Fluid Analysis:- part 7 – Pericardial fluid Analysis

Pericardial fluid
Sample of Pericardial fluid
- Pericardial fluid is aspirated and is tested.
Definition of pericardial fluid
- The pericardial cavity is formed by two thin membranes that surround the heart.
- These membranes are separated by a fluid-containing space called the pericardial cavity.
- Pericardial fluid is secreted by the mesothelial cells, and it will lubricate the membranes that line the pericardial cavity.
Pathophysiology of Pericardial fluid
- Normally there is 10 to 50 mL pericardial fluid (another reference: 15 to 20 mL) between the pericardial serous membrane.
- This pericardial fluid formation is due to a change in the membrane’s permeability, which may be because of infection (pericarditis), malignancy, injury, and metabolic disorders like uremia.
- The function of the pericardial fluid:
- It will allow the heart to move easily during contraction and relaxation.
- Pericardial fluid lubricate the membranes.
- It enables the membranes to slide over one another with minimal friction as the heartbeats.
- Pericardiocentesis is the removal of fluid from the pericardial sac.
- It is advised as a therapeutic emergency procedure in the case of cardiac tamponade to diagnose the cause of fluid accumulation.
- Purpose of the cardiocentesis:
- It will remove the fluid from the pericardial cavity to relieve the tamponade.
- Through this procedure, can administer drugs.
- Fluid was removed for diagnostic purposes.
Causes and classification of pericardial fluid:
- Inflammation causes pericardial fluid accumulation, and there are other causes as well.
- The pericardial effusion may be classified as:
- Serous type of fluid seen in congestive heart failure and hypoalbuminemia.
- The chylous type is seen in mediastinal lymphatic obstruction
- Serosangineous type is seen due to trauma and malignant tumors.
Signs and symptoms of pericardial effusion:
- These patients are usually symptomatic.
- Sometimes the large volume of the fluid is accommodated without any symptoms when it accumulates slowly.
- When there is a massive accumulation of the fluid, that may lead to cardiac tamponade.
Normal pericardial fluid:
- Appearance = Clear or straw-colored
- Bacteria = Negative
- WBCs = No WBCs are seen.
- Glucose = Equal to serum level.
Causes of Pericardial effusion:
- Active rheumatic fever in 40% of the patients.
- Bacterial infection in 20% of the cases is due to tuberculosis, streptococcus pneumonia, staphylococci, and gram-negative bacteria.
- Other infections like Coxsackievirus rickettsia, parasites, and fungi.
- Uremia may be the cause in 11% of the cases.
- Benign nonspecific pericarditis.
- Collagen diseases like SLE (2% of the cases).
- Trauma.
- Myxedema.
- Malignant diseases (3.5% of the patient).
- Rarely caused by severe anemia, scleroderma, polyarteritis nodosa, Wegner granulomatosis, rheumatoid arthritis, radiation, and mycotic infections.
The pericardial fluid | Clinical significance |
Appearance | |
Clear and pale | Normal |
Grossly bloody | Cardiac puncture and anticoagulant medications |
Blood tinged | Infection and malignancy |
Milky | Chylous and pseudonymous |
Microscopic examination | |
Neutrophils | Increased in bacterial infection (>1000/cmm) |
Lymphocytes | Chronic infection |
Gram stain | Bacterial endocarditis |
AFB stain | Tuberculous infection |
Malignant cells | Metastatic carcinoma (lung, breast) |
Chemicals test | |
CEA | Metastatic carcinoma |
Adenosine deaminase | Tuberculous infection |