Value of examining buffy coats for intragranulocytic micro-organisms in patients with fever

Aetiology and management of children with acute fever of unknown origin

This is part I of a 2-part paper on fever of unknown origin (FUO) in children. FUO is best defined as fever without obvious source on initial clinical examination and then classified into acute (illness of < or =1 week's duration) and prolonged (>7 to 10 days' duration). Aetiologically, there is a marked overlap between acute and prolonged FUO, and infections are major players in both. Age, climate, local epidemiology and host factors are the major aetiological factors that should be considered in the choice of definitive tests. Depending on age, serious bacterial infections (including bacteraemia, meningitis and urinary tract infection) occur in 3 to 20% of cases of acute FUO. Prevention of mortality and sequelae from these infections, particularly bacteraemia and meningitis, is of particular concern in acute FUO. An individualised approach, based on clinical evaluation supplemented with screening and definitive laboratory tests to determine the need for empiric antibiotic therapy and hospitalisation, seems to be the best approach to acute FUO (although this may be less applicable to neonates and infants younger than 90 days, particularly those aged 0 to 7 days). The place of laboratory tests, empiric antibiotic therapy and hospitalisation are important issues that are likely to remain so for some time.

Capnocytophaga canimorsus bacteraemia demonstrated by a positive blood smear. A case report

The observation of bacteria in a peripheral blood smear was conducive to the diagnosis of Capnocytophaga canimorsus septicaemia in a patient with no definite record of animal bites. Multiple rods were seen extracellularly and within the cytoplasm of neutrophils. The blood culture became positive after 18 h of incubation. Disseminated intravascular coagulation (DIC) was manifest and infarction of the spleen was suspected. Direct examination of peripheral blood smears could be a valuable adjunct in the diagnosis of overwhelming bacteraemia.

Culture-negative infective endocarditis

Culture-negative endocarditis is not uncommon; the most frequent causes of the culture negative state are prior antibiotic therapy and problems with or inadequacies in bacteriologic technique. In addition to blood culture, studies that can aid in substantiating a presumptive diagnosis of infective endocarditis include echocardiography. Immunologic tests, and cardiac catheterization. Empiric antibiotic therapy often is necessary and should not be delayed to await positive blood cultures and results of antimicrobial sensitivity studies.

Evaluation of buffy-coat microscopy for the early diagnosis of bacteraemia

Three hundred and sixty samples of blood from 230 hospital patients were examined and compared with the results of simultaneous blood culture to determine the value of buffy-coat microscopy in detecting bacteraemia. One observer found 86 positive smears, 12 of which were from patients with positive blood cultures and 74 from patients with negative blood cultures. The buffy-coat smear was negative in 274 specimens, 8 of which yielded positive blood cultures. A second observer considered that only 34 of the buffy coats were positive. Only six of these were associated with positive blood cultures. Although there was a statistically significant association between positive smears and positive blood cultures, the procedure has little practical value because of the high incidence of false positives and negatives.

Septic shock

Septic shock is a dynamic syndrome of inadequate tissue perfusion caused by invasion of the blood by micro-organisms. Gram-negative rod bacteremia accounts for about two-thirds of patients with this syndrome. The fully developed syndrome of high fever, chills, cold, moist extremities, hypotension and oliguria is easy to recognize. However, the initial features of the syndrome may be quite non-specific and subtle, particularly in elderly patients. Treatment is aimed at eliminating the infection, improving tissue perfusion, supporting ventilation and managing specific complications.