Infection in an elderly patient may be difficult to diagnose because:
(1) the patient may have multiple comorbid conditions that may mask or mimic infection
(2) the patient may not develop significant fever or have other reasons for fever
(3) the patient may not show a leukocytosis (because of myelodysplasia or other cause)
An elderly patient with a high serum CRP prior to therapy is more likely to be infected.
|
Serum CRP
|
Percent Infected
|
|
> 50 mg/L
|
75%
|
|
> 100 mg/L
|
94%
|
A higher initial serum CRP is associated with a higher mortality rate, with the median serum level in nonsurvivors 70 mg/dL.
An elderly patient with an infection will show a fall in CRP if s/he is being adequately treated.
Reasons why the serum CRP may not fall:
(1) an inappropriate antibiotic was prescribed
(2) the organism is resistant
(3) the patient has an abscess or other localized focus of infection
(4) the patient has a neoplasm or other reason for an increased CRP
Correction of an underlying cause for a persistently high serum CRP should be associated with a subsequent decline.
