Overview Of Acquired Lipodystrophy
Acquired lipodystrophy refers to types of lipodystrophy that are not genetic/inherited. Instead, they are acquired during the course of the person’s life. Lipodystrophy is the name for a set of disorders. Theu involve either the total or partial loss of adipose (fat) tissue in the body. How severe and where the loss occurs can vary among the different types of lipodystrophies. This disorder also goes by the name lipoatrophy.
In contrast to genetic forms, any number of different factors can cause acquired lipodystrophy. Some examples of these causes include an autoimmune disorder, various medications, or even randomly (idiopathic is the term for a disorder stemming from something unknown).
This disorder can occur at any stage in life. Those with the disorder typically lose body fat in specific regions of the body, especially the legs, arms, neck, face, chest, or thoracic regions.
Sometimes, other symptoms can occur. For example, insulin resistance-associated complications can occur – these include glucose intolerance (the inability to break down glucose), higher than normal levels of triglycerides in the blood (triglycerides are a specific type of fat, andhypertriglyceridemia is when their levels are too high in the blood), and diabetes.
Another example is the accumulation of fat in the liver (hepatic steatosis or fatty liver) that can occur in some people.
Some examples of subtypes of the disorder include:
- Acquired generalized lipodystrophy (Lawrence syndrome)
- Acquired partial lipodystrophy (Barraquer-Simons syndrome)
- Localized lipodystrophy
- High active antiretroviral induced lipodystrophy, which often occurs in HIV-infected people undergoing treatment
Causes Of Acquired Lipodystrophy
The major symptom of acquired lipodystrophy is the either complete or partial loss of adipose tissue. Fat cells called adipocytes make up adipose tissue itself. Each one of these cells is around 90% liquid fat storage. This liquid storage hold fats known as triglycerides.
When acquired lipodystrophy damages adipose tissue, proper fat storage cannot occur as it usually does. Typical adipose tissue storage areas lose fat because of this. The body can store the fat improperly in the wrong areas, such as the skeletal muscles or the liver. This can cause symptoms such as insulin resistance and liver disease.
The main role of adipose tissue is to store fat to later use for energy. However, another important function of adipose tissue is the secretion of a variety of substances. They are involved with/influence various types of hormonal functions.
A variety of different mechanisms can cause acquired lipodystrophy, including autoimmune conditions, medications, or other factors that are not possible to narrow down. One important facet of the condition is that in order to qualify as acquired lipodystrophy, the condition must not be genetic in any way.
Subtypes of Acquired Lipodystrophy
Acquired generalized lipodystrophy (AGL) is one common subtype of the disorder. It often occurs after an infection or autoimmune condition. Infections that frequently precede the onset of AGL include measles, varicella, osteomyelitis, pertussis, pneumonia, infectious mononucleosis, diphtheria, and parotitis. Autoimmune disorders linked to AGL include Sjogren’s syndrome, autoimmune hepatitis, autoimmune hemolytic anemia, juvenile dermatomyositis, rheumatoid arthritis, autoimmune thyroiditis, and Sicca syndrome. In many cases, though, the cause of AGL remains unknown.
It is thought thatthe immune system mistakenly destroying fat cells (officially called the “autoimmune-mediated destruction of adipocytes”) causes acquired partial lipodystrophy (APL). More than 80% of patients with APL have low blood levels of the protein factor known as complement 3, which helps aid the body’s immune response. Patients with APL also have an autoantibody within them (autoantibodies are immune proteins that accidentally target and destroy or damage healthy tissue by mistake) called the complement 3-nephritic factor.
Localized lipodystrophy is the last type of acquired lipodystrophy listed. Several different types of injections below the skin (into subcutaneous tissue) can cause it. One notable example is the injection of insulin. Pressure-caused problems, called panniculitis, can also results in localized lipodystrophy.
AGL usually affects a majority of organs and body systems, whereas APL often affects specific areas, such as the chest, arms, neck, and face. APL sufferers often experience a loss of fat from the upper body and extremities, and then an accumulation of fat into their lower bodies. APL also does not particularly associate with metabolic problems or conditions.
With any type of acquired lipodystrophy, doctors often see hyperphagia (excessive eating due to an unusually high appetite) as a generalized symptom. Acromegaly is also common, along with a hormonal imbalance. Scattered areas of skin changes that are dark in appearance also occur. Biologically female patients with AGL have a predisposition to develop polycystic ovarian syndrome (PCOS).
Medical professionals diagnose lipodystrophy that is local to specific parts of the body by an examination of the surface of the skin. One or more pits or protrusions on the skin, usually limited to small areas, are signifiers of the disorder. Despite appearances, the condition does not affect the skin itself. The appearance is due to abnormal fat deposits under the skin in those specific areas.
Treatment Of Acquired Lipodystrophy
Generally speaking, there are no effective treatments currently available that stop the progression of lipodystrophy. Most treatments consist of cosmetic or dietary options. However, an important aspect of medical care for this condition is the treatment of associated problems (comorbidities) that accompany it. Unfortunately, associated conditions often don’t have cures either, only treatments for the symptoms.
For those with metabolic conditions, metformin, lifestyle changes (such as exercise and diet), fibrates, or statins are often prescribed. Insulin and other treatments for diabetes (such as thiazolidinediones and metformin) could also be used if needed.
Lastly, for those with leptin deficiency associated with acquired lipodystrophy, they may take metreleptin, which will replace the missing leptin in their bodies.
Diagnosis and Testing
Medical professionals use a wide range of information when it comes to diagnosing acquired lipodystrophy. Typically, a health care provider will perform a clinical exam, examine the patient for characteristic symptoms, take a detailed patient health history, and perform a variety of specialized tests before they diagnose a patient with acquired lipodystrophy.
When diagnosing AGL, the provider will look out for a generalized lack of fat during childhood, the presence of panniculitis, or an autoimmune disorder. With APL, they will also look for a preceding autoimmune disorder, along with a progressive loss of fat from the upper region of the body that doesn’t affect the lower body in those under the age of 16.
A variety of tests will rule out other possible conditions and/or help with the diagnosis of acquired lipodystrophy. These include:
- A renal biopsy or surgical removal of kidney tissue to examine under a microscope and check for kidney involvement in those with suspected APL.
- Tests for levels of various chemicals that are normally within the blood. Patients with APL can have normal C1 and C4 levels, decreased serum C3 levels, and high levels of the autoantibody C3NeF. For AGL, some patients can have low serum C4 levels.
- A blood chemical profile to assess the levels of lipids, glucose, uric acid, and liver enzymes in the body.
- An MRI (magnetic resonance imaging) to check for the characteristic pattern of fat loss typical to acquired lipodystrophy.