Symptoms definition

While there is disagreement about what exposure levels are needed to produce the earliest symptoms, most experts agree that symptoms definitely can occur at blood lead levels of 60 ng/dl whole blood and therefore recommend a 40 ng/dl maximum. The central nervous system effects frequently are not reversible following discontinued exposure or chelation therapy and when improvement does occur, it is almost always only partial. 

The unusual physical complaints and findings in workers overexposed to teUurium include somnolence, anorexia, nausea, perspiration, a metallic taste in the mouth and garlic-like odor on the breath (48). The unpleasant odor, attributed to the formation of dimethyl teUuride, has not been associated with any adverse health symptoms. Tellurium compounds and metaboUc products have been identified in exhaled breath, sweat, urine, and feces. Elimination is relatively slow and continuous exposure may result in some accumulation. No definite pathological effects have been observed beyond the physical complaints outlined. Unlike selenium, teUurium has not been proved to be an essential biological trace element. 

Atrioventricular block in general is treated by implantation of an electrical pacemaker. A pharmacological alternative (although no longer used today) was atropine. However, atropine can be used for bridging the time between the onset of symptoms and the definitive implantation of a pacemaker. 

Diagnosing viral hepatitis may be difficult because most infected individuals are asymptomatic. Because symptoms cannot identify the specific type of hepatitis, laboratory serologies must be obtained (Table 21-2). In addition, liver function tests may be obtained to assess the extent of cholestatic and hepatocellular injury. However, the definitive test to determine the amount of damage and inflammation of hepatic cells is a liver biopsy. 

For approximately 20% to 30% of people with schizophrenia, drug treatment is ineffective. A standard definition of treatment resistance includes patients who have persistent positive symptoms despite treatment with at least two different antipsychotics given at adequate doses (at least 600 chlorpro-mazine equivalents) for an adequate duration (4 to 6 weeks). In addition, patients must have a moderately severe illness as defined by rating instruments, and have a persistence of illness for at least 5 years.40 These patients are often highly symptomatic and require extensive periods of hospital care. 

The traditional definition of menorrhagia is a menstrual blood loss of greater than 80 mL per cycle. This definition has been questioned for several reasons, including difficulty with quantifying menstrual blood loss in clinical practice. Many women with heavy menses but blood loss of less than 80 mL will merit consideration for treatment because of problems with containment of flow, unpredictable heavy flow days, and other associated symptoms.8,9... 

Historically, osteomyelitis has been classified as acute or chronic based on duration of disease (Fig. 78-2).2,4 However, there are no established definitions for acute and chronic infections.2-4 Acute infection has been defined as first episode or recent onset of symptoms (less than 1 week).2,3 Chronic osteomyelitis is generally defined as relapse of the disease or symptoms persisting beyond 4 weeks.2,3 Others describe chronic osteomyelitis as the presence of necrotic bone.3 ... 

In cases of elevated intracranial pressure (ICP) owing to cerebral herniation, mechanical hyperventilation to decrease the arterial Pco2 down to 25 mm Hg (3.33 kPA) acutely decreases ICP by causing cerebral vasoconstriction. Elevation of the patient bed also may quickly reduce the ICP. It should be noted that these strategies only relieve symptoms and that definitive therapy is still required. 

Corticosteroids are a mainstay in the management of brain I metastases. They reduce edema that typically surrounds sites of metastasis, thereby reducing ICP. A loading dose of dexam-ethasone 10 mg followed by 4 mg by mouth or intravenously every 6 hours typically is used. Symptom relief may occur shortly after the loading dose, although the maximum benefit may not be seen for several days (after definitive therapy). 

Menorrhagia Menstrual blood loss of greater than 80 mL per cycle a more practical definition is heavy menstrual flow associated with problems of containment of flow, unpredictably heavy flow days, or other associated symptoms. 

This is evidenced by a definite shift to higher doses, as shown in Table II. Acute symptoms develop within a few hours, the most obvious being salivation, lachrymation, exophthalmia, peripheral tremors, and diarrhea. When these are severe the animal usually succumbs within 12 to 18 hours following application. 

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