Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Job Classification

In most duration tables, five job classifications are displayed. These job classifications are based on the amount of physical effort required to perform the work. The classifications correspond to the Strength Factor classifications described in the United States Department of Labor's Dictionary of Occupational Titles. The following definitions are quoted directly from that publication.

Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Influenza


Medical Codes

ICD-9-CM:
487.0 - Influenza with Pneumonia
487.1 - Influenza with Other Respiratory Manifestations; Influenza NEC
487.8 - Influenza with Other Manifestations

Related Terms

  • Flu
  • Influenza B
  • Influenza, A H1N1 Virus

Overview

Influenza is an acute respiratory infection caused by one of three types of influenza viruses in the Orthomyxoviridae family of viruses. The symptoms, severity, and length of disability attributed to influenza are variable, ranging from fever and fatigue to respiratory failure. Influenza should not be confused with the stomach flu, which is a gastrointestinal condition, not a respiratory condition.

Influenza viruses are designated types A, B, and C. Type A and type B influenza usually occur during the flu season (November to April in the northern hemisphere). They are the more common and more serious forms and are associated with higher rates of hospitalization and death. Type C influenza is a milder type of respiratory infection that often does not cause any symptoms. Types A and B influenza viruses mutate frequently, so new influenza vaccines are developed annually in anticipation of the expected predominant strain(s). Type C virus is fairly stable. Although immunization against influenza (annual flu shots) can help protect anyone during flu season, it is most important for individuals at highest risk to receive annual vaccination. Those individuals allergic to eggs should not receive annual flu shots because the vaccine is cultured in eggs.

Influenza is highly contagious. Spread occurs through airborne respiratory droplets containing the virus. After contact, the affected individual may begin to experience symptoms within 18 to 72 hours; onset can be abrupt (Derlet). Influenza occurs more frequently and severely in smokers or in anyone with compromised respiratory function (e.g., seizure disorders, neuromuscular disorders, or spinal cord injury) ("People"). The highest morbidity and mortality rates are reported among the elderly and infants, whose immune system functioning is not adequate. Individuals with chronic medical conditions such as asthma, chronic obstructive pulmonary disease (COPD) (chronic bronchitis, emphysema), chronic heart disease, diabetes, severe anemia, and kidney dysfunction, are prone to complications of influenza, as are individuals who are immunosuppressed.

Influenza is well known as a cause for epidemics in closed groups, including children in schools and the elderly in long-term care facilities, as well as entire communities or whole countries. Occasionally, there are worldwide pandemics due either to important mutations of a strain of the influenza virus (antigenic drift), or worse, to combinations of genes from a strain of the influenza virus with genes from other strain of influenza virus or from other virus either from humans or from animals (antigenic shift). Epidemics in temperate climates occur during the winter months, but in tropical climates, they can occur at any time.

For information about the A H1N1 influenza pandemic, please refer to Influenza, A H1N1.

Incidence and Prevalence: Influenza is responsible for thousands of deaths each year, the majority of which are among those aged 65 and older, but those who are younger than 65 are by no means immune. Among adults aged 19 to 64 years, an estimated annual average of 666 deaths (range: 173 in 1981–82 to 1,459 in 2004–05). The number of influenza-related hospitalizations varies widely from season to season ("Estimates").

Source: Medical Disability Advisor



Diagnosis

History: Common to almost all cases of influenza are fever and systemic symptoms, followed by upper and lower respiratory symptoms several days later. Individuals may report an abrupt onset of fever, chills, headache, muscle aches (myalgia), joint pain, cough, sore throat, runny nose, and fatigue. Some individuals may have diarrhea, nausea, and vomiting. When the systemic symptoms such as chills, fever, myalgia, and fatigue subside somewhat, respiratory symptoms may become dominant as the infection progresses.

Physical exam: Upon examination, individuals may seem weary and tired. Their skin may feel warm, and they may have a fever of 101° F to 104° F (38.8° C to 40° C). A runny nose may be evident. The mucous membrane of the throat may appear reddened. Lymph nodes in the neck may be slightly swollen. Accurate diagnosis of influenza is not always possible based on symptom evaluation alone since several other viruses can cause flu-like symptoms, including adenovirus, enterovirus, and paramyxovirus. However, identifying the specific causative virus is not always done since treatment for upper respiratory tract infection (URTI) is fairly standard ("Estimates").

Tests: Diagnosis of influenza is based primarily on the medical history (symptoms) and physical examination (signs), particularly in the setting of a confirmed influenza outbreak in the community. Viral cultures of material from the nose and throat can be definitive for diagnosing influenza A and B; however, they are expensive and require 24 hours minimum for results. They generally do not influence the type of treatment provided, and are not always performed. Definitive serologic tests and immunofluorescent tests can be performed in the diagnostic laboratory, but they are labor-intensive, time-consuming, and less sensitive than cultures. Rapid tests are also available for diagnosis of influenza. These require a throat or nasal swab sample and can sometimes be helpful in determining whether a patient should receive antiviral treatment. Although test sensitivity for these rapid methods is 50% to 70%, false negatives for influenza A and B are common (“Rapid Diagnostic”). For these reasons, during a local outbreak of influenza, the diagnosis is most often made based on symptoms and physical examination alone.

Arterial blood gases (ABG) may be performed in hospitalized individuals whose breathing is compromised or whose oxygen level is low when monitored. Lumbar puncture may be done to rule out possible meningitis suggested by physical exam findings.

A chest x-ray may be indicated in individuals who are at high-risk of developing pneumonia, including individuals with COPD, the elderly, and the immunosuppressed, or in the individual with abnormalities detected on physical exam.

Source: Medical Disability Advisor



Treatment

Supportive treatment includes rest, fluids, painkillers (analgesics), fever-reducing medications (antipyretics), and cough suppressants (antitussives), if necessary. Antibiotics are not warranted unless a concomitant bacterial infection is confirmed or strongly suspected. Overexertion during symptomatic illness should be avoided.

Antiviral medications may be used to treat influenza A and B. Two antiviral drugs are recommended by the CDC and approved by the FDA for flu treatment. These are oseltamivir (brand name Tamiflu®) and zanamivir (brand name Relenza®). Use of these drugs significantly reduces severity and duration of flu symptoms and reduces complications in high-risk groups. Studies show that flu antiviral drugs work best when they are started within 2 days of development of symptoms. However, starting them later can still be helpful, especially if the sick individual has a high-risk health condition or is very sick from the flu (“Treating”).

Influenza can be prevented, or its symptoms reduced, by yearly vaccination. The vaccine is effective against the most common strains of influenza A and B strains. Influenza vaccine is recommended for all individuals over age 6 months, with rare exceptions (e.g., severe egg allergy). The type of vaccine that should be given varies depending on the age and health status of the individual. Individuals at high risk of developing complications due to influenza infection are most strongly encouraged to get an annual vaccination.

Source: Medical Disability Advisor



Prognosis

In healthy young and middle-aged adults, full recovery from influenza with no residual effects can be expected in several days. In older adults and those with underlying pulmonary and cardiac disease, recovery may be prolonged, and the outcome may leave them in a partially disabled condition by worsening their underlying chronic disease process.

The body can be so weakened by influenza that its defenses against bacteria are low. In influenza complicated by bacterial pneumonia, full recovery is expected in healthy young and middle-aged adults. Those who might contract the more serious primary viral influenza pneumonia are at risk of prolonged disability. If they are hospitalized because of respiratory failure, there is a mortality rate of 50%.

Source: Medical Disability Advisor



Differential Diagnosis

Source: Medical Disability Advisor



Specialists

  • Infectious Disease Internist
  • Internal Medicine Physician
  • Pulmonologist

Source: Medical Disability Advisor



Comorbid Conditions

Source: Medical Disability Advisor



Complications

Three types of pneumonia can occur as complications to influenza: viral, bacterial, and mixed viral and bacterial.

Influenza viral pneumonia occurs most frequently in individuals with underlying pulmonary or cardiac disease and in those who are immunosuppressed. It has a rapid, debilitating onset that may require hospitalization. If the pneumonia worsens, it may result in respiratory failure and death. The mortality rate for those with respiratory failure is close to 50%.

Secondary bacterial pneumonia follows a different course. It affects mostly the drug abusers who use nonsterile needles, hospitalized individuals, and those with chronic medical diseases. Generally, bacterial pneumonia can develop about 5 days after viral influenza. Bacterial pneumonia can be treated with antibiotics.

Mixed viral and bacterial pneumonia generally involves a milder form of viral pneumonia combined with a bacterial pneumonia. The condition will respond at least partially to antibiotic therapy.

Other nonpulmonary complications are rare in adults but can occur. These include toxic shock syndrome, inflammation of the membrane enveloping the brain and spinal cord (meningitis), inflammation in the brain (encephalitis), and inflammation of the heart muscle or lining (myocarditis or pericarditis).

Source: Medical Disability Advisor



Factors Influencing Duration

Factors that affect the length of disability include the age of the individual, any underlying chronic medical conditions, the individual's immune response, the severity of the symptoms, the type of influenza virus causing the infection, the number and severity of complications, the individual's compliance with medical treatment, the stage of illness at which medical intervention was begun, and the type of work to which the individual must return.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Because of the ease with which influenza is transmitted, individuals should stay home until body temperature has returned to normal.

Risk: In an immune compromised individual, working with heavy public contact, indigent or incarcerated populations, or in health care settings, may place the individual at increased risk of further or recurrent infection. An individual with symptom onset within the last 24-48 hours is at a more infectious state and should avoid working in settings with immune compromised individuals. Some risk can be mitigated by frequent hand washing, gloves or masks.

Capacity: During active infection, capacity will be reduced related to the type and severity. Once healed, capacity should return to pre-illness state. Capacity can be evaluated with pulmonary function tests (PFT) and stress testing.

Tolerance: Patients generally require 6 weeks after completion of treatment or resolution of infection to feel they have recovered their baseline pre-infection abilities. Milder infections may be managed with over the counter analgesics which may permit an earlier return to work in recovering individuals.

Source: Medical Disability Advisor



Failure to Recover

If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case.

Regarding diagnosis:

  • Did individual have an influenza immunization this year?
  • Does individual have respiratory symptoms?
  • Is individual a smoker?
  • Does individual have asthma, COPD (chronic bronchitis, emphysema), chronic heart disease, diabetes, severe anemia, kidney dysfunction or are immunosuppressed?
  • Did individual have an abrupt onset of fever, chills, headache, muscle aches, joint pain, sore throat, runny nose, and fatigue?
  • Does individual also have diarrhea, nausea, and vomiting?
  • Have respiratory symptoms become dominant?
  • On exam, did individual have a fever of 101° F to 104° F (38.8° C to 40° C)?
  • Does individual have a runny nose, red throat, or swollen lymph nodes?
  • Has individual had a chest x-ray?
  • Have conditions with similar symptoms been ruled out?
  • Has individual been seen by a specialist?

Regarding treatment:

  • Is individual receiving symptomatic treatment such as rest, fluids, analgesics, antipyretics, and cough suppressants, if necessary?
  • Did individual seek treatment within 48 hours of the onset of symptoms?
  • Is individual being treated with an antiviral medication?

Regarding prognosis:

  • Does individual have any conditions that may affect the ability to recover?
  • Does individual have any complications, such as viral, bacterial, or mixed viral and bacterial pneumonia resulting in respiratory failure? Does the individual have toxic shock syndrome, meningitis, encephalitis, carditis, or pericarditis?

Source: Medical Disability Advisor



References

Cited

"Estimates of Deaths Associated with Seasonal Influenza --- United States, 1976-2007." Morbidity and Mortality Weekly Report 59 (2010): 1057-1062.

"People at High Risk of Developing Flu-related Complications." CDC. 7 Nov. 2013. Centers for Disease Control and Prevention. 22 Jun. 2014 <http://www.cdc.gov/flu/about/disease/high_risk.htm>.

"Rapid Diagnostic Testing for Influenza: Information for Clinical Laboratory Directors." CDC. 10 Jul. 2013. Centers for Disease Control and Prevention. 22 Jun. 2014 <http://www.cdc.gov/flu/professionals/diagnosis/rapidlab.htm>.

"Treating Influenza." CDC. 12 Jul. 2012. Centers for Disease Control and Prevention. 22 Jun. 2014 <http://www.cdc.gov/flu/pdf/freeresources/updated/treating_flu.pdf>.

Derlet, Robert W., et al. "Influenza." eMedicine. Eds. Michael Stuart Bronze, et al. 17 Mar. 2014. Medscape. 22 Jun. 2014 <http://emedicine.medscape.com/article/219557-overview>.

Source: Medical Disability Advisor