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Diagnostic Tools. HB6 2010. Signs. Subjective observations (things that are observed or measured by another person) Examples: Rash Blood in urine Vomiting Temperature. Symptoms. Objective observations (things that a patient reports) Examples: Headache Stomach ache Tiredness/fatigue.
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Diagnostic Tools HB6 2010
Signs • Subjective observations (things that are observed or measured by another person) • Examples: • Rash • Blood in urine • Vomiting • Temperature
Symptoms • Objective observations (things that a patient reports) • Examples: • Headache • Stomach ache • Tiredness/fatigue
Identify the following as signs or symptoms: • Nausea • High blood pressure (hypertension) • Broken leg identified on X-ray • Blisters on foot • Painful area of foot • Deformed kidney identified by ultrasound • Sore back • Mental confusion
Blood tests • Proportions of various blood cells • Morphology (shape) of blood cells • Biochemistry • Glucose • Calcium, sodium, potassium • Liver enzymes • Hormone levels • Blood urea nitrogen (BUN)
Urine tests • Red blood cells • White blood cells • Bacteria • Protein • Crystals • Glucose, ketones
Other non-invasive tests • Listening to chest sounds • Heart rate, blood pressure • Visual observations • Peak flow meter • Breath test for Helicobacter pyloris • Reflexes
Endoscopy • A tube containing optic fibres is passed into the body • Some fibres transmit light • Some fibres transmit an image back to a monitor • Surgical tools can be used to take biopsies or carry out surgical procedures
Arthroscopy • Bronchoscopy • Gastroscopy- e.g. pill cam • Colonoscopy • Laparoscopy
X-rays • X-rays are produced by some radioactive materials • High energy beams are passed through the body & strike a photographic film • Gives limited information on soft tissues • Too many X-rays can involve high exposures to radiation
CT/CAT scans • Computed axial tomography • Multiple high quality X-ray images are taken, & a computer builds them up into a 3-dimensional image • Contrast dyes improve the image quality
The negative side of CT scans • Chest X-ray 0.1 mSv • Head CT 1.5 mSv • Screening mammography 3 mSv • Abdomen CT 5.3 mSv • Chest CT 5.8 mSv • Chest, abdomen and pelvis CT 9.9 mSv
MRI • Magnetic resonance imaging involves the use of powerful magnets • These magnets excite electrons in cells, & a detector is used to take this information & build up an image from this • Multiple scans can be used to build up a 3-dimensional image
Functional MRI • Areas of the brain ‘light up’ when carrying out certain processes • Can identify regions of the brain involved in emotions etc.
Ultrasound • High frequency soundwaves are sent into the body • The soundwaves bounce off structures (like radar/sonar), & a detector builds up an image • Often used for pre-natal examinations of a developing baby
Comparison X-ray CT scan MRI Ultrasound
Biopsies • A small piece of tissue is excised (cut out) and examined under the microscope