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GENERAL PRINCIPLES
Disability evaluation and determination is an important medical function because it impacts both the patient and the economy. Although it is important, it can be quite challenging for clinicians to accomplish. Clinicians must synthesize clinical and nonclinical information to make a medical decision and communicate it to multiple administrative and legal entities. Primary care clinicians will continue to perform evaluations because as the treating provider, they can provide the best medical evidence to make an appropriate disability determination.1
Definition
Disability is often confused with impairment. It is important for clinicians to know the difference between the two to provide appropriate evaluation. There are several definitions for each of these terms from different organizations and the most common definitions have been included at the end of this chapter (Table 21.1-1). The following are general definitions of the term.
Disability Definitions |
Definitions of impairment
A significant deviation, loss, or loss of use of any body structure or body function in an individual with a health condition, disorder or disease.2
A loss, loss of use or derangement of any body part, organ system or organ function.3
Results from anatomical, physiological, or psychological abnormalities, which can be shown by medically acceptable clinical and laboratory diagnostic techniques. A physical or mental impairment must be established by medical evidence consisting of signs, symptoms, and laboratory findings—not only by the individual’s statement of symptoms.4
Definitions of disability
Activity limitations and/or participation restrictions in an individual with a health condition disorder or disease.2
An alteration of an individual’s capacity to meet personal, social, or occupational demands or statutory or regulatory requirements because of an impairment.3
The inability to engage in any substantial, gainful activity (SGA) by reason of a medically determinable physical or mental impairment(s), which can be expected to result in death or which has lasted or can be expected to last for a continuous period of not less than 12 months.4
Impairment is typically defined as “a significant deviation, loss, or loss of use of any body structure or body function in an individual with a health condition, disorder or disease.”2 It can be defined as permanent or temporary or partial or total depending on the issue. It does not vary based on environment.
Disability is typically defined as a limitation due to impairment in the ability to perform activities of daily living or complex activities, like work.4 It is determined by environmental factors. A person with an impairment may be disabled only in certain situations or jobs.
Epidemiology
In 2005, the United States Census Bureau found that 54.4 million people in the noninstitutional population had some level of disability, with 35 million of them reporting severe disability.5 In that population, African Americans and Hispanics had higher rates of disability than whites.5
Arthritis, back or spinal problems, and heart conditions are the top three conditions that cause disability.6–8 In addition, disability also increases with age. The United States Census Bureau found that 41.9% of those over 65 years old had a disability compared with 18.6% of younger people.6,7
Classification
There are several guides available that can be used to classify impairment and disability. One of the most popular ones, The American Medical Association (AMA) “Guides to the Evaluation of Permanent Impairment,” has standardized the approach to impairment assessment. There are several editions of the guides and each state has mandated specific editions or portions of them as the standard for impairment determination. Provider should check with their respective states to determine which one they should use.
The predominant guides for disability determination, the Blue Book and the Green Book, were created by the Social Security Administration (SSA). The Blue Book describes the disability process and contains a listing of impairments for treating clinicians to determine disability. The Green Book is for consulting clinicians. If a patient meets criteria for a medical diagnosis, the condition is on the list of impairments, and it has lasted or is expected to last at least 12 months or death, he or she will meet the medical criteria for disability.
History and Physical Examination
Clinicians should gather information about the individual’s medical problems and their functional limitations, which may involve performing diagnostic testing and imaging, completing a detailed physical examination, and collecting consultant reports. The clinician needs to then determine whether the patient has an impairment based on the medical issues. Once impairment has identified, additional factors can be evaluated to determine whether there are situations where the individual has disability.
Documenting the medical and limitation information is as important as collecting it. Clinicians need to create a coherent picture in their documentation to assist disability agencies, such as the SSA, which can make an appropriate decision.
TREATMENT
Treatment is determined by the underlying medical problem and does not change based on disability status. All therapy should be directed to minimizing or eliminating impairment. Treatment may include medications, surgeries, physical and occupational therapy, and behavioral and mental health care.
Referrals
Depending on the nature of the patient’s impairment, referrals may be necessary for additional recommendations or treatment. There should be ongoing communication between the referring and primary physician.
Patient Education
Patients should be educated about the difference between impairment and disability. They should also be directed to resources that can educate them about the disability process.
Follow-Up
Follow-up with the primary physician and consultants will be based on the patient’s medical problems.
HELPFUL INTERNET SITES
• http://www.nhchc.org/wp-content/uploads/2012/02/DocumentingDisability2007.pdf
• www.geriatric.theclinics.com
• www.who.int/classifications/icf/en/
• http://www.socialsecurity.gov/disability/professionals/bluebook/
REFERENCES
1. O’Connell JJ, Zevin BD, Quick PD. Documenting Disability: Simple Strategies for Medical Providers. The National Health Care for the Homeless Council. September 2007. http://www.nhchc.org/wp-content/uploads/2012/02/DocumentingDisability2007.pdf. Accessed June 1, 2014.
2. Rondinelli R. Guides to the evaluation of permanent impairment. 6th ed. Washington, DC: American Medical Association; 2007.
3. Cocchiarella L, Anderson GB. Guides to the evaluation of permanent impairment. 5th ed. Washington, DC: American Medical Association; 2001.
4. Social Security Administration. Disability Evaluation Under Social Security (Blue Book). http://www.socialsecurity.gov/disability/professionals/bluebook/. Accessed June 1, 2014.
5. National Council on Disability (NCD). The Current State of Health Care for People with Disabilities. http://www.ncd.gov/publications/2009/Sept302009/. Accessed June 16, 2014.
6. Brault M. Americans with disabilities: 2005. Washington, DC: U.S. Census Bureau; 2008.
7. Altman B, Bernstein A. Disability and health in the United States, 2001–2005. Hyattsville, MD: National Center for Health Statistics; 2008.
8. Centers for Disease Control and Prevention (CDC). Public Health and aging: projected prevalence of self-reported arthritis or chronic joint symptoms among persons aged >65 years—United States, 2005–2030. MMWR Morb Mortal Wkly Rep 2003;52:489.
| Pesticide and Related Poisoning |
GENERAL PRINCIPLES
Pesticides represent hundreds of chemicals mixed into thousands of formulations targeted at a specific pest, crop, or structure. They are used throughout the world in home, office, industrial, agricultural, and military applications. These chemicals are used in gaseous, liquid, and in solid forms. The range of chemicals includes organophosphates, organochlorides, carbamates, dipyridyls, chlorophenoxy compounds, anticoagulants, hydrocarbons, organic and inorganic compounds, and many more.1
Epidemiology
A person’s presence in an area where pesticides are used does not necessarily mean that there will be exposure. Exposure does not necessarily mean there will be adequate contact to produce the physiologic changes of poisoning. Poisoning may not automatically lead to impairment or disability. There is accumulating evidence to support that pesticide self-poisoning is one of the most commonly used methods of suicide worldwide, with approximately 250,000 deaths annually.2
Pathophysiology
As in all poisonings, time since exposure, dosage, and route of exposure (inhalation, ingestion, or absorption) will influence the effects on the patient’s systems. Organophosphates and carbamates are acetylcholinesterase inhibitors used in insecticides and nerve agents. This class of pesticides accounts for the majority of severe exposures due to its mechanism of action.1 Organophosphates immediately penetrate the central nervous system (CNS) and inactivate acetylcholinesterase, producing acute cholinergic symptoms from the accumulation of acetylcholine in the body. Inactivation is initially reversible, but becomes irreversible with time.3 The duration of the reversible period is based primarily on the agent of exposure. Treatment during this reversible phase greatly reduces systemic effects.4 Although organophosphates enter the CNS immediately, carbamates do not and their action on the enzyme is reversible leading to limited toxicity.
Symptoms
The effects of the increased acetylcholine are felt by the muscarinic and nicotinic receptors producing miosis and mydriasis, bradycardia or tachycardia, salivation, lacrimation, urination, nausea, vomiting, bronchorrhea, bronchospasm, weakness, hypertension, and diaphragmatic failure. The most life-threatening concerns are the bronchorrhea, bronchospasm, and respiratory insufficiency. Persons affected can also develop severe pancreatitis, which can be painless and fatal.5,6 Effects on the CNS include headache, confusion, delirium, seizures, and coma. Exercise caution as some pesticides may exhibit delayed onset of symptoms and signs. Organophosphates, for example, have a well-documented intermediate syndrome that can begin 2 to 4 days after initial symptoms have resolved and results in rapidly developing respiratory distress and failure often requiring ventilator support for up to 21 days after onset.7 The signs and symptoms of other pesticide and related poisonings vary and the diagnosis is many times made upon history alone.
DIAGNOSIS
Mild poisonings are associated with few symptoms and normal vital signs. Moderate poisonings are associated with more severe symptoms, objective signs, and normal vital signs. Severe poisonings are associated with multiple complaints, objective signs, and unstable vital signs. Whenever possible, physicians should learn the name of the chemical and its properties before embarking on nonemergency treatment. Sources include the safety data sheet (SDS), reference texts, poison control centers, telephone numbers on the pesticide container, TOXLINE, and MEDLINE. In suspected poisonings where the substance is not known and the clinical picture is confusing, consulting the poison control center and local toxicologists is highly recommended. In any poisoning, early communication with the poison control center is advisable as it will have the latest information on diagnosis and treatment.
History
• Contact the employer or applicator for the name of the formulation and the material SDS.
• Question how the exposure occurred, with emphasis on the exact mechanism of exposure, cause and effect relationship of exposure and symptoms, previous exposures and poisonings, and drug- or alcohol-related problems.
• Symptoms (and signs) may vary by the type of formulation to which the person was exposed, the length and concentration of exposure, and decontamination. Nausea, vomiting, and fatigue are common to most poisonings but may also represent other diseases as well as psychogenic illness. Symptoms may also be attributable to solvents used as the carriers for the pesticides, such as xylene, benzene, carbon tetrachloride, and several others.
Physical Examination
• Skin. Rashes should be carefully described and secondary changes caused by scratching and treatment documented. Halogenated hydrocarbons can produce chloracne, often confused with acne vulgaris.
• Respiratory. Inhalation of dusts, mists, and gases may cause instantaneous or delayed bronchospasm with only minimal reversibility.6
• Gastrointestinal (GI). Nausea, vomiting, diarrhea, and abdominal pain occur as a result of eating contaminated food or by direct ingestion of poison in attempted suicides and homicides.
• Neurologic. Acute or delayed polyneuropathy and chronic lapses in concentration and memory can result from exposure to organophosphates and halogenated hydrocarbons. Electroencephalogram abnormalities can be noted without frank seizure activity at even low levels of exposure to organophosphates and may require benzodiazepine administration for normalization.3
• Ocular. Sprays or mists to the eyes can cause problems ranging from simple conjunctivitis to corneal opacities.
Laboratory Tests
Laboratory tests are of limited usefulness and care should not be delayed waiting for them. Blood, liver, and kidney test results may be clouded by the presence of other diseases and may be abnormal only in the most severe poisonings. Cholinesterase (ChE) activity tests are useful only in organophosphate and carbamate poisoning and are most effective when used in a monitoring program for applicators where baselines have been established.4 These tests do have usefulness in tracking a return to normal function of ChE activity, and may guide longer term clinical treatment.8 Many military facilities are able to detect weaponized agents from samples and may represent a useful confirmatory tool for suspected exposures.
DIFFERENTIAL DIAGNOSIS
Until a specific agent is identified and confirmed as the cause of the exposure, a wide differential should be maintained. These can include many of the following general categories:
• Medication toxicity
• Viral syndromes
• Idiopathic epilepsy
• Non-pesticide toxin ingestion
TREATMENT
As previously stated, the cornerstone of pesticide treatment is decontamination, stabilization, and supportive care. In more severe cases, this may include airway and circulation support. Decontamination should not be ignored in the hospital setting. Many pesticides and nerve agents are formulated for persistence, placing medical workers at risk for contamination. Decontamination, both at the site and again upon arriving at a medical facility, should be considered a high priority to protect others from harm, especially if the exposure was during a terrorist or other malicious act, as these are more likely to involve weapon-grade chemicals. Inadvertent exposures from agricultural pesticides do not represent the same level of risk, and emergency medical treatment should not be delayed for extensive decontamination.4 Gastric elimination of the substance, if ingested, may be performed, but studies have shown no evidence of benefit, likely due to the rapid absorption of the agents involved.4 Mild poisonings may be able to be evaluated and followed on an outpatient basis, depending on the poison. Individuals may require only decontamination, reassurance, antiemetics for nausea and vomiting, and steroids for rash. Contact with the poison control centers will help determine whether this is an option, as many pesticides have delayed action and an initially stable patient may not remain so. Moderate symptoms (to include eye irritation without intense blepharospasms, minor skin erythema, and small blisters less than 2 cm in size) should be hospitalized and monitored for any deterioration in clinical condition.
Severe poisonings (from early eye irritation worsening to severe blepharospasm, obvious skin blister, weakness, neurologic involvement, and respiratory difficulty) require hospitalization and intensive physiologic support. Forced diuresis, exchange transfusion, and chelation are replete with complications and should be considered only when the patient’s condition is severe, on an inpatient basis, when the specific agent has been identified, and after consulting toxicology experts. Atropine is the hallmark of initial treatment in organophosphate and carbamate poisoning. Goal-directed therapy with atropine is aimed at increasing heart rate to over 80, systolic blood pressure to over 80, and minimizing bronchospasm and bronchorrhea.4 The initial dosage is 2 to 4 mg IV every 2 to 5 minutes as needed for control of airway secretions. Dosages as high as 70 mg in the first 30 minutes of therapy may be required.4 Nerve agent poisonings generally require less atropine than agricultural pesticides. More lipid-soluble poisons may require large doses of atropine (up to a total of 40 to 100 mg per day). Continuous IV infusion of atropine, starting at 0.05 mg/kg/hour and titrated, can also be used in severe cases.4
Pralidoxime (2-PAM) or obidoxime should be given to all symptomatic patients who require atropine. Oxime therapy allows for the reactivation of ChEs if it is given before irreversible binding of the toxin occurs (24 to 48 hours depending on the specific agent). Initial dosing is a 2-g loading dose given IV, then 1 g every 1 to 4 hours for 48 hours, then another 1 g every 4 hours until recovery.4
Benzodiazepines, specifically diazepam, should be used in cases of agitated delirium or in the event of seizure activity.4
Complications
As discussed earlier, organophosphate-induced intermediate syndrome may present 2 to 4 days after exposure and affects approximately 20% of patients with an oral exposure to organophosphates. Respiratory distress and failure may develop rapidly requiring ventilator support for as long as 21 days.7
Follow-Up
Serial examinations to follow chronic problems may be necessary, especially with neurologic and respiratory involvement. Work impairments and disability status must be documented.
SPECIAL CONSIDERATION
In jurisdictions where required, reports must be made to the appropriate agencies in accidental poisonings. Intentional poisoning and any suspected terrorist or malicious poisoning should be immediately reported to the appropriate authorities. Long-term exposure to organophosphates has the potential to cause adverse reproductive outcomes, certain malignancies, and cause neurodevelopmental issues. Women, especially those in agricultural settings, should receive counsel to avoid exposure during routine prenatal counseling.9–12
REFERENCES
1. Roberts JR, Karr CJ. Pesticide exposure in children. Pediatrics 2012;130(6):e1757–e1763.
2. Gunnell D, Eddleston M, Phillips M, et al. The global distribution of fatal pesticide self-poisoning: systematic review. BMC Public Health 2007;7:357.
3. Barthold CL, Schier JG. Organic phosphorus compounds—nerve agents. Crit Care Clin 2005;21(4):673–689.
4. Eddleston M, Buckley N, Eyer P, et al. Management of acute organophosphorus pesticide poisoning. Lancet 2008;371:597–607.
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