Body Fluids
Deborah Goldstein
Argy Resident
September, 2005
Fluids
• CSF
• Pleural Fluid
• Peritoneal Fluid
Pt with fever, nuchal rigidity....
1. Get blood cx
2. Give Abx
• S. pneumo (30-50%), N. Meningitidis (10-35%), H. influenza (1.5
• Platelets 250mmHg
• If elevated, likely due to cerebral edema
from intracranial pathology
• Infection (cryptococcal meningitis), tumor,
benign ICH (pseudotumor)
RBCs
Always send tube #1 and #4 for cell count and
compare RBCs
Traumatic tap: Elev RBC in tube 1, nl in tube 4
– 1000 RBC : 1 WBC to adjust WBC count in bloody tap
SAH or HSV: Elev RBC in tube 1 AND tube 4
• “Crenated RBCs” and xanthochromia (yellow
supernatant after centrifuge)
– Seen in hyperbilirubinemia (ESLD), old SAH, old
blood from prior traumatic LP or bleed
WBC’s
• Infection!
• PMN predominance: likely bacterial
meningitis
• Lymphocytic predominance: viral vs. fungal
vs. TB vs. malignancy
Protein
• Normal: protein is excluded from CSF by
blood-CSF barrier
• Increased: nonspecific
• Elevated in all infectious meningitis
– May remain elevated for months post-
meningitis (viral or bacterial)
• Increased in malignancy and inflammatory
conditions (ie Guillain-Barre)
Glucose
Normal
• Viral infection
Low glucose
• Bacterial meningitis, TB, fungal
Really low
• 50% of serum concentration
Typical Bacterial Meningitis
• CSF WBC >1000, PMN predominance
• CSF protein >500mg/dl
• CSF glucose 2, platelets 1 cm and free flowing in lateral
decubitus view
• If CT shows free-flowing fluid, you don’t
also need lateral X-ray
Thoracentesis Procedure
• Confirm fluid is free-flowing, not loculated
• Obtain consent
• Consider US mark if medium-size effusion or
loculated
• Have pt sitting up and leaning forward over table
• Percuss fluid level and go 1-2 spaces below, in
midclavicular line
• Enter just ABOVE the rib to avoid neurovascular
bundle
• ALWAYS obtain a CXR post-tap
Pt gets dyspneic after you’ve
withdrawn 150cc from L chest....
You took 2.3L clear fluid off this
pt’s Right chest. F/u CXR shows....
Other Thoracentesis
Complications
• PTX
• Re-expansion pulmonary edema
– Don’t take off more than 1L
• Hemothorax
• Infection
• Hypotension
• Hepatic or Splenic puncture
What to order?
Serum LDH, total protein (Add on to am labs)
Pleural fluid:
• Total Protein, LDH
• Glucose, cell count and diff, pH (on ice)
• Gram stain, culture, fungal stain and culture, AFB
• Cytology
• Other: triglyceride level to r/o chylothorax;
amylase to r/o pancreatitis, esoph perf; Adenosine
deaminase to eval TB
Light’s Criteria for Exudates
Fluid is exudate if it meets 1 of 3 criteria:
1. Pleural fluid LDH/serum LDH > 0.6
2. Pleural fluid protein/serum protein > 0.5
3. Pleural fluid LDH > upper limit of normal
serum LDH
• If all 3 negative, fluid is Transudate
Transudate
• Result from imbalances in oncotic and hydrostatic
pressure
• Usually low oncotic +/- high hydrostatic pressure
• Pulm Edema/CHF
• Cirrhosis with ascites
• Hypoalbuminemia/Nephrotic syndrome, ESLD
• Fluid overload s/p aggressive IVF
• Peritoneal dialysis
Exudate
Caused by local, not systemic, factors
• Infection
• Neoplasm
• Pancreatitis
• Esoph perf
• RA
• SLE
• Sarcoid, Wegeners, PE, Meig’s, Chylothorax
Lymphocytosis
• Malignancy (50-70% lymphs)
• Also TB, sarcoid, RA, chylothorax (>90%
lymphs)
Pleural eosinophilia
• Pneumothorax • Fungal infection
• Hemothorax • Drugs
• Pulm infarct • Malignancy
• Parasitic disease • Asbestos
Why is glucose low?
(10 mm thick on decub, pH>7.2 , Glucose>40 mg/dL
• GS neg, cx neg
• Diagnostic tap, then Abx alone
Class 3 = “Borderline complicated”
• pH>7.0, 1,000 and glucose>40 mg/dL
• GS neg, cx neg
• Abx and serial thoracenteses
Grading Effusions
Class 4 = “Simple complicated”
• pH0.6 to be exudate
• Pleural fluid protein/serum protein=2700/5600=
0.4
– needs to be >0.5 to be exudate
• Pleural fluid LDH is upper limits of normal serum LDH
Class 4 = “Simple complicated”
• pH1.1:
• Portal HTN (drives fluids into peritoneum)
• SBP, cirrhosis, Alcoholic hepatitis, CHF
If the gradient is 1.1
• Suspect if >250 PMNs (>100 PMNs in pt
on peritoneal dialysis)
• 70% GNR (E.coli, Klebsiella)
30% GPC (S. pneumo, Enterococcus)
• Treat with ceftriaxone, cefotaxime
• “Culture negative SBP” if >250 PMNs but
cx neg; treat the same
Bowel Perforation
• GPC in chains, GPR, GNR, fecal flora...
• Increased PMN’s, Total protein >1g/dl,
• Glucose <50mg/dl, LDH elevated
• Pt is SICK