War Surgery and Medicine
AN inquiry was made in August 1943 by Colonel J. R. Boyd into the relative frequency of the non-committal ‘diagnosis’ PUO. The term was essentially a provisional diagnosis which lasted only until such time as the correct nature of the illness had been elucidated by clinical examination. It was a handy way of classifying many fevers which, in the early stages, might resemble any one of many different feverish conditions, and where an early definite diagnosis would be largely guesswork. There were two main groups.
The first group was a comparatively large one and was made up of all those short-term fevers whose onset and clinical course presented no special distinguishing features and where the whole illness was over and recovery complete in a matter of perhaps twenty-four to ninety-six hours. These cases were held and treated in forward medical units and returned direct to duty without further evacuation down the line. The provisional diagnosis thus became the final diagnosis and was registered accordingly in the Field Medical Card 3118.
The second group consisted of those cases which remained feverish for more than four or five days. Some more serious condition had to be thought of and they were evacuated to the base hospital for investigation. They represented a considerable number, but in most of them diagnosis was readily made with the facilities available in hospital. The minority were the unexplainable few who remained undiagnosed after the exhaustion of almost every accessory aid to diagnosis.
In our base hospitals we made it a rule not to give a definite name to any case of fever unless and until clinical evidence completely justified the diagnosis. Furthermore, it was our practice in all such cases never to make a final diagnosis of PUO without having first excluded, by repeated physical examinations and the help of all relevant laboratory tests, malaria, relapsing fever, the enteric group of fevers, tuberculosis, meningitis, and septicaemia. Influenza was usually fairly easily excluded.
It was said that sandfly fever had to some extent taken the place of PUO as a ready diagnosis, and that in this way the total cases page 575 of PUO registered were less than they should have been. This affected the position in two ways, and it was possible that the one cancelled out the other. It had to be admitted that not infrequently an early diagnosis of sandfly fever had to be corrected later on in the light of fresh evidence, and this lent support to the contention that the diagnosis might have been too readily made. As a matter of fact the clinical picture of sandfly fever was not just as clean-cut and easy to distinguish with certainty as textbooks depicted it. Nevertheless, the converse was also probably true. Except in the presence of an epidemic, many medical officers hesitated to diagnose sandfly fever, preferring to label the case PUO. Colonel Boyd was inclined to think that the boot was on the other foot, and that the majority of the short-term fevers which recovered before diagnosis was made were, in fact, cases of phlebotomus fever (sandfly fever).
In 2 NZEF, between June 1941 and December 1942, a large number of cases of PUO were dealt with in forward medical units.1 Some 364 of these were able to return direct to their units without being evacuated farther than to a Field Ambulance or Casualty Clearing Station. The diagnosis of PUO was registered on the Form 3118 and was the only diagnosis. Of a considerable number whose illness was of sufficient duration or severity to make evacuation to hospital advisable, only in 25 was it found impossible to make a diagnosis, and the final diagnosis remained PUO.
Of the 364 cases returned to their units, 44 had blood films examined by a mobile laboratory unit with negative findings. In 47 per cent the fever lasted approximately three days; in 49 per cent approximately five days, and in only 4 per cent did it last longer than five days.
Eighty-five per cent of the cases occurred during the summer months, June to October. The incidence thus appeared to be seasonal, and suggested a relationship to atmospheric temperature and insect life. The incidence in different units appeared to be fairly evenly distributed.