Renal amyloidosis overview

# Overview
Nicolaus Fontanus was the first to describe amyloidosis based on the result of an autopsy while Rudolph Virchow was the first to introduce the term amyloidosis. Renal amyloidosis can be classified according to the site of amyloid deposition into glomerular, vascular, and tubular amyloidosis. Suggested mechanisms of renal involvement include abnormal protein production or hereditary mutation. If left untreated, renal amyloidosis may progress into end stage renal disease. Common complications include chronic renal failure and nephrotic syndrome. After a few years, renal amyloidosis eventually leads to end stage renal disease and it may be progressed  in presence of certain factors such as steroid administration, renal vein thrombosis, infections and surgery. There is insufficient evidence to recommend routine screening for renal amyloidosis. Renal biopsy is the gold standard test for the diagnosis of renal diagnosis. The mainstay of treatment for renal amyloidosis is to decrease the production or increase clearing of amyloid. Pharmacologic medical therapies for renal amyloidosis include colchicine, azathioprine, dimethylsulfoxide, chlorambucil, methotrexate, cyclophosphamide and TNF-alpha antagonists (ie, etanercept, infliximab, and adalimumab).

# Historical Perspective
Nicolaus Fontanus was the first to describe amyloidosis based on the result of an autopsy while Rudolph Virchow was the first to introduce the term amyloidosis.

# Classification
Renal amyloidosis can be classified according to the site of amyloid deposition into glomerular, vascular, and tubular amyloidosis.

# Pathophysiology
Suggested mechanisms of renal involvement include abnormal protein production or hereditary mutation.

# Causes
Most common causes of renal amyloidosis include primary and secondary amyloidosis. Other causes include transthyretin and fibrinogen amyloid deposition.

# Differentiating Renal amyloidosis from Other Diseases

# Epidemiology and Demographics
The incidence is 97 to 140 cases per 100,000 individuals. The incidence of renal amyloidosis increases with age; the median age at diagnosis is 65 years.

# Risk Factors
Common risk factors in the development of renal amyloidosis may be environmental and genetic such as heterozygous mutations in the genes for lysozyme, apolipoprotein AI, apolipoprotein AII, or fibrinogen A alpha-chain.

# Screening
There is insufficient evidence to recommend routine screening for renal amyloidosis.

# Natural History, Complications, and Prognosis
If left untreated, renal amyloidosis may progress into end stage renal disease. Common complications include chronic renal failure and nephrotic syndrome. After a few years, renal amyloidosis eventually leads to end stage renal disease and it may be accelerated by some factors such as steroid administration, renal vein thrombosis, infections and surgery.

# Diagnosis

## Diagnostic Study of Choice
Renal biopsy is the gold standard test for the diagnosis of renal diagnosis

## History and Symptoms
The majority of patients with renal amyloidosis have proteinuria. Swelling is very common in lower limbs. Numbness or tingling in hands or feet (carpal tunnel syndrome) is a less common finding.

## Physical Examination
Physical examination of patients with renal amyloidosis is usually remarkable for swelling, hepatosplenomegaly, facial or neck purpura and macroglossia. Fatigue and unintentional weight loss, are common in patients with AL amyloidosis. Tachycardia/bradycardia depends on the accompanying complication. Pulmonary fine crackles, faint pulmonary auscultation, suggestive of pleural effusion, decreased tactile fremitus and dull percussion.

## Laboratory Findings
In patients with secondary amyloidosis, urinalysis should be routinely examined. Laboratory findings consistent with the diagnosis of renal amyloidosis include proteinuria and increased serum creatinine

## Electrocardiogram
There are no ECG findings associated with renal amyloidosis.

## X-ray
There are no definitive findings on x-ray associated with renal amyloidosis.

## Echocardiography and Ultrasound
There are no echocardiography/ultrasound findings associated with renal amyloidosis

## CT scan
There are no CT scan findings associated with renal amyloidosis

## MRI
There are no MRI findings associated with renal amyloidosis.

## Other Imaging Findings
There are no other imaging findings associated with renal amyloidosis

## Other Diagnostic Studies
Kidney biopsy can represent amyloid deposition as vascular, tubulo-interstitial and/or glomerular deposits. All types of amyloidogenic proteins show affinity for Congo red dye.

# Treatment

## Medical Therapy
The mainstay of treatment for renal amyloidosis is to decrease the production or increase clearing of amyloid. Pharmacologic medical therapies for renal amyloidosis include colchicine, azathioprine, dimethylsulfoxide, chlorambucil, methotrexate, cyclophosphamide and TNF-alpha antagonists (ie, etanercept, infliximab, and adalimumab).

## Surgery
In renal amyloidosis, surgery is usually reserved for patients developed with end stage renal disease. The patients with renal amyloidosis are good candidates for transplantation. In primary amyloidosis, renal transplantation is considered and it will improve long-term survival and quality of life.

## Primary Prevention
There are no established measures for the primary prevention of renal amyloidosis.

## Secondary Prevention
Treatment of the primary disease and underlying cause will provide favorable renal outcome.