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CURRENT Diagnosis & Treatment: Occupational & Environmental Medicine, 5e

Section III: Occupational Illnesses

Section III. Occupational Illnesses

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Nanoparticles

a. are engineered structures that are less than 100 nm in size

b. have no chemical properties

c. are blocked from the central nervous system

d. are easily measured in biologic tissues

a. Nanoparticles are engineered structures that are less than 100 nm in size.

Toxicity

a. affects all ages to the same degree

b. is independent of racial and genetic background

c. has no important genetic factors

d. is affected by atmospheric pressure, temperature, and humidity

d. Toxicity is affected by atmospheric pressure, temperature, and humidity.

G6PD deficiency

a. primarily affects white males and persons of Mediterranean descent

b. is an X-linked recessive disorder

c. prevents hemolysis from many drugs

d. screening is supported by solid evidence

b. G6PD deficiency is an X-linked recessive disorder.

Biotransformation

a. occurs in the liver by hydrolysis, oxidation, reduction, and conjugation

b. is independent of microsomal cytochrome P450

c. can be arrested by many environmental and pharmacologic agents

d. is accelerated in neonates

a. Biotransformation occurs in the liver by hydrolysis, oxidation, reduction, and conjugation.

Clearance

a. is the rate at which a toxic agent is excreted, multiplied by the average concentration of the agent in the plasma

b. is a function of concentration in the urine, unrelated to dose

c. is a measure of how many milligrams of toxin is being removed

d. is a measure of the volume of fluid that is freed of the toxic agent per unit of time

d. Clearance is a measure not of how many milligrams of toxin is being removed but rather of the volume of fluid that is freed of the toxic agent per unit of time.

Hair analysis

a. is used only for evaluating heavy metal exposures

b. is the preferred method for evaluating toxic exposures

c. requires little training in collection and analysis

d. results are difficult to interpret as hair samples are subject to external contamination

d. The results of hair analysis are difficult to interpret as hair samples are subject to external contamination.

Management of acute toxicity

a. consists of removal from exposure, symptomatic treatment, and supportive care

b. first identifies the exact toxin so the appropriate antidote can be given

c. follows contact with public health authorities

d. focuses on preventing damage to the central nervous system

a. Management of acute toxicity consists of removal from exposure, symptomatic treatment, and supportive care.

Lymphocytes are

a. about 70–80% B cells

b. about 10–15% T cells

c. responsible for the initial specific recognition of antigen

d. distinguished visually from each other under the microscope

c. Lymphocytes are responsible for the initial specific recognition of antigen.

Cytotoxic or “killer” T cells are

a. generated after immature T cells interact with foreign antigens

b. responsible for defense against intracellular pathogens

c. unable to cause programmed cell death

d. do not secrete TNF

b. Cytotoxic or "killer" T cells are responsible for defense against intracellular pathogens (eg, viruses), tumor immunity, and organ graft rejection.

Macrophages

a. become monocytes after they are recruited to sites of inflammation

b. are unable to synthesize proinflammatory mediators

c. are involved in the ingestion, processing, and presentation of antigens for interaction with lymphocytes

d. inhibit production of bacterial endotoxin

c. Macrophages are involved in the ingestion, processing, and presentation of antigens for interaction with lymphocytes.

Eosinophils.

a. play both a proactive and a modulating role in inflammation

b. are attracted to the site of the antigen-antibody reactions by temperature change

c. play no role in the defense against parasites

d. primarily release prostaglandins

a. Eosinophils play both a proactive and a modulating role in inflammation.

Type I anaphylactic or immediate hypersensitivity reactions

a. are initiated by the interaction of antigen with specific IgE antibodies

b. have no subsequent release of inflammatory mediators

c. have a destructive role in inflammation

d. are unrelated to proinflammatory mediators

a. Type I anaphylactic or immediate hypersensitivity reactions are initiated by the interaction of antigen with specific IgE antibodies bound to mast cells and basophils with the subsequent release of inflammatory mediators.

Reactive airways dysfunction syndrome (RADS)

a. symptoms develop slowly

b. is characterized by symptoms of asthma

c. has a long latency period

d. occurs in the presence of preexisting pulmonary disease

b. Reactive airways dysfunction syndrome (RADS) is a syndrome characterized by the acute emergence of bronchial hyperreactivity and symptoms of asthma, after an acute exposure to high levels of respiratory irritants, usually toxic chemicals, smoke, or particulates.

Allergic contact dermatitis (ACD)

a. usually involves skin covered by clothing

b. is not caused by exposure to latex

c. predominantly results from solvent exposure

d. is a type IV, delayed hypersensitivity disorder

d. Allergic contact dermatitis (ACD) is a type IV delayed hypersensitivity disorder, caused by a variety of agents in the occupational setting including latex, nickel, formaldehyde, potassium dichromate, thiurams, epoxy resins, mercaptos, parabens, quaternium-15, ethylenediamine, and cobalt.

Trimetallic anhydride (TMA) flu

a. is characterized by cough, occasional wheezing, and dyspnea

b. is a type IV disorder

c. occurs after low-dose exposure to TMA fumes

d. occurs immediately following exposure to TMA fumes

a. The late-reacting systemic syndrome ("TMA flu") is characterized by cough, occasional wheezing, dyspnea, and systemic symptoms of malaise, chills, myalgia, and arthralgia.

Patch testing

a. is useful in evaluating irritant contact dermatitis

b. is useful in evaluating skin contact sensitivity

c. is read after 24 hours

d. follow-up reading is done 1 week after the first reading

b. Patch tests are useful in evaluating skin contact sensitivity (type IV delayed hypersensitivity).

Inhalation challenge tests

a. expose the worker to the suspected antigen

b. entail no significant risk

c. should not be performed in the work environment

d. do not require omitting corticosteroids, antihistamine, and bronchodilators prior to the test

a. Inhalation challenge tests are conducted by exposing the worker to the suspected antigen.

Methemoglobin

a. is like sulfhemoglobin since it is irreversiblyassociated with the heme moiety

b. is dangerous because of its ability to bind oxygen

c. decreases the oxygen affinity of heme groups in hemoglobin

d. decreases oxygen delivery to the tissues

d. Methemoglobin is dangerous because of its inability to bind oxygen and because it increases the oxygen affinity of the remaining heme groups in hemoglobin tetramer, thereby decreasing oxygen delivery to the tissues.

Porphyrias

a. are a group of disorders characterized by bluishdiscoloration of the skin

b. result in the abnormal accumulation of hemoglobin in the skin

c. are genetic disorders that affect only royal families

d. can occur as a result of inappropriate overstimulation of δ-aminolevulinic acid synthetase

d. Clinically, symptomatic porphyria can occur either as a result of inadequate enzymatic function along any step in heme biosynthesis or as a result of inappropriate overstimulation of δ-aminolevulinic acid synthetase, usually in the setting of decreased heme concentration.

Acute intermittent porphyria causes

a. symptoms and signs quite different than thoseassociated with lead intoxication

b. a classic triad of abdominal pain, constipation, and jaundice

c. an increase in neuropsychiatric signs compared with lead intoxication

d. a more pronounced anemia than occurs with lead intoxication

c. The major differences between the two diseases are (1) an increase in neuropsychiatric signs in acute intermittent porphyria compared with lead intoxication and (2) anemia, which is present in lead intoxication but virtually absent in porphyria.

Aplastic anemia

a. is distinct from medullary aplasia and secondary aplastic anemia

b. is largely an hereditary abnormality of the pluripotent hematopoietic stem cells

c. results in pancytopenia (anemia, neutropenia, and thrombocytopenia)

d. cases are largely caused by hereditary diseases

c. Aplastic anemia, or medullary aplasia, is an acquired abnormality of the pluripotent hematopoietic stem cells resulting in pancytopenia (anemia, neutropenia, and thrombocytopenia).

Myelodysplasic syndromes

a. are a group of acquired nongenetic disorders of the blood-forming cells

b. are characterized by ineffective hematopoiesis

c. are characterized by a bizarre hematopoieticmorphology confirming cancer

d. have in nearly all cases a progression to frankleukemia.

b. The myelodysplastic syndromes are a group of acquired genetic disorders of the blood-forming cells similar to cancer and characterized by ineffective hematopoiesis, clinically resulting in anemia, neutropenia, thrombocytopenia, or a combination of cytopenias.

Multiple myeloma

a. is an acute leukemia of differentiated B cells (termed plasma cells)

b. accounts for 50% of all hematologic cancers

c. is characterized by anemia, painful lytic and osteopenic bone disease

d. has a long survival rate

c. Multiple myeloma is characterized by anemia, painful lytic and osteopenic bone disease, monoclonal immunoglobulin production (in serum or urine or both), hypogammaglobulinemia, and short survival.

Latency period

a. is different than the induction-latency orincubation period

b. is unrelated to the general requirement for multiple heritable changes in the cell before a cancerdevelops

c. is the interval of time required from first exposure to the responsible agent to the development of malignancy

d. for most occupational cancers in humans istypically 2–8 years

c. In both experimental animal models of cancer and human cancers with known causes, a significant interval of time is required from first exposure to the responsible agent to the development of malignancy. This interval is referred to as the induction-latency (or sometimes just latency) or incubation period.

Epidemiologic studies

a. provide the strongest evidence for human carcinogenicity

b. evaluate effects on animals and human subjects

c. involve a small and discrete number ofindividuals

d. typically confirm carcinogenic effects

a. Epidemiologic studies provide the strongest evidence for human carcinogenicity.

Short-term tests

a. provide evidence of carcinogenicity or the ability to induce chromosomal damage by chemicals

b. assessed endpoints exclude gene mutation and induction of DNA damage and repair

c. rely solely on the fact that carcinogens covalently bind to DNA and thereby induce DNA damage

d. include the Ames test

d. One of the best-studied and most commonly performed short-term tests is the Ames test, which uses a mutant strain of Salmonella typhimurium that is deficient in the enzymes required to synthesize histidine and which will not grow unless histidine is added to the growth medium.

Tests for DNA repair

a. can demonstrate that DNA damage has occurred following exposure to a chemical

b. include cytogenetic tests that assess changes in the morphologic structure of chromosomes

c. consistently can be indicative of the effects of both genotoxic and nongenotoxic carcinogens

d. include chromosomal translocations and the formation of micronuclei

a. Tests for DNA repair can demonstrate that DNA damage has occurred following exposure to a chemical.

DNA or protein adducts

a. are a potentially valuable tool in the measurement of levels of specific carcinogens covalently bound to DNA or proteins

b. are detectable only in white blood cells

c. do not quantify internal dose better than older available methods such as air monitoring or measuring blood or urine levels of an agent

d. help identify smokers in occupationally exposed groups

a. DNA or protein adducts are a potentially valuable tool in the measurement of levels of specific carcinogens covalently bound to DNA or proteins.

Lung cancer

a. has a latency period of approximately 10 years

b. is readily detected by screening studies

c. is a major asbestos-related disease, accounting for 20% of all deaths in asbestos-exposed cohorts

d. is increased 10-fold in smoking asbestos-exposed workers

c. Lung cancer is a major asbestos-related disease, accounting for 20% of all deaths in asbestos-exposed cohorts.

Diesel-engine exhaust

a. has been demonstrated to increase the risk of lung cancer solely in studies of miners and railroad workers

b. is not considered a human carcinogen

c. in animal studies provides equivocal results

d. contains a number of nitroarenes, which arenitro-substituted derivatives of polycyclic aromatic hydrocarbons (arenes)

d. Diesel-engine exhaust contains a number of nitroarenes, which are nitro-substituted derivatives of polycyclic aromatic hydrocarbons (arenes).

Cancers of the nasal cavity and paranasal sinuses

a. are common wherever smoking is prevalent

b. are common in younger than 40–50 years of age

c. are primarily adenocarcinomas

d. are linked to many different occupational exposures

d. Many different occupational exposures are linked to cancer of the nasal cavity and paranasal sinuses.

All benzidine-derived dyes

a. cause bladder cancer in the highest incidence in developing countries

b. are ultimately metabolized to form nitroarenes, which are the active carcinogenic agent derived from the dyes

c. cause bladder cancer with a mean latency period of about 10 years

d. should be considered to be potential human carcinogens

d. NIOSH has concluded that all benzidine-derived dyes should be considered to be potential human carcinogens.

Arsenic

a. is suspected to be a human carcinogen, although it has not been definitively confirmed throughepidemiologic studies

b. skin tumors associated with arsenic occurexclusively from skin contact

c. induced skin cancers tend to be isolated andsingular

d. cancers occur in younger patients than thoseattributable to UV light

d. Skin cancers from arsenic exposure tend to be multiple and occur in younger patients than those attributable to UV light.

Acute nonlymphocytic leukemia (ANLL)

a. decreases with age with the highest rates in younger than age 50

b. and chronic myelogenous leukemia (CML) are linked to occupation

c. is characterized by a diminished number ofimmature blood cell progenitors in the bonemarrow

d. due to benzene exposure is distinct from de novo leukemia

b. The two major forms of leukemia that have been linked to occupation are acute nonlymphocytic leukemia (ANLL)—including myelodysplasia and preleukemia—and chronic myelogenous leukemia (CML).

Middle East Respiratory Syndrome is

a. a bacterial respiratory illness

b. quite unlike Severe Acute Respiratory Syndrome (SARS)

c. caused by a coronavirus

d. of small concern to health care workers

c. MERS is caused by a coronavirus.

Tuberculosis

a. incidence is increasing worldwide because of the emergence of drug-resistant strains

b. is most frequently a gastrointestinal infection

c. is transmitted solely by airborne route

d. is most prevalent in the African region

d. The African region has approximately one quarter of the world's cases, and the highest rates of cases and deaths relative to population.

Tuberculin skin test

a. is recommended on a monthly basis for occupational high-risk workers

b. is reliably positive even in the presence of overwhelming tuberculosis

c. is reliably positive even in the presence of measles, Hodgkin disease, sarcoidosis, or immunosuppressive states

d. is considered positive in high-risk occupational groups with a reaction of 10 mm or more

d. The TST test is considered positive in high-risk occupational groups with a reaction of 10 mm or more.

Hepatitis C

a. is a bacterial infection of the liver caused by the hepatitis C virus

b. causes an estimated 25% of what was previously termed posttransfusion non-A, non-B hepatitis

c. is infrequently associated with a history of blood transfusion

d. transmission following mucous membrane exposure is rare, with no apparent transfer following exposures to intact skin

d. Transmission following mucous membrane exposure is rare, with no apparent transfer following exposures to intact skin.

Hepatitis A

a. is a viral hepatitis transmitted through the fecal-oral route

b. is rarely encountered by travelers

c. always causes pronounced acute symptoms in children

d. has been eradicated in the United States

a. Hepatitis A is a viral hepatitis transmitted through the fecal-oral route.

Occupational brucellosis

a. infection is systemic and may result in gastric, intestinal, neurologic, hepatic, or musculoskeletal involvement

b. occurs as a result of inhalation of infected animal tissues

c. has an incubation period from 6 to 12 weeks

d. onset is profound and acute, with fever, sweats, malaise, aches, and weakness

a. Occupational brucellosis infection is systemic and may result in gastric, intestinal, neurologic, hepatic, or musculoskeletal involvement.

Irritant contact dermatitis (ICD)

a. accounts for nearly 80% of all occupational dermatitis

b. is caused by a single chemical

c. is unrelated to environmental factors

d. is not affected by ethnicity

a. Irritant contact dermatitis is a common form of occupational skin disease and, in the United States, accounts for nearly 80% of all occupational dermatitis.

ICD

a. is an immunogenic skin reaction to toxic substances

b. is caused by a limited number of substances

c. has no predisposing factors

d. is caused by skin exposure to irritating toxic substances

d. ICD is a nonimmunogenic skin reaction to toxic substances either in low or high concentrations.

Phototoxic (Photoirritation) reactions

a. may result from exposure to natural or artificial light alone

b. can be caused by numerous systemic drugs

c. is unrelated to the dose or concentration of phototoxic substance

d. may be followed by loss of pigmentation

b. Numerous systemic drugs can cause phototoxic reactions.

Occupational leukoderma

a. results in hyperpigmentation

b. occurs without inflammation

c. usually involves the hands and forearms

d. remains localized

c. The initial site of leukoderma is usually the hands and forearms.

Allergic contact dermatitis (ACD)

a. is controlled by ordinary protective measures

b. seldom requires job change

c. does not prevent immediate return to work

d. is an immunologic reaction classified as a delayed type IV

d. ACD is an immunologic reaction classified as a delayed type IV or cell-mediated hypersensitivity. This distinguishes it from type I reactions, which are immediate and antibody mediated.

ACD

a. is less severe when following reexposure to the allergen

b. can evolve into subacute but not chronic stages

c. produces considerable variation in the intensity of reaction depending on the body area affected

d. usually affects the mucous membranes

c. ACD results in considerable variation in the intensity of reaction depending on the body area affected.

ACD

a. sensitization requires at least 4 days to develop

b. eventually affects all workers exposed to allergens

c. is unrelated to irritant dermatitis

d. is unrelated to epoxy resins, biocides, chromate, and formaldehyde

a. ACD sensitization requires at least 4 days to develop.

Patch testing

a. is the key to diagnosis of allergic contact dermatitis

b. allows the use of a large concentration of test substance

c. tests a more resistant organ than that affected by the disease

d. tests a different mechanism than that which causes the disease

a. The key to diagnosis of allergic contact dermatitis is diagnostic patch testing.

Photoallergic reactions

a. are more common than phototoxic reactions

b. are immunologically based

c. appear slowly with an acute eczematous eruption

d. appear only on the face, neck, and dorsum of the hands

b. Photoallergic reactions are immunologically based.

Nonimmunologic (nonallergic) contact urticaria

a. affects only a few exposed individuals

b. requires no previous sensitization

c. spares gardeners

d. spares cooks and other food handlers

b. With sufficient provocation, nearly all exposed individuals will develop nonallergic contact urticaria. Previous sensitization is not necessary.

Immunologic (allergic) contact urticaria

a. is caused most commonly by latex in natural rubber, but not rubber gloves

b. is limited to mild erythema with itching at the site of contact

c. reactions are immunoglobulin E (IgE)–mediated type I

d. is less common in atopics

c. Allergic contact urticaria reactions are immunoglobulin E (IgE)–mediated type I immediate hypersensitivity reactions and appear to be more common in atopics.

Chloracne

a. is a common occupational skin disorder

b. especially affects the nose

c. spares the conjunctivae

d. may lead to peripheral neuritis and hepatotoxicity, suggesting systemic toxicity

d. Peripheral neuritis and hepatotoxicity may occur with chloracne, suggesting systemic toxicity.

Atopic dermatitis

a. protects workers from skin colonization with staphylococci

b. produces immunity through development of eczematous skin

c. requires prophylactic oral antibiotics

d. may restrict employment in food service industries and hospital patient care

d. Employment of persons with active atopic dermatitis in food service industries and hospital patient care may need to be restricted.

Atypical mycobacterial infections

a. are caused most commonly by infection with M chelonae

b. are acquired from exposure to infected fowl

c. are usually effectively treated with rifampicin or ethambutol

d. are not predisposed in persons with AIDS

c. Treatment of atypical mycobacterial infections with rifampicin or ethambutol is usually effective.

In the management of contact dermatitis

a. avoidance and protective measures remain the best approach

b. highly potent steroids are always required

c. water-based cleaners are recommended as skin cleansers

d. alcohol-based cleaners are recommended as skin cleansers

a. Avoidance, substitution with less-allergenic chemicals, modification of work activities and protective measures are the best approach to management.

Prevention of occupational skin disorders

a. is not necessary because the long-term outcome is always the same once exposure has occurred

b. should be limited to the affected employees to prevent stigmatization

c. requires close cooperation between the employee, employers, company physicians, dermatologists, and other relevant stakeholders such as workers unions

d. does not involve giving employees information on the involved chemical substances

c. Prevention of occupational skin disorders requires close cooperation between the employee, employers, company physicians, dermatologists, and other relevant stakeholders such as workers unions.

Occupational allergic rhinitis

a. is work exacerbated, but not work induced

b. is linked with occupational asthma

c. may result in release of mediators such as antigens

d. is associated with a negative epicutaneous skin prick test

b. A growing body of evidence links the development of rhinitis with that of asthma, making the prevention (and early recognition) of upper airway inflammation a priority.

Allergens responsible for occupational allergic rhinitis

a. are distinct from those producing occupational asthma

b. include only low-molecular-weight substances

c. include only high-molecular-weight substances

d. may include common aeroallergens, such as grass pollen

d. Workplace allergens producing allergic rhinitis may be either commonly encountered allergens, exposure to which may be incidental to the work environment (eg, grass pollen exposure in a landscaping gardener), or unusual agents encountered only in industrial environments (eg, trimellitic anhydride exposure in a plastics worker).

Irritant rhinitis

a. produces definitive symptoms and signs distinct from those of allergic rhinitis

b. is diagnosed by a positive allergy workup

c. predisposes to oral breathing via reflex nasal congestion

d. via reflex nasal congestion

c. High-grade nasal obstruction (a reflex response to irritants and allergens) predisposes to oral breathing, bypassing the filtration and air-conditioning functions of the upper airway. This may be one of the mechanisms whereby rhinitis and asthma severity are linked.

Vasomotor rhinitis

a. is a subcategory of allergic rhinitis

b. is defined by reactivity to specific chemical stimuli

c. causes rhinorrhea, with nasal pruritus being definitive

d. also occurs in many individuals with allergic rhinitis

d. Nasal hyperreativity is a defining characteristic of vasomotor rhinitis, but can also be found in a subset (~40%) of allergic rhinitics.

Sinusitis

a. has been linked to asthma incidence and severity

b. may follow allergic but not irritant rhinitis

c. spares active smokers because they develop resistance

d. always involves bacterial infections

a. Sinusitis has been linked to asthma incidence and severity.

The diffusing capacity of the lung for carbon monoxide (DL_CO)

a. is the amount of inhaled carbon monoxide returned in exhaled air

b. is closely correlated with the capacity of the lungs to absorb oxygen

c. is increased with obstructive, restrictive, or vascular diseases

d. is often misused to assess respiratory impairment

b. The diffusing capacity of the lung for carbon monoxide (DL_CO) is closely correlated with the capacity of the lungs to absorb oxygen.

Bronchoprovocation tests

a. are useful in the diagnosis of occupational asthma

b. should be done in a hospital environment

c. give an indication of the presence and degree of inflammation of the airways

d. are usually terminated after a 40% fall in FEV₁

a. Bronchoprovocation tests are useful in the diagnosis of occupational asthma.

The site of deposition of an inhaled gas

a. depends on the duration of exposure and its concentration

b. is determined primarily by water solubility

c. such as phosgene is the moist surfaces of the nose and throat

d. such as ammonia is likely the alveoli

b. The site of deposition of an inhaled gas is determined primarily by water solubility.

Occupational asthma

a. may be caused by such diverse agents as diisocyanates, snow crab, and western red cedar

b. resolves rapidly after removal from the offending agent

c. is predicted by a history of childhood asthma

d. treatment with inhaled corticosteroids does not improve prognosis

a. Occupational asthma caused by such diverse agents as diisocyanates, snow crab, and western red cedar show persistence of symptoms and the presence of nonspecific airway hyperresponsiveness for periods up to 6 years after removal from the offending agent.

Hypersensitivity pneumonitis

a. should be distinguished from extrinsic allergic alveolitis

b. is an immunologically mediated inflammatory disease of the airway

c. is induced by inhalation of organic dusts that contain a variety of etiologic agents

d. has different clinical and pathologic findings for each etiologic agent

c. Hypersensitivity pneumonitis, also known as extrinsic allergic alveolitis, refers to an immunologically mediated inflammatory disease of the lung parenchyma that is induced by inhalation of organic dusts that contain a variety of etiologic agents (eg, bacteria, fungi, amoebae, animal proteins, and several low-molecular-weight chemicals).

Silicosis

a. is a thoracic pleural disease

b. results from the inhalation of silicon dioxide, or silica, in crystalline form

c. is primarily the result of cytotoxic effects on lymphocytes

d. produces small round opacities (<10 mm in diameter) in both lungs, with a predilection for the lower lung zones

b. Silicosis is a parenchymal lung disease that results from the inhalation of silicon dioxide, or silica, in crystalline form.

Coal workers' pneumoconiosis

a. is, unlike silicosis, often asymptomatic

b. is seen often in those who have spent more than 2 years in underground mining

c. may lead to progressive massive fibrosis, identical to that of silicosis

d. is confirmed by biopsy of the coal macule

c. Coal workers' pneumoconiosis may lead to progressive massive fibrosis, identical to that of silicosis.

In reflex bronchoconstriction

a. neuroreceptors in the airway are stimulated by agents such as cold air, dusts, mists, vapors, and fumes

b. the reaction involves immunologic mechanisms and leads to airway inflammation

c. the patient has no history of preexisting nonoccupational asthma

d. there is no history of nonspecific airway hyperresponsiveness

a. In reflex bronchoconstriction, neuroreceptors in the airway are stimulated by agents such as cold air, dusts, mists, vapors, and fumes.

Chronic exposure to carbon disulfide

a. appears to accelerate atherosclerosis and/or precipitate acute coronary ischemic events

b. increases serum thyroxine levels

c. decreases serum cholesterol levels, particularly those of the very-low-density lipoproteins

d. is reliably monitored in biologic fluids

a. Chronic exposure to carbon disulfide appears to accelerate atherosclerosis and/or precipitate acute coronary ischemic events.

Carbon monoxide exposure

a. enhances maximal exercise capacity in healthy workers

b. may aggravate angina pectoris but not intermittent claudication

c. has no effect on chronic obstructive lung disease

d. may aggravate or induce cardiac arrhythmias

d. Carbon monoxide exposure may aggravate or induce cardiac arrhythmias.

Nitrates

a. directly constrict blood vessels, including those of the coronary circulation

b. deactivate the rennin-angiotensin system

c. typically cause immediate chest pain

d. appear to cause a 2.5- to 4-fold increase in the risk of cardiovascular death in workers handling explosives

d. Case-control studies suggest a 2.5- to 4-fold increase in the risk of cardiovascular death in workers handling explosives.

Organophosphate and carbamate insecticides

a. can produce diverse cardiovascular disturbances, including tachycardia and hypertension, bradycardia and hypotension, heart block, and ventricular tachycardia

b. stimulate acetylcholinesterase, which causes accumulation of acetylcholine at cholinergic synapses and myoneural junctions

c. typically result in ataxia, nystagmus, and slurred speech

d. invariably result in arrhythmias with chronic exposure

a. Intoxication with organophosphate and carbamate insecticides can produce diverse cardiovascular disturbances, including tachycardia and hypertension, bradycardia and hypotension, heart block, and ventricular tachycardia.

Arsine gas

a. causes red blood cell hemolysis

b. leads to hypokalemia resulting in cardiac arrest

c. electrocardiographic manifestations are diagnostic

d. only indirectly affects the myocardium

a. Arsine gas causes red blood cell hemolysis.

Direct hepatotoxins

a. injure the hepatocyte and its organelles by a direct physicochemical effect

b. may produce centrilobular necrosis but not steatosis

c. such as chloroform cause indirect hepatic necrosis

d. including benzene, toluene, xylene, and styrene cause massive acute hepatic injury

a. Direct hepatotoxins or their metabolic products injure the hepatocyte and its organelles by a direct physicochemical effect, such as peroxidation of membrane lipids, denaturation of proteins, or other chemical changes that lead to destruction or distortion of cell membranes.

Indirect hepatotoxins

a. produce hepatic injury by interference with metabolic pathways

b. increase bile flow

c. include drugs such as antihistamines and aspirin

d. do not include botanicals

a. Indirect hepatotoxins are antimetabolites and related compounds that produce hepatic injury by interference with metabolic pathways.

Mixed-function oxidases (MFOs)

a. make the liver the primary defense against infections

b. are cellular enzyme systems

c. are attached to the membrane layers of the smooth endoplasmic reticulum

d. do not defend against inhaled xenobiotics

b. The strategic role of the liver as the primary defense against xenobiotics depends largely on cellular enzyme systems (mixed-function oxidases [MFOs]).

Carbon tetrachloride

a. is an atypical or unusual form of hepatotoxin

b. causes immediate anesthesia

c. hepatic disease usually follows exposure by 2–4 hours

d. causes renal failure after the hepatic damage becomes manifest

d. Renal failure may ensue a few days after the carbon tetrachloride hepatic damage becomes manifest and in fact has been the cause of death in most fatal cases.

Toxicant-associated steatohepatitis (TASH)

a. describes hepatic steatosis, inflammation, and liver failure

b. has occurred among vinyl chloride production workers

c. reduces total cytokeratin 18 as a marker of cell death

d. causes insulin resistance with elevated adiponectin levels

c. TASH has recently been used to describe hepatic steatosis, inflammation, and fibrosis among vinyl chloride production workers.

Hepatitis A

a. is transmitted primarily by person-to-person contact, generally through fecal contamination

b. outbreaks have been reported among day-care workers

c. affects correctional settings and dentists

d. primarily affects waste water treatment plant workers

a. While contaminated food and water are common epidemic sources, hepatitis A is transmitted primarily by person-to-person contact, generally through fecal contamination.

Hepatitis B

a. affects only those health care workers with significant contact with blood

b. is not transmitted via the fecal-oral route or by contamination of food or water

c. causes a skin rash, but is unrelated to arthritis

d. incubation period ranges from 45 to 60 hours

b. Transmission occurs via percutaneous or permucosal routes when exposure to blood or potentially infectious body fluids occurs; HBV is not transmitted via the fecal-oral route or by contamination of food or water.

Hepatitis C virus (HCV)

a. has a marginal ability to persist in the host after infection

b. infects nearly 1 million people annually in the United States

c. is spread primarily through parenteral exposures from blood transfusions or intravenous drug abuse

d. shows minimal evidence for sexual transmission

c. HCV is spread primarily through parenteral exposures from blood transfusions or intravenous drug abuse.

Clearance tests

a. provide the least sensitive and reliable means of detecting the early phase of liver disease

b. fail to determine when recovery has occurred in reversible liver disease

c. may demonstrate liver dysfunction in the absence of clinical or serologic abnormalities

d. confirm occupational etiology of disease in workers with known liver dysfunction

c. In the occupational setting, measures of hepatic functional capacity have been used epidemiologically to demonstrate liver dysfunction in the absence of clinical or serologic abnormalities.

Cytokeratin 18 (CK18)

a. has recently been explored as a tool to assess occupational liver disease

b. is a cytoskeletal protein found in hepatocytes and renal cells

c. is absorbed by dying cells

d. detects cases of toxicant-associated liver cancer

a. The use of Cytokeratin 18 (CK18) has recently been explored as a tool to assess occupational liver disease.

The kidney

a. is especially vulnerable to occupational and environmental exposures

b. receives about half the cardiac output

c. reabsorbs and dilutes filtrate

d. prevents development of toxins in ionic forms

a. The kidney is especially vulnerable to occupational and environmental exposures.

Acute kidney injury

a. occurs only after high-dose exposure

b. always develops as acute tubular necrosis

c. leads to a decrease in BUN and creatinine

d. may require dialysis until the renal function recovers

d. In acute kidney injury, patients may require dialysis until the renal function recovers.

Chronic kidney disease (CKD)

a. is rarely in the form of chronic interstitial nephritis

b. does not include lead nephropathy

c. does not follow exposures to organic solvents

d. is characterized by tubular proteinuria

d. Most chronic kidney diseases associated with exposure to agents such as lead or cadmium present with chronic interstitial nephritis characterized by tubular proteinuria (usually <2 g/24 h) and a urine sediment usually lacking any cellular elements.

Balkan-endemic nephropathy (BEN)

a. is a form of aristolochic acid nephropathy

b. is an interstitial nephropathy associated with urinary tract infections

c. strikes farm workers at all ages

d. affects children living on farms

a. Balkan-endemic nephropathy (BEN) is now considered a form of aristolochic acid nephropathy.

Lead nephropathy

a. is an acute kidney disease accompanied by a history of hypertension and gout

b. should not be considered in patients who do not have gout or hypertension

c. ultrasonography typically shows small, contracted kidneys

d. reveals no tubular atrophy on renal biopsy

c. Lead nephropathy renal ultrasonography typically shows small, contracted kidneys.

Overt lead nephropathy

a. is one of the few preventable renal diseases

b. treatment has no impact on the management of gout

c. treatment consists of continued EDTA injections once weekly

d. treatment is continued until urine lead chelate is below 20 μg

a. Overt lead nephropathy is one of the few preventable renal diseases.

Cadmium

a. primarily affects the kidneys and liver

b. renal effects include the Fanconi syndrome

c. symptoms usually result from the increased calcium excretion that accompanies the glomerular injury

d. causes ureteral colic from calculi in most patients subjected to industrial exposure

b. Once a critical concentration of 200 μg/g of renal cortex is achieved, the renal effects of cadmium, such as Fanconi syndrome, become evident.

Silicosis

a. can result in a generalized systemic disease resembling collagen-vascular disease

b. is the most common cause of systemic lupus erythematosus

c. decreases the occurrence of positive antinuclear antibody

d. has no effect on the occurrence of antineutrophil cytoplasmic autoantibodies

a. Heavy exposure to silica can result in a generalized systemic disease resembling collagen-vascular disease, such as systemic lupus erythematosus.

The epidemic of chronic kidney disease in Central America

a. primarily affects automobile factory workers

b. is caused by heavy metals

c. disproportionately affects agricultural workers at lower, warm weather altitudes

d. is a form of aristolochic acid nephropathy

c. The cause of the epidemic of chronic kidney disease in Central America is unknown. It disproportionately affects agricultural workers at lower, warm weather altitudes.

Toluene inhalation (glue sniffing)

a. is a cause of nephrotic syndrome

b. may lead to the development of respiratory acidosis

c. is a cause of renal tubular acidosis

d. is associated with Fanconi syndrome

c. Toluene inhalation (glue sniffing) is a classic cause of distal renal tubular acidosis.

Encephalopathy

a. raises the level of consciousness

b. symptoms may be cognitive but not psychiatric

c. may be the result of toxins

d. is never confused with parkinsonism

c. Encephalopathy is a general term that denotes a diffuse dysfunction of the central nervous system. The clinical manifestations may be diverse. Depressed level of consciousness is common, as are cognitive and psychiatric symptoms. Other manifestations depend on the selectivity of the injury. For instance, some toxins may cause more selective injury to the vestibular system or cerebellum resulting in dysequilibrium, vertigo, and gait or limb ataxia. Others may affect the basal ganglia causing an extrapyramidal syndrome of bradykinesia, tremors, and rigidity.

Cognitive complaints

a. should include at least a mini–mental state examination

b. require referral to neuropsychological testing

c. mask the pattern and severity of the cognitive deficits

d. are reliable symptoms of lead poisoning

a. Evaluation of cognitive complaints should include at least a mini–mental state examination.

Peripheral nervous system disorders

a. lead to sensory disturbances but no weakness

b. are often accompanied by impairment of the deep tendon reflexes

c. demonstrate heightened CNS vulnerability to toxins

d. occur because toxins directly affect single nerves

b. Peripheral nervous system disorders lead to sensory disturbances and weakness, often accompanied by impairment of the deep tendon reflexes on physical examination.

Polyneuropathy

a. is a syndrome with asymmetric peripheral neuropathy

b. frequently results from local mechanical injury

c. is typically characterized by the distal distribution of the symptoms and signs

d. has no neuropathic pain

c. The hallmark of most polyneuropathies is the distal distribution of the clinical symptoms and signs.

Peripheral neuropathy

a. has only a few known causes

b. is seldom caused by systemic diseases

c. often does not have an identified cause despite extensive testing

d. is almost always painful

c. Peripheral neuropathy may result from a wide range of systemic conditions. Despite continuing advances, the causes of many neuropathies remain elusive despite testing.

A focal neuropathy

a. produces localized motor and sensory disturbances

b. leads to generalized weakness

c. causes symmetrical atrophy of limb muscles

d. is usually caused by systemic exposures to toxins

a. Focal neuropathy is a condition in which a single nerve is affected. Symptoms arise from the motor and sensory fibers in the affected nerve, typically resulting in weakness and sensory loss in a restricted anatomic distribution.

Acrylamide

a. exposure typically leads to irreversible dysfunction

b. acts primarily on the central nervous system

c. may produce a delayed neuropathy

d. rarely causes an autonomic involvement

c. A neuropathy may develop as a delayed manifestation a few weeks after acute acrylamide exposure or insidiously after chronic exposure.

Arsenic

a. leads to peripheral neuropathy at only high-dose exposure

b. may produce an acute polyneuropathy within 1–3 hours

c. neuropathy precedes Guillain-Barré syndrome

d. chronic exposure leads to a more insidious sensorimotor polyneuropathy

d. Chronic exposure leads to a more insidious sensorimotor polyneuropathy, although there is no agreement for a threshold limit.

Mercury

a. poisoning causes a diffuse encephalopathy

b. exposure may present with euphoria, irritability, anxiety, and emotional lability

c. exposure may cause tremor but not cerebellar ataxia

d. causes Guillain-Barré syndrome

a. Like many other toxins, mercury poisoning causes a diffuse encephalopathy.

Organophosphates

a. diminish muscarinic and nicotinic activity

b. with severe intoxication cause convulsions, coma, muscle paralysis, and respiratory arrest

c. intoxication typically lasts less than 12 hours

d. acetylcholinesterase activity must be restored before recovery occurs

b. Severe organophosphate intoxication may cause convulsions, coma, muscle paralysis, and respiratory arrest occur with severe intoxication.

Chemical exposures

a. during weeks 1 and 2 after conception may cause early pregnancy loss if they interfere with tubal transport, implantation, or endocrine control

b. predictably appear as a late or heavy menstrual flow

c. cause a short rise and subsequent plateau in hCG

d. are likely to cause congenital anomalies from very early embryo exposures

a. Chemical exposures during weeks 1 and 2 after conception may cause early pregnancy loss if they interfere with tubal transport, implantation, or endocrine control or if they are cytotoxic to the fetus itself.

Chemical exposures

a. later in pregnancy spare the endocrine, central nervous, and other systems

b. that are of less concern later in pregnancy are organic mercury, tobacco smoke, and lead

c. after the first trimester may induce minor morphologic abnormalities or growth deficits

d. to carcinogens are of no concern because they do not cross the placenta

c. Chemical exposures after the first trimester may induce minor morphologic abnormalities or growth deficits.

Endocrine-disrupting chemicals (EDCs)

a. do not vary structurally to persistent pesticides such as DDT and plasticizers such as phthalates and bisphenol-A

b. are hormonally active agents (HAAs)

c. may persist for years in the environment but do not enter the food chain

d. are not implicated in thyroid hormone disruption

b. Endocrine-disrupting chemicals are hormonally active agents.

Solvents

a. include many compounds used in the workplace but seldom in the home

b. are considered a potential reproductive hazards only among laboratory workers

c. such as perchloroethylene, methylene chloride, toluene, xylene, and glycol ethers have been associated with concurrent elevation in SAB risk

d. show associations with cardiac but no other congenital anomalies

c. Solvents such as perchloroethylene, methylene chloride, toluene, xylene, and glycol ethers have been associated with concurrent elevation in SAB risk.

Tobacco smoking

a. is always associated with a number of developmental and reproductive endpoints

b. results in ten times the risk of low birth weight compared with infants of nonsmokers

c. does not induce preterm delivery, fetal and infant death, and behavioral deficits in offspring

d. is associated with infertility, menstrual disorders, and menopause at earlier age

d. Tobacco smoking is associated with infertility, menstrual disorders, and menopause at earlier age.

Semen abnormalities can include

a. azoospermia (low sperm count)

b. oligospermia (increased sperm count)

c. teratospermia (abnormally motile sperm)

d. asthenospermia (sperm showing decreased motility)

d. Semen abnormalities can include azoospermia (complete absence of sperm), oligospermia (decreased sperm count), teratospermia (abnormally shaped sperm), and asthenospermia (sperm showing decreased motility).

Male reproductive toxicants

a. include DBCP, ionizing radiation, mercury, and lead

b. are of concern only in occupational settings

c. mostly involve low-level exposures

d. include DBCP and exogenous estrogens

d. Most occupational events involving high-level exposures and documented adverse reproductive effects have occurred in male workers with exposure to DBCP and exogenous estrogens.

DBCP

a. is a nematocide that is associated with reproductive and developmental abnormalities

b. exposed workers exhibit azoospermia, oligospermia, and decreased plasma FSH levels

c. causes decreased sperm fertility among all exposed workers

d. exposure may result into a permanent azoospermia in some workers

d. Decreased fertility was experienced among workers with testicular changes, and the most extreme FSH elevations were found in workers who did not recover after a period of no exposure.

Inorganic lead

a. is the only form of lead with male reproductive effects

b. has been implicated in cases of increased libido

c. presents in some males as endocrine changes (decreased testosterone and increased LH levels)

d. is frequently detected in the sperm of workers with low-level exposure

c. Inorganic lead presents in some males as endocrine changes (decreased testosterone and increased LH levels).

Phthalates

a. should not be considered as an endocrine disruptors

b. metabolites are detectable in the general population at all ages

c. are associated with short anogenital distance together with incomplete testicular descent

d. may cause human male reproductive damage at levels found in the general population

d. Phthalates may cause human male reproductive damage at levels found in the general population.

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Section III: Occupational Illnesses

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Section III. Occupational Illnesses

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