Chapter 7e
ACUTE APPENDICITIS
1. DEFINITION AND OVERVIEW
Acute appendicitis, as its name indicates, is an acute inflammation of the vermiform appendix, a vestigial organ of uncertain significance. However, the significance of an acute inflammatory process there is considerable; the operation of appendicectomy (appendectomy in the US) is the most frequent of all urgent abdominal operations. Its ICD 10AM Code is K35.
Although there are isolated reports of fatal inflammation in the caecal region dating back five centuries, recognition of acute appendicitis as a clinical entity is attributed to Reginald Fitz who in 1886 reported five cases of “perforating inflammation of the vermiform appendix” shortly after which Charles McBurney delineated the clinical features including the critical feature of tenderness in the right iliac fossa at the point that bears his name to this day.
2. DESCRIPTIVE EPIDEMIOLOGY 2.1 Incidence and Prevalence
During the first half of the 20th Century it seems that the incidence rose, particularly in Europe, North America and Australasia so that up to 16% of population had an appendicectomy but in the latter three decades of the century, its incidence has fallen. For example, in England and Wales the number of appendicectomies has fallen from 113,000 in 1966 to 48,000 in 1990 (1). On the other hand its incidence in developing countries is rising
922 Chapter 7e from a near zero level. Burkitt in an experience of 20 years in African mission hospitals around 40 years ago indicated its near absence in African tribal people but no such contemporary change in whites (2). In California 1983-86, the incidence of acute appendicitis in whites and Hispanics was double that of black and Asian/other groups (3) .
2.2 Risk Factors
These have been poorly investigated in contradistinction to the emphasis given to diagnosis and management. The disease is relatively rare in infants and in the elderly with a major incidence in children, adolescents and young adults (1). It is rather more frequent in males than females in whom the diagnosis is made more difficult by its confusion with gynaecological disorders.
2.3 Social class/race/occupation
There is considerable anecdotal evidence to indicate not only its rarity in primitive societies such as rural Africa in the earlier parts of 20th century and in the Himalayas where one observer noted no cases in nine years experience there. In 1939 it was reported to be eight times more common in whites than blacks in Johannesburg South Africa and all cases in blacks occurred in city dwellers in contact with western type civilization. By 1969, 200 cases in blacks were being admitted annually to Baragwanath Hospital Johannesburg (2). An urban incidence has also been reported from Germany, Rumania, Egypt and Japan. The experience of the American blacks is typical. In the first half of the 20th Century, the whites in New Orleans had four times the incidence of blacks, a ratio that had fallen to 2:1 by 1950.
2.4 Associated Diseases
Burkitt has emphasized the rarity of diverticular disease, colonic polyps and carcinoma as well as Crohn’s disease and ulcerative colitis in black societies with a low incidence of appendicitis.
3. AETIOLOGY
The evidence, such as it is, strongly suggests that a dietary factor is involved, but its nature is unclear; Burkitt, who has extensively studied the
ACUTE APPENDICITIS 93 largely anecdotal evidence, makes a strong case incriminating a Western, urban, affluent diet rich in white flour and sugar rather than the high vegetable cellulose, low meat diet of most primitive societies. Studies of migrating populations - African students in Europe, Japanese migrants in Hawaii, Sudanese soldiers on British Army rations, all support this proposition. One of the most intriguing reports is from a surgeon who cared for boys in an upper class college and in an orphanage in the early part of the 20th Century. He noted a high prevalence in the cake and pastry eating college students and its rarity in the orphans (2). None of this explains the actual pathogenesis of acute appendicitis. Burkitt again has speculated on the role of a low fibre, high sucrose diet producing slower intestinal transit thus facilitating the production of the appendiceal faecoliths - pellets of inspissated faeces, calcium salts, cellular debris and bacteria, often associated with acute inflammation in the appendix. However, quantitative data from the National Health and Nutrition Survey (NHANES II) showed, in the US, a lower fibre intake in black than in whites (3). Two other hypotheses are now gaining credibility in other conditions such as IBD and
|Bronchial Asthma (4). There is also some evidence of a polygenic inheritance which could explain its tendency to run in families (5).
4. NATURAL HISTORY
This is poorly documented. Whilst there is a presumption in much of the literature that acute appendicitis demands appendicectomy to prevent severe complications, it is clear that spontaneous resolution may occur. It may be that this follows the expulsion of an obstructing faecolith from the appendix allowing appendiceal drainage. Evidence for this is the finding of fibrotic appendices indicating prior inflammation and we have seen appendicitis patients giving a clear history of a prior milder attack which spontaneously resolved. Indeed, of Fitz’s original 72 cases at the end of the 19th Century, the mortality rate was 26% in those not operated on although nearly all had an appendiceal abscess. By the 1970's, Massachusetts General Hospital reported one death in 246 cases of confirmed appendicitis (6).
References
1. O’Connell PR .The Vermiform Appendix. In: Russel RCG, Williams NS, Bulstrode CJK eds. Bailey and Love’s Short Practice of Surgery. (OUP, Oxford, 2000), pp.1076-92.
2. Burkitt, DP. The aetiology of appendicitis. Brit. J. Surg. 58,695-9 (1971).
3. Koepsell TD. In search of the causes of appendicitis. Epidemiology 2,319-20 (1991) 4. Barker DJP. Acute appendicitis and dietary fibre : an alternative hypothesis. BMJ
290,1125-7 (1985).
5. Basta M, Morton NE, Mulvihill JJ, Radovanovic Z, Radojicic C, Marinkovic D. Am. J .JJ Hum. Genet. 46,377-82 (1990).
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6. Berry J(Jnr) Malt RA. Appendicitis Near its Centenary. Ann. Surg 200,567-90 (1984).
