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.

Typhus Fever


Related Terms

  • Brill's Disease
  • Brill-Zinsser Disease
  • Epidemic Typhus
  • Flea-borne Typhus
  • Louse-borne Typhus
  • Mite-borne Typhus
  • Murine Typhus
  • Rat Typhus
  • Recurrent Typhus
  • Scrub Typhus
  • Tsutsugamushi Disease
  • Typhus

Differential Diagnosis

Specialists

  • Cardiologist, Cardiovascular Physician
  • Gastroenterologist
  • Hematologist
  • Infectious Disease Internist
  • Internal Medicine Physician
  • Nephrologist
  • Neurologist
  • Ophthalmologist
  • Pulmonologist

Comorbid Conditions

  • Compromised immune system

Factors Influencing Duration

Factors that may influence the length of disability include the type and severity of typhus, the stage of the disease at beginning of treatment, response to treatment, and development of complications. Elderly individuals and those with compromised immune systems have longer recovery periods and increased risk of mortality.

Medical Codes

ICD-9-CM:
081.0 - Typhus, Other; Murine Typhus, Typhus: Endemic, Flea-borne
081.1 - Typhus, Other; Brills Disease; Brill-Zinsser Disease; Recrudescent Typhus (Fever)
081.2 - Typhus, Scrub; Japanese River Fever, Kedani Fever, Mite-borne Typhus, Tsutsugamushi
081.9 - Typhus Fever, Unspecified; Typhus NOS

Overview

Typhus fever or typhus is an acute infection caused by various species of the bacteria Rickettsia. Forms of typhus depend on the particular species of bacteria responsible for the infection.

Epidemic typhus is caused by Rickettsia prowazekii and is transmitted from human to human by the body louse. Rickettsia bacteria may remain in the body for months or years after treatment. When epidemic typhus recurs several years after the initial attack, this condition is called Brill-Zinsser disease. Native (endemic), mouse (murine), and flea-borne typhus (caused by Rickettsia typhi) are spread to humans by mouse or rat fleas. Mites infected with Orienta (formerly Rickettsia) tsutsugamushi spread scrub typhus or tsutsugamushi disease.

The various forms of typhus have abrupt onsets with typical incubation periods of 1 to 2 weeks. Epidemic typhus outbreaks typically occur where people are crowded together in unsanitary conditions (times of war, military camps, or natural disasters). Outbreaks are more prevalent in the winter months when blankets are shared and more clothing is worn. The disease is serious and can be fatal, particularly in the elderly.

Endemic typhus is primarily an urban disease occurring in late summer to early autumn. Control of the rodent population and associated flea problems is essential in managing this disease.

Scrub typhus occurs primarily in Asia and the Western Pacific. Americans are only affected if they travel to parts of the world where this disease exists.

A typhus vaccine is available, but it does not provide complete immunity to infection. It does, however, substantially reduce the severity of the disease.

Incidence and Prevalence: Epidemic typhus is very rare in the US; only about 15 cases are reported annually (Hansen). Epidemic typhus outbreaks still occur in other parts of the world, particularly in the highlands and cold sections of Africa, Asia, and Central and South America. About 100 cases of endemic typhus are reported in the US each year, although this form tends to be under-reported. Most cases occur in the Gulf States, particularly in south Texas. Scrub typhus does not occur in the US, so the only US cases arise from travelers who are infected overseas. Scrub typhus occurs only on the Indian subcontinent, on some islands in the western Pacific and in northern Australia.

Source: Medical Disability Advisor



Causation and Known Risk Factors

Individuals who live in crowded conditions with poor sanitation and rodent control, and who share clothing and blankets are at higher risk of contracting typhus. Incomplete antibiotic treatment increases the risk of reappearance of the disease after an apparent cure (Brill-Zissner disease).

Source: Medical Disability Advisor



Diagnosis

History: Individuals with typhus may indicate a history of crowded living conditions or relocation to refugee camps because of natural disaster or war. They may also report flea bite. Individuals often report severe headache, nonproductive cough, nausea, muscle aches (myalgia), chest pain, and a general feeling of illness (malaise). These are followed by a sudden onset of chills, high fever, and extreme fatigue (prostration) that may progress to delirium and stupor. At around 4 to 7 days, a rash may appear on the trunk that spreads across most of the body, but rarely involves the face, palms, and soles.

With scrub typhus, the individual may report a black, crusted bite, tender lymph nodes, eye pain and redness (conjunctivitis), and a short-term rash. However, symptoms of scrub typhus are milder and less specific than other forms of typhus, making this disease difficult to diagnose, especially since it is rare in the US.

Physical exam: Rash is the major physical finding upon physical examination. Lymph nodes may be enlarged. The individual may show signs of delirium or stupor. Typhus affects many organs, including the intestines, liver, heart, kidneys, and brain. As these organs are affected, corresponding pathology may include constipation, pneumonia, enlargement of the liver or spleen (splenomegaly), kidney damage (renal failure), or slowed heartbeat (bradycardia).

With scrub typhus, the site of the bite becomes a black, crusted area. Nodes may be enlarged not only in the vicinity of the bite (regional) but also throughout the body (generalized adenopathy).

Tests: Typhus is diagnosed primarily from history and symptoms. Blood tests (serologic tests) are used to assess severity and exclude other possible diagnoses. Specific tests (complement fixation, immunofluorescence) performed on blood serum drawn 5 to 12 days after onset of symptoms can detect antibodies for Rickettsia prowazekii, but treatment usually begins before this test can be performed.

With scrub typhus, the rickettsial organism may be identified by injecting a laboratory animal with blood drawn during the first few days of illness (mouse inoculation). Although tests identifying antirickettsial antibodies (fluorescein-labeled antirickettsial assays) are preferred over complement fixation tests (tests that determine if antigen-antibody reactions have occurred), a process investigating genetic material (polymerase chain reaction, or PCR) is the most sensitive method of diagnosis.

Chest x-rays show evidence of lung involvement. Blood (hematuria) and protein (proteinuria) are usually evident in the urine. In some cases, particularly when scrub typhus is suspected, fluid from the spinal column (cerebrospinal fluid or CSF) may reveal low numbers of mononuclear immune cells. Blood tests can also reveal abnormalities that reflect the involvement of other organs.

Source: Medical Disability Advisor



Treatment

Typhus is treated with antibiotics. Medication may also be prescribed to reduce fever (antipyretics) and relieve muscle aches (analgesics). Severe headaches may require a narcotic pain reliever. Bed rest is necessary for recovery. Any remaining lice, fleas, or mites should be removed and the individual isolated in a clean environment free from rodents. Supportive care may be necessary depending on the involvement of other organ systems. Although symptoms may recur, they are usually responsive to antibiotic therapy.

Source: Medical Disability Advisor



Prognosis

Even though typhus is effectively treated with antibiotics, outcome still depends on age and immunization status. With prompt, appropriate treatment, most individuals recover completely. Death is uncommon with treatment. The fatality rate for epidemic typhus varies considerably and is reported as 1% to 20%. Vaccination can change a potentially serious disease into a mild one.

Without treatment fever may last 2 weeks, followed by a prolonged recovery time and a significantly greater chance of developing complications. The mortality in untreated epidemic typhus can be as high as 60%, especially in the elderly. Untreated scrub typhus is associated with a mortality rate of approximately 30%. Endemic typhus has a lower mortality rate of 1% to 2% in untreated cases.

Source: Medical Disability Advisor



Complications

Complications associated with typhus vary depending on the organ systems involved. Possible complications include diminished blood volume (hypovolemia), vessel inflammation (vasculitis) resulting in obstruction and gangrene, blood clots (thrombosis), circulatory collapse, uremia (a toxic condition associated with renal failure), kidney failure, inflammation of the heart muscle (myocarditis), heart failure, liver infection, pneumonia, respiratory failure, deafness, delirium, coma, inflammation of the spinal column and / or brain (meningoencephalitis, encephalitis), seizures, shock, and death.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Although in uncomplicated cases symptoms usually subside within 2 weeks, fatigue and lack of stamina may continue for several months. Reassignment to lighter physical duties may be necessary. In individuals not properly diagnosed or treated, nervous and mental symptoms may persist long after the acute phase subsides. In these cases, work restrictions and accommodations require consideration on a case-by-case basis.

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 experience symptoms of abrupt onset fever, severe headache, nonproductive cough, nausea, muscle aches (myalgia), chest pain, and malaise?
  • Was a rash noted on the physical exam?
  • Was the diagnosis of typhus fever confirmed with serologic tests by the presence of antibodies for Rickettsia prowazekii?
  • Were other febrile diseases (i.e., Rocky Mountain spotted fever, meningococcemia, bacterial meningitis, Boutonneuse fever, measles, rubella, toxoplasmosis, leptospirosis, typhoid fever, Dengue fever, relapsing fever, secondary syphilis, and infectious mononucleosis) eliminated as causative factors?

Regarding treatment:

  • How soon after onset of symptoms was treatment with antibiotics initiated?
  • What was the response to treatment?
  • Is individual following the doctor's orders with regard to bed rest and activity limitations?
  • If individual is unable to adequately care for himself/herself, is inpatient care being considered?

Regarding prognosis:

  • Have all symptoms resolved? If not, what impairment remains?
  • Was individual isolated from the causative fleas, lice, or mites?
  • Is it possible that individual was reinfected?
  • Would additional antibiotic therapy be appropriate at this time?
  • Were underlying conditions such as immunosuppression that may impact recovery identified or ruled out?
  • Have complications occurred, such as organ dysfunction, systemic infection, or shock, that can impact recovery and prognosis?

Source: Medical Disability Advisor



References

Cited

Hansen, Eric, and Burke A. Cunha. "Typhus." eMedicine. Eds. John M. Leedom, et al. 10 Jan. 2003. Medscape. 5 Jan. 2005 <http://emedicine.com/med/topic2332.htm>.

Source: Medical Disability Advisor






Feedback
Send us comments, suggestions, corrections, or anything you would like us to hear. If you are not logged in, you must include your email address, in order for us to respond. We cannot, unfortunately, respond to every comment. If you are seeking medical advice, please contact your physician. Thank you!
Send this comment to:
Sales Customer Support Content Development
 
This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is published with the understanding that the author, editors, and publisher are not engaged in rendering medical, legal, accounting or other professional service. If medical, legal, or other expert assistance is required, the service of a competent professional should be sought. We are unable to respond to requests for advice. Any Sales inquiries should include an email address or other means of communication.