Right Iliac Fossa Pain

Pain in the right iliac fossa (RIF) immediately raises the suspicion of appendicitis. Appendicitis can be varied in how it presents but there are also many other diagnoses to consider when a patient presents with RIF pain. Assessment of abdominal pain in children can be very difficult. Abdominal pain in pregnancy also causes problems because of distortion of the normal anatomy and stretching of structures by the gravid uterus.

The general articles: Abdominal Pain, Acute Abdomen and Pelvic Pain have some overlap with this article. There are also separate articles entitled Acute Appendicitis and Surgical Emergencies in Childhood.

• RIF pain represents about 50% of all cases of acute abdominal pain.¹
• In surgery performed for suspected appendicitis, the preoperative diagnosis is correct in only about 50% of cases.¹
• Appendicitis is more common in men. Appendicectomy is performed more often in women and women are more likely to have a normal appendix removed.

• Enquire about the pain:
  • Ask the patient to point to where it is. Do they use a single finger or is it more diffuse? Visceral pain due to appendicitis may start around the umbilicus and move to the RIF.
  • When did it start?
  • Was the onset sudden or gradual?
  • Is it continuous or intermittent?
  • Describe the nature of the pain, stabbing, burning, gripping etc.
  • Aggravating or relieving factors, e.g. food, position, medication?
  • Is there any radiation of the pain, e.g. back/groin (renal colic), shoulder (diaphragmatic irritation secondary to visceral perforation)?
• Make a systematic enquiry:
  • Appetite; any nausea or vomiting?
  • Fever symptoms?
  • Weight - stable? Any weight loss (probably more relevant in chronic LIF pain when considering colorectal carcinoma)?
  • Bowels - when were they last open? Ability to pass stool/flatus? Any blood, mucus, melaena? Consistency of stool?
  • LMP, menstrual history, irregular vaginal bleeding and form of contraception?
  • Vaginal discharge?
  • Urine - are any urinary symptoms present?
• Enquire about smoking and drinking history.
• Note past medical history.
• List any medication.

Further details can be found in the article Abdominal Examination.

• Note the general condition of the patient, e.g. well, shocked, pyrexial.
• Note temperature, pulse rate and quality, BP.
• With the patient adequately undressed and comfortable, systematically examine the abdomen - inspection, percussion (abdomen may be tympanitic in bowel obstruction), palpation, auscultation (absent bowel sounds indicate obstruction/volvulus). Is it an acute abdomen - is there distension, guarding, rigidity or rebound tenderness? Is a mass palpable, and if so, is it pulsatile?
• Examine testes and hernial orifices.
• A definitive diagnosis may well require a rectal and/or vaginal examination. Usually a GP will do this only if it affects the decision of whether or not to refer the patient acutely. If it will be performed by the admitting team, it may be omitted.

RIF pain may be acute or chronic/subacute.

Causes of acute RIF pain

• Gastrointestinal causes
  • Appendicitis: if the appendix is retrocaecal there may be no guarding. In pregnancy the gravid uterus will push up the appendix and hence the site of tenderness. Carcinoid tumours may occasionally present as appendicitis.
  • Crohn's disease: the commonest site for Crohn's disease is the terminal ileum and here it may mimic appendicitis.
  • Mesenteric adenitis: this primarily affects children. It is caused by a viral or bacterial infection. Adenoviruses, Epstein Barr Virus, beta-haemolytic streptococcus, Staphylococcus spp., Escherichia coli, Streptococcus viridans and Yersinia spp. have all been implicated as well as Mycobacterium tuberculosis, Giardia lamblia, and non-salmonella typhoid.² It may occur in adults but is mostly in those under 15. Patients have a higher temperature than those with appendicitis. There is also other evidence of viral infection including enlarged submandibular lymph glands and leucocytosis. If laparotomy is performed, enlarged mesenteric lymph nodes will be apparent.
  • Diverticulitis: diverticular disease affects the distal colon more than the proximal colon. However, diverticula and inflammation and/or abscesses may occur in the ascending colon. Perforation may also occur.
  • Meckel's diverticulitis: a Meckel's diverticulum is a congenital anomaly that is present in about 2% of the population. Meckel's diverticulitis can mimic appendicitis.
  • Perforated peptic ulcer: this usually produces upper quadrant pain but pain may be lower.
  • Right inguinal/femoral hernia: an incarcerated right inguinal or femoral hernia may present as RIF pain. There will be tenderness and an irreducible swelling over the hernial orifice and symptoms and signs of bowel obstruction. Cough impulse is lost if hernia is incarcerated. Requires urgent surgical referral.
  • Malignancy: carcinoma of caecum or ascending colon can present with bowel perforation.
• Gynaecological causes
  • Pelvic inflammatory disease/salpingitis/pelvic abscess: typically vaginal discharge is present. More common if multiple sexual partners, history of PID and if intrauterine device in situ.
  • Ectopic pregnancy in the right fallopian tube: pain rather than vaginal bleeding is the prominent feature. If in doubt, admit. When rupture occurs bleeding is profuse and 2 or 3 litres can be lost in a short space of time with consequent hypovolaemic shock.
  • Ovarian torsion: this usually happens when an ovary is enlarged by a cyst. Diagnosis can be difficult. There may be adnexal tenderness. Ultrasound may show the abnormal ovary.
  • Threatened or complete abortion: if pregnancy test is positive and there is a history of bleeding, always refer for an ultrasound scan to exclude an abortion. If there is associated pain, an ectopic needs excluding by immediate referral to secondary care.
  • Mittelschmerz: this is a sudden onset of mid-cycle pain.
  • Fibroid degeneration.
  • Pelvic tumour.
• Urological causes
  • Ureteric colic: this can cause pain that may be intermittent and "shooting". A stone may cause microscopic haematuria. 70% are visible on plain x-ray. Ultrasound is a good diagnostic technique.
  • Urinary tract infection: urinary frequency, dysuria, haematuria, urgency and smelly urine may raise this as a differential diagnosis.
  • Testicular torsion or epididymo-orchitis: may produce pain that is referred to the lower abdomen on that side. The testis will be very tender.
• Other causes
  • Infections: tuberculosis, typhoid and Yersinia spp. can all produce ulceration of the ileum that can perforate. Herpes zoster infection in the T10, 11, or 12 dermatome can produce RIF pain. There is usually a characteristic rash. The skin is usually tender rather than a deeper pain.
  • Abdominal aortic aneurysm: this can present with atypical symptoms resembling renal colic or diverticular disease rather than the classic back or flank pain. Do not forget this differential diagnosis. Look for a pulsatile abdominal mass. Approximately 30% of patients with a ruptured AAA are misdiagnosed initially.³
  • Situs inversus: here the differential diagnosis for RIF pain is that for left iliac fossa (LIF) pain (refer to separate article entitled Left Iliac Fossa Pain). Only half of those with dextrocardia have total situs inversus.

Causes of chronic RIF pain

• Gastrointestinal causes
  • Irritable bowel syndrome: should be a diagnosis of exclusion. The bowel may be loaded and tender.
  • Carcinoma of the caecum or ascending colon: there is usually an associated change in bowel habit, weight loss and rectal bleeding.
  • Crohn’s disease and ulcerative colitis: with inflammatory bowel disease, there will probably be associated diarrhoea with blood and mucus.
• Gynaecological causes
  • Ovarian/pelvic tumour
  • Endometriosis
• Other causes
  • Right hip pathology: may cause referred pain in the right iliac fossa.
  • Familial Mediterranean fever: this may cause recurrent abdominal pain, mostly in the first decade of life.

These should be tailored to the patient's symptoms and the examination findings. In the GP setting there are a number of bedside tests that can be done to aid diagnosis:

• Dip urine for pus cells, leucocytes and/or nitrites if UTI suspected. Microscopic haematuria is usually present in ureteric colic. It can also occur in abdominal aortic aneurysm (AAA).³
• Perform a pregnancy test if ectopic pregnancy or miscarriage suspected.

If the pain is non-acute and can be managed in the GP setting, further investigations may be requested:

• Blood tests may include full blood count, renal function, liver function tests.
• Vaginal swab tests can help to exclude pelvic infection.
• Ultrasound scanning can show ovarian or other mass.
• Referral for further bowel investigations may be necessary, e.g. referral under 2 week wait rule if bowel carcinoma suspected.
• Further urological investigations may be needed, e.g. cystourethroscopy.

If the patient has an acute abdomen and is referred immediately to hospital, further diagnostic tests may be carried out there:

• Ultrasound scanning, blood and swab tests as above. Appendicitis produces a mild leucocytosis unless it has progressed to general peritonitis.
• CT scanning is good for the diagnosis of diverticulitis, nephrolithiasis, ureterolithiasis.³ Helical CT has also been used to differentiate appendicitis and acute gynaecological conditions.⁴
• Plain AXR may show dilated bowel loops in bowel obstruction, ileus and perforation. It may show renal tract calcification.
• Erect CXR may show intraperitoneal air under the diaphragm if there is a ruptured viscus.
• Some departments use early laparoscopy as a routine diagnostic tool.⁵ It is minimally invasive and gives reliable results.

• This depends on the diagnosis and is of the underlying disorder.
• An acute abdomen and/or a haemodynamically unstable patient requires immediate referral to hospital for further assessment. If AAA or ectopic pregnancy are suspected, refer to secondary care immediately. Keep patient nil by mouth. The threshold for referral for suspected appendicitis should be low, especially with children or young women.
• Airway, Breathing and Circulation should be assessed and managed appropriately.
• Traditional teaching was that analgesia shouldn't be given to patients with an acute abdomen before they see a surgeon as it can suppress physical signs. This has been subject to much debate and modern opinion is that it is unkind and unnecessary to withhold pain relief.⁶ The receiving doctor should be told that analgesia has been given. A Cochrane systematic review published in 2007 provided some evidence to support the notion that the use of opioid analgesics in patients with abdominal pain is helpful in terms of patient comfort and doesn't retard decisions to treat.⁷
• NSAIDs (care if risk of peptic ulcer disease) or opioids (if severe pain) are good analgesics.

Appendicitis is a common condition but this and other causes of RIF pain can be difficult to diagnose. A GP should have a high index of suspicion, especially in girls and adolescent females because of the potential effect on fertility if operation is delayed. Quite often a GP will refer a patient to hospital, the patient is admitted, observed and discharged without operation. You should not feel that this was an inappropriate admission.