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.

Nephritis, Interstitial


Related Terms

  • Acute Interstitial (Allergic) Nephritis
  • Balkan Nephropathy
  • Papillary Necrosis
  • Pyelonephritis
  • Tubulointerstitial Nephritis

Differential Diagnosis

Specialists

  • Nephrologist
  • Urologist

Comorbid Conditions

Factors Influencing Duration

Length of disability may be influenced by the underlying cause of the condition, the extent and severity of the disease at initial presentation, the effectiveness of treatment, the age of the individual, and the presence of hypertension or complications.

Medical Codes

ICD-9-CM:
583.89 - Nephritis and Nephropathy, Other; Exudative or Interstitial
590.00 - Pyelonephritis, Chronic, without Lesion of Renal Medullary Necrosis
590.01 - Pyelonephritis, Chronic, with lesion of Renal Medullary Necrosis
590.10 - Pyelonephritis, Acute, without Lesion of Renal Medullary Necrosis
590.11 - Pyelonephritis, Acute, with Lesion of Renal Medullary Necrosis

Overview

Interstitial nephritis is an inflammation of the tubules and the spaces between the tubules and the glomeruli in the kidney, almost without involvement of the glomeruli and renal vessels. The condition may be a temporary lesion, or it may be chronic and progressive.

Acute interstitial nephritis causes reduction in kidney function, ranging from mild impairment to acute kidney failure. Signs of acute renal failure, such as decreased urine output (oliguria), may occur in about half of acute interstitial nephritis cases. The kidney may fail to concentrate the urine when water intake is reduced creating an alteration of the acid/base balance in the body. Failure to excrete appropriate acid in the urine may cause acid build-up in the blood (metabolic acidosis) to occur. The disorder may progress to chronic renal failure (CRF) or end-stage renal disease (ESRD).

Incidence and Prevalence: Primary tubulointerstitial diseases constitute 10 to 15% of all cases of renal diseases both in the US and internationally (Alper).

Source: Medical Disability Advisor



Causation and Known Risk Factors

Acute interstitial nephritis is most often caused by an allergic reaction to a drug or as a side effect of certain medications such as antibiotics, diuretics, anticonvulsants, and nonsteroidal anti-inflammatory drugs (NSAIDs); the condition may occur two or more weeks after exposure to the medication. It may also be caused by infections, autoimmune disorders, and acute obstructive disorders. Chronic interstitial nephritis can be caused by vesicoureteral reflux, reflux nephropathy, genetic disorders (drepanocytosis), metabolic disorders, and chronic exposure to toxins or certain therapeutic drugs such as heavy metals (including lead, cadmium, and mercury), aristolochic acid (Chinese herbal nephropathy and Balkan endemic nephropathy), cyclosporine, and tacrolimus.

Source: Medical Disability Advisor



Diagnosis

History: Symptoms are usually those of renal failure. The individual may report increased or decreased urine output (polyuria or oliguria), abnormally excessive nocturnal urination (nocturia), nausea, vomiting, swelling of the body (any area), weight gain (from fluid retention), and drowsiness or confusion. There may be fever, a rash, and blood in the urine (hematuria).

Physical exam: The physical exam may reveal edema, or fluid overload, or signs of volume depletion, with abnormal sounds heard when examining with a stethoscope. There may be hematuria, fever, nausea, and mental changes, ranging from drowsiness to confusion to coma. Blood pressure is often high (hypertension).

Tests: Urinalysis may reveal the presence of red blood cells (RBC) in the urine (hematuria), increased protein (proteinuria), renal tubular cells, and other abnormalities. A complete blood count (CBC) may reveal eosinophilia (higher than normal count of eosinophils, a type of white blood cell). A failure to concentrate urine even when water intake is restricted may be revealed with urine specific gravity and osmolality tests. Urine pH may show a failure to acidify urine properly. Arterial gases and blood chemistry may reveal metabolic acidosis. BUN (blood urea nitrogen) and creatine levels are measured to assess the level of kidney functioning.

The diagnosis of interstitial nephritis and degree of damage to the kidney may be confirmed with a kidney biopsy.

Source: Medical Disability Advisor



Treatment

If the acute interstitial nephritis is caused by a specific drug, the drug should be discontinued or changed or the dosage modified. Corticosteroids or anti-inflammatory medications such as cyclophosphamide may help in some cases. A restriction of protein in the diet may be needed to control accumulation of nitrogenous waste products in the blood (azotemia) associated with acute renal failure; restriction of fluid and sodium in the diet may also be needed.

Dialysis may be required for a short time.

Source: Medical Disability Advisor



Prognosis

The outcome depends on the cause or type of the nephritis. Most individuals with acute interstitial nephritis recover completely. Individuals with prolonged and severe acute interstitial nephritis may progress to renal failure.

Although most individuals with chronic interstitial nephritis will recover some function with treatment, a few individuals will progress to chronic renal failure.

Source: Medical Disability Advisor



Rehabilitation

An exercise rehabilitation program under the direction of a physician may benefit individuals who are receiving dialysis treatment.

Source: Medical Disability Advisor



Complications

Complications include acute and chronic renal failure.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

An extended leave of absence may be required. Upon returning to work, the individual may need to work part-time hours for a short period, and periodic rest breaks will need to be scheduled. Individuals receiving dialysis may need to be reassigned to sedentary duties on the days of treatment.

Risk: Upon return to work, individuals with acute interstitial nephritis may require temporary work restrictions for safety reasons if drowsiness or confusion persists. Work-related activities should not pose a risk to individuals with chronic interstitial nephritis. Exceptions would be industries with exposures to known kidney toxins. However, encephalopathy for safety reasons work restrictions may be appropriate for individuals with mental cloudiness or dizziness and for those who develop hypertensive encephalopathy. Concomitant presence of poorly controlled hypertension, heart failure, or ascites may require a preclusion from heavy or very heavy work.

Capacity: In acute conditions, capacity may be temporarily reduced secondary to malaise. Individuals with resulting chronic renal failure who normally perform heavy or very heavy work may require job reassignment. Individuals with advanced chronic interstitial nephritis may have decreased capacity secondary to dyspnea, renal failure, severe anemia, or CHF. Physician-prescribed work limitations may be appropriate for individuals with these complications. Objective testing with stress ECHO would be helpful.

Tolerance: Tolerance for physical activity may be reduced during recovery. Once an acute episode of interstitial nephritis has resolved, tolerance is unlikely to be a concern. In chronic interstitial nephritis, tolerance may be affected by malaise and fatigue caused by disease-related sleep impairments, altered dialysis schedules, or the uremic effects on the blood.

Source: Medical Disability Advisor



Maximum Medical Improvement

180 days.

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 a recent change in medication regimen? Did individual have fever, rash, or hematuria?
  • Has individual used analgesics chronically or abused analgesics?
  • Was individual exposed to heavy metals such as lead, mercury, or cadmium?
  • Did individual receive appropriate testing to confirm the diagnosis?
  • Were conditions such as tumors, diabetes, renal tuberculosis, and chronic obstructive uropathy ruled out?

Regarding treatment:

  • What was the underlying cause? Was it corrected?
  • Did individual require dialysis?

Regarding prognosis:

  • Can individual's employer accommodate part-time work?
  • Was individual compliant with restrictions in diet?
  • Does individual have any conditions such as lupus nephritis, Sjögren's syndrome, mixed cryoglobulinemia, crescentic glomerulonephritis, IgA nephropathy, Wegener's granulomatosis, congestive heart failure, hypertension, systemic lupus erythematosus, diabetes mellitus, or thyrotoxicosis?
  • Did individual have any complications such as acute or chronic renal failure?

Source: Medical Disability Advisor



References

Cited

Alper, A. Brent, et al. "Tubulointerstitial Nephritis." eMedicine. 23 Jan. 2015. Medscape. 27 Apr. 2015 <http://emedicine.medscape.com/article/243597-overview>.

Source: Medical Disability Advisor






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