Right Iliac Fossa Pain

Pain in the RIF immediately leads to a suspicion of appendicitis. Appendicitis can be very varied in how it presents but there are many other possibilities to consider.

The presentation 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.

• RIF pain represents about 50% of abdominal pain and 2% of hospital admissions. About 1 person in 10 will develop appendicitis some time. The incidence rises in childhood to peak between about 8 and 12 and falls as the years progress to be very uncommon but not unknown beyond 80.
• 70,000 appendicectomies are performed each year in the UK but the number is falling
• Appendicitis is more common in men
• Appendicectomy is performed more often in women
• In around 20% of cases a normal appendix is removed, more often in women than men

Symptoms

Enquire first about the pain:

• Point to where it is. Does the patient use a single finger or is it more diffuse?
• When did it start? Visceral pain, such as appendicitis, may start around the umbilicus and move to the RIF.
• Was the onset sudden or gradual?
• Is it continuous or intermittent?
• Describe the nature of the pain; stabbing, burning, gripping etc. Note the body language and use of hands.
• Are there any aggravating or relieving factors?
• Is there any radiation?
• The patient may volunteer information such as pyrexia or dysuria?

Note past medical history.

Make a systematic enquiry:

• Appetite, any nausea or vomiting
• Weight
• Bowels
• Urine
• Smoking and drinking
• LMP if appropriate and form of contraception
• Medication

Signs

• Note the general condition of the patient, eg fairly well, shocked, pyrexial.
• Note temperature, pulse rate and quality, BP.
• With the patient adequately disrobed, get comfortable and perform a systematic abdominal examination. Is there an acute abdomen? Are there any abdominal masses?
• 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. If it will be performed by the admitting team it can be omitted as an unnecessary and intrusive procedure, especially in children.

Children

Children can be especially difficult as explained in acute surgical problems in childhood. One problem is that all pain is "tummy pain" when they are small and they point to the umbilicus. The aetiology of that pain may include pathology outside the abdomen including otitis media and tonsillitis. Examining children also needs special skills, as explained in that article.

• 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.
  • An audit of 300 women of childbearing age who presented with RIF pain, found appendicitis in 97. ¹ Just 2 women of the 300 were pregnant.
  • The Alvarado score² was devised to aid the diagnosis of appendicitis and to reduce the number of negative laparotomies. A modified score has been assessed and reported to the Royal College of Surgeons of Edinburgh.³ The authors found that the sensitivity and specificity were lower than their own clinical judgment and they do not recommend it. Another study found that patients with a score of 4 or less are unlikely to have appendicitis.⁴
• Pelvic Inflammatory Disease - Pelvic inflammatory disease is more likely to occur with an IUCD in situ. It more often affects young women.
• Ectopic Pregnancy - Consider pregnancy in the right fallopian tube. The more medial the implantation, the sooner it presents. 30% of ectopic pregnancies present before a missed period. If there has been a previous ectopic pregnancy there is a 10 to 20% chance of having another. When rupture of the fallopian tube occurs bleeding is profuse and 2 or 3 litres can be lost in a short space of time with consequent hypovolaemic shock. It is a significant contributor to maternal mortality. Pain rather than vaginal bleeding is the predominant feature. Additional risk factors include use of emergency oral contraception and an IUCD in situ. Occasionally it can occur after sterilization operations. Serum progesterone above 25ng/ml suggests a viable intrauterine pregnancy. Lower figures suggest ectopic or non-viable intrauterine pregnancy. The Americans sometimes use MRI to show the position of an ectopic⁵ although MRI is usually avoided in the 1st trimester. In the UK the RCOG advises transvaginal ultrasound as the diagnostic technique of choice. If in doubt, admit as when rupture occurs bleeding is profuse.
• Torsion of ovary -This usually happens when an ovary is enlarged by a cyst. Diagnosis can be difficult. There may be adnexal tenderness. US may show the abnormal ovary. It tends to occur in women in their mid-20s or after the menopause. 20% occur during pregnancy. Ovarian tumours and fibroids in pregnancy can be very difficult.
• Crohn's disease - The commonest site for Crohn's disease is the terminal ileum and here it may mimic appendicitis. If a laparotomy is performed and Crohn's disease found it is the one indication to leave the appendix as appendicectomy may lead to sinus formation. The patient must be told that his appendix is intact as if he develops appendicitis at a later stage a doctor who sees a grid-iron scar will assume that the appendix has been removed.
• Mesenteric adenitis - This is a disease primarily of children most often caused by a viral (Adenovirus, EBV, Coxsackie B, influenza B) or a streptococcal URTI, although enteric pathogens such as Yersinia, Campylobacter and Salmonella can also be responsible. It may occur in adults but is mostly in those under 15. They have a higher temperature than with appendicitis, other evidence of viral infection including enlarged submandibular lymph glands and leucocytosis are present. If laparotomy is performed, enlarged mesenteric lymph nodes will be apparent.
• Irritable Bowel Syndrome - Irritable bowel syndrome may cause diagnostic difficulty. There may be a history of IBS although this does not exclude other conditions.
• Diverticulitis - Diverticular disease affects the distal colon more than the proximal part but diverticula and inflammation, even with abscesses, may occur in the ascending colon. Perforation may also occur.
• Meckel diverticulitis - Meckel's diverticulum is a congenital anomaly that is present in about 2% of the population but causes trouble much less often.
• Perforated Peptic Ulcer - This usually produces upper quadrant pain but it can be lower. If the patient takes corticosteroids physical signs can be much reduced or absent.
• Infections - Tuberculosis, typhoid and yersinia can all produce ulceration of the ileum that can perforate.
• Malignancy - Carcinoma of caecum or ascending colon can produce stercoral perforation.
• Ureteric Colic -This will 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.
• Testicular Pain - Torsion of testis or epididymo-orchitis may produce pain that is referred to the lower abdomen on that side. The testis will be very tender.
• Hernia - An incarcerated inguinal or femoral hernia may present as low abdominal pain. There will be tenderness over the hernial orifice.
• Herpes zoster- Shingles of right T10, 11, or 12 can produce RIF pain. There is usually a characteristic rash but even before it appears the skin is tender rather than deeper.
• Rarities
  • Familial Mediterranean fever may cause recurrent abdominal pain, mostly in the first decade of life.
  • Fitz-Hugh-Curtis syndrome tends to affect the right upper rather than lower quadrant.
  • In situs inversus the differential diagnosis for RIF pain is the one for LIF pain. Only half of those with dextrocardia have total situs inversus.

• Check urine for pus cells or nitrites in case of UTI.
• Pregnancy test in case of ectopic pregnancy.
• Appendicitis produces a mild leucocytosis unless it has progressed to general peritonitis.
• Ultrasound can improve the diagnostic accuracy for appendicitis⁶ but CT is even more accurate.⁷ In children MRI in addition to US has improved diagnostic reliability. US will show an enlarged ovary or a tubo-ovarian mass. Helical CT has also been used to differentiate appendicitis and acute gynaecological conditions.⁸
• Some departments use early laparoscopy as a routine diagnostic tool.⁹ It is minimally invasive and gives reliable results.

Non-Drug

An acute abdomen will require referral to a surgeon. The threshold for referral for suspected appendicitis should be low, especially with children or young women.

If there is PID and an IUCD in situ the foreign body should be removed. Enquire about intercourse in the last week as the IUCD works retrospectively and if in doubt give emergency oral contraception.

Drugs

The traditional teaching has been that analgesia should not be given to patients with an acute abdomen before they see a surgeon as it can suppress physical signs but this has been subject to much debate^10,11,12 and modern opinion is that it is unkind and unnecessary to withhold pain relief. The receiving doctor should be told that analgesia has been given as it may influence the interpretation of findings.

Surgical

Traditionally appendicectomy is performed through a small grid-iron incision. A different incision may be required if the diagnosis is uncertain or unlikely, especially in the elderly where carcinoma or diverticular disease are more likely. Laparoscopy for diagnosis and treatment is being used more often. It has received a favourable Cochrane review.¹³

Diagnostic laparoscopy is commonly used for gynaecological conditions. Ruptured ectopic pregnancy requires urgent laparotomy, often before full resuscitation as the rate of bleeding is so fast.

Appendicitis is a common condition but this and other causes of RIF pain can be difficult to diagnose. The 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. The GP should never feel that this was an inappropriate admission.