Body fluids

Order of CSF collection tubes

• Chemistry

  • Cellular or bacterial contamination usually not a problem

• Microbiology

  • only want organism growing in CSF not skin flora

• Hematology

  • interested in RBC or WBC in CSF (traumatic tap usually stops by tube 3)

CSF appearance: normal

clear liquid

CSF appearance: subarachnoid hemorrhage

red blood is evenly distributed in all four tubes

CSF appearance: Traumatic tap

• redness decreases as collection of tubes progresses

  • no xanthochromia because its fresh blood

What is Xanthochromia

yellow color of CSF denotes “old blood”

4 general conditions that cause CSF protein to increase

1. damage to blood brain barrier (BBB)

2. inflammation

3. increased endogenous production (can indicate MS)

4. Hemorrhage

2 most common causes of CSF protein increasing

1. Hemorrhage

2. inflammation causing increases capillary permeability

Fraction of CSF protein that is in the greatest concentration

albumin

reason for spurious elevation in CSF protein

fluid is contaminated with serum or blood cells during traumatic tap

Clinical significance of increase CSF IgG index calculation

calculated to determine if there is a compromised BBB with leakage across BBB or increased endogenous production of immunoglobulins

Normal proportion of CSF glucose related to concomitant blood glucose measurements

should be 60-70% of concomitant blood glucose

Clinical significance of CSF lactate measurements

• Values > 25mg/dL indicate bacterial, tubercular, or fungal meningitis with better predictive value then CSF glucose

• also monitor effectiveness of antibiotic therapy

Colloid osmotic pressure

• pressure caused by albumin

• protein moves from high to low concentration

Hydrostatic pressure

exerted by the pumping heart drives the fluid out of the capillaries into cavity

Capillary permeability

• normal ability of water/small molecules in intravascular space to pass to the extravascular cavity and lymphatic system

• prevents large molecules and cells from doing so

What causes Effusion

• Increased capillary permeability

• increased hydrostatic pressure

• decreased colloid osmotic pressure

• decreased absorption

Pleural fluid: glucose

decreased in tubercular and rheumatoid inflammations

Pleural fluid: Amylase

increased in pancreatic disorders

Pleural fluid: pH

pH <7.2

• indicates need for ATB and chest tube damage

pH >7.4

• malignancy

pH <6.0

• esophageal rupture

Pericardial fluid: glucose

decrease in bacterial infections and malignancy

Pericardial fluid: carcinoembryonic antigen (CEA)

indicates malignancy

Abnormal peritoneal fluid: glucose

decrease in tubercular peritonitis and malignancy

Abnormal peritoneal fluid: Amylase

increased in pancreatitis and GI perforations

Abnormal peritoneal fluid: Alkaline phosphatase

increase in intestinal perforations

Abnormal peritoneal fluid: Urea nitrogen and creatinine

indicates a ruptured bladder or accidental puncture of bladder during paracentesis

Abnormal peritoneal fluid: CEA and CA 125

increase in malignancy

Synovial fluid: glucose

marked decreases indicates inflammatory or septic disorders

Synovial fluid: Lactate

• if < 7.5 mg/dL = septic arthritis excluded

• if > 7.5 mg/dL = septic/rheumatoid arthritis indicated

Synovial fluid: total protein

increased in inflammatory or hemorrhagic disorders

Synovial fluid: uric acid

may indicate crystal induced joint disorder like gout even when crystals not seen in examination

Usefulness of sweat analysis using pilocarpine iontophoresis

gold standard for cystic fibrosis diagnosis

Procedure of iontophoresis in sweat analysis

• a mild electrical current pushes medicine into skin to cause sweating

• levels of chloride used to diagnosis

  • > 60 mmol/L = CF likely

  • < 40 mmol/L = CF not likely

  • b/w 40-60 requires retesting

Bronchalveolar lavage

one side of lungs is pumped with fluid to pick up pneumocytis jirovecii in HIV patient while the other lung is open for air

2 conditions which cause neutrophils to be present in stool

1. shigella/salmonella

2. ulcerative colitis

2 conditions that cause the presence of muscle fibers in stool

1. Malabsorption

2. Maldigestion

Principle of fecal occult blood analysis

tests how much blood is in fecal

• more blue = more blood

most common diagnosis use for fecal occult blood analysis

colon cancer or gastrointestinal tract bleeds

Reagents used in fecal occult analysis

• Pseudoperoxidase or peroxidase

• guaiac (indicator)

fecal clinitest assays

increased reducing substances (galactose or glucose) indicate carbohydrate malabsorption (intolerance)

Visceral membrane

the surface membrane which lines he organs

Parietal membrane

the surface membrane that lines the body wall

Pleural fluid

fluid from the thoracic area

Thoracentesis

surgical puncture of the chest wall done to obtain pleural fluid

Empyema

pus in the pleural cavity

Peritoneal fluid

fluid secreted by cells of the peritoneum

Pericardial fluid

fluid around the heart

Paracentesis

aspiration of fluid from a cavity

Ascites

bloated abdomen from patient affected with massive accumulation of peritoneal fluid

• comes from the Latin word “bag”

Hemothorax

whole blood in the pleural cavities

Hemorrhagic fluid

bloody fluid which can come from a traumatic tap, malignancy, pulmonary infarction, pancreatitis, TB, but usually malignancy

Hyaluronic acid

gives the synovial fluid viscosity

Which balance fluids are transudate and causes

• Colloid osmotic pressure

  • Hypoalbuminemia, nephrotic syndrome, cirrhosis

• Hydrostatic pressure

  • Cardiovascular ( congestive heart failure, heart failure)

Which balance fluids are exudate and causes

• lymphatic drainage

  • Malignancy (leukemias, super vena cava blockage, tumors)

• capillary permeability

  • infection, inflammation, empyema

Classification of transudate

• Clear

• Gravity < 1.015

• Total protein < 3.0 g/dL

• Lactic < 200 IU

• Cell count (WBC) < 1000

• No spontaneous clotting

Classifications of exudate

• cloudy

• gravity > 1.015

• Total protein > 3.0 g/dL

• Lactic > 200 IU

• Cell count (WBC) > 1000

• Spontaneous clotting

feces: Orange-brown specimen

normal

Feces: pale grey or chalky specimen

• Bile duct obstruction

• barium

Feces: Red specimen

• Lower GI bleed

• Beets and food coloring

• Rifampin

Feces: black specimen

• upper Gi bleed

• Iron therapy

• Charcoal

• Bismuth

Feces: green specimen

• Bilirubin

• green veggies

• antibiotics

Feces: Cylindrical consistency

normal

Feces: small round and hard consistency

constipation (water reabsorption to great deal)

Feces: soft, loose, ribbon like consistency

• intestinal constriction

• decreased water reabsorption

Feces: Watery consistency

• diarrhea

• water not reabsorbed

Feces: Mucus and bloody diarrhea consistency

• dysentery

• translucent gelatinous substance

• Malignancy

• rectal inflammation

Feces: Bulky and Frothy consistency

• Steatorrhea

• undigested food

• gas and increased fat

Bacterial Meningitis CSF

• cloudy

• glucose ~25 mg/dL

• Protein ~ 100 mg/dL

• Lactate elevated

• WBC: marked neutrophils

• possible + gram stain

• Positive strep. pneumo

Viral meningitis CSF

• Clear to cloudy

• glucose ~50 mg/dL

• Protein ~75 mg/dL

• Lactate normal

• WBC: increased lymphocytes

• = gram stain or polys

Fungal meningitis CSF

• clear to cloudy

• glucose ~35 mg/dL

• Protein ~75 mg/dL

• Lactate elevated

• WBC: increased monocytes

• + gram stain and fungal culture

• possible + india ink if encapsulated

Tubercular meningitis CSF

• cloudy “cobwebs”

• glucose `35 mg/dL

• Protein ~75 mg/dL

• Lactate elevated

• WBC:

  • Early: neutrophils increased

  • late: lymphocytes increased

• possible acid fast and culture

Intracranial CSF

• bloody with xanthochromia

• glucose normal or decreased

• protein > 45 mg/dL

• RBC: increased due to peripheral blood

• WBC: normal (peripheral blood percentages)

• = gram and culture

Neoplasm CSF

• clear to xanthochromia

• glucose normal to decreased

• protein normal or increased

• WBC: normal to increased lymphocytes/blasts

Normal CSF

• colorless and clear

• glucose 60-70% concomitant blood glucose

• protein

  • adults = ~15-45 mg/dL

  • newborn = <70 mg/dL

• Lactate 10-22 mg/dL

• WBC: no neutrophils, newborns <10 WBC