Evaluation of Body Fluids Flashcards
What are the main body cavities and how much fluid do they hold
- Pleural cavity: visceral and parietal membrane contain pleural fluid
- Pericardium: contains pericardial fluid
- Peritoneum: contains peritoneal fluid
*norm 1-10cc in pleural and pericardial space
Collection of Body fluids.. how do you get to them?
Thoracentesis, Pericardiocentesis, Paracentesis, Arthrocentesis, LP, Venipuncture for blood cultures
What are the two main types of Effusions and main distinctions between them?
- Transudative: due to filtration of blood serum across physiologically intact vascular wall usually due to SYSTEMIC dz (CHF, cirrhosis, nephrotic syndrome)
- Exudative: due to active accumulation of fluid w/in body cavity due to inflam and vascular wall damage. Caused by infection, malig, inflam d/o
Components of chemical analysis of body fluid?
a) Total protein
b) Total pro fluid to serum ratio
c) LDH with fluid to serum ratio
d) glucose level (lower in exudate)
e) amylase (help dz pancreatitis, bowel perf, mets)
d) TAG (confirm chylous effusion)
e) pH of pleural fluid (ID parapneumonic effusion)
f) CEA (eval effusion in pt with CEA prod tumor)
Transudative vs Exudative: Total protein level
Transudative: < 3 g/dl
Exudative: > 3 g/dl
Transudative vs Exudative: total protein fluid/serum ratio
Transudative: < 0.5
Exudative: >0.5
Transudative vs Exudative: LDH fluid/serum ratio
Transudative: < 0.6
Exudative: >0.6
Transudative vs Exudative: WBC cell count and diff
Transudative: 500 cells/uL, neutrophils
Transudative vs Exudative: Gluocse compared to plasma/serum
Transudative: glucose equal to serum
Exudative: glucose less
Transudative vs Exudative: appearance
Transudative: clear, thin fluid
Exudative: cloudy, viscous
Transudative vs Exudative: etiology
Transudative: cirrhosis, nephrosis, HF, low pro
Exudative: infection, inflammation, malignancy, collagen vascular dz (lupus, etc)
Microbiological eval of body fluid includes
gram stain, C&S (bacterial, fungal, viral, TB)
Hematologic Eval and Cytology: cells found in normal serous fluid include?
Lymphocytes
Monocytes and macrophages
Mesothelial lining cells
Hematologic Eval and Cytology: nonmalignant cells found in dz states
- Neutrophils: in exudate in inflammation/infection
- Eosinophils: in hypersensitvity rxn, infections, malignancy, and MI
- RBCs: in hemorrhage, malignancy, traumatic procedure
Malignant cells
Leukemia, lymphoma, Mets
Rule of thumb: Transudative vs Exudative
Transudates dues to PRESSURE diff bw body compartments; form the same way interstitial fluid does; usually do NOT need further testing
Exudates: significant; imply inflammation, infection or malignancy; require further testing (cytology for malignancy, culture to check infection, cell count, differential; chemistries)
Lab values consistent with pleural effusion are?
Specific gravity: >1.016
Pleural fluid pro: > 3 g/dL
Pleural fluid/serum pro: >0.5
Pleural fluid/serum LDH: >0.6
How do you dx Hemothorax?
RBC >100,000/uL
Hct of body fluid usually >50% of peripheral blood
Common causes of hemothorax? BOARD*
Trauma
Malignancy
Pulmonary Embolism
What is empyema and how is it dx
pus in pleural space
WBC >50,000-100,000 cell/uL
if >50% neutrophils = inflammation/infection
if >50% lymphocytes = neoplasm or TB
If eosinophilia: collagen vascular dz, drug induced pleuritis, neoplasm, TB
If pleural fluid has bw 50,000-100,000 WBC/uL and >50% are neutrophils then…
Empyema due to inflammation/infection
If pleural fluid has bw 50,000-100,000 WBC/uL and >50% are lymphocytes then..
Empyema due to neoplasm or TB
If pleural fluid has bw 50,000 - 100,000 WBC/uL and eosinophilia then
Empyema due to collagen vascular disease, neoplasm, TB, drug induced pleuritis
If pleural fluid pH<7.2 what does this suggest
infection, neoplasm, RA, esophageal rupture
If pleural fluid has glucose <60 what does this suggest (exudative)
infection, neoplasm, RA
If pleural fluid is +amylase, then suggests
pancreatitis, esophageal rupture
If pleural fluid +TAG this suggests
chylous effusions seen in trauma, neoplasm, obstructed lymphatics
*note that PE may cause what type of effusion
either transudative OR exudative can be cause by pulmonary embolism
pH of pleural fluid helps identify what
parapneumonic effusion
pH<7.2
The most common types of exudative pleural effusions are
- Parapneumonic effusion: due to bacterial pneumonia, lung abscess or bronchiectasis
- Malignant effusion: 3 tumors responsible for 75% malignant exudative pleural effusions are lung, breast, lymphoma CAs
How do you obtain pericardial fluid
Needle aspiration below xiphoid process
- alligator clip EKG monitoring is emergent
- ECHO GUIDED is PREFERRED
*general features similar to pleural and peritoneal fluid
When should you NOT perform pericardiocentesis
Most of the time you DONT
Do not if pericarditis and no effusion
Do not if pericardial effusion without tamponade unless need fluid for dx purpose
When is pericardiocentesis indicated
if need fluid for dx purpose
Pericardial effusion with tamponade
Elevated platelet count (thrombocytosis) think..
MALIGNANCY
An enlarged heart on a CXR could be?
cardiomyopathy, or pericardial effusion (potentially malignant)
*cardiac failure, myocarditis, or dilated cardiomyopathy are all potential dx
How do you obtain peritoneal fluid (Paracentesis)
Abdominal “tap” 4 quadran
look for signs of bleeding
What are the types of guarding (tensing of abdominal wall) and what do they suggest
- voluntary (pt does consciously)
2. Involuntary (usually occurs due to inflammation of peritoneum)
General process for development of ascites due to cirrhosis
1) decreased albumin, decreased oncotic pressure = ascites
2) increased intrahepatic vascular resistance (due to build up of tissue), increase protal HTN, increased hepatic lymph = ascites
3) increased portal HTN, increased central SNS, decrease effective intravascular volume, sodium retention, increase plasma renin and aldosteron = ascites
Routine ascitic fluid tests include
albumin, cell count, culture
Peritoneal Fluid (ascites) lab findings
Lab findings and significant similar to pleural fluid
- following trauma: r/o intraabdominal bleed
- If tender: r/o peritonitis (sometimes Spontaneous Bacterial Peritonitis in cirrhosis)
- Malignant ascites: check cytology on fluid
- infectious process: gram stain, C&S, AFB smear and culture (peritoneal biopsy better0
What is the SAAG classification (serum to ascites albumin gradient)
replaced separating ascitic fluid into transudative vs exudative
*SAAG = serum alb - ascitic fluid alb
If SAAG gradient >1.1 g/dL, then ascites is due to
PORTAL HTN condition (transudative high gradient)
*cirrhosis, alcoholic hep, CHF, liver mets, portal vein thrombosis, veno-occlusive dz, myxedema, mixed ascites
If SAAG gradient <1.1 g/dL then ascites is due to
NON portal HTN condition (exudative, low gradient)
- malignancy or infection:
- peritoneal carcinomatosis, peritoneal TB, pancreatic ascites, biliary ascites, nephrotic syndrome, serositis, bowel obstruction or infarction
What is the most useful test in ascitic fluid analysis
Ascitic fluid cell count
WBC uncomplicated cirrhosis <500 cell/ mm^3
in ascitic fluid cell count (most useful ascitic fluid analysis test), WBC cound increase may occur with
any inflammatory process
ex: Spontaneous bacterial peritonitis is most common (WBC >500 cell/mm^3)
other: TB peritonitis, Carcinomatosis, bloody or chylous ascites
Who develops Spontaneous Bacterial Peritonitis and what are the features of SBP
occurs in pt with cirrhosis and ascites
- often no infectious source, may originate in bowel
- abrupt onset fever, chills, abdominal pain
- rebound tenderness
- ascitic fluid WBC count >500cell/uL with >50% neutrophils
- treat with abx NOT surgery
How do you treat SBP
ABX!
not surgery
where do you aspirate joint fluid from
synovial fluid from knee, shoulder, ankle and elbow usually
What are indications for arthrocentesis
single inflamed joint! worry about septic arthritis
*remove as much fluid as possible
what are the categories of synovial fluid
Normal Group I (noninflammatory): OA Group II (mild inflam): SLE, scleroderma Group III (severe inflam): RA, gout, pseudogout Group IV (infectious): acute bacterial, TB
*can be overlap dependign on severity of dz process
What information is the most helpful in categorizing synovial fluid
synovial fluid appearance
WBC with diff
Presence of RBC (hemorrhage, malig, trauma)
Crystal exam (+/- birefringent)
*gram stain and culture if clinically indicated
OA is what synovial fluid category
group I (noninflammatory)
SLE, scleroderma are what synovial fluid category
group II (mild inflam)
RA, gout, pseudogout are what synovial fluid category
Group III (severe inflam)
TB, acute bacterial are what synovial fluid category
Group IV (infectious)
hemorrhagic synovial fluid can be due to
traumatic aspiration vs bloody fluid from underlying process
*traumatic aspiration will have significantly lower RBC count in 3rd tube compared to 1st
appearance of synovial fluid may be
clear or pale yellow vs turbid vs very turbid or purulent
*if can read newsprint through it, it is clear
SYnovial fluid WBC <150 cell/uL is
normal
Synovial fluid WBC <2000 is
noninflam
Synovial fluid WBC >100,000 is
septic till proven otherwise
Synovial fluid WBC 50,000-100,000…?
hard to dx, need to r/o sepsis
WBC diff of synovial fluid: 90% neutrophils? RA?
90% neutrophils implies infection
*RA <90% neutrophils
What should you do if you suspect a septic joint
Gram stain to check for bacteria
culture for bacteria
if indicated, check for fungi, TB, etc
*URGENT condition, dx prompty, tx with ABX
Hemarthrosis (hemorrhagic joint) can be due to
a) trauma, with or w/o fx
b) coagulation d/o or anticoagulation tx
c) thrombocytopenia (low platelet)
d) Malignancy
e) sickle cell
f) postop joint surgery
g) pigmented villonodular synovitis
h) unknown
When should you consider synovial fluid aspiration and analysis?
Monarthritis (acute or chronic)
Trauma w/ joint effusion
Monarthritis in pt with chronic polyarthritis
Suspicious of joint infection, crystal induced arthritis or hemarthrosis
Just for the heck of it, what other joint fluid tests are there (limited or no additional value in joint fluid evaluation)
- glucose (usually low in setting of severe inflam
- Pro: little value
- viscosity: low in inflam fluid
- Mucin clot: suggests fluid is synovial, little value
- immunologic tests: since synovial fluid is derived from plasma, not much advantage over plasma
What is the gold standard for evaluating crystals
Polarized light microscopy
- crystal is Birefringent if it shines white aginst dark background produced by two polarizing plates, *direction +/- based on lab criteria
- if not birefringent, no direction associated
under polarized microscopy gout will be confirmed by
monosodium urate crystal that is needle shaped, strongly (-) birefringence
Under polarized microscopy, pseudogout will be confirmed by
calcium pyrophosphate dihydrate crystal that is rhomboid shpaed and weakly (+) birefringence
under polarized microscopy, hydroxyapatite arthropathy will be confirmed by
hydroxyapatite crystal that is very small and nonbirefringent
what significance does intracellular vs extracellular crystals have on dx?
none
What is CSF function, where is it produced, what information does it provide and how do we get it?
- CSF protects and cushions CNS, provides nutrients to neural tissue and removes metabolic waste
- produced by choroid plexus
- analysis of CSF provides info about pt condition
- obtain CSF via LP: at L3-4 or L4-5 interspace
What disease can be detected by CSF analysis
- Hemorrhage (subarachnoid or intracerebral)
- Infection (meningitis -bacterial, fungal, viral, parasitic; abscess; encephalitis)
- Malignant process (brain tumor -primary or mets; leukemia or lymphoma)
How do you collect CSF for analysis
usually 3 tubes
1: chem analysis (glu, pro, immunology)
2: micro (gram, Acid fast, C&S, India ink prep for cryptococcus neoformans, VDRL, FTA abs)
3: hematology (cell count and diff)
- prompt lab delivery
- draw plasma protein and glucose to compare to CSF values
CSF glucose compared to plasma glucose?
CSF glu is 2/3 plasma normally
*range 50-80 mg/dL
CSF glucose (2/3 plasma glu usually) decreased suggests?
bacterial meningitis and fungal infections
CSF glu (normal 2/3 plasma glu) INCREASED suggests
hyperglycemia
What is the CSF pro range and when is it increases
CSF pro 20-50 mg/dL
*may increase w bleeding, hemolysis, infection
Presence of oligoclonal bands in CSF is dx of
Multiple sclerosis
Presence of myelin basic proteins in CSF helps dx
MS and other demyelinating disorders
Are RBC present in CSF? what if RBCs are noted in CSF?
NOT NORMALLY
if present: cerebral hemorrhage or traumatic tap
*spin down: xanthochromic vs clear supernatant
- xanthochromic suggests blood present before tap, clear suggests traumatic tap
in CSF WBC with diff, what is normal?
1-5 cells/uL (mononuclear)
In CSF WBC with diff, if there are increased neutrophils this suggests
bacterial meningitis
if increased lymphocytes in CSF WBC diff
suggests viral, TB, fungal infection
If increased plasma cells in CSF WBC diff, suggests?
MS or chronic inflammation
if eosinophilia in CSF WBC diff then?
parasitic or fungal infection
In a pt with meningitis, how frequently does altered mental status occur?
in >75%
Note: N/V and photophobia are also common in meningitis
ADEM? MNC?
acute disseminated encephalomyelitis
Mononuclear cells
Why do we obtain blood cultures?
To assess fro presence of bacteria in blood stream (bacteremia)
*Bacteremia may be intermittent or continuous?
Bacteremia may be frequently accompanied by what? and when is the best time to draw blood to check for bacteremia?
bacteremia may be accompanied by fever, chills
*best time to draw is during one of these episodes
Intermittent/transient bacteremia occurs when?
may occur during manipulation of infected tissues (abscess, dental procedures, cystoscopy, sigmoidoscopy/colonoscopy) or at onset of infection (pneumonia)
Continuous bacteremia is most likely if
there is an endovascular infection such as endocarditis, suppurative thrombophlebitis
How do you obtain a blood culture
Draw blood from at least 2 sites
- do not draw from existing IV catheter unless concerned that catheter is source of infection
- cleanse site and memrane of BC bottle with antiseptic, let dry 1-2 min
- collect 10-15 cc blood in sterile syring and inject into BC bottles with culture media (both anaerobic and aerobic bottles)
- culture yield increases with increased volume of blood
If there is bacterial growth in both sets of BC then
highly indicative of bacteremia
If bacterial growth in only one set of BC
could be due to contamination esp if organism is normal skin flora (coag neg staph)
*probably real bacteremia if group A strep, pnemococci, H flu, pseudomonas or candida
