Systemic mastocytosis
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Systemic mastocytosis is a rare disorder characterized by the overproduction of mast cells, a type of white blood cell crucial for immune response. Normally, mast cells protect against disease by responding to allergens and other threats. In systemic mastocytosis, however, these cells abnormally multiply, leading to accumulation in various body parts such as skin, bone marrow, and digestive tract. This often results in symptoms similar to allergic reactions and severe inflammation that can cause organ damage. Common triggers include alcohol, spicy foods, insect stings, and certain medications.
While there is no cure for systemic mastocytosis, symptoms and complications are manageable. Most people experience mild symptoms manageable with medication and avoidance of triggers. However, symptoms may worsen or progress to cancer in some cases. All individuals with this condition face an increased risk of anaphylaxis, a severe, life-threatening allergic reaction.
There are six types of systemic mastocytosis, each varying in presentation and severity:
- Indolent systemic mastocytosis: The most common form, characterized by a gradual increase in abnormal mast cells affecting the skin, liver, spleen, and gastrointestinal tract. Symptoms develop slowly over several years, and most individuals manage these with medication, maintaining normal lifespans.
- Mast cell leukemia: A rare progression of systemic mastocytosis to acute myeloid leukemia.
- Systemic smoldering mastocytosis: In this type, abnormal mast cells proliferate primarily in the liver and spleen, potentially leading to organ enlargement.
- Mast cell sarcoma: Very rare, this involves tumors composed of abnormal mast cells that aggressively invade tissues.
- Systemic mastocytosis with associated hematologic neoplasm: This form coexists with blood disorders like myeloproliferative neoplasms and myelodysplastic syndrome, affecting approximately one-fifth of those diagnosed.
- Aggressive systemic mastocytosis: Abnormal mast cells in the bone marrow disrupt blood cell production, causing conditions such as leukopenia and anemia, and may infiltrate bones, increasing fracture risk.
Each type of systemic mastocytosis poses different challenges and risks, generally correlating the severity of symptoms to the quantity of abnormal mast cells present.
Symptoms
Symptoms of systemic mastocytosis vary depending on the location where the excess mast cells accumulate. For instance, if they cluster in the stomach, it may result in the development of ulcers and abdominal discomfort. Occasionally, individuals with this condition may experience a sudden onset of multiple symptoms, only to have them dissipate afterward. Healthcare professionals may refer to this occurrence as a mastocytosis attack.
Common signs and symptoms include:
- Maculopapular skin lesions, or flat, red patches with several tiny bumps on it
- Bleeding disorders, bruising or anemia
- Hives, itching, or flushed face
- Diarrhea, vomiting, nausea, or abdominal pain
- Muscle and bone aches
- Swollen lymph nodes, the liver, or the spleen
- Depression, mood swings or difficulty focusing
- Extreme fatigue
Excess mast cells can accumulate in various parts of the body, including the skin, liver, spleen, bone marrow, and intestines. Sometimes, less common organs like the brain, heart, or lungs can also be affected by this buildup.
Experiencing symptoms like flushing, hives, or digestive issues does not automatically mean one have systemic mastocytosis, as these symptoms can be caused by other conditions too. However, if the symptoms are consistently experienced together or if they persist, it is essential to consult a healthcare provider for proper diagnosis and treatment.
Causes
Most cases of systemic mastocytosis, a condition where excessive mast cells accumulate in tissues and organs causing inflammation, are linked to a mutation in the KIT gene. This mutation, which is found in about 80% of affected individuals, is not inherited but occurs after conception. The KIT gene is crucial for the development of various cell types, including blood cells and mast cells. The mutation leads to the overproduction of mast cells, which release inflammatory substances like histamine, leukotrienes, and cytokines, contributing to the symptoms of the disease.
Diagnosis
The diagnosis of systemic mastocytosis often involves discussing one’s medical history and medications, assessing the symptoms experienced as well as ordering several tests.
Tests that may be required include:
- Blood or urine tests: These can check the levels of tryptase, an enzyme released by mast cells during reactions to invaders.
- Bone marrow biopsy: This can examine for abnormal mast cell numbers in the bone marrow.
- Imaging tests: To detect any bone damage, an X-ray, ultrasound, bone scan and computed tomography (CT) scan may be required.
- Genetic testing: These are done to identify mutations in the KIT gene.
- Other tests: Skin biopsy and biopsy of organs affected by the disease, such as the liver can help confirm the diagnosis.
Treatment
The treatment approach for systemic mastocytosis typically revolves around symptom and complication management, alongside regular monitoring. Treatment strategies also vary depending on the type of mastocytosis and the organs affected. For instance, if excessive stomach acid is problematic, healthcare providers may prescribe H-2 blockers (antacids) to relieve symptoms. Conversely, if the condition results in anemia, treatment will target that specific concern.
Treatment approaches include:
- Avoiding triggers: To prevent systemic mastocytosis attacks, steer clear of spicy foods, alcohol, specific medications, and activities that trigger them. These triggers differ from person to person, so it is crucial to identify them. If certain medications triggers the condition, wearing a medical alert bracelet with details about medications to avoid can help ensure that one receives appropriate treatment in case of emergencies.
- Medications: This may include antihistamines to alleviate itching and flushing, as well as steroids to reduce inflammation. Bisphosphonates can also help address bone weakness commonly associated with the condition. Using an epinephrine injection in cases of severe allergic reaction may also be necessary.
- Bone marrow transplantation: For severe or advanced cases, bone marrow transplantation may be considered, offering a chance for a cure. This is often recommended for patients with mast cell leukemia, an advanced type of systemic mastocytosis.
- Chemotherapy: Chemotherapy drugs are used to reduce the number of mast cells in patients with aggressive systemic mastocytosis, systemic mastocytosis coupled with another blood condition, and mast cell leukemia.
- Frequent monitoring: Bone density may require regular monitoring to watch for issues like osteoporosis and ensure timely intervention if needed. Blood and urine tests may also be done regularly to keep track of the condition and understand how a person is affected by the condition.
