Beta-2 microglobulin related amyloidosis
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Synonyms and keywords:Dialysis related amyloidosis, 2-microglobulin amyloidosis,  2 amyloidosis, Amyloidosis due to dialysis, Amyloidosis due to Beta 2 microglobulin

# Overview
In 1975, Warren and Otieno were thee first to discover the association between 2-microglobulin related amyloidosis and Carpal tunnel syndrome. In 1985, Gejyo et al. identified 2-microglobulin as the protein precursor of the amyloid associated with chronic hemodialysis. There is no established system for the classification of beta2-microglobulin related amyloidosis. The exact pathogenesis of 2-microglobulin related amyloidosis is not fully understood.

# Historical Perspective
- In 1975, Warren and Otieno were thee first to discover the association between 2-microglobulin related amyloidosis and Carpal tunnel syndrome.
- In 1985, Gejyo et al. identified 2-microglobulin as the protein precursor of the amyloid associated with chronic hemodialysis.
- In 1993, advanced glycation end products were first implicated in the pathogenesis of 2-microglobulin related amyloidosis by Miyata et al.

# Classification
There is no established system for the classification of beta2-microglobulin related amyloidosis.

# Pathophysiology
- The exact pathogenesis of 2-microglobulin related amyloidosis is not fully understood.
- Advanced glycation end products can be responsible for 2-microglobulin deposition.

# Causes
The exact cause of 2-microglobulin related amyloidosis has not been identified.

# Differentiating 2-Microglobulin Related Amyloidosis from other Diseases
2-microglobulin related amyloidosis must be differentiated from other diseases that cause joint pain and joint stiffness, such as bursitis and Carpal tunnel syndrome.

# Epidemiology and Demographics
- The exact incidence/prevalence of 2-microglobulin related amyloidosis can not be determined as the biopsy is the only way to find out the diagnosis and can not be done in every patient undergoing hemodialysis.
- In a prospective postmortem study, amyloid deposition in joints was found in 21% of patients receiving hemodialysis for  13 years.
- The incidence of 2-microglobulin related amyloidosis increases with age especially in patients on chronic dialysis.
- It can be seen in as much as 20% of patients after 24 years of dialysis and in 100% of patients after 13 years of hemodialysis.
- There is no racial predilection to 2-microglobulin related amyloidosis.

# Risk Factors
The most potent risk factor in the development of  beta2-microglobulin related amyloidosis is chronic Hemodialysis. Other risk factors include initiation of dialysis in young age, hemodialysis treatment with low purity dialysate and use of dialysis membranes with low flux.

# Screening
There is insufficient evidence to recommend routine screening for beta2-microglobulin related amyloidosis

# Natural History, Complications, and Prognosis
- Common complications of beta2-microglobulin related amyloidosis include bone complications that comprises carpal tunnel syndrome, chronic arthropathy like spondyloarthropathy, presence of subchondral bone cysts and pathological fracture.
- Pulmonary complications include Pulmonary hypertension
- Cardiac complications are rare but include heart failure and Mitral regurgitation.

# Diagnosis

## Diagnostic Study of Choice
- The diagnostic study of choice is biopsy which is considered the gold standard diagnostic technique.
- The diagnosis of 2-microglobulin related amyloidosis is made with the combination of clincal and radiological features where biopsy is not or can't be performed.

## History and Symptoms
- The majority of patients with beta2 microglobulin related amyloidosis initially are asymptomatic.
- A positive history of chronic hemodialysis expressing Carpal tunnel syndrome is suggestive of beta2 microglobulin related amyloidosis. The most common symptoms of  2-microglobulin related amyloidosis include joint pain, tingling; enlargement of the tongue, dysphonia,Dysphagia and Dysgeusia(when gastrointestinal tract is involved)

## Physical Examination
Common physical examination findings of beta2 microglobulin related amyloidosis include Tinel's sign.

## Laboratory Findings
- There are no diagnostic laboratory findings associated with beta2-microglobulin related amyloidosis.

## Electrocardiogram
- There are no ECG findings associated with beta2-microglobulin related amyloidosis.

## X-ray
- An x-ray may be helpful in the diagnosis of beta2-microglobulin related amyloidosis. Findings on an x-ray suggestive of beta2-microglobulin related amyloidosis include radiolucent lesions or bone cysts, frequently with thin sclerotic margins.

## Echocardiography
- Echocardiography may be helpful in the diagnosis of . Findings on an echocardiography suggestive of beta2-microglobulin related amyloidosis include findings of heart failure and Mitral regurgitation.
- For more findings of echocardiography of cardiac amyloidosis due to beta2-microglobulin related amyloidosis, please click here.

## CT scan
- CT scan may be helpful in the diagnosis of beta2-microglobulin related amyloidosis. Findings on CT scan suggestive of beta2-microglobulin related amyloidosis include , , and .

## MRI
- MRI may be helpful in the diagnosis of beta2-microglobulin related amyloidosis Findings on MRI suggestive of beta2-microglobulin related amyloidosis include , , and .

## Other Imaging Findings
- Scintigraphy may be helpful in the diagnosis of beta2-microglobulin related amyloidosis. Findings suggestive of beta2-microglobulin related amyloidosis include amyloid deposits in the carpal tunnel.

## Other Diagnostic Studies
- Biopsy is helpful in the diagnosis of beta2-microglobulin related amyloidosis . Findings diagnostic of beta2-microglobulin related amyloidosis include apple-green birefringence under polarized light when prestained with Congo red.

# Treatment

## Medical Therapy
- The mainstay of treatment for beta2-microglobulin related amyloidosis is Kidney transplantation
- Those who are not able to get a kidney transplant needs Hemodialysis with high flux membrane and dialysate

## Surgery
- Surgical intervention is not recommended for the management of beta2-microglobulin related amyloidosis.
- Arthroscopic surgery done in the cases with joint infiltration with B2 microglobulin where removal of synovium provides relief.

## Primary Prevention
- There are no established measures for the primary prevention of beta2-microglobulin related amyloidosis.
- Effective measures for the primary prevention of beta2-microglobulin related amyloidosis include kidney transplant as soon as available.

## Secondary Prevention
- Effective measures for the secondary prevention of beta2-microglobulin related amyloidosis include avoiding the use of low flux membrane, clearing dialysate regularly, performing DEXA scan.