Accuracy of Infection Biomarkers in the Investigation of Patients With Suspected Acute Pyelonephritis
Accuracy of Infection Biomarkers in the Investigation of Patients With Suspected Acute Pyelonephritis
The aim of this study is to investigate the diagnostic and prognostic value of C-reactive
 protein (CRP), serum procalcitonin (PCT) and soluble urokinase plasminogen activator receptor
 (suPAR) in the initial investigation of patients hospitalized with suspected acute
 pyelonephritis (APN).
Acute pyelonephritis (APN) is a severe acute infection in the upper urinary tract, which
 quite frequently is seen in the emergency department (ED). In our study, we define APN as a
 urinary tract infection with extension above the bladder, implicated by systemic affection in
 a suspected urinary tract infection (ie, fever, chills, malaise and/or lethargy beyond
 normal, signs of sepsis). Most often, an infection of the bladder ascends to the kidneys,
 causing APN. Symptoms and clinical affection range from mild to severe, but it is always
 important to recognize and treat APN fast in order to prevent progression to sepsis, renal
 failure and ultimately death. Uncertain or delayed diagnosis will often lead to an
 overconsumption of broad-spectrum antibiotics, which contributes to increased development of
 resistant bacteria and thus threaten the treatment options of the future.

 APN diagnosis is primarily made today on the basis of clinical symptoms and findings in the
 form of flank tenderness, fever and nausea/vomiting. Typical symptoms of cystitis (dysuria,
 pollakisuria, suprapubic pain, hematuria) are possible but often absent. Especially elderly
 can present with more generalized signs of infection with nothing clearly indicating
 localization to the urinary tract. A positive urine culture verifies the diagnosis, but it is
 only available after a minimum of 24 hours.

 To support the diagnosis of an APN and assess its severity, a measure of the systemic
 inflammatory response is useful such as abnormal temperature, elevated leucocyte count with
 neutrocytosis, or elevated C-reactive protein (CRP). Some uncertainty is associated with CRP
 because it has a delayed response to bacterial infection and is often elevated in
 non-infectious inflammatory conditions. A more sensitive and specific marker is desired that
 can differentiate between bacterial and viral infection and reflect the severity of the APN.
 Serum procalcitonin (PCT) has potential as a diagnostic tool in suspected bacterial
 infections and can distinguish between viral and bacterial urinary infections. Soluble
 urokinase plasminogen activator receptor (SuPAR) might have a potential as a marker for acute
 bacterial infections requiring antibiotic treatment. However, there are no well-conducted
 studies which compare simultaneously all three biomarkers diagnostic abilities for bacterial
 infections in general or in relation to APN.

 The investigators hypothesize that serum CRP, PTC and suPAR have an impact on diagnosing,
 prognosis, and treatment of patients with a verified APN.

 The objectives of the study are:

 -  To investigate the diagnostic value of CRP, PCT and suPAR in the diagnosis of APN

 -  To identify the prognostic value of CRP, PCT and suPAR in relation to adverse events in
 patients with verified APN
Inclusion Criteria:

 -  Suspicion of APN assessed by the receiving physician at the ED

 Exclusion Criteria:

 -  If the attending physician considers that participation will delay a life-saving
 treatment or patient needs direct transfer to the intensive care unit.

 -  Admission within the last 14 days

 -  Verified COVID-19 disease within 14 days before admission

 -  Pregnant women

 -  Severe immunodeficiencies: Primary immunodeficiencies and secondary immunodeficiencies
 (HIV positive CD4 <200, Patients receiving immunosuppressive treatment (ATC L04A),
 Corticosteroid treatment (>20 mg/day prednisone or equivalent for >14 days within the
 last 30 days), Chemotherapy within 30 days)