Exam 2: Body Fluids Flashcards
Why is KOH prep a good test for fungal infections?
The KOH dissolves host cells and bacteria, but spares the fungi and elastin fibers
What do multinucleated giant cells indicate on a Tzank prep?
HSV
What kind of testing do you use for cryptococci in CSF?
India ink
What is dark field microscopy and with what kind of infection is it useful for?
Used to evaluate bacteria that are too thin to absorb light from traditional microscopy.
Useful for diagnosing T. Pallidum (Syphilis)
Other than dark field microscopy, what other tests are useful for diagnosing Syphilis?
- Venereal Disease Research Laboratory (VDRL)
- Rapid plasma Reagin
CSF test and Fluorescent treponema antibody absorption Test (FTA-ABS) fall under what category of testing?
VDRL
What is the latex agglutination assay and what is it commonly used for?
- Detect pathogen specific antibodies and antigens.
- Used for CSF for meningococcal capsular antigen
What does Enzyme linked immunoassay do?
-Detect antibodies in the serum (requires previous infection) and used for multiple body fluids
What does indirect immunofluorescence assay do and what is it the primary test for?
- Detects antibodies in the serum or other body fluid
- primary test for ANA antibody
What is the minimun inhibitory concentration?
The lowest concentration of an Abx necessary to inhibit the visible growth of a specific organism
What is the procedure for obtaining blood cultures?
- Two different specimens must be ordered from at least two different sites that are not from the IV
- If one is positive and one is negative, the postive result is likely contaminant
What are the two types of effusions?
Transudative and exudative
What is a transudative effusion?
Accumulation of fluid in the body cavity due to filtration of blood serum across a physiologically intact vascular wall
What usually causes transudative effusions?
Pressure differences between body compartments (Hydrostatic and oncotic pressure) usually caused by systemic disease (CHF, hepatic cirrhosis, and nephrotic syndrome)
What is a exudative effusion?
Accumulation of fluid within a body cavity due to inflammation and vascular wall damage.
What are some common causes of exudative effusions?
Infection, malignancy, inflammatory disorder (RA, lupus), and trauma
What is the normal pleural fluid amount?
50ml
What is the normal WBC for pleural fluid?
<300ml
What are the most common cause of transudative pleural effusions?
CHF, cirrhosis, and nephrotic syndrome
What is the most common cause of exudative effusions and what most commonly causes that condition?
Exudative effusion most commonly caused by parapneumonic effusion, which is most commonly caused by bacterial PNA, Lung abscess, and bronchiectasis
What it the second most common cause of exudative pleural effusions?
Malignancy (Lung CA, breast CA, and lymphoma
What kind of effusion can a pulmonary embolism cause?
Both transudative and exudative
What kind of effusions are hemothorax and chylothorax?
Exudative effusion
What is the contraindication of thoracentesis?
Caution with significant thrombocytopenia
How can you prevent re-expansion pulmonary edema when performing a thoracentesis?
- Do remove more than 1 L
- Do not perform bilaterally
How does the protein fluid/protein serum ratio of pleural fluid differ in transudative and exudative pleural effusions?
Transudative: Protein fluid/protein serum ration <0.5
Exudative: Protein fluid/protein serum ratio >0.5
How does the LDH fluid/LDH serum ratio in pleural fluid differs in transudative and exudative pleural effusions?
Transudative: LDH fluid/LDH serum ratio <0.6
Exudative: LDH fluid / LDH serum ratio >0.6
What are the possible causes of pleural fluid with a pH of <7.3?
Infection, esophageal rupture, and neoplasm
What are the possible causes of amylase elevation in pleural fluid?
Pancreatitis, esophageal rupture, and malignancy
What are the possible causes of triglycerides or lipids in the pleural fluid?
Chylous effusion
What are the possible causes of eosinophilia in pleural fluid?
Parasitic infection, malignancy, TB
What is Lights criteria?
If one of the following is present, the patient has a exudative effusion:
- Pleural fluid protein/serum protein ratio >0.5
- pleural fluid LDH/Serum LDH ratio >0.6
- Pleural fluid LDH >2/3rds of the upper limits of the labs normal serum LDH
How much peritoneal fluid is present normally?
<50ml
Wha are the causes of ascites?
-Portal hypertension (most common), which is most commonly caused by hepatic cirrhosis
What is the gold standard for evaluation of peritoneal effusion?
Abdominal US
What are the indications for a paracentesis?
New onset ascites with or without:
- fever
- abdominal tenderness
- Mental status change
- hypotension
- Peripheral leukocytosis
- worsening renal function
- Trauma/ severe cirrhosis
What are the potential contraindications for paracentesis?
- coagulation abnormalities
- patients with small amount of fluid
- previous abdominal surgeries
- massive ileus with bowel distention
What are the potential complications of a paracentesis?
- hypovolemia
- hepatic coma
- peritonitis
- tumor seeding
- organ perforation
How does the alubumin gradient of peritoneal fluid differ in transudative or exudative effusions?
Transudative: Albumin gradient >1.1
Exudative: Albumin gradient <1.1
What can a LDH fluid/LDH serum ratio of >0.6 in peritoneal fluid indicate?
Bowel perforation, malignancy, or infection
What can elevated amylase in peritoneal fluid indicate?
Pancreatic source, bowel perforation, malignancy, and esophageal rupture
What can elevated ammonia in peritoneal fluid indicate?
Ruptured or strangulated bowel
What can elevated bilirubin in peritoneal fluid indicate?
Bowel/biliary perforation
What can urea and creatinine in the peritoneal fluid indicate?
Possible bladder rupture
What can triglycerides in the peritoneal fluid indicate?
Possible chylous effusion
Patient presets with an abrupt onset of fever, chills, and abdominal pain. Patient has rebound abdominal tenderness and labs reflect an exudative effusion. What are you concerned about?
Spontaneous bacterial peritonitis
What is the normal RBC and WBC count in pericardial fluid?
None for both
What is a normal amount of pericardial fluid?
<50ml
What is the diagnostic method of choice or a periocardial effusion?
US
When should a pericardiocentesis not be performed?
- Most of the time!
- Contraindicated in patients with pericarditis if there is no effusion
- if patient has an effusion, is stable, and source is known, can treat cause with serial follow up echos
What are the therapeutic indications for pericardiocentesis?
Pericardial effusion with tamponade
What are the contraindications of pericardiocentesis?
- Coagulopathy
- Uncooperative patients
What is the normal amount of CSF?
150-200ml
What is the classic triad of meningitis?
AMS, nuchal rigidity, and fever
What is the gold standard in diagnosing the causative organism of meningitis?
CSF culture
What are the indications for an LP?
- Infection (meningitis, encephalitis)
- Malignancy
- MS
- Cerebral/subarachnoid hemorrhage
What are the contraindications for an LP?
- Patients with increased intracranial pressure
- Severe vertebral degenerative joint disease
- infection near LP site
- Patients taking anticoagulants
What is the normal pressure for CSF?
<20 CM H2O
What is the normal RBC and WBC count of CSF?
0-5 cells/uL for both
What is a normal protein count for CSF?
15-45
What is a normal glucose count for CSF?
50-75
What is a normal LDH for CSF?
<40
What does it mean if the CSF is yellow?
Xanthochromia, lysis of RBCs, which releases hemoglobin, converted to oxyhemoglobin, converted to methemoglobin, and ultimately to bilirubin
What does decreased opening pressure indicate?
Hypovolemia, chronic CSF leak, or nasal fracture with dural tear
What does increased opening pressure indicate?
Infection, intracranial bleeding, tumor, or hydrocephalus
What are the possible causes of neutrophilia in CSF?
- Bacterial meningitis
- cerebral abscess
- Subarachnoid bleed
- tumor
What are the possible causes of lymphocytosis in CSF?
- Viral, tubercular, fungal, or syphilitic meningitis
- MS, Guillain-Barre
What are the possible causes of increased macrophages in CSF?
- Tubercular or fungal meningitis
- subarachnoid bleed
- brain infarction
What are the possible causes of eosinophilia in CSF?
- Parasitic meningitis
- allergic reaction to radiopaque dyes
What are the possible causes of increased RBCs in CSF?
-Traumatic tap or subarachnoid hemorrhage
What is present in 90% of patients with a subarachnoid hemorrhage within 12 hours?
Xanthochromia
What can be found in the CSF that is indicative of MS?
Oligoclonal gamma globulin bands
What is a CSF glucose <2/3s of the serum glucose indicative of?
- Meningitis
- neoplasm
What can increased LDH in CSF indicate?
Bacterial meningitis, malignancy, and intracranial hemorrhage
What can increased lactic acid in CSF indicate?
Bacterial/fungal meningitis, but not viral
What does increased glutamine in CSF indicate?
Hepatic failure
What does elevated C-reactive protein in CSF indicate?
Bacterial meningitis, not viral