Incomplete or absent acute phase response in some postoperative patients

Area of Science:

• Orthopedic Surgery
• Clinical Chemistry
• Immunology

Background:

• The acute phase response (APR) is a systemic reaction to tissue injury.
• C-reactive protein (CRP) is a common marker for APR, but its absence doesn't always indicate a lack of response.
• Transthyretin (TTR) and alpha-1 acid glycoprotein (AAG) are also APR markers.

Purpose of the Study:

• To investigate the prevalence and implications of an incomplete or absent acute phase response in patients with open lower limb fractures.
• To compare the reliability of CRP, AAG, and TTR as markers for APR in this patient cohort.

Main Methods:

• Prospective study of 74 patients undergoing osteosynthesis for open lower limb fractures.
• Monitoring of serum CRP, AAG, and TTR levels postoperatively.
• Assessment for infectious complications and evaluation of hepatic function and nutritional status.

Main Results:

• None of the 74 patients developed postoperative infectious complications.
• 67 patients showed a classical APR with elevated CRP.
• 7 patients (9%) exhibited an incomplete (low/undetectable CRP with elevated AAG and decreased TTR) or absent APR, without hepatic insufficiency or malnutrition.

Conclusions:

• An incomplete or absent APR, particularly when assessed by CRP alone, is not uncommon in lower limb fracture patients treated with osteosynthesis.
• The TTR response (transient decrease) was observed in all patients with an atypical APR.
• Absence of a classical CRP-based APR did not correlate with an increased risk of postoperative infection in this study.