With the exception of the development ot shin lesions and epilation, plrysacad oxi blonis atone time revealed findings many group that could be attributed with certainty Ce cadiation The various clinteal conditions encounteredin the most severely exposed proaups were aot re markably different from those seen in the least exposed Utirtk group “Phe skin lestons and epilation appeared abuut the [2th to 14th post-exposure days 2.3 CLINICAL OBSERVATION AND THERAPY AS RELATED TO HEMATOLOGICAL, FINDINGS ~ Although detailed hematological findings are presented in chapter 4, certain considerations of the religion of clameal to hematological findings are discussed here 2.8.10 Leukocyte Counts Between the 33rd and 43rd post-exposure days, 10 per cent of the Rongelap individuals reached wn absolute pranulocyie level of F000 per cubre millimeter or below. observed during. this period was 700 granulocytes, ‘The lowest count Daring this interval (he advisability of piv - ing prophyhectie antibiotic therapy to such individuals was carefully reconsidered. Hawever, prophylictic antibiotics were pot instituted because of the following considerations: (1) All individuals were under continuous medical observation so that intection would be discovered in its earliest stages. (2) Since some individuals might require antibiotics for long periods of time if infection occurred, the premature administration of such drugs would not only possibly obscure medical indication of treatment, but might potentially lead to the development of drug resistant organisms in an individual with an already lowered resistance to infection. (3) There is no accurate knowledge of the number of grarulocytes required by manto prevent the types of infection seen in agranulocytosis. : (4) The observed situation was not strictly comparable tu agranulocytosis with un aplastic marrow due to potentially lethal doses of radiation. In the latter instance, franulocytes fall rapidly and there are practically none in the circulation wher infection occurs. In the present group of individuals exposed to radiation, although most counts were approximatcly one-fourth of normal, the fall to that Jevel was gradual and there was some evidence of granulocyte regeneration. White counts were repeated at three or four day intervals on all of the exposed individuals and more frequently on those with the lowest counts. Those with symptoms or elevated temperatures were treated only after an attempt to establish a diagnosis was made, even if a period of observation was necessary. During the observation period, the patients were examined at frequent intervals and the temperature checked every few hours. Twenty-seven individuals had total leukucyte counts of 4000 or below or absolute neu- troplile counts of 2500 or less at some time during the period of observation. Of these 27, 13 had symptoms of disease that required evaluation for possible antibiotic therapy. Eleven of the 13 had severe upper respiratory infections, one individual had abdominal pains and fever, and one had urticaria (hives) with fever. The incidence and type of symptomis in the group with low leukocyte counts did not differ materially from those in the remainder of the population and it appeared that the occurrence of disease and the presence of leukopenia was coincidental. The 13 instances in which it was necessary to consider the use of antibiotic therapy in neutropenic individuals are summarized below: Eleven of the 13 individuals had severe upper respiratory infections. Eight of these had malaise, sore throat, nasal discharge, and temperatures that varied between 99 and 101.4°F and then fell to normal within a 12 hour period. Since the response of this group to upper respiratory infection appeared identical with that of individuals without neutropenia, no therapy was given. Two of the 11 had marked malaise, headache, abdominal pain, nausea, diarrhea, and high fever. Both were children, one age seven, the other age two. In both instances, the symptoms were out of proportion to the physical findings, which were negative except for head colds and mild pharyngeal injection. The seven-year old child had a temperature of 102.6 when first seen “~ 25