For poorly understood reasons the CRP is of no use as a useful guide of disease activity in Systemic lupus Erythematosus, Scleroderma, Ulcerative colitis and leukaemia
| Cause |
Clinical Features |
Investigations |
Management |
| Bacterial Infections (e.g., Sepsis, Pneumonia) |
Fever, chills, tachycardia, hypotension, altered mental status, cough, difficulty breathing. |
Blood cultures, complete blood count (CBC), chest X-ray, urine analysis, lactate levels, CRP, and procalcitonin levels. |
Broad-spectrum antibiotics, intravenous fluids, supportive care, source control (e.g., drainage of abscess), monitoring in ICU if severe. |
| Severe Systemic Inflammatory Response (e.g., Acute Pancreatitis) |
Severe abdominal pain, nausea, vomiting, fever, tachycardia, hypotension, jaundice. |
Serum amylase and lipase levels, abdominal CT scan, CRP, liver function tests (LFTs), complete blood count (CBC). |
Supportive care, intravenous fluids, pain management, enteral nutrition, monitoring for complications, surgical intervention if necessary. |
| Autoimmune Diseases (e.g., Rheumatoid Arthritis, Systemic Lupus Erythematosus) |
Joint pain, stiffness, swelling, fatigue, malaise, skin rashes (e.g., malar rash in SLE), photosensitivity. |
Autoantibody tests (e.g., RF, anti-CCP, ANA), CRP, ESR, joint imaging (e.g., X-ray, MRI), renal function tests if SLE is suspected. |
Immunosuppressive therapy (e.g., methotrexate, corticosteroids), disease-modifying antirheumatic drugs (DMARDs), biological agents, monitoring for disease progression and complications. |
| Severe Viral Infections (e.g., COVID-19, Influenza) |
Fever, cough, shortness of breath, myalgia, fatigue, anosmia (COVID-19), headache. |
RT-PCR for viral RNA, chest imaging (X-ray, CT scan), CRP, CBC, liver function tests, oxygen saturation levels. |
Supportive care, antiviral treatment if indicated (e.g., remdesivir for COVID-19), corticosteroids for severe cases, oxygen therapy, ICU care if severe. |
| Malignancies (e.g., Lymphoma, Solid Tumours) |
Weight loss, fatigue, night sweats, lymphadenopathy, unexplained pain, or mass, fever. |
CRP, CBC, imaging (CT, MRI, PET scans), biopsy of the suspicious lesion, tumour markers, bone marrow biopsy if hematological malignancy is suspected. |
Chemotherapy, radiotherapy, surgical resection, targeted therapy, monitoring for response to treatment and complications. |
| Trauma or Major Surgery |
Postoperative pain, swelling, erythema, fever, signs of infection or inflammation at the surgical site, delayed wound healing. |
CRP, CBC, imaging (e.g., ultrasound, CT) if abscess or hematoma is suspected, wound cultures if infection is suspected. |
Postoperative care, pain management, antibiotics if infection is suspected, wound care, surgical intervention if necessary for complications (e.g., abscess drainage). |
| Severe Burns |
Pain, extensive skin damage, fluid loss, hypovolemic shock, infection, hypermetabolic state. |
CRP, CBC, electrolytes, renal function tests, wound cultures if infection is suspected, blood gas analysis. |
Fluid resuscitation, pain management, wound care, antibiotics if infection is present, nutritional support, monitoring in a burn unit. |
| Vasculitis (e.g., Giant Cell Arteritis, ANCA-associated Vasculitis) |
Fever, weight loss, fatigue, headache (GCA), vision changes, muscle pain, joint pain, skin ulcers. |
CRP, ESR, ANCA test (if suspected ANCA-associated vasculitis), temporal artery biopsy (for GCA), imaging (e.g., angiography), renal function tests. |
Corticosteroids, immunosuppressive agents, monitoring for complications (e.g., aneurysms, renal failure), surgical intervention if necessary. |
| Adult Still's Disease |
High spiking fevers, salmon-colored maculopapular rash, arthralgia, sore throat, lymphadenopathy, hepatosplenomegaly. |
CRP, ESR, ferritin (often markedly elevated), CBC, liver function tests, autoantibody screen to exclude other conditions. |
NSAIDs for symptom control, corticosteroids for severe cases, DMARDs (e.g., methotrexate), biological agents (e.g., IL-1 or IL-6 inhibitors), monitoring for complications like macrophage activation syndrome (MAS). |
C-reactive protein (CRP) is a key marker of inflammation produced by the liver in response to various inflammatory stimuli. It plays a crucial role in the acute phase response, opsonization, complement activation, and immune modulation. CRP levels are widely used in clinical practice to diagnose and monitor inflammatory conditions, assess cardiovascular risk, and evaluate infections and autoimmune diseases. Understanding the function and regulation of CRP is essential for its effective use in medical diagnostics and treatment monitoring.