Urinary tract infection is considered the main risk factor for SC development and thus, affected individuals typically have a medical history of urinary stasis or recurrent infection. Most SC correspond to so-called "infection stones" composed of magnesium ammonium phosphate/struvite, which are characterized by very rapid growth  . Indeed, complete SC may form within little more than a month . They rarely pass spontaneously and provoke clinical symptoms in the vast majority of cases. Patients may claim flank pain and constitutive symptoms like fever, nausea and vomiting. SC may be associated with sepsis.
Diagnostic measures may reveal the following:
Recurrence is likely . If particles of renal calculi remain in the renal pelvis after therapy, they may serve as nuclei for renewed crystallization. Thus, a medical history of urolithiasis should prompt a suspicion of SC and other types of renal calculi.
The presence of SC is usually confirmed by means of diagnostic imaging. While most SC are readily observable in images obtained by plain radiography and sonography, computed tomography scans have largely replaced the former: Computed tomography scans allow for an assessment of the overall stone burden, the condition of the renal pelvis and its calyces . Of note, this technique permits for a reliable estimation of a small calculus' volume, but such measures have proven less precise in case of large, branched calculi. The three-dimensional reconstruction of SC may help to resolve this issue .
Additionally, laboratory analyses of blood and urine samples should be performed. The former should include measurements of serum electrolyte concentrations, urea and creatinine, and results may not only reveal renal function impairment but also metabolic pathologies that predispose for the development of renal calculi. With regards to urine analyses, the vast majority of SC patients presents with microscopic hematuria and crystalluria. The morphology of urine crystals may indicate the composition of the renal calculus and since most SC are composed struvite , "coffin lids" are typically seen upon the microscopic examination of urine sediment. In case of a concomitant urinary tract infection, leukocytes and bacteria may be detected.
Staghorn calculus (SC) is a branched renal calculus that occupies the renal pelvis and at least two the major calyces. SC may fill large parts of the collecting system, though, and partial calculi may be distinguished from complete calculi according to their size and morphology. In this context, the following classification system has been proposed years ago :
From a clinical point of view, it is important to assess the overall stone burden, the involvement and compromise of components of the collecting system, and possible renal function impairment. SC may be associated with life-threatening conditions like end-stage kidney disease and sepsis. In order to prevent these complications and because the incomplete removal of the renal calculus is likely to result in renewed urolithiasis, it is of utmost importance to assure the complete elimination of SC by means of extracorporeal shock wave therapy, percutaneous nephrolithotomy, retrograde ureteroscopic stone disintegration, open surgery, or any combination thereof . Percutaneous nephrolithotomy is commonly recommended as first-line treatment .