Term
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Definition
| Increased in: Hyperthyroidism, increased thyroid-binding globulin (TBG) (eg, pregnancy, drug). Drugs: amiodarone, high-dose beta-blockers (especially propranolol |
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Term
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Definition
| Decreased in: Hypothyroidism, low TBG due to illness or drugs, congenital absence of TBG. Drugs: phenytoin, carbamazepine, androgens. |
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Term
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Definition
Physiologic Basis
Total T4 is a measure of thyroid gland secretion of T4, bound and free, and thus is influenced by serum thyroid hormone-binding activity. |
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Term
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Definition
Physiologic Basis
FT4 (if done by equilibrium dialysis or ultrafiltration method) is a more direct measure of the free T4 hormone concentration (biologically available hormone) than the free T4 index.
The presence of rheumatoid factor or drug treatment with furosemide, intravenous heparin, and subcutaneous low-molecular-weight heparin may interfere with newer assays for free thyroxine. |
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Term
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Definition
| Increased in: Hyperthyroidism, nonthyroidal illness, especially psychiatric. Drugs: amiodarone, -blockers (high dose). |
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Term
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Definition
| Decreased in: Hypothyroidism, nonthyroidal illness. Drugs: phenytoin. |
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Term
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Definition
| The TSH assay detects subclinical dysfunction and monitors thyroxine treatment better; the free thyroxine test detects central hypothyroidism and monitors rapidly changing function better. |
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Term
| Thyroid Stimulating Hormone |
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Definition
TSH is an anterior pituitary hormone that stimulates the thyroid gland to produce thyroid hormones.
Secretion is stimulated by thyrotropin-releasing hormone from the hypothalamus. There is negative feedback on TSH secretion by circulating thyroid hormone. |
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Term
| Thyroid Stimulating Hormone-increased |
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Definition
| Increased in: Hypothyroidism. Mild increases in recovery phase of acute illness. Subclinical hypothyroidism defined as a mild increase in serum TSH and normal free thyroxine and triiodothyronine levels occurs in 4–8.5% of the population. |
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Term
| Thyroid Stimulating Hormone |
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Definition
| Measurement of serum TSH is the best initial laboratory test of thyroid function. It should be followed by measurement of free thyroxine if the TSH value is low and by measurement of anti-thyroperoxidase antibody if the TSH value is high. |
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Term
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Definition
Indications
Evaluation of pleural and parenchymal pulmonary disease, mediastinal disease, cardiogenic and noncardiogenic pulmonary edema, congenital and acquired cardiac disease.
Screening for traumatic aortic rupture (though CT is playing an increasing role).
Evaluation of possible pneumothorax (expiratory upright film) or pleural effusion |
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Term
| Chest Radiograph-contraindications |
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Definition
| Contraindications and risks: Caution in pregnancy because of the potential harm of ionizing radiation to the fetus. |
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Term
| Chest Computed Tomography |
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Definition
Indications
Evaluation of thoracic trauma.
Evaluation of mediastinal and hilar tumor.
Evaluation and staging of primary and metastatic lung neoplasm.
Characterization of pulmonary nodules.
Differentiation of parenchymal versus pleural process (ie, lung abscess versus empyema). |
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Term
| Chest Computed Tomography-contraindications |
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Definition
| Caution in pregnancy because of the potential harm of ionizing radiation to the fetus. See Risks of CT and Angiographic Intravenous Contrast Agents. |
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Term
| Chest Computed Tomography-preparations |
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Definition
Preferably NPO for 2 hours before study.
Normal hydration.
Sedation of agitated patients.
Recent serum creatinine determination |
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Term
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Definition
Indications
Differentiation of cystic versus solid lesions of the liver and kidneys.
Detection of intra- and extrahepatic biliary ductal dilation, cholelithiasis, gallbladder wall thickness, pericholecystic fluid, peripancreatic fluid and pseudocyst, hydronephrosis, abdominal aortic aneurysm, appendicitis, ascites, primary and metastatic liver carcinoma. |
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Term
| Abdominal Ultrasound-contraindications |
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Definition
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Term
| Abdominal Ultrasound-prep. |
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Definition
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Term
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Definition
Indications
Evaluation of essentially all intracranial disease
Contraindications
Contraindicated in patients with cardiac pacemakers, intraocular metallic foreign bodies, intracranial aneurysm clips, cochlear implants, and some artificial heart valves.
Preparation
Sedation of agitated patients.
Screening CT or plain radiograph images of orbits if history suggests possible metallic foreign body in the eye. |
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Term
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Definition
Indications
Evaluation of primary or metastatic neoplasm, osteomyelitis, arthritis, metabolic disorders, trauma, avascular necrosis, joint prosthesis, and reflex sympathetic dystrophy.
Evaluation of clinically suspected but radiographically occult fractures. Identification of stress fractures.
Contraindications
Caution in pregnancy because of the risk of ionizing radiation to the fetus.
Preparation
Patient should be well hydrated and void frequently after the procedure. |
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Term
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Definition
Colonoscopy is performed by passing a flexible colonoscope through the anal canal into the rectum and colon. The cecum is reached in >95% of cases, and the terminal ileum can often be examined. Colonoscopy is the "gold standard" for diagnosis of colonic mucosal disease.
Conscious sedation is usually given before colonoscopy in the United States, although a willing patient and a skilled examiner can complete the procedure without sedation in many cases. |
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