No CRP itis

 CRP (C-reactive protein) is usually high in pneumococcal sepsis—so if it’s not rising, that’s a red flag rather than reassuring. There are a few important explanations:

1) Too early in the illness

CRP is made by the liver in response to cytokines (mainly IL-6), but it:

• Starts rising 6–12 hours
• Peaks around 24–48 hours

➡️ Very early sepsis can still have a normal or low CRP.

2) Impaired immune response

A blunted CRP can happen if the body can’t mount an inflammatory response:

• Elderly patients
• Immunosuppression (e.g. chemo, steroids)
• Advanced illness

3) Liver dysfunction

CRP is produced in the liver, so if there’s:

• Acute liver failure
• Severe chronic liver disease

➡️ CRP may stay low despite severe infection.

4) Overwhelming sepsis (“immune paralysis”)

In severe cases, including advanced septic shock:

• The immune system can become dysregulated or exhausted
• Cytokine signalling drops

➡️ CRP may be inappropriately low or not rising

5) Prior antibiotics

Early antibiotics can:

• Reduce bacterial load
• Blunt the inflammatory response

➡️ Smaller CRP rise than expected

6) Lab timing / trend issue

• A single CRP value is less useful than trend over time
• It may simply not have peaked yet

Clinical takeaway

• A low or non-rising CRP does NOT exclude severe infection
• In suspected pneumococcal sepsis, decisions should rely on:
  
• Clinical picture (shock, confusion, etc.)
• Other markers (lactate, WBC)
• Imaging and cultures
• 
  

If you’re seeing this in practice, it’s worth asking:

• How long since symptom onset?
• Any liver dysfunction or immunosuppression?
• What’s the lactate and clinical state?

Because a “normal CRP” in someone who looks septic is actually concerning, not reassuring.