Body Fluids and Infectious Complications

Body Fluids Intracellular Extracellular Plasma (fluid component of blood) Interstitial fluid (surrounds the cells)

Pleural fluid Ascites Joint fluid CSF

Pleural Effusion Collection of fluid in pleural space resulting from excess fluid production, decreased absorption, or both. Normal 1cc of fluid pH <1000 WBC Glucose = Plasma LDH < 50% of plasma

Pleural Effusion Most common causes Cardiac Failure Pneumonia Malignancy 20-40% of pneumonias will develop an infected pleural effusion

Transudate Due to imbalance in oncotic/hydrostatic pressures pH > 7.2 LDH <200 Glucose >60 Common causes CHF Cirrhosis Hypoalbuminemia Exudate Due to inflammation or decreased lymphatic drainage pH <7.2 LDH >3x normal Glucose ≤ 60 Common Causes Pneumonia Malignancy Pancreatitis Collagen-Vascular disorders

Light et al. criteria Exudate if : LDH > 2/3 upper limit of nl serum value Pleural:Serum LDH >.6 Pleural:Serum Protein >.5

Pleural Fluid Testing Cell Count with Differential Gram Stain Culture Cytology Tumor Markers Triglyceride Cholesterol

Ascites

Abdominal Fluid Common Causes of Ascites Cirrhosis (80% of cases) Malignancy Heart Failure Can develop over days or months

Paracentesis Essential to determine diagnosis and to rule out or confirm spontaneous bacterial peritonitis (SBP) In presence of SBP, mortality by 3.3%/hr delay of paracentesis Is infection present? Is portal HTN present? Appearance (clear, bloody, cloudy, milky) Serum:Ascites albumin gradient (SAAG) Cell count & differential Total protein

Ascites Fluid Culture with bedside Glucose concentration LDH Amylase Cytology Triglyceride concentration

Ascites Fluid Appearance Clear (uncomplicated) Cloudy (infected) Milky (chylous / malignant) Bloody (traumatic tap / cirrhosis / malignancy) Brown (high bilirubin concentration) SAAG Identifies presence of portal HTN Ascites fluid albumin – serum albumin ≥ 1.1g/dL = portal HTN

Ascites Fluid Cell count & differential >250 WBC = consider infection Needs corrected in bloody taps WBC # - 1 for every 750 RBCs Neutrophil # - 1 for every 250 RBCs Protein ≥ g/dL = exudate < 2.5 g/dL = transudate < 1g/dL = high risk of SBP LDH (ascitic fluid/serum ratio) ~.4 = uncomplicated, likely due to cirrhosis ~ 1.0 = SBP Amylase ~2000 int. unit/L = pancreatic ascites

Septic Arthritis

Synovial Fluid Analysis is used to determine presence of inflammation Unexplained inflammatory fluid should be considered infected until proven otherwise Repeat aspirates may be needed to monitor response to treatment Normal synovial fluid Highly viscous Clear Acellular Protein ~1/3 of plasma Glucose = to plasma

Synovial Fluid Analysis Inflammatory Gout Rheumatologic conditions Non-inflammatory DJD Trauma Hemorrhagic Trauma Tumor Anticoagulation Septic Bacterial Viral Fungal

Synovial Fluid Analysis Cell count < 2000 WBC = non-inflammatory > 2000 WBC = inflammatory 50k – 150k WBC = bacterial Crystals Gram stain & Culture Cytology Lower WBC counts can do not rule out infection. Septic joints can coincide with inflammatory “gouty” joints.

Cerebrospinal fluid

Cerebrospinal Fluid Produced in Choroid Plexus & ventricles Normal volume = cc Normal production = 20cc/hr Reabsorbed in Arachnoid Villi One-way valve for CSF into blood Alteration of CSF Balance Infection Bleeding Tumor

Inflammation of meninges (tissue surrounding the brain and spinal cord) Bacteria enter through blood-brain barrier Bacteria rapidly replicate due to low concentration of immunoglobulins Inflammatory response can lead to cerebral edema, increased ICP, and neuronal damage Nuchal rigidity, Brudzinksi sign, Kernig sign Viral / Aseptic / Bacterial Meningitis

Cerebrospinal Fluid Diagnosis of infection / malignancy Consider CT or MRI before LP Immunocompromise h/o CNS disease (mass, stroke, infection) New onset seizure Mental status change Focal neurological deficit Papilledema (optic disc swelling)

CSF Composition Clear & Colorless Xanthochromia – discoloration of CSF due to RBC WBC: 0-5 Increase WBC can be seen in infectious/non-infectious etiologies RBC: 0-5 Protein: mg/dL Can be elevated by SAH, traumatic LP, infection, non- infectious etiologies (flow obstruction) Glucose (CSF:Serum ratio): ~.6 Typically low in infections

Pleural Fluid Normal pH 7.6 – 7.64 WBC <1000 Glucose = Plasma LDH <50% of plasma Exudate pH < 7.2 WBC >1000 Glucose < 60 LDH >3x normal of plasma

Ascites Normal WBC < 250 Protein < 2.5g/dL LDH (ascites: serum) ~.4 Infectious/ Inflamed WBC >250 Protein > 2.5 g/dL LDH (ascites:serum) ~ 1.0 SAAG Ascites albumin – serum Albumin > 1.1g/dL = Portal HTN

Synovial Fluid Normal WBC = none Infected WBC <2000 = non- inflammatory >2000 = inflammatory > 50K = septic

CSF Normal WBC 0-5 Glucose: CSF:Serum ratio = ~.6 Protein mg/dL Abnormal WBC = elevated Glucose = decreased Protein = elevated

Jessica Doiron, DNP, ANP-BC Washington University School of Medicine