A case report on the development of sacroiliitis post laparoscopic appendicectomy for acute appendicitis: a rare cause of sacroiliitis in an adult

Abstract

Introduction and importance

Acute appendicitis is the most common abdominal surgical emergency in the world and often requires surgical intervention. One of the complications of appendicitis is abscess formation. In rare cases, a localised abscess can occur in the adjacent organs, such as the iliac and psoas muscles. Sacroiliitis occurring secondary to, or concomitant with, acute appendicitis is extremely rare. However, a missed diagnosis of either or both conditions can lead to serious complications, including mortality.

Case presentation

A 27-year-old male patient presented to the emergency department with a history of acute severe right hip pain that was aggravated by movement and associated with nausea and vomiting. CT suggested acute uncomplicated appendicitis with no localised contamination. He underwent an emergent laparoscopy which showed mild appendiceal inflammation and appendicectomy was performed. He became septic a few hours after the operation, resulting in admission to the high dependency care unit for close observation. On review the following day, he reported ongoing right hip pain and lower back pain with a new onset inability to weight-bear. An MRI scan was performed which showed features of infection around the right sacroiliac joint and Staphylococcus aureus grew in his blood culture. A diagnosis of acute pyogenic sacroiliitis was then made. The patient was treated with IV antibiotics for a total of four weeks, followed by two weeks of oral antibiotics.

Clinical discussion

Acute pyogenic sacroiliitis is one of the rarer conditions seen that can mimic the acute abdomen, in this case acute appendicitis. MRI is the best diagnostic modality in sacroiliitis, in comparison to CT for appendicitis. In most cases of acute appendicitis, mixed bacteria including aerobes and anaerobes are seen in the blood culture while staphylococcus aureus is seen mostly in acute pyogenic sacroiliitis. Staphylococcus aureus-induced appendicitis is reported in less than 3.7 % of cases. An early diagnosis of either or both conditions can significantly reduce complications and, more importantly, expedite implementation of appropriate treatment.

Conclusion

In our case we present a combination acute appendicitis, acute sacroiliitis and staphylococcus aureus septicaemia and provide proof that acute pyogenic sacroiliitis can be a rare complication of acute appendicitis. Thus, a high clinical index of suspicion should be considered in the appropriate clinical scenario.

Highlights

• •Acute appendicitis is the most common abdominal surgical emergency in the world.
• •Acute pyogenic sacroiliitis can mimic symptoms of appendicitis with 12.6% of cases mimicking the acute abdomen.
• •Sacroiliitis that presents secondary to, or concomitantly with, acute appendicitis is extremely rare.
• •Early recognition and appropriate investigation is key to successful treatment and to prevent further complications.

1. Introduction

Appendicitis is defined as inflammation of the vermiform appendix. Often caused by obstruction of the appendiceal lumen. Classically, it presents within 24 h of onset of symptoms; initially, as periumbilical pain that later localises in the right lower quadrant (RLQ) [1], and often associated with fever, nausea, vomiting, diarrhoea, and, occasionally, urinary tract infection (UTI) [2]. Typical presentations of appendicitis are frequently found when the appendix is in the retro-caecal position [3]. Laparoscopic appendicectomy is the gold standard of treatment for acute appendicitis [4]. Postoperative complications include formation of an abscess or haematoma, and wound complications. In cases where too much of the appendiceal stump is left behind, recurrent infection can occur. This is known as “recurrent” or “stump” appendicitis. If left untreated, appendicitis can lead to abscess formation. This can progress into enterocutaneous fistula, diffuse peritonitis and, later, sepsis [1]. Multiple case reports have shown psoas and iliac abscess formation to be uncommon complications of appendicitis. However, very few have suggested a correlation between appendicitis and sacroiliitis in adults. We describe a case of acute appendicitis in a 27-year-old man, who later developed sacroiliitis post-operatively. The following work has been reported in line with the SCARE criteria [20].

2. Case report

A 27-year-old male patient presented to the emergency department complaining of a two-day history of severe right hip pain, which started suddenly when he was walking, was aggravated by movement, and associated with nausea and vomiting. He had no past medical history and no history of trauma. He was not prescribed any current or previous immunosuppressive treatment or corticosteroid therapy. On examination, he was tender in the right iliac fossa (RIF) with associated rebound tenderness, a positive psoas sign, normal digital rectal examination (DRE), and limited right hip flexion, secondary to new onset lower back and hip pain. Initial investigations were as follows: Hb 15, WCC 13.2, CRP 372, normal amylase, U&E and LFTs.

He had clinical features consistent with a sub-acute retro-caecal appendicitis with an Alvarado score of 8. A computed tomography (CT) scan of the abdomen and pelvis was obtained. The patient was treated with empiric intravenous antibiotics, fluids, and given analgesia. The CT scan reported acute uncomplicated appendicitis with no destructive osseous lesion or para vertebral abscess (Fig. 1, Fig. 2). After updating the patient about the diagnosis, a detailed informed consent for surgical intervention was obtained and a laparoscopic appendicectomy was performed. Mild appendiceal inflammation was noted during the laparoscopy with no other significant findings.

Fig. 1.

Computed tomography (CT) scan - axial view of abdomen and pelvis, showing acute appendicitis.

Fig. 2.

Computed tomography (CT) scan - coronal view of abdomen and pelivs, showing acute appendicitis.

Overnight the hospital's Emergency Response Team (ERT) was alerted as the patient became hemodynamically unstable. He was pyrexic, with a temperature of 38.8 degrees, with an increased oxygen requirement, and had an Early Warning Score (EWS) of 7. A full septic screen was performed, and the patient was commenced on IV Ceftriaxone, Clindamycin and Gentamicin as per the local hospital sepsis policy. The patient was later transferred to the high dependency care unit (HDU) for close observation. Day 1 post-operative examination in HDU showed no signs of peritonism, postoperative complications or superficial wound infection. However, the patient reported worsening of his ongoing lower back and right hip pain with a new onset inability to weight-bear on his right leg and persistently raised CRP despite multi-antibiotic therapy. A Magnetic Resonance Imaging (MRI) scan of his lumbar spine and pelvis was performed which showed features of infection around the right sacroiliac joint (Fig. 3). Furthermore, the patient's blood culture was positive for Staphylococcus aureus and his CT thorax confirmed ARDS. His echocardiogram did not show endocarditis.

Fig. 3.

Magnetic resonance imaging (MRI) scan - T2 weighted image of pelvis, axial view showing sacroiliitis.

An MDT approach of managing the patient involved the general surgery, orthopaedic, microbiology and interventional radiology teams, who decided the patient was for medical management with IV antibiotics for a total of four weeks, followed by two weeks of oral antibiotics. The patient made good progress both clinically and biochemically and was subsequently discharged with outpatient antibiotic therapy (OPAT) and was later reviewed in the surgical outpatient department.

Upon his outpatient review, 4 weeks after discharge, the patient had recovered completely, and his follow-up outpatient MRI pelvis (3 months post laparoscopic appendicectomy) showed resolution of his sacroiliitis. (Fig. 4).

Fig. 4.

Magnetic resonance imaging (MRI) scan - T2 weighted image of pelvis, axial view showing resolution of pathology.

The patient's appendix histology confirmed acute uncomplicated appendicitis with no features of Crohn's disease.

3. Discussion

Acute pyogenic sacroiliitis is one of the rarer conditions seen in children and young adults. In 12.6 % of cases, it mimics the acute abdomen [17]. This poses great challenges and requires a high index of suspicion for diagnosis. The predisposing factors are trauma, immunosuppression, sickle cell disease, insect bites, folliculitis and atopic dermatitis [12].

Clinically, patients with acute sacroiliitis can present with fever, low back pain, gluteal or hip pain and abdominal pain. Differential diagnosis includes hip septic arthritis, lumbar disc or pelvic abscess [19]. MRI is the best diagnostic modality in comparison with CT scan and should be obtained for patients with symptoms suggestive of sacroiliitis [15].

The treatment of sacroiliitis is antibiotic therapy and, according to the most recent British recommendations, should consist of 3 weeks parenteral antibiotics, followed by 6–12 weeks oral antibiotics [11]. However, treatment of more than 6 weeks does not prevent relapse [16]. Patients may require further treatment via surgery or interventional radiology in cases where antibiotics fail or complications arise, such as abscess, necrosis or bone involvement [14]. Undiagnosed pyogenic sacroiliitis can lead to septic shock and ARDS [5].

The presence of staphylococcus aureus in a patient's blood culture plays a significant role in establishing the diagnosis of sacroiliitis post appendicectomy. In most cases, acute appendicitis is primarily caused by mixed bacteria including aerobes, such as gram negative enterobacteria, and anaerobes, such as E. coli. By comparison, staphylococcus aureus-induced appendicitis is extremely rare and has been reported in less than 3.7 % of cases [13]. In contrast, staphylococcus aureus septicaemia is often seen in acute pyogenic sacroiliitis [19].

The lifetime risk of acute appendicitis is 7 % [9]. Appendicectomy or empiric antibiotic treatment can be used for management [6]. Acute appendicitis carries a perforation risk of 16 % [7], with a mortality rate of 0.8/1000 in non-perforated and 5.1/1000 in perforated appendicitis [8].

Sacroiliitis occurring secondary to, or concomitant with, acute appendicitis is extremely rare in children, and even more so in adults. Currently, there are two reported cases in children [18,22] and only one reported case in an adult – a 29-year-old male who developed osteomyelitis secondary to a perforated appendicitis [21]. However, a missed diagnosis of either or both conditions can lead to serious complications, including mortality.

4. Conclusion

In our case we present a combination acute appendicitis, acute sacroiliitis and staphylococcus aureus septicaemia and provide proof that acute pyogenic sacroiliitis can be a rare complication of acute appendicitis and high clinical index of suspicion should be considered in the appropriate clinical scenario.

Consent

The patient was contacted by a Varit Suwanwalaikorn (co-author) via telephone, explaining his participation in the case report. The patient has agreed to participate and the consent form was sent via post.

Written informed consent was obtained from the patient for publication of this case report, and all accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

The patient's right to privacy is respected and the name, initials and hospital number has not been used in this case report.

Ethical approval

The case report has been assessed and ethical approval has been provided by the author's institution.

Funding

There were no sources of funding for this paper.

Author contribution

Hannah McKay - Writing the paper, data collection.

Varit Suwanwalaikorn - Obtaining consent, data collection and ethical approval.

Mekki Hassan - Writing the paper and supervision.

Maria Whelan - Supervision.

Guarantor

Mekki Hassan.

Research registration number

N/A.

Conflict of interest statement

The authors declare that they have no conflict of interest.