A normal platelet count at admission in acute meningococcal disease does not exclude a fulminant course.

OBJECTIVE

To determine the value of the platelet count at admission for the assessment of the severity of disease in acute meningococcal infections.

DESIGN

Retrospective and prospective, descriptive patient study.

SETTING

University Hospital Intensive Care Unit (ICU).

PATIENTS

All patients (n = 92) with acute meningococcal disease from 1985 to 1997, who arrived at the ICU within 12 h after hospital admission and had more than one platelet count during the first 12 h.

MEASUREMENTS AND RESULTS

After admission, platelets dropped in 95% of the patients. At admission, 2/41 (5%) of the non-hypotensive patients and 13/51 (25%) of the hypotensive patients had platelets fewer than 100 x 10(9)/l. During the following 12 h, these percentages increased to 15% and 71%, respectively. Fatalities had, at admission, a median platelet count of 111 x 10(9)/l (range, 19-302 x 10(9)/l), whereas the nadir, occurring at median 7.0 h (range, 1.3-12 h), was 31 x 10(9)/l (range, 12-67 x 10(9)/l). Plasma TNF, measured shortly after admission, correlated better with the platelet nadir (r = -0.65, p < 0.0001) than with the platelet count at admission. Similarly, serum lactate correlated better with the platelet nadir.

CONCLUSIONS

As platelets drop after admission, the use of the platelet count at admission for the assessment of the prognosis in acute meningococcal disease may be misleading. Frequently repeated platelet counts are a better tool for evaluating the severity of disease.