From the Guidelines
Yes, you can have a kidney infection without leukocytosis, as the clinical presentation of acute pyelonephritis (APN) can range from mild to severe and may not always include elevated white blood cell counts. According to the 2022 update on acute pyelonephritis by the American College of Radiology 1, the diagnosis of APN is based on a combination of clinical symptoms, urinalysis, and urine cultures, rather than relying solely on leukocytosis. In fact, up to 20% of patients with APN may lack classic symptoms such as bladder inflammation, and the absence of leukocytosis does not rule out the diagnosis.
Key symptoms of kidney infection that may be present even without leukocytosis include:
- Flank pain or tenderness
- Fever
- Urinary frequency
- Dysuria (burning during urination)
- Urgency
Diagnosis in these cases relies on other indicators such as:
- Bacteria in urine cultures yielding >10,000 colony-forming units of a uropathogen per milliliter of urine
- Elevated inflammatory markers
- Imaging studies showing kidney inflammation
Treatment typically involves antibiotics, and the choice of antibiotic depends on bacterial sensitivity and patient factors, such as ciprofloxacin 500mg twice daily for 7 days, trimethoprim-sulfamethoxazole DS twice daily for 14 days, or amoxicillin-clavulanate 875/125mg twice daily for 14 days. The absence of leukocytosis should not delay treatment if other clinical signs point to kidney infection, as prompt antibiotic therapy is essential to prevent complications like sepsis or kidney damage.
From the Research
Kidney Infection without Leukocytosis
- A kidney infection, also known as pyelonephritis, can occur without the presence of leukocytosis, which is an increase in white blood cell count 2.
- A study found that 22.5% of patients with acute pyelonephritis had normal white blood cell counts (0-5/HPF) on urine microscopy, indicating that leukocytosis is not always present in kidney infections 2.
- The absence of pyuria, which is the presence of white blood cells in the urine, does not rule out the diagnosis of pyelonephritis, especially if the patient has already taken antibiotics before visiting the emergency room 2.
- The diagnosis of pyelonephritis should be based on clinical and radiologic findings, rather than relying solely on laboratory results such as white blood cell count or urinalysis 2.
Treatment of Pyelonephritis
- The treatment of pyelonephritis typically involves antibiotics, with the choice of antibiotic and duration of treatment depending on the severity of the infection and the presence of any underlying medical conditions 3, 4, 5, 6.
- Studies have compared the effectiveness of different antibiotics, including ciprofloxacin, trimethoprim-sulfamethoxazole, and cephalosporins, in the treatment of pyelonephritis 3, 4, 5.
- The duration of treatment for pyelonephritis can range from 7 to 14 days, depending on the specific antibiotic and the severity of the infection 3, 4, 6.