Body Fluids Deborah Goldstein Argy Resident September, 2005
Fluids CSF Pleural Fluid Peritoneal Fluid
Pt with fever, nuchal rigidity Get blood cx 2.Give Abx S. pneumo (30-50%), N. Meningitidis (10-35%), H. influenza (<5%), Listeria (5-10%), Staph Ceftriaxone 2mg IV q12h for GPC, GNR Vanc 1g IV BID for PCN-resistant Strep pneumo Ampicillin for Listeria (in elderly, young) Decadron 0.4mg/kg IV q12 if concern for Bact infxn Give with first dose of Abx! Improves mortality, reduces incidence of hearing loss 3. R/O increased ICP w/Head CT if needed 4. Do LP
Who to LP? Indications Fever, vomiting, HA, photophobia, altered level of consciousness, leukocytosis, meningeal signs...to r/o infection, malignancy Contraindications INR>1.5 Platelets <50,000
Risks of LP First Do No Harm... Post-lumbar puncture HA –Have pt lie down 1-3hrs after to prevent CSF leak Bleeding; spinal hematoma Infection (poor sterile technique) Herniation
Lumbar Puncture Procedure Pt lies in L lateral decub position, knees to chest Posterior iliac crest as marker for L3-L4 space Prep/drape lower back in sterile fashion...lidocaine Insert LP needle pointing towards umbilicus until “pop” Obtain opening pressure (only if pt lying down) Fill tubes #1-4 with CSF
CSF Evaluation Tube 1-cell count and differential Tube 2-glucose, protein Tube 3-cultures, gram stain, cytology, (HSV PCR, West Nile, India ink, Crypto Antigen, VDRL, Lyme Ab, AFB...) Tube 4-cell count and differential
Normal CSF Composition Clear color <5 RBC’s <5 WBC’s Protein 23-38mg/dl (can use 14-45) Glucose—60% of serum level (75-100)
Opening pressure Normal = mmHg Obese pts: up to 250mmHg can be normal Pathologically elevated: >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 <18 is strongly suggestive of bacterial meningitis
Typical Viral Meningitis CSF WBC elevated, but <250 (first PMNs, then lymphocytes) CSF protein elevated, but <150 Glucose > 50% of serum concentration
Example A previously healthy 33-year-old lawyer presents to the ER with acute onset headache and confusion. He develops grand mal seizures in the ER. He is treated and sent for a head CT, which shows bilateral hemorrhage in the temporal lobes (and no hydrocephalus). CSF: mild pleocytosis (mostly lymphocytes), gluc= 60, protein = 30 a)Arbovirus encephalitis b)Brain toxoplasmosis c)Echovirus encephalitis d)Herpetic encephalitis e)Metastatic melanoma
HSV Encephalitis Aseptic meningitis: CSF w/mild lymphs, nl gluc, nl prot Most common etiologic agent of sporadic viral encephalitis Previously healthy pt with rapid onset of confusion and seizures CT: hemorrhagic necrosis of the temporal lobes Arbovirus encephalitis: most important cause of epidemic viral encephalitis; clinical course is milder and prognosis is better than herpetic encephalitis CNS Toxo: in immunocompromised pts; round, ring-enhancing intracerebral masses Echovirus encephalitis: common cause of asceptic meningitis; mild symptoms (headache, malaise) with normal CSF Metastatic melanoma: CNS lesions may hemorrhage; but mets appear as space-occupying masses
Example Pt with AIDS on Combivir (AZT/3TC) and Indinivir c/o leg weakness, incontinence. On exam, reduced strength in lower extremities with mild spasticity. Also diminished sensation in b/l feet, legs. Brain MRI: nonfocal CSF: Opening pressure=100 mm H20, Cell count=5 lymphs, Glucose=48, Protein=33 Normal serum B12, negative serum RPR, hct nl. What’s he got? A. AIDS dementia complex B. CMV polyradiculopathy C. Cryptococcal meningoencephalitis D. Vacuolar (HIV) myelopathy E. AZT neurotoxicity
HIV Myelopathy Common neurologic complications of AIDS Degeneration of spinal tracts in posterior, lateral columns (causing them to look vacuolated) Physical findings are similar to B12 deficiency Diagnosis of exclusion! AIDS dementia complex: progressive memory loss, alterations in fine motor control, urinary incontinence, altered mental status CMV polyradiculopathy: CSF has neutrophilic pleocytosis Crypto meningoencephalitis: presents with signs/symptoms of meningitis, and CSF shows fungus Zidovudine-related toxicity: can cause asthenia, myopathy
Thoracentesis Indications Diagnostic - All NEW effusions (except if clearly due to heart failure) Therapeutic – Respiratory distress Suspected parapneumonic effusions must be tapped ASAP (“Don’t let the sun set on a pleural effusion”)
Don’t do Thoracentesis if... Coagulopathy (INR>2, platelets <25,000) Severe lung disease on contralateral side (risk of PTX) Mechanical ventilation (not due to risk of PTX from PEEP, but due to decreased re- sealing)
Loculated? Must be >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 > Pleural fluid protein/serum protein > 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
Why is glucose low? (<60) RA TB Empyema SLE Malignancy Esophageal rupture
Who needs a chest tube? Frank pus OR Positive gram stain OR pH < 7.0
Non-TB Parapneumonic Effusions Class 1 = “Nonsignificant” <10 mm thick on decub. Don’t tap, just observe Class 2 = “Typical parapneumonic” >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” pH<7.0 and/or glucose<40 mg/dL and/or Gram stain/culture positive Not loculated or frank pus Chest tube and Abx Class 5 = “Complex complicated” pH<7.0 and/or glucose<40 mg/dL and/or Gram stain/culture positive Multiloculated Chest tube and fibrinolytics (rarely require thoracoscopy or decortication)
Grading Effusions Class 6 = “Simple empyema” Frank pus Single locule or free flowing Chest tube +/- decortication Class 7 = “Complex empyema” Frank pus present Multiple locules Chest tube and fibrinolytics Often requires thoracoscopy or decortication
Example A 59-year old man with HIV and Hepatitis C develops progressive SOB and presents to the ER satting 90% RA. On CXR, he has a large Right-sided pleural effusion. Serum LDH=200, serum protein = 5.6. Pleural fluid: LDH 100, protein 2700, WBC 400, pH 7.35, glucose=85 Exudate or Transudate? Retap? Abx?
Pleural fluid LDH/serum LDH=100/200= 0.5 –needs to be >0.6 to be exudate Pleural fluid protein/serum protein=2700/5600= 0.4 –needs to be >0.5 to be exudate Pleural fluid LDH is < ULN serum LDH Transudate Cause is cirrhosis/ascites Presents w/Right sided pl effusion No Abx or need to retap Tx the underling problem (ascites) w/diuretics, aldactone; optimize treatment for Hep C, HIV
Example A 34 y.o. woman with cystic fibrosis presents to the ER with fever, cough and night sweats for 10 days. CXR shows LLL consolidation and surrounding free-flowing effusion. The lab loses tubes for serum LDH, protein Pleural fluid: cloudy, LDH=1360, pH=6.9, gluc=36, gram stain neg Does she need a chest tube? Fibrinolytics?
Exudate because LDH>upper limits of normal serum LDH Class 4 = “Simple complicated” pH<7.0 and/or glucose<40 mg/dL and/or Gram stain/culture positive Not loculated or frank pus Chest tube and Abx, no fibrinolytics
Indications for paracentesis A febrile pt with ascites is assumed to have SBP until proven otherwise New onset ascites—etiology? Increasing abdominal pain/discomfort Respiratory compromise Unexplained leukocytosis, acidemia, renal failure AMS
Contraindications Coagulopathy is NOT a contraindication –But don’t do paracentesis if pt is in DIC Must be careful if minimal fluid visualized on U/S If peritoneal carcinomatosis, do not do this procedure yourself –Gut gets tethered to the anterior abdominal wall and can’t move away from your needle; you can perforate it.
Paracentesis Percuss pt’s abdomen for dullness/shifting dullness Avoid obviously visible abdominal wall collaterals Avoid inferior hypogastric artery (midway between ASIS and lateral border of pubis) If therapeutic, can drain up to 4L safely for symptomatic relief (BP check pre and post safe) Large-volume tap: give 1 bottle (12.5g) 25% SPA for each 2L ascitic fluid removed
Inferior hypogastric artery
After paracetesis, SBP drops to 90 and hct drops by 4 points...
What to send fluid for Cell count with diff Albumin LDH Total protein glucose Gram stain/cx cytology
Serum-to-ascites albumin gradient (SAAG) =Serum albumin – ascitic fluid albumin If the gradient is >1.1: Portal HTN (drives fluids into peritoneum) SBP, cirrhosis, Alcoholic hepatitis, CHF If the gradient is < 1.1: (protein leaks into peritoneum and fluid follows) Peritoneal carcinomatosis, peritoneal TB, pancreatitis, nephrotic syndrome
SBP SAAG > 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