2i6 Postgrad Med J: first published as 10.1136/pgmj.33.379.216 on 1 May 1957. Downloaded from

AMOEBIASIS AS IT CONCERNS THE GENERAL PHYSICIAN By A. R. D. ADAMS, M.D., F.R.C.P., D.T.M. Physician, Royal Infirmary, Liverpool and W. E. KERSHAW, M.D., D.Sc. Leverhulme Lecturer in Liverpool School of Tropical Medicine ~..Parasitology,

Amoebiasis and Amoebic intestinal flora is one of the most important. Amoebiasis and amoebic dysentery are not Asymptomatic, and so presumably commensal, synonymous. The term amoebiasis usually is parasitization of the in the in- employed-to mean. infestation of the large bowel digenous inhabitants of the British Isles can safely with the protozoan parasite histolytica be ignored-as in practice it invariably is; even if without symptomatology as a result of the its presence is detected it need not be treated. infection. Quite otherwise is an infection acquired in an The organism may dwell in the lumen of the area when clinical amoebic dysentery is known bowel on the surface of the mucous membrane, to be endemic. Such an infection, whether as does Entamoeba coli, living commensally with causing obvious clinical manifestations or not, its host and producing no symptoms. are can not be disregarded in view of its potentialities. copyright. produced within the lumen of the gut and these This applies to infections found in residents in can be recognized in the faeces. This benign Great Britain who have returned from overseas, equilibrium may be modified, the amoeba assuming and who therefore may have become infected invasive properties by secreting a cytolysin, abroad. Pathogenic intestinal infections with eroding the mucosa, penetrating to the deeper E.histolytica commonly are characterized by tissues, and producing the typical flask-shaped periods, often lengthy, of latency. An infection ulcers which may spread widely. Under these in a returned traveller, therefore, even when conditions, it feeds on cytolysed tissue cells and apparently causing no manifestations at the time may engorge -red cells. the patient is seen, must always be suspect; it http://pmj.bmj.com/ Amoebiasis is world-wide in distribution and can not safely be ignored. It should be eradi- is found quite irrespectively of climate; it is cated, f.r if allowed to remain not only may it common in the inhabitants of this country who cause a relapsing dysentery but it may originate a have not been out of the British Isles-at present much more serious amoebic liver infection going possibly it occurs in about 5 per cent. of people on to amoebic formation. This and continuously resident here. Only very rarely in similar complications of a pathogenic primary cause with are conditions the temperate climates does the infection bowel infection E.histolytica on October 2, 2021 by guest. Protected clinical manifestations-amoebic dysentery-and of much gravity unless diagnosed early, and the recorded number of such authochthonous cases promptly and efficiently treated. of amoebic dysentery in indigenous inhabitants At the present time, both in this country and of the British Isles is very small. Why the in the tropics, there is a great deal of needless infection should almost invariably remain non- confusion about amoebiasis, and about amoebic pathogenic in these people is a matter for specula- dysentery and its complications. The primary tion. It is not that certain local races or strains of essential to all of these is the establishment and the the parasite possess no pathogenicity, while other persistence of the parasite in the large intestine. strains are pathogenic. Nearly all strains of the Its presence there can only be proved, or dis- parasite, whatever their source, prove pathogenic proved, by competent examination of the stools, when suitably introduced into experimental in which some of the parasites escape to the 'animals." Probabl:y, active pathogenicity of the exterior. If there is loosehess of the bowel the parasite in the bowel is determined by a variety of parasites will be passed in the amoeboid stage; factors, of which the constitution of the associated in this stage they must be sought for within a few May 1957 ADAMS and KERSHAW: Amoebiasis as it Concerns the Gen*ral Physician 2I7 Postgrad Med J: first published as 10.1136/pgmj.33.379.216 on 1 May 1957. Downloaded from hours of their passage or they die and disintegrate, irregular abscess, which continues to expand and so become unrecognizable. If the stools are peripherally. formed the parasites will be passed in the cystic The earliest stage of liver infection clinically is stage; these cysts are resistant to environmental referred to as that of amoebic . This is change and so will survive and remain recognizable of insidious onset, with intermittent or remittent for several days. Cysts are the only stage of the and pronounced sweating, and it may pro- parasite infective to others; they are formed solely gress slowly over weeks, with a steady loss of in the lumen of the lower large intestine; they are weight and of condition. The liver is enlarged never found actually in lesions in the wall of the and tender, and there is a moderate degree of bowel or elsewhere. Unfortunately, the number polymorphonuclear leucocytosis. At this stage of parasites-particularly in the cystic stage- 'the clinical signs respond rapidly to treatment with present in the stools fluctuates greatly. Sometimes or with . The later stage they may be very numerous and so they can easily of frank amoebic abscess may follow evidence be found; the following day they may be so scanty of an amoebic hepatitis, but in some cases there is that they can not be found even on long search. only a history of ill health and dyspepsia with It follows that repeated daily stool examinations, bowel irregularity, and but little direct clinical usually over at least six days, are necessary before evidence of the antecedent liver infection. The the presence of the parasite can with reasonable localizing signs of an amoebic liver abscess are certainty be excluded. dependent upon the site and size of the abscess. Having found parasites in the stools it is next Most abscesses develop in the right lobe; probably necessary to arrive at a decision as to the signifi- they'arise from infection from lesions in the cance of the finding. In view of the foregoing it caecum and ascending colon, which drain to the obviously is important to find out where the right lobe through the superior mesenteric vein. patient has been, not merely recently but for many The contour and movement of the diaphragm years back; whether he has a history suggestive of commonly are modified. When the infection relapsing dysentery; and what his recent and extends through the diaphragm changes occur current indicate. Amoebiasis is within the chest due to invasion of the pleura and

symptomatology copyright. common and universal; it therefore does not follow the lung. An amoebic liver abscess may extend that the discovery of the parasite accounts for a into the peritoneal cavity, the gut and other patient's condition, unless the history and the abdominal organs, the pleura and lung or peri- clinical condition conform to the recognized cardium, or directly through the chest or ab- picture. Specific treatment for an E.histolytica dominal wall. The direction of its extension is infection is almost never justified until the parasite dependent on its location in the liver, and in every has been found and competently identified. case the organ or tissue involved is the site of an Under reasonably good conditions for the practice extension of the amoebic infection.

of medicine, speculative treatment for the in- http://pmj.bmj.com/ fection and a post hoc diagnosis are a confession of Treatment incompetence. A 'therapeutic diagnosis' is a The clinical arrest of an acute attack of amoebic thoroughly unsatisfactory one in this as in other dysentery is a simple matter. One grain of parasitic diseases. It should not be indulged in. emetine hydrochloride, subcutaneously or intra- muscularly, daily for three or four days will Amoebic Hepatitis and Liver Abscess achieve this. But neither this dosage nor any In individuals who have harboured the organism other of emetine, however long continued, will do as a pathogen in the colon, often for some years, more than stop the attack. Emetine alone will on October 2, 2021 by guest. Protected liver infection with the parasite may occur. It is not sterilize the bowel infection, and so when it is probable that amoebae from time to time are stopped the infection continues and clinical released into the portal blood stream from in- relapse of the disease can occur. As emetine is a testinal lesions and are carried embolically to the toxic drug it should not be continued needlessly. liver. They may not always establish themselves Having stopped the dysentery with emetine in the liver and it has been suggested that they further treatment is needed to eradicate the only do so when the gut infection has produced residual bowel infection, and a variety of in the liver a state of tissue sensitivity. However amoebicidal drugs such as EBI chiniofon and this may be, at times they cause a number of Diodoquin are usually given simultaneously to small scattered foci of infection in the liver; and achieve this end. Their selection and methods of the great mass of liver parenchyma between these administration are matters of choice and experi- foci remains singularly unaffected. As they ence, but competently given over a period of from enlarge and spread adjacent foci of amoebic two to three weeks successful sterilization of the colonization in the liver fuse, so forming an bowel infection is obtained in all but a very small 2I8 POSTGRADUATE MEDICAL JOURNAL May 1957 Postgrad Med J: first published as 10.1136/pgmj.33.379.216 on 1 May 1957. Downloaded from minority (less than 5 per cent.) of cases. It is a destruction--a big abscess-drainage of this by not unusual practice to give amoebicidal drugs aspiration may be desirable, but this is not always continuously for many weeks or months but such necessary, especially if the patient is treated before a practice has nothing to commend it if the drugs the abscess becomes large. are in fact effective; if they are not effective there is no point in prolonging their use. An alternative to emetine for the treatment of The small minority of cases not cleared of the liver amoebiasis (but not effective at other sites of bowel infection by three weeks treatment with the infection) is the antimalarial drug chloroquine. recognized amoebicides should be retreated with a This is concentrated and stored in the liver, and second course of these with the addition of one there very effectively destroys amoebae, It is of the tetracycline antibiotics. Such treatment given orally in doses of j to i g. daily for five to very rarely demands repetition. The gauge of seven days. cure is absence of parasites on daily examinationof Finally, xwhen the extra-intestinal infection has the stools over a couple of weeks, done some few successfully been dealt with by emetine, or weeks after the completion of treatment. chloroquine, treatment of the still persisting The extra-intestinal infections with amoebae, primary bowel infection must not be overlooked. such as an amoebic hepatitis or amoebic liver If allowed to remain dysentery and its complica- abscess, are more susceptible to treatment with tions can recur; unfortunately this is allowed to emetine than is the primary bowel infection. A happen only too frequently after a patient makes course of daily emetine injections should be given an excellent recovery after specific treatment of an for io to I2 days, and this almost invariably will amoebic liver abscess. His treatment is in- sterilize the extra-intestinal lesions of their complete while his intestinal infection remains, parasites. If there is a large amount of liver and this must never be forgotten. copyright.

HEPATIC DISEASE

(Postgraduate MedicalJournal, October, 1956 ) http://pmj.bmj.com/ Price: 3s. 9d. post free JAUNDICE ASCITES IN Sheila Sherlock, M.D., M.R.C.P. Michael Atkinson, M.D. (Lond.) M.R.C.P. HEPATIC COMA J. M. Walshe, M.A., M.R.C.P. PSYCHIATRIC ASPECTS OF LIVER on October 2, 2021 by guest. Protected DISEASE SURGICAL TREATMENT OF PORTAL Esther A. Davidson, M.R.C.P.Ed., and HYPERTENSION W. H. J. Summerskill, M.A., M.R.C.P. A. I. S. Macpherson, Ch.M., F.R.C.S.E. PERCUTANEOUS PORTdAL WILSON'S DISEASE VENOGRAPHY A. G. Beam, M.D. David Sutton, M.D., M.R.C.P., F.F.R. Published by IHE FELLOWSHIP OF POSTGRADUATE MEDICINE 60, Portland Place, London, W.1