Sign-in
(your email):
(case sensitive):



 
 

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.

Porphyria


Text Only Home | Graphic-Rich Site | Overview | Risk and Causation | Diagnosis | Treatment | Prognosis | Differential Diagnosis | Specialists | Rehabilitation | Comorbid Conditions | Complications | Factors Influencing Duration | Length of Disability | Ability to Work | Failure to Recover | Medical Codes | References

Medical Codes

ICD-9-CM:
277.1 - Porphyria

Related Terms

  • Acute Intermittent Porphyria
  • Congenital Erythropoietic Porphyria
  • Erythropoietic Protoporphyria
  • Hereditary Coproporphyria
  • Porphyria Cutanea Tarda
  • Proporphyria
  • Variegate Porphyria

Overview

Porphyrias are a group of disorders caused by abnormalities in the synthesis of heme, the oxygen-carrying molecule of blood. This results in the overproduction of a toxic intermediate, porphyrin. Heme is produced primarily in the liver and by red blood cell precursors in the bone marrow. Porphyrias can be classified by the site of porphyrin overproduction: bone marrow (erythropoietic), liver (hepatic), or both.

The three most common porphyrias are: acute intermittent porphyria (AIP, acute abdominal symptoms with or without neurological symptoms), porphyria cutanea tarda (PCT, chronic sensitivity of the skin to light with severe blister formation, no neurological symptoms), and erythropoietic protoporphyria (EPP, acute pain and swelling of the skin with exposure to light, no neurological symptoms).

Incidence and Prevalence: Acute intermittent porphyria occurs in individuals of all races but is probably most common in northern Europeans, with an estimated prevalence of about 5 cases per 100,000 individuals (Anderson 1123). In northern Europe and North America, approximately 1 individual in 10,000 carries the gene for acute intermittent porphyria. Although acute intermittent porphyria varies widely, estimated incidence is generally 1 case per 100,000 individuals. The number of cases of erythropoietic porphyria worldwide is less than 200 total (Matthews).

Source: Medical Disability Advisor



Causation and Known Risk Factors

Most porphyrias are inherited in an autosomal dominant pattern but environmental factors can cause worsening of symptoms. Acute intermittent porphyria attacks can be precipitated by decreased intake of carbohydrates and calories; ingestion of progesterone, barbiturates, or sulfonamides; and smoking.

Porphyria cutanea tarda (PCT), the most common porphyria, can be inherited or acquired and is more common in men than women. Individuals with inherited PCT may experience worsening of symptoms after ingestion of alcohol, estrogen, iron, or certain medications (some NSAIDs, sulfonylureas). Smoking and infection with hepatitis C or HIV are other known risk factors. Acquired cases resembling PCT have been reported after exposure to fungicides and dioxin.

Erythropoietic porphyria (EP) is inherited as an autosomal recessive trait, and symptoms usually begin in childhood.

Source: Medical Disability Advisor



Diagnosis

History: Acute intermittent porphyria is characterized by attacks of abdominal pain, nausea, vomiting, and constipation. The attacks may be accompanied by neurological symptoms ranging from muscle weakness to depression, hallucinations, paranoia and seizures. Attacks can be precipitated by decreased intake of carbohydrates and calories; ingestion of progesterone, barbiturates, or sulfonamides; and smoking.

In porphyria cutanea tarda, the most common and easily treated type of porphyria, the individual's skin is extremely sensitive to light. This photosensitivity is chronic and can lead severe blister formation. There are no abdominal or neurological symptoms. Individuals with inherited PCT may experience worsening of symptoms after ingestion of alcohol, estrogen, iron, or certain medications (certain NSAIDs and sulfonylureas); smoking; or infection with hepatitis. Acquired cases resembling PCT have been reported after exposure to fungicides and dioxin.

Symptoms of erythropoietic protoporphyria usually begin in childhood and include acute pain and swelling of the skin with exposure to light. There are no abdominal or neurological symptoms.

Physical exam: Physical findings depend on the type of porphyria. During attacks of acute intermittent porphyria, symptoms such as high blood pressure, restlessness, sweating, abnormal reflexes, and muscle weakness may occur. With porphyria cutanea tarda, blisters or ulcers occur in sun-exposed areas; there may be residual thickening and scarring of the skin.

Tests: Blood, urine, and stool are tested for abnormal levels of porphyrins and porphyrin precursors. Red blood cells may also be tested for abnormalities in the enzymes involved in heme production.

Source: Medical Disability Advisor



Treatment

In general, porphyrias are treated using preventive measures, such as avoiding precipitating factors (sunlight and certain drugs) and supportive therapy, such as drugs for relief of pain and nausea. Screening and genetic counseling is recommended for family members.

Attacks of acute intermittent porphyria often require hospitalization for treatment of pain, nausea, and vomiting. Early intravenous therapy with heme products (hematin, heme albumin) and carbohydrate loading is important. Complications such as seizures, severely elevated blood pressure (hypertension), rapid heartbeat (tachycardia), and problems with breathing (respiratory failure) are easier to monitor in the hospital setting. Affected individuals should avoid weight loss diets since decreased intake of carbohydrates and calories can precipitate an attack.

Porphyria cutanea tarda is associated with excess iron; an effective treatment is depletion of the body's iron by repeated blood removal through a vein (phlebotomy). This can be done on an outpatient basis. Deferoxamine, an iron chelator, is also used, but is less effective than phlebotomy. Chloroquine or hydroxychloroquine can be used in individuals where phlebotomy is contraindicated.

Beta-carotene is highly effective in the treatment of EPP.

Source: Medical Disability Advisor



Prognosis

Prevention is crucial in controlling acute intermittent porphyria. With preventive measures and appropriate treatment of attacks, the outlook for individuals with AIP is good. Recurrent attacks do occur in some individuals but this is uncommon. If chronic symptoms and depression develop, good psychiatric care is essential.

Source: Medical Disability Advisor



Differential Diagnosis

Source: Medical Disability Advisor



Specialists

  • Hematologist
  • Internal Medicine Physician
  • Neurologist
  • Psychiatrist

Source: Medical Disability Advisor



Rehabilitation

Rehabilitation for porphyria depends on the residual effects of the condition. However, the general goal of rehabilitation for individuals who complain of weakness from the disease is to improve function and enhance mobility. If joint stiffness occurs, range of motion (ROM) exercises begin with passive ROM exercises in which the therapist moves the body part without effort; movement is initiated by the individual. Active-assisted ROM exercises are then initiated in which the individual performs some of the motion/effort with the help of the therapist. As the individual improves with increased motion of the joint, active ROM exercises are introduced where the individual performs all the motion independently.

Strengthening is initiated with isometric exercises in which the muscles around the involved joint contract without any movement taking place, and is progressed to exercises that involve joint movement (isotonic exercises). The physical therapist may need to modify this regimen for individuals taking medication for porphyria or who have arthritis or other joint irritations.

Source: Medical Disability Advisor



Comorbid Conditions

  • Depression
  • Infection
  • Seizure disorders

Source: Medical Disability Advisor



Complications

Complications depend on the type of porphyria and may include peripheral neuropathy associated with muscle weakness, kidney dysfunction, scarring of the skin, and skin infections. Hypertension, tachycardia, psychiatric disturbances, or seizures may accompany attacks of acute intermittent porphyria.

Source: Medical Disability Advisor



Factors Influencing Duration

Disability from porphyria is highly variable. Acute attacks usually resolve rapidly. Duration depends on the type of porphyria and any complications. Scarring of the skin, established neuropathy with associated muscle weakness, poor response to treatment, and other medical illnesses can influence the length of disability.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Individuals with a history of seizures need a safe environment. Those with photosensitivity need to avoid sunlight by working indoors and using protective cotton clothing. Sunscreens do not protect the skin of individuals with porphyria. Conditions that could further damage fragile skin, such as putting pressure on bony prominences, or exposure to cleaning solutions or other chemicals, should be avoided. Individuals should wear a Medic-Alert bracelet or other identification that tells healthcare providers of their condition in case of an accident or an attack at work. Regular meal times should be scheduled to avoid attacks precipitated by fasting.

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:

  • Does individual have symptoms and history characteristic of a type of porphyria?
  • Was thorough investigation of family history, medication history, and alcohol use done in the initial evaluation?
  • Would individual benefit from consultation with specialist?
  • Did analysis of porphyrin levels in blood, urine, or stool confirm diagnosis?
  • If diagnosis was uncertain, were other conditions with similar symptoms ruled out?

Regarding treatment:

  • Have triggering factors been identified?
  • Has individual been compliant with preventive measures?
  • Was supportive care given to relieve associated symptoms?
  • Was hospitalization required?
  • Were family members screened for disorder and counseled as appropriate?

Regarding prognosis:

  • Was appropriate treatment received?
  • Did individual have pre-existing conditions that may have influenced ability to recover and length of disability?
  • Did individual have complications that may have influenced ability to recover?

Source: Medical Disability Advisor



References

Cited

Anderson, K. E. "The Porphyrias." Cecil Textbook of Medicine. Eds. Lee Goldman and J. Claude Bennett. 21st ed. Philadelphia: W.B. Saunders, 2000. 1123-1130.

Matthews, Jeanette H., and Maureen B. Poh-Fitzpatrick. "Erythropoietic Porphyria." eMedicine. 22 May. 2002. Medscape. 22 Feb. 2005 <http://emedicine.com/derm/topic145.htm>.

Source: Medical Disability Advisor