Thrombocytopenia is common in ICUs and constitutes a simple and readily available risk marker for mortality, independent of and complementary to established severity of disease indices. Both a low nadir platelet count and a large fall of platelet count predict a poor vital outcome in adult ICU patients.

Compared with older series, we observed more prosthetic valve IE, nosocomial IE, and surgery. Staphylococcus aureus and Enterococcus faecalis were predominant microorganisms. Age, staphylococci, and a contraindication to surgery predicted 6-month mortality. Nearly half of deaths had a contraindication to surgery. Six-month mortality did not differ significantly between patients who received surgical treatment as against those who received medical treatment without a contraindication to surgery.

Prolonged febrile illnesses remain a diagnostic challenge. Despite the technological progress of the late 20th century, the origin of the fever remains elusive in many patients, especially in those with episodic fevers. Noninfectious inflammatory diseases emerge as the most prevalent diagnostic category.

Only one in three patients has an (moderately) increased vascular FDG uptake, especially in the subclavian arteries. The vast majority has inflammation of shoulders and hips, and half of them have increased FDG-uptake at the processi spinosi. Results of FDG-PET scans in patients with PMR did not correlate with their risk of relapse.

A revision of the criteria of fever of unknown origin (FUO), established in 1961, is desirable because of important evolutions in medical practice and the emergence of new patient populations. The development of rapid laboratory tests and powerful diagnostic tools, such as ultrasonography, computed tomography and magnetic resonance imaging often makes hospitalization unnecessary and new categories of patients such as those with HIV infection, neutropenia, immunosuppression and nosocomial illness require an approach different from classical FUO. The more then 200 reported causes of FUO can be classified into four diagnostic categories; infections, tumours, noninfectious inflammatory diseases (NIID) and miscellaneous. A uniform classification system is highly wanted to allow comparison between different series. The reports of the 1990s show slight changes in the distribution of causes, namely less infections, less tumours, more NIID and more undiagnosed cases. A uniform diagnostic strategy cannot be determined. The initial investigation should be directed by potentially diagnostic clues revealed by extensive history, meticulous physical examination and a standard set of laboratory tests.18 Fluoro-deoxy-glucose-positron-emittedtomgraphy is a new valuable total body scintigraphy in the search for the site of origin of the fever. In view of the rather good long-term prognosis, a wait-andsee strategy may be more appropriate than a systematic staged approach. Elderly patients and patients with episodic fever represent two specific groups of classical FUO that require a distinct approach. HIVassociated, nosocomial and neutropenic FUO should be considered as separate clinical entities.