# Tropical Diseases/Chapter 23

CHAPTER XXIII
IMPERFECTLY DIFFERENTIATED FEVERS OF THE TROPICS
THERE can be little doubt that in the tropics there are a number of fevers specifically distinct from any of the foregoing, and also from the better-known fevers of temperate climates. Such fevers are constantly met with and are a perpetual puzzle to the conscientious diagnostician; and, up to the present, little of a truly scientific character has been done towards describing, separating, and classifying them. Some attempts have been made to arrange these imperfectly differentiated fevers on a clinical basis; but, until their causes have been discovered and, above all, until they have been studied in reference to any possible connection they may have with the known pathogenic tropical parasites, anything like a sound classification and description has to be postponed. So far as known, they are not associated with distinctive exanthems or even with distinctive visceral lesions; a circumstance which has contributed, doubtless, to retard our knowledge in a very important department of tropical medicine.
The late Colonel Crombie, I.M.S., attempted a classification of these fevers on a clinical basis, which, so far as it goes, is of distinct value. His remarks apply solely to the fevers of India; but I can recognize in his descriptions clinical forms which I frequently met with formerly in China. It is fair to infer from this latter circumstance that, if these fevers are found in India and China, they probably occur also in other warm countries.
Crombie divided them into simple continued fever, low fever, and non-malarial remittent. To these I would add yet another, which, from experience in China, I regard as a distinct ​clinical entity, and which from its peculiar feature I would call double continued fever.
Since Crombie wrote, several observers have made important contributions to the subject, notably Thompstone and Bennett, who described under the name of hyperpyrexial fever what appears to be a special form of fever in West Africa; McCarrison, who has described a fever of three days' duration occurring in Chitral, and which is now identified as phlebotomus fever ; and Rogers, who has more recently described one of seven days' duration in Calcutta (p. 389).
Simple continued fever.— Simple continued fever generally, if not invariably, commences with a rigor, the temperature rapidly or more slowly mounting to 104°, 105°, or even 106° F. There are headache, malaise, a white furred tongue, anorexia, thirst, and perhaps vomiting. The fever lasts usually from three to eight days; occasionally it is prolonged for two, three, or four weeks. Crombie remarked that these cases are particularly common in towns, and were known locally as Bombay fever, Calcutta fever, and so forth. It might be suggested that such fevers are mild or aborted typhoid; but, in 'view of the absence of the characteristics of enteric, the insignificant mortality, and the freedom from complications, so grave a diagnosis does not seem to be justified. It is customary to attribute them to heat, chills, change of season, acclimatization, irregularities in diet, exposure to the sun, and the like. How far these etiological speculations are correct it is hard to say.
LOW fever— Like the preceding, this type of fever is not an unusual one among Europeans in the tropics. Its characteristics are indefinite duration— weeks or months; a persistent though slight rise of temperature, rarely above 101.5° F. but never below 99°; anorexia, debility, loss of flesh, and a tendency to bilious diarrhœa. It is unrelieved by quinine or arsenic ; but it almost invariably responds to a change of air, especially to a trip at sea.
Non-malarial remittent.— Crombie remarked that it is a pity we have no better name for this fever, which is of very frequent occurrence in India, and is ​one of the most fatal of the fevers there. Remittent is a misnomer, for the symptoms are even less remitting than those of typhoid. The temperature runs high, touching 104° or 105° F. for a long part of its course. It begins not unlike simple continued fever. By some it is considered a variety of typhoid, notwithstanding the absence of many of the symptoms of that disease. Hepatic enlargement and congestion are early and constant conditions; but the spleen, as a rule, is not distinctly enlarged.
" Bilious diarrhœoea, in no respect resembling the diarrhœa of typhoid, is also a very frequent symptom. Quinine often given in large and repeated doses in these cases is not only not useful, but so obviously adds to the distress of the patient, without in any way producing an improvement in the progress of the symptoms, that it is very soon abandoned. Meanwhile, the temperature continuing persistently high, marked head symptoms, especially delirium of a muttering and irritable kind, come on, and the patient may even, and often does, pass into a condition of coma from which he can hardly be roused. This condition of persistent high temperature without marked remission, a distinctly enlarged and congested liver, bilious diarrhœa, congestion of the back of both lungs; and a low, muttering delirium, is generally reached by the eighteenth to the twenty-fourth day. If coma supervenes, the patient frequently dies about this period. In more favourable cases, where the symptoms are less severe, they may continue for a week or two longer. In such the average duration of the case is six weeks." (Crombie.)
Crombie, although he had seen this fever in Europeans, regarded it as being essentially a disease of natives. It is seldom met with after the age of 30, but is frequent enough in childhood.
Double continued fever.— In South China I encountered, both in Amoy and in Hong Kong, a peculiar type of fever, apparently of very little gravity as affecting life, but sufficiently distressing while it lasted. Thorpe has recorded a case occur ring in Wei-hai-wei. The disease is characterized ​by an initial pyrexial stage of from ten days' to a fortnight's duration, followed by a stage of from three to seven days' relative or absolute apyrexia, which, in its turn, is succeeded by another spell of about ten days' duration of smart fever, and then by convalescence (see Chart 6). Both in the primary and the terminal fever the evening temperature may rise to 104° or 104.5° F. It might be said that such cases are relapses of simple continued fever; but as I have seen, on at least two occasions, the same succession of events occurring almost simultaneously in two patients living in the same house—once in husband and wife, and once in brother and sister—it seems probable that this is a special form of disease, and that the double fever is a constant and characteristic feature. In the case of the brother and sister the march of their fevers was strictly simultaneous, the primary
Chart 6.—Double continued fever, Hong Kong. o indicates a dose of antipyrin.
Hyperpyrexial fever.— From time to time we have accounts from the West Coast of Africa, where it is not uncommon in certain parts, of a peculiar type of fever, especially prevalent during the dry season, and which doubtless was formerly regarded and treated as malarial, but which, from the absence of the malaria parasite in the blood, and the impotence of quinine in checking it, we now know cannot be malarial. From its gradual incidence and prolonged course, although it is associated with hyperpyrexia, we know that it cannot be siriasis or heat apoplexy. "What it may be is difficult to say; the probabilities seem to be in favour of its being a special form of tropical disease, associated with an animal intermediary occurring in and limited to the endemic localities.
Symptoms.— Thompstone and Bennett describe the clinical features thus: "This fever is generally ushered in by a slight rise of temperature, followed by profuse perspiration and a fall in the temperature to about 99° F. After a period of apyrexia of perhaps twenty-four hours' duration, the temperature begins again to rise, slowly at first, but when 105° is passed, with alarming rapidity, one degree in ten minutes having been frequently observed, and it may reach 107° on the second day. For fourteen or even for thirty days subsequently there is absolutely no tendency for it to fall. The skin acts either very slightly or not at all, and all antipyretic drugs fail."
In due course the tongue becomes dry and shrivelled, but the spleen and liver are not enlarged; the urine is normal and abundant, the bowels being regular or loose. The conjunctivas are injected, the pupils contracted. There is much anxiety and restlessness; but the mind is clear in most cases except when the temperature is very high.
If the patient is to recover, a change for the ​better may be looked for about the end of the third week. Convalescence is very gradual, and it may be six weeks before temperature is normal. Half the cases die.
A curious feature is the remarkable rapidity with which the blood coagulates the moment it is exposed to the air.
Malaria parasites, though carefully sought for, have not been found; neither have attempts at cultivations from the blood yielded any micro-organism. The white corpuscles are rather in excess.
Treatment.— The only treatment which has been of value is the diligent use of the cold bath and the cold pack.
Seven-days' fever of Indian ports.— Definition.— A short fever occurring epidemically during the summer months in Indian ports, and characterized by sudden invasion, severe headache, pains in the back and limbs, and pyrexia of a peculiar saddle-back type— occasionally of a continued— type lasting from six to seven days and associated with a pulse which is relatively slow in relation to temperature.
History.— Possibly this fever is one of several fevers included under the somewhat comprehensive term "simple continued fever." Rogers, by a careful study of a vast number of cases of fever in Calcutta, observing that this particular type has a definite seasonal incidence— the late hot weather and the early monsoon months in Calcutta— and declines just at the time when the principal malarial rise of the year takes place, concludes from this and from the absence of malarial parasites that it cannot be malarial, from the absence of respiratory symptoms that it is not influenza, and from the absence of violent joint-pains and eruption that it cannot be dengue. He cultivated a bacillus from the blood, but did not succeed in establishing any causal relationship of the organism to the disease. He further states that it usually begins amongst the sailors and spreads later to the townspeople; that it occurs in other Indian ports, but is probably ​unknown in the interior of the country. Apparently it is a mild disease, has no mortality, and no distinctive pathological anatomy.
'Pseudo-typhus of Deli.— Schüffher has described a fever endemic in Deli, Sumatra, which resembles very closely, if it be not identical with, Japanese river fever (see p. 315). As in the case of the latter disease, it is communicated probably by an acarus or a tick; there is an initial necrotic ulcer on the skin, followed by a typhus-like fever and eruption, and a considerable mortality.
Similar fevers have been described as occurring in the Philippines, Tonquin, and Corea. In the Corean cases no mention is made of the initial ulcer.
Endemic glandular fever.— Recently, several writers in Australia have described a peculiar form of glandular fever endemic in the Mossman district of North Queensland, and occurring among natives and whites of both sexes and all ages, and particularly in manual labourers. It is characterized by an irregular remittent fever of from three days' to three weeks' duration, non-suppurating swellings of the lymphatic glands, especially those of the axilla and groin, a macular and, occasionally, a vesicular rash, and an incubation period of from six to ten days. The mortality is very low— 1 per cent. The disease does not spread in hospital, but is transmissible to monkeys by blood inoculation.
An insect transmitter is conjectured, but nothing positive is known about the etiology of the disease.
Diagnosis of imperfectly differentiated fevers.— The diagnosis of these fevers is always a difficult matter, especially so during their early stages. Among other possibilities that of typhoid, of undulant (Mediterranean) fever, of malaria, of kala-azar, of dengue, of influenza, and of other infections has to be considered. The persistent absence from the blood of the malaria parasite and of pigmented leucocytes —if vouched for by an experienced observer— and the negative results attending administration of quinine, together with the absence of definite periodicity in ​the symptoms, of pronounced anæmia and of marked enlargement of the spleen, should be decisive against malaria. But in the present state of our knowledge it is very hard indeed, until the case is well advanced, to exclude typhoid, paratyphoid, and undulant fever. It may be that further experience of the blood -serum tests will establish their title to be regarded as absolutely pathognomonic signs. In this event the practitioner will have in his possession an invaluable aid in the diagnosis of tropical fevers. As things are at present, in cases in which there is the slightest doubt it is an excellent rule to regard all doubtful fevers as being possibly typhoid.
Treatment.— It is well at the commencement of doubtful tropical fevers to be as guarded in treatment as in diagnosis, and to eschew active purgatives, to enjoin rest in bed, to place the patient on a bland, unstimulating fluid diet, and to confine medication to some innocent fever mixture. There is no specific treatment for any of these imperfectly differentiated fevers. Each case has to be dealt with on its own merits and on general principles. Headache may be relieved by cold applications to the forehead, by an ice-cap, or, especially if temperature rises high, by sponging and, if not otherwise contraindicated, by occasional doses of phenacetin or some similar drug. If quinine, on the supposition that the case is malarial, has been freely tried, and without benefit, it must not be persisted with. As already hinted, "low fever" should be treated by change of air, and more especially, where feasible, by a sea trip.