C-reactive protein = inflammation? Perhaps overlooked more

C-reactive protein (CRP) is an acute phase protein
synthesized by liver cells when the body is exposed to inflammatory stimuli such as microbial invasion or tissue damage.

Note: Acute phase reaction (APR) includes changes in the concentration of certain serum proteins during infection, inflammation, and trauma, including serum amyloid A, fibrinogen, haptoglobin, α1 acid glycoprotein, ceruloplasmin, α1 antitrypsin, etc
.
in addition to CRP.

Among them, the concentration of CRP in the serum of healthy people is very low (<5 mg/L), and its concentration is significantly increased in bacterial infection or tissue damage, so it is considered the most valuable<b10>.

What does CRP reflect?

1.
Screening of organic diseases;

2.
Acute or chronic inflammation if accompanied by bacterial infection;

3.
Autoimmune or immune complex disease;

4.
Tissue necrosis and malignant tumors
.

Structure of CRP

CRP is a cyclic five-spheroid protein, belonging to Oligomeric calcium-binding protein, with a relative molecular mass of about 120000, composed of 5 identical monomers with non-covalent bonds, which is the inflammatory lymphoid ethers interleukin-6, interleukin-1, tumor necrosis factor to stimulate the synthesis of
liver epithelial cells.

Top 10 clinical uses of CRP

1.
Diagnosis and identification of infection

CRP began to increase 6~8 h after the occurrence of bacterial infection, peaked at 24~48 h, and its content decreased sharply after the infection was eliminated, and returned to normal
within one week.
CRP is not significantly elevated
in viral infections.

2.
Predict the risk of future myocardial infarction and stroke CRP is the strongest risk indicator of cardiovascular disease, and CRP level can predict the risk of
future myocardial infarction and stroke.

Compared with <1 mg/L with CRP content > 2.
1 mg/L, the risk of future myocardial infarction was 2.
9 times that of the latter, the risk of ischemic stroke was 1.
9 times that of the latter, and the risk of peripheral arterial vascular disease was 4.
1 times
that of the latter.
Within a few hours after the onset of pain, CRP increased, peaked at 3~4 d, and dropped to normal 7~10 d after CK-MB returned to normal
.

3.
Autoimmune or immune complexes

There are no significant changes in CRP in systemic lupus erythematosus, polymyositis, and systemic sclerosis, so it can be used to distinguish
it from rheumatic diseases.
If fever is present, it is a complication rather than worsening
of illness.

4.
CRP where the cancer has been elevated or is being elevated indicates a poor prognosis and often indicates metastasis
.
Colon cancer is the second most fatal cancer
.
Studies have shown that patients with the highest blood levels of CRP have twice the risk of colorectal cancer than those with the lowest levels of CRP
.

5.
Evaluate disease activity and efficacy, and monitor CRP of 10~50 mg/L, indicating mild inflammation
.
A rise in CRP to 100 mg/L indicates more severe disease, and its severity requires intravenous administration if necessary
.
CRP> 100 mg/L indicates a severe disease process and often indicates the presence of
bacterial infection.

6.
Antibiotic treatment monitoring series of plasma CRP determination, can be used as therapeutic monitoring for the following conditions: (1) antibiotic treatment when encountering infection; (2) the dose of anti-inflammatory drugs needs to be determined according to changes in CRP levels; (3) Interrupt antimicrobial therapy when CRP drops to normal; (4) When there is a lack of microbiological diagnosis in high-risk groups, it is a guide
for antibiotic therapy.

7.
24~72 h after surgery, the level of CRP in the blood increased significantly, and returned to normal
on the 5~7th day.
Persistently high levels after a sudden rise are more indicative of co-infection
.
For patients with medium and major surgery, routine testing is done once
before surgery and 3~7 days after surgery.
If the level of CRP continues to be high 5~7 days after surgery, co-infection should be suspected and followed up with
treatment.

8.
Internal medicine pneumonia: CRP > 100 mg/L, strongly suggesting bacterial infection, such as purulent bronchitis or pneumonia; Typical viral pneumonia does not exceed 50 mg/L
.
In cardiovascular disease, CRP rises within a few hours after the onset of pain, peaks in 3~4 days, and decreases to normal 7~10 days after CK-MB returns to normal
.

Metabolic syndrome, which can be divided into CRP levels into:

low-risk group, <1 mg/L;
Medium risk group, 1~3 mg/L;
High-risk group, >3 mg/L
.

9.
Obstetrics and gynecology pelvic inflammatory disease and uterine adnexitis, CRP value is elevated
.
Pelvic masses and uterine fibroids are usually negative
.

Diagnose intrauterine infection with premature rupture of membranes
.
Prelabour rupture of membranes, such as maternal CRP exceeding 50 mg/L 6-19 hours before delivery, can be used as a standard for the appearance of AIS; The CRP of acute ischemic stroke (AIS) that occurs on the first postpartum day will be 2~3 times
higher than that of normal delivery.

Uncomplicated infection with Neisseria urogenital gonorrhoeae (NG) and Chlamydia trachomatis (CT) does not cause elevated CRP, but spread to the pelvis can cause acute phase reactions
.

10.
Pediatrics

Neonatal sepsis: CRP >10 mg/L before 3 days of life indicates infection
.
If CRP does not exceed 10 mg/L within 24 hours, neonatal infection
is absent.
Fever in children: more than 12 hours of illness, significant CRP > 40 mg/L, significant ESR > 30 mm/h should be concerned as bacterial infection
.

Meningitis: CRP>20 mg/L suggests bacterial infection; CRP > 100 mg/L has diagnostic value
for bacterial infection.
Tuberculous meningitis CRP is 20~60 mg/L
.
Successful treatment can reduce CRP to normal
within a week.