Infection (UTI): This is the most common cause of hematuria and fever, especially in women. Bacteria such as E. coli can infect the urinary tract, leading to symptoms like dysuria, frequency, and hematuria, along with systemic symptoms like fever.

Kidney Stones: Stones in the urinary tract can cause obstruction, leading to infection and subsequent hematuria and fever. The pain associated with kidney stones can be severe and is often accompanied by nausea and vomiting.
Pyelonephritis: An infection of the kidney, pyelonephritis can cause fever, flank pain, and hematuria. It is more severe than a lower urinary tract infection and requires prompt antibiotic treatment.
Prostatitis: In men, an inflamed prostate can cause symptoms including hematuria, fever, and difficulty urinating. It can be acute or chronic and is usually caused by bacterial infection.

Sepsis from a Urinary Source: Although less common, sepsis originating from a urinary tract infection is a medical emergency. It can present with hematuria, fever, and signs of systemic inflammation, requiring immediate intervention.
Renal Tuberculosis: A less common but serious condition, renal TB can cause hematuria, fever, and weight loss. It is crucial to consider in endemic areas or in patients with a history of TB.
Malignancy: Certain cancers, like bladder or kidney cancer, can present with hematuria and, less commonly, fever. Early detection is critical for treatment outcomes.

Vasculitis: Conditions like IgA vasculitis (Henoch-Schönlein purpura) can cause hematuria and fever, along with skin and joint symptoms. It is more common in children but can occur in adults.
Sickle Cell Disease: Patients with sickle cell disease can experience hematuria due to sickling in the kidney, and if infected, may also present with fever.
Goodpasture Syndrome: A rare autoimmune disease that can cause glomerulonephritis, leading to hematuria, and if there's an associated infection, fever. It is characterized by antibodies against the glomerular basement membrane.