We have investigated the clinics, diagnostics and treatment of acute iliopsoitis in 29 patietnts and determined the main peculiarities if this disease with regard to purulent paranephritis, which was observed in 38 patients. The most characteristic symptoms of the iliopsotitis were pain in ilio-inguinal area, lameness, fever of the permanent type, tenderness and palpable infiltrate in the area of the iliac-psoas muscles, psoas-symptom. Of special diagnostic methods the most informative in the differential diagnosis of paranephritis was ultrasound as well as CT and MRI. Improvement in the diagnosis and differential diagnosis has enabled the authors to establish the correct preoperative diagnosis of iliopsoitis in 85,7% of the patients and in 98.5% of cases to differentiate it from the paranephritis. Improved technique of surgery for purulent iliopsoitis allowed for recovery in 96.6% of patients with late good functional outcomes. This study is important for practical healthcare, while it reveals the differences between the clinical picture, diagnosis and treatment of iliopsoitis and paranephritis. 

Authors declare lack of the possible conflicts of interests.