Isolated hip pain in a 46-year-old female patient with otherwise asymptomatic appendicitis: a diagnostic “long way round”

D. Faessler 1, M. Aepli 1, R. Patzwahl 2, C. Meier 1 1 Clinic of Orthopaedics and Traumatology, Cantonal Hospital Winterthur, Winterthur, Switzerland 2 Department of Radiology, Cantonal Hospital Winterthur, Winterthur, Switzerland

Introduction A B We report the case of a rare clinical manifestation of appendicitis. The history, diagnostic work-up and therapies are presented and discussed.

Case presentation A 46-year-old, otherwise fit and healthy woman was admitted to the emergency department with a 9-day history of right-sided groin pain with limping and an intermittently elevated body temperature. She complained of no abdominal symptoms and the clinical examination Fig. 3. A. Standard axial CT reconstruction. Detection of an appendicolith without of the was normal. A painful swelling of the right groin was appendicitis or any other intra-abdominal pathology. B. Axial MR plane (T1 SPAIR with Gadolinium) shows the typical target sign (12mm diameter) of an acute appendicitis with noticed and the range of motion of the hip was painfully restricted. surrounding fluid collection. Laboratory findings showed an increased C-reactive protein level of 89mg/l and a normal leucocyte count. Contrast-enhanced abdominopelvic CT revealed a fluid collection with rim enhancement along the right muscle expanding into the right and a joint effusion of the hip. No abdominal pathology was found.

A C

Fig. 4. Intraoperative images. A. Laparoscopy reveals acute retrocecal appendicitis without clinical signs of perforation. B. Situation after stapler division and removal of the appendix. D Follow-up CT 3 days postoperatively demonstrated a growing abscess along the iliopsoas muscle and the femoral vessels into the thigh. B The abscess was drained through an incision distal to the . Antibiotic treatment was continued for a total of 7 days. The further clinical course was uneventful and symptoms resolved quickly. The histopathology revealed a perforated appendicitis with aspects of granulomatous inflammation. The colonoscopy performed 6 weeks postoperatively did not reveal any clinical or histopathological signs of an inflammatory bowel disease. Fig. 1. A. Standard axial CT plane shows a marginal effusion of the right hip joint. Furthermore, concomitant iliopectineal bursitis is suspected. B. Axial STIR MR Discussion sequences confirm the intraarticular effusion.C/D. Axial T1 SPAIR with Gadolinium (C) and coronal STIR MR sequences (D) show a large fluid collection extending from the right Retroperitoneal and groin abscesses are known complications of through the muscular lacuna into the thigh. intestinal perforations, such as sigmoid diverticulitis, retrocecal appendicitis or Crohn‘s disease. The covered perforation forms a A septic hip arthritis with a concomitant abscess of the iliopectineal retroperitoneal abscess which follows the iliopsoas muscle through the bursa was suspected and an ultrasound-guided hip aspiration was muscular lacuna into the thigh.1,2,3 Due to occasional communication performed. Analysis of the sample did not reveal any evidence for between the psoas tendon and the hip joint capsule concomitant psoas a bacterial infection. On the next day, MR-imaging of the and abscesses and septic hip arthritis are described in the literature. The lumbar spine was performed to rule out spondylodiscitis as a possible similarity of symptoms and clinical signs may complicate the clinical source of the iliopsoas abscess. Unexpectedly, retrocecal appendicitis distinction between a retroperitoneal abscess and septic hip arthritis.4,5 with a small abscess was detected. We report the first case in the literature with clinical manifestation of isolated hip pain in an adult due to complicated appendicitis.6 The A B existence of a reactive joint effusion of the right hip with a fluid collection along the iliopsoas muscle without any abdominal symptoms delayed the correct diagnosis and appropriate treatment in this case.

Conclusion Due to the anatomy and its variations a retroperitoneal abscess may cause reactive hip joint effusion, concomitant iliopectineal bursitis or septic hip arthritis. The diagnostic work-up of these manifestations may be difficult, complex and time consuming. Despite the lack of any abdominal clinical signs, a covered intestinal perforation should be considered as a potential origin. Fig. 2. A. Axial T1 SPAIR with Gadolinium MR demonstrates an abscess formation within the right iliacus muscle. B. Sagittal T2 MR sequences show a large retroperitoneal References abscess extending into the right thigh with concomitant effusion of the hip joint. 1. Hsieh CH, Wang YC, Yang HR, Chung PK, Jeng LB, Chen RJ. Extensive retroperitoneal and right thigh abscess in a patient with ruptured retrocecal appendicitis: an extremely fulminant form of a common disease. World J Gastroenterol. 2006;12(3):496-9. 2. Rao PK, Sharpe H, Sherlock R, Muralikrishnan V. Uncommon presentation of a common condition: an Laparoscopic appendectomy and peritoneal lavage was performed 2 easily missed cause of hip pain. BMJ Case Rep. 2013;2013. days following admission. No communication between the peritoneal 3. Mascolino A, Scerrino G, Gullo R, Genova C, Melfa GI, Raspanti C, et al. Large retroperitoneal abscess extended to the inferior right limb secondary to a perforated ileal Crohn‘s disease: the importance of the cavity and the iliopsoas abscess was found. An intra-abdominal drain multidisciplinary approach. G Chir. 2016;37(1):37-41. was placed and antibiotic treatment with cefepime and metronidazole 4. Song J, Letts M, Monson R. Differentiation of psoas muscle abscess from septic arthritis of the hip in children. Clin Orthop Relat Res. 2001(391):258-65. was initiated. In the further clinical course, groin pain increased. 5. Dala-Ali BM, Lloyd MA, Janipireddy SB, Atkinson HD. A case report of a septic hip secondary to a psoas abscess. J Orthop Surg Res. 2010;5:70. 6. Waseem M, Raja A, Al-Husayni H. Hip pain in a child: myositis or appendicitis? Pediatr Emerg Care. 2010;26(6):431-3.