The white blood cell (WBC) count is used to help diagnose and determine the severity of pneumonia. Previous studies have shown that a low or normal WBC count at admission for pneumonia has a poor prognosis.
We analyzed a database of 495 patients with presumptive (positive sputum Gram stain and culture) or proven (positive blood culture) pneumococcal pneumonia to determine whether very low (≤5,000) or very high (>20,000) WBC counts were associated with increased mortality at 7 and 30 days after diagnosis. Patient charts were reviewed to determine the WBC count and differential on the day of presentation or diagnosis and collect results of blood and sputum culture.
Thirty-three (6.6%) patients presented with a WBC count ≤5,000, 109 (22%) with a WBC count 5,000-10,000, and 95 (19.3%) with a WBC count >20,000. Patients with a low WBC count were 6.82 times more likely (p < 0.001) to die within 7 days when compared to patients with a WBC count of 10,000-20,000 (n = 258). WBC count within the normal range (5,000-10,000) and very high WBC counts (>20,000) were not significantly associated with increased mortality (p = 0.87 and p = 0.70, respectively). Thirty-two patients (6.5%) had 5-10% bands, and 71 (14.4%) had >10% bands. There was no association between band counts and mortality. Four hundred and forty patients (89%) had blood cultures drawn and 170 (28%) were found to be bacteremic. Bacteremia was not significantly associated with increased risk for death at 7 days (p = 0.095).
In this patient population, very low WBC counts (≤5,000) correlated significantly with increased mortality. Alhough prior research has demonstrated WBC counts in the normal range (5,000-10,000) have been associated with a poor prognosis, that finding was not replicated in our patient population. WBC counts >20,000, elevated band counts, and bacteremia were not associated with death. Thus, we suggest that there be a low threshold for intensive care for patients with suspected pneumococcal pneumonia and very low WBC counts.
J. G. Gardner,
A. M. Rueda, None
E. Graviss, None
D. Nguyen, None
D. M. Musher, None
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