Lesson Outline in Amniotic Fluid, Gastric Fluid and Sputum Analysis
AMNIOTIC FLUID
Reasons for testing
1. To allow antenatal diagnosis of genetic and congenital disorders (15 to 18 weeks) and later in
pregnancy (20 to 42 weeks):
2. To assess fetal pulmonary maturity
3. To assess degree of fetal distress
4. HDN- hemolytic disease of the newborn or EBF – Erythroblastic Fetalis
5. Anomalies: UTI, neural tube, intestinal, etc.
6. Fetal Infections: bacterial, viral, etc.
Physiology and composition
•
AMNION/amniotic sac – single layer of cuboidal EC
Functions:
–
Disease marker
–
Protects the fetus
–
Enables fetal movement
Formation
1. Initially produced by placenta & amnion
2. As gestation progresses, fetus plays more of an active role in its composition
3. Exchange bet. Amniotic fluid & maternal plasma comes into completion every 2 to 3 hours
Volume
•
Increases steadily throughout pregnancy
•
25 to 50 ml at 12 weeks’ gestation
•
Max vol = 1100 to 1500 ml at 36 weeks gestation
•
Abnormally decreased (oligohydramnios):
•
Abnormally increased (hydramnios):
Lesson Outline in Amniotic Fluid, Gastric Fluid and Sputum Analysis
Specimen collection
•
Methods
–
Transabdominally
–
Vaginally
•
Increased risk of infection
•
Risk of contamination w/ vaginal cells & bacteria
Timing

After 14 wks (depending on purpose)


Genetic studies (bet 15 & 18) e.g. to consider termination of pregnancy
To assess health status of fetus (later in preg) in cases of Rh isoimmunization, toxemia &
Diabetes mellitus (DM)
Indications
Volume: 10 to 20 ml
Containers:


plastic, why not glass? ( Your assignment)
Cover with aluminum if not colored, why?
Transport & storage:



ASAP- as soon as possible
Refrigerate after centrifugation for 5-15 min (24 hours) or after filtration (Whatmann #40)
Freezing (if storage >24 hrs)
Transport & storage:
–
Centrifugation
Differentiation from urine:
o
o
Fern test
Amniotic fluid = 2 to 8 g/L CHON & glucose, crea similar to plasma but increases as gestation
progresses
Physical examination
•
COLOR
–
Colorless or very pale yellow
–
Distinct yellow or amber – Bilirubin
–
Green – meconium
Lesson Outline in Amniotic Fluid, Gastric Fluid and Sputum Analysis
•
–
Pinkish to red – blood (e.g. HDN)
–
Brown – severe hemolysis
TURBIDITY
–
Slightly turbid due to Vernix caseosa (fetal cells, hair and secretions)
Meconium
•
Gelatinous/mucoid-like mixture of secretions from the intestinal tract of the fetus
•
Varying shades of green, dependent upon the amount of biliverdin present.
Chemical examination
•
FETAL LUNG MATURITY TESTS
–
L/S ratio (via TLC)
•
–
Lecithin: major pulmonary surfactant
Phosphatidyl glycerol/PG
•
Detectable only in mature fetus
FETAL LUNG MATURITY TESTS
–
–
Foam Stability Index (FSI)
 “shake test”
 Shake vigorously w/ differing concentrations of ethanol (to prevent false +) to produce
bubbles that remain stable at the air-liquid interface/meniscus for 15 min
 Normal: 0.48 (possible indices 0.43 to 0.55)
KLEIHAUER-BETHKE TEST/KLEIHAUER RBC ACID ELUTION TEST
 Staining technique to identify the presence of maternal or fetal red bloods in amniotic
fluid
. Tests for metabolic disorders
4.1. Galactosemia: galactose-1- phosphate-uridyl transferase deff.
4.2. Pompe’s disease: 1,4 glucosidase deff.
4.3. Tay Sach’s disease: hexoseaminidase A deff.
4.4. Hurler’s disease: alpha-L-iduronidase
4.5. Lesch-Nyhan disease: hypoxanthine guanine phosphoribosyl
transferase deff
4.6. Faby’s disease: alpha-galactoside deff
Lesson Outline in Amniotic Fluid, Gastric Fluid and Sputum Analysis
Gastric Fluid analysis
Physiology
•
Three physiologic functions of the stomach
1. Acts as an expandable reservoir for ingested food
2. Initiation of protein digestion by pepsin
3. Gastric mucosa secretes intrinsic factor for binding and absorption of vitamin B12 in the
ileum
•
Three general phases of gastric secretion
1. Cephalic (neurogenic) phase
1. Gastrin secreted by G cells in the pyloric gland & stomach + delta cells of
pancreas
2. Gastrin stimulates HCl by parietal cells & Pepsin by the chief cells
3. Vagal excitation lowers the threshold of parietal cells to gastrin stimulation
4. Gastric peristalsis and emptying is promoted
2. Gastric phase - gastric distention & continued secretion of digestive juices
3. Intestinal phase- GIP inhibits gastric secretion, lowering of pH levels
Chemical composition of GF
1. HCl
2. Pepsin
3. Mucus
Why analyze Gastric Fluid (GF)?
1. Gastric acidity
1. Anacidity (=/> 6.0 even w/ stimulation)
2. Hypochlorhydria (=/<3.5, 1.0 upon stim)
3. Achlorhydria (=/< 3.5 even w/ stimulation)
2. Peptic ulcer
3. Zollinger-Ellison syndrome
4. Completeness of surgical vagotomy
Routine Analysis of GF
Lesson Outline in Amniotic Fluid, Gastric Fluid and Sputum Analysis
Appearance
•
Translucent, pale gray, slightly. viscous
Volume - 50-75 mL
Odor- Faintly pungent
Mucus
Microscopic exam
Measurement of gastric acid and pH
Collection
Patient Preparation
: fasting at least 8 hrs
: avoid stimulation of gastric acid
Types of Stomach tubes
1. Ewald or Boas tube
2. Levine Tube
3. Rehfuss Tube
Test Meal
: based on the definite quality and quantity of food to stimulate gastric flow
1. Ewald Test Breakfast
: 40gm bread, 400ml water
: well masticated
2. Dock Test Breakfast
: same as Ewald but uses shredded wheat biscuits
3. Boas Test Breakfast
: 1tbsp rolled oats, 1 qt water
4. Riegel Test Meal
: 400ml broiled beef steak, 150gm mashed potato
5. Fischer Test Meal
: similar to Riegel but adds Ewald breakfast, ¼ lb lean Hamburg steak
Lesson Outline in Amniotic Fluid, Gastric Fluid and Sputum Analysis
: higher acidity values
6. Alcohol Test of Gastric Function
: substitute for test meals
: 50ml of 7% alcoholic solution into the gastric tube
Physical Examination
•
Volume: 50-80ml, fasting
•
Color: Normal is colorless, pale gray and translucent
: green to yellow green- from bile
: red to coffee brown- blood
: drugs- orange, variable
•
Odor: odorless
: rancid, sour or fecal- pathologic
•
Starch
: 1gtt of Gram’s Iodine
: blue color
•
pH: 1.6 to 1.9
: neutral in gastric cancer, marked chronic gastritis, presence of saliva
: Töpfer Reagent: free acid- pink to red color
•
Specific.gravity.: 1.001 to 1.010
: cell-free
Chemical Examination
•
Euchlorhydria
: normal: 20 to 40 mmol/L
: fasting: 5-20 mmol/L
•
Hyperchlorhydria- increase of HCl
Hypochlorhydria- low HCl
Achlorhydria – absence of HCl
•
Achylia Gastrica
: complete absence of free HCl
Lesson Outline in Amniotic Fluid, Gastric Fluid and Sputum Analysis
SPUTUM ANALYSIS
Sputum physiology
 Not normally expectorated
 Quantity of coughed/expectorated material is roughly parallel to the severity of the malady
 Material secreted by the tracheobronchial tree
 Mucus (normal bronchopulmonary cleansing)
 5 um thick before it is swept into the oropharynx
 Normally swallowed
Normally sterile
Mechanical cleansing action
Attacks inhaled bacteria directly via:

Antibody activity (predominantly IgA)
Gross appearance
 Descriptive terms:
 Mucoid
 Mucopurulent
 Frankly purulent
 Blood-tinged
 Frankly bloody
 Dust-flecked
Purulent sputum:

Acute bacterial pneumonias
Gradual progression from scant, sticky sputum to more abundant, loose, purulent

Chronic changes (e.g. bronchiectasis)
Change from mucoid to purulent or mucopurulent:

Bacterial infection overlying chronic inflammatory process
Abundant, purulent, often foul-smelling
Macroscopic exam
Volume:
Lesson Outline in Amniotic Fluid, Gastric Fluid and Sputum Analysis
Few or nothing at all
increased volume: progression of disease
decreased volume: healing
A. Over 100 ml/day
1. pulmonary edema
B. Over 500ml/day
1. amoebic abscess of the lungs
C. as much as 1,000ml/day
1. bronchiectasis
D. Small amounts
1. diffused bronchitis
2. healing
Odor
a. sweetish: tb, brochiectasis, bronchomoniliasis
b. putrid or foul: necrosis, infection
c. cheesy: malignant tumors
d. fecal: rutured subphrenic or liver abscess
Color:
influenced by mucus and pus
A. colorless or translucent: mucus
B. white or yellow: advanced pulmonary tb, chronic bronchitis, jaundice
C. gray: pus and epithelial cells
D. red or bright red: hemorrhage, pulmonary tb, bronchiectasis
E. rusty brown or anchovy sauce: tb, gangrene, hemorrhage from the lungs
F. Olive green: cancer
H. Black: dust or dirt, carbon, charcoal
Consistency
A. serous: pulmonary edema
Lesson Outline in Amniotic Fluid, Gastric Fluid and Sputum Analysis
B. Mucoid: acute bronchitis, asthma, lobar pneumonia
C. Purulent: ruptured empyema, bronchiectasis
D. Seropurulent: asthma and lung abscess
Macroscopic exam
1. Cheesy masses: necrotic, pulmonary tissues
2. Curschmann’s spirals: yellowish-white spiral MTs
: bronchial asthma, also in acute bronchitis, pneumonias and chronic pulmonary tb
3. Bronchial casts: branching tree-like, white or grayish
4. Dittrich’s plugs: yellow or gray, pin head caseous masses
Microscopic exam
1. Curschmann’s spirals:
2.a. Charcot-Leyden Crystals: colorless hexagonal double pyramid
: disintegrated eosinophils
: bronchial asthma
2.b. Hematoidin crystals: rhombic brownish red arranged in rosettes
: pulmonary infarctions, lung abscess,
bronchiectasis, perforating empyema
GOOD LUCK