Appendicitis is now not generally thought to be an interesting subject for research, but it remains an important disease. Appendicitis is the commonest reason for an operation in young adults and is still a cause of mortality, especially at the extremes of life. Fundamental issues such as the possible function of the appendix and the exact causes of appendicitis remain unresolved. Accepted notions that the appendix is vestigial, that appendicitis is usually obstructive and that post-appendicitis adhesions are a significant cause of infertility in females have been challenged.1-3 Recent studies reveal an intriguing protective effect of appendicectomy against ulcerative colitis.4 The epidemiology of appendicitis may hold clues to its still-obscure aetiology; this highlights the importance of careful epidemiological studies such as the one by Donnelly et al reported in this issue of the Journal.5
A crucial paper by Fitz (Harvard Medical School) in 1886, in which the term "appendicitis" was first used,6 swept away earlier, unfounded notions of the disease implied by the use of terms such as "perityphlitis". Fitz outlined the clinical diagnosis and suggested early removal of the appendix — but acceptance of this new concept was far from universal or immediate. The first recorded appendicectomy in Australia, done on a kitchen table in Toowoomba, did not occur until 1893.7 Early appendicectomy did not gain wide acceptance in the UK until 1902, when Sir Frederick Treves operated on King Edward VII 12 days before his coronation.
The epidemiology of appendicitis poses many unanswered questions. Almost unknown before the 18th century, there was a striking increase in its prevalence from the end of the 19th century, with features suggesting it is a side effect of modern Western life. Rendle Short8 and Burkitt1 summarised the rapid emergence of appendicitis in developed countries in the 20th century, and Burkitt noted its rarity in rural areas and in undeveloped countries. By the mid-1920s, appendicitis was sufficiently common, and the hazards of treating abdominal pain by purgation sufficiently recognised, that life insurance companies took advertisements in magazines warning against the use of laxatives for abdominal pain.9
Dietary theories, notably an inadequate fibre intake, have been advanced to account for the geography of the disease,1,8 but it is clear that diet can not fully explain the epidemiology. An alternative hypothesis, advanced by Barker in 1985,10 proposed that improved hygiene in developed countries reduced the exposure of infants to enteric organisms, modifying the immune response to virus infections, which might then cause appendicitis. Neither the dietary nor hygiene hypothesis adequately explains the significant decline in the frequency of appendicitis in the latter half of the 20th century.11,12
The authors of the Western Australian study have taken advantage of excellent hospital morbidity data collected by the health department in that State.5 They document a striking decline in the age-standardised appendicectomy rate in both sexes from 1981 to 1997. There was a greater decline in women, especially in metropolitan hospitals, where the rate more than halved. Another finding was a decline in the practice of incidental appendicectomy, although this procedure continued at a relatively high rate in non-metropolitan hospitals.
How can these data be interpreted? Unfortunately, owing to changes in diagnostic coding practices and a lack of correlation with histology, no firm conclusions can be reached about changes in the frequency of appendicitis in WA. It is likely that the fall in appendicectomy rates is because of more accurate diagnosis, possibly associated with the use of ultrasound examination, computed tomography and laparoscopy, and to a change in surgical attitudes to avoid "unnecessary" operations. Donnelly et al raise the question of whether rural doctors have taken full advantage of these changes, but provide valid reasons why rural approaches to appendicitis appropriately may differ from city practice.
An important unresolved question is whether the pendulum of declining appendicectomy rates has swung too far. Incidental appendicectomy was clearly overdone in the past, but it is justifiable in younger patients and should not be abandoned. In patients with acute abdominal pain, reluctance to operate for fear of an "unnecessary" procedure may result in delayed diagnosis of appendicitis, with a consequent increase in morbidity and mortality. Delayed diagnosis of appendicitis is the most common cause of litigation against emergency room physicians.13 One such delayed diagnosis nearly cost the late Sir Donald Bradman his life in 1934, at the peak of his cricketing career; he was so close to death that the cricketing writer Neville Cardus was instructed to prepare his obituary.
Although ultrasound examination and computed tomography are valuable aids to diagnosis in equivocal cases, they are not infallible.14 Laparoscopy, although invasive, is more precise and also allows identification and treatment of non-appendiceal causes of pain, especially in females.
Further collection of data on appendicitis is important. A rising proportion of perforated or gangrenous cases may indicate an inappropriately conservative approach to appendicectomy or an inadequate use of newer diagnostic methods. In the end, though, the diagnosis of appendicitis remains clinical; in the absence of sophisticated diagnostic tools, the old adage "if in doubt, take it out" is safe. Perhaps, in the laparoscopic era, this might be updated to "if they're crook, take a look". Even though appendicectomy rates may be declining, appendicitis is still a common and sometimes diagnostically challenging problem.
Thomas B Hugh
Visiting Surgeon, St Vincent's Hospital and St Vincent's Clinic,
Sydney NSW
thugh@dingoblue.net.au
Thomas J Hugh
Senior Lecturer in Surgery, Royal North Shore Hospital, Sydney, NSW
thugh@med.usyd.edu.au
©MJA 2001
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