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17 August 2011

Eosinophilia

An eosinophil is a type of white blood cell that is produced in the bone marrow. These cells, which are normally found in the bloodstream and gastrointestinal tract, produce proteins that help the body fight against infections from parasitic organisms like hookworms.

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BACKGROUND

An eosinophil is a type of white blood cell that is produced in the bone marrow. These cells, which are normally found in the bloodstream and gastrointestinal tract, produce proteins that help the body fight against infections from parasitic organisms like hookworms.

Eosinophilia is a condition that develops when there are too many eosinophils in the bloodstream or body tissues. Eosinophils make up about 1-3% of a healthy person's white blood cells, which is about 350 to 650 eosinophils per cubic millimeter of blood. Eosinophilia can be mild (less than 1,500 eosinophils per cubic millimeter), moderate (1,500 to 5,000 per cubic millimeter) or severe (more than 5,000 per cubic millimeter).

Many disorders can cause eosinophilia. Parasitic infections (like hookworm schistosomiasis), allergic conditions (like asthma and hay fever), immune disorders (like Churg-Strauss syndrome), Hodgkin's disease, Addison's disease and drug reactions are responsible for most cases of eosinophilia.

TYPES AND CAUSES

Pulmonary eosinophilia: Pulmonary eosinophilia, also known as Loffler's syndrome or pulmonary infiltrates with eosinophilia, is inflammation in one or more areas of the lungs, which is associated with an increase in eosinophils.

Many cases are idiopathic (have no known cause). However, most cases are the result of an allergic reaction to a medication, such as aspirin or antibiotics. It can also be caused by a parasitic infection, (usually caused by the worm Ascaris lumbricoides), although it is rare.

Pulmonary eosinophilia usually resolves without treatment. However, relapses may occur.

Eosinophilic esophagitis: Eosinophilic esophagitis occurs when the lining of the esophagus becomes inflamed as a result of an increased number of eosinophils. Eosinophilic esophagitis affects both children and adults. For unknown reasons, men are more commonly affected than women.

The most common cause of eosinophilic esophagitis is acid reflux. Less common causes include oral mediations that get stuck in the esophagus.

Eosinophilic gastroenteritis (EG): Eosinophilic gastroenteritis (EG) is a rare digestive disorder that occurs when the gastrointestinal tract (stomach, small intestine and large intestine) are inflamed as a result of an increase in the number of eosinophils. Since 1937, when the condition was first described, there have been 280 cases of eosinophilic gastroenteritis reported in the United States, according to medical literature.

Eosinophilic gastroenteritis is considered idiopathic because the exact cause is unknown.

Eosinophilic meningitis: Eosinophilic meningitis is an infection in the meninges (membranes that cover the spinal cord and brain) that is characterized by a high number of eosinophils in the cerebral spinal fluid (CSF). It is defined by the presence of 10 or more eosinophils/microL in the cerebrospinal fluid (CSF).

Most cases are caused by the parasite known as Angiostrongylus cantonensis, (the rat lungworm). Individuals can become infected with the parasite by ingesting its larvae in raw or undercooked snails, slugs, frogs, freshwater prawns or fish. It may also be acquired by ingesting contaminated produce, such as lettuce. Once the larvae are ingested, they enter the intestines and go into the blood vessels. Eventually, the larvae reach the meninges (membranes that cover the brain and spinal cord). The larvae usually die soon after. However, an eosinophilic reaction occurs in response to the dying larvae. Large numbers of eosinophils enter the CSF to destroy the invading larvae.

Most cases of eosinophilic meningitis that are caused by the rat lungworm are reported in Southeast Asia and the Pacific Basin. However, in 2002, 12 young adults developed the disease after returning to the United States from Jamaica. Nine of the patients were hospitalized.

Idiopathic hypereosinophilic syndrome (HES): Idiopathic hypereosinophilic syndrome (HES) refers to a group of leukoproliferative disorders, which are characterized by an overproduction of eosinophils that causes tissue and organ damage.

Patients are diagnosed with HES when they have an eosinophil counter greater than 1,500 per microL of blood for longer than six months. In addition there must not be any other explanation for eosinophilia, and patients must have symptoms of organ involvement.

The exact incidence of HES is unknown because it is a diagnosis of exclusion.

SYMPTOMS

Pulmonary eosinophilia: In most cases, pulmonary eosinophilia is not a serious medical condition. The main symptom is a persistent cough. Other symptoms include fever, chest pain, shortness of breath, wheezing, respiratory distress, rapid breathing and rash. A rare but serious complication of pulmonary eosinophilia is acute eosinophilic pneumonia (AEP), which may result in pulmonary failure. AEP occurs most often in people who smoke.

Eosinophilic esophagitis: The most common symptom among adults is dysphagia (difficulty swallowing). Other symptoms may include heartburn and chest pain. Children often experience abdominal pain, coughing, nausea and vomiting.

Eosinophilic gastroenteritis: Symptoms often include abdominal pain, weight loss, nausea, vomiting and diarrhea (with or without blood).

Eosinophilic meningitis: Common symptoms include headache, neck pain, loss of vision (temporary), and hyperesthesias (increased sensitivity). Most cases resolve without medical complications. However, there have been rare reports of neurological sequelae (like cerebral palsy).

Idiopathic hypereosinophilic syndrome (HES): Symptoms vary from person to person. Symptoms may arise simultaneously or individually. Virtually any organ system can be involved. Reported symptoms include, chest pain, dyspnea (shortness of breath), orthopnea (difficulty breathing unless standing upright), fatigue, anemia, stroke, encephalopathy (degenerative brain disease), slurred speech, decreased motor abilities and muscle coordination, angioedema, cough, pulmonary fibrosis, rhinitis, arthralgia (joint pain), myalgia (general discomfort), diarrhea, nausea, night sweats, heart murmur, restrictive heart disease and rales (crackling sound in the chest as a result of fluid in the alveoli).

DIAGNOSIS

Complete blood count: A complete blood count may be performed to detect an increased number of eosinophils in the blood. A blood sample is taken from the patient and analyzed under a microscope in a laboratory.

Bronchoscopy: A bronchoscopy may be performed to help diagnose pulmonary eosinophilia. During the test, a bronchoscope (thin, flexible tube with a camera) is inserted into the esophagus, through the mouth. The test allows the healthcare provider to look inside the lungs and remove a small amount of lung tissue (biopsy) for analysis. If the patient has pulmonary eosinophilia, the lung tissue will show elevated numbers of eosinophils.

Chest X-ray: A chest x-ray may be conducted to confirm a diagnosis of pulmonary eosinophilia. Chest X-rays of patients with pulmonary eosinophilia will show abnormal shadows (infiltrates) in the lungs, similar to pneumonia.

Sputum analysis: If the physician suspects a parasitic infection is causing eosinophilia, the patient's sputum can be analyzed under a microscope to determine whether larvae of the parasitic worm are present.

Endoscopy (EDG): When a patient experiences dysphagia, a physician will usually conduct an endoscopy (EDG) to determine the cause. During the EGD, a flexible tube with a camera (endoscope) is inserted through the mouth and into the esophagus. The healthcare provider is able to view the inner lining of the esophagus. Patients who have eosinophilic esophagitis may have a narrow esophagus. Others may have several abnormal rings of tissue along the esophagus (similar to a Schatzki ring). If the doctor suspects eosinophilia after the EDG is performed, a biopsy will be conducted to confirm the diagnosis.

Biopsy: The healthcare provider will insert long thin biopsy forceps through the endoscope tube. A small tissue sample is removed from the esophagus and analyzed under a microscope to determine whether eosinophils are present.

Biopsy: A qualified healthcare provider will perform a tissue biopsy to determine whether an increased number of eosinophils are present in the gastrointestinal tract. During the procedure a needle is inserted into the patient's gastrointestinal tract, and a small tissue sample is removed. The sample is then analyzed under a microscope for the presence of eosinophils.

Lumbar puncture: A qualified healthcare provider may conduct a lumbar puncture (spinal tap) to determine whether there is an elevated number of eosinophils present in the CSF. During the procedure, a local anesthetic is injected into the lower back. Then a needle is inserted between the third and fourth vertebrae, and a small amount of fluid is extracted. The CSF is then analyzed under a microscope to confirm a diagnosis.

Sputum analysis: If the physician suspects a parasitic infection is causing eosinophilia, the patient's sputum can be analyzed under a microscope to determine whether larvae of the parasitic worm are present.

Biopsy: A biopsy may be performed to determine whether there are an increased number of eosinophils in the organs. During the procedure a small piece of tissue is removed and analyzed under a microscope for the presence of eosinophils.

TREATMENT

General: In most cases, pulmonary eosinophilia improves without treatment, typically within a few months. If eosinophilia is a reaction to medication, discontinuing the treatment usually resolves the condition.

Corticosteroids: Corticosteroids like prednisone have been used to reduce inflammation associated with pulmonary eosinophilia. Treatment generally lasts about six months. After one to two weeks of treatment, a low-dose of corticosteroids is administered until symptoms improve.

Esophageal dilation: Gentle esophageal dilation has been performed in patients with eosinophilic esophagitis. During the procedure, a qualified healthcare provider stretches the strictures of the esophagus with an endoscope, flexible dilators of different width or with balloons that are inserted into the esophagus through the endoscope tube. If balloons are used, they are inflated next to the structures of the esophagus. This procedure will make it easier for solid food pass through the esophagus.

Proton pump inhibitors: Proton pump inhibitors like Protonix©, Nexium©, Aciphex©, Prevacid©, Prilosec© and Zegarid© have been used to treat acid reflux by reducing the amount of acid produced in the stomach. These medications are often prescribed because acid reflux may aggravate the symptoms of eosinophilia esophagitis.

Fluticasone propionate: Fluticasone propionate (Flovent©) has been used to decrease inflammation in the esophagus. The medication is administered with an inhaler. However, patients do not inhale the medication into the lungs. Instead, the medication is deposited into the mouth and swallowed with water, usually twice daily for several weeks. Patients should abstain from food or water for two hours after taking the medication. Patients should rinse their mouths after every use to prevent thrush (a fungal infection of the mouth). Treatment duration varies from days to weeks, depending on the severity of the symptoms.

Corticosteroids: Corticosteroids like prednisone have been used to reduce inflammation associated with eosinophilic gastroenteritis.

Mast cell stabilizers: Mast cell stabilizers like cromolyn (Intal© or Gastrocrom©) have been used to inhibit the release of histamine, which reduces allergic symptoms such as inflammation. Cromolyn is FDA-approved for adults and children older than five years of age.

Leukotriene receptor antagonists: Leukotriene receptor antagonists like montelukast (Singulair©) have been used to reduce inflammation. Montelukast is approved by the FDA.

Anthelmintics: Anthelmintics like Albendazole (Albenza©), ivermectin (Stromectol©), niclosamide (Niclocide ©), mebendazole (Vermox©), diethylcarbamazine (Hetrazan©) and thiabendazole (Mintezol©) have been used to kill parasitic worms that cause eosinophilic meningitis. Treatment generally lasts about three weeks.

Corticosteroids: Corticosteroids like dexamethasone (Decadron© or Dexone©) have been used to reduce inflammation in the meninges, which is associated with eosinophilic meningitis. Treatment generally lasts about two weeks. Corticosteroids may increase the risk of severe infections.

Corticosteroids: Corticosteroids like prednisone (Deltasone©, Meticorten© or Orasone©) are most often used to treat HES. The medication decreases inflammation and reduces the number of eosinophils in the body.

Immunomodulators: Immunomodulators like interferon alfa-2a (Roferon-A©) and interferon alfa-2b (Intron A©) have been used to suppress the production of eosinophils.

INTEGRATIVE THERAPIES

Oregano: Early study shows that taking oregano by mouth may help get rid of parasites. Further research is needed to confirm these results. Research suggests that oregano is well tolerated in recommended doses. Avoid if allergic or hypersensitive to oregano or to other herbs from the Lamiaceae family including hyssop, basil marjoram, mint, sage and lavender. Use cautiously with diabetes and bleeding disorders because oregano may increase the risk of bleeding or decrease blood sugar levels. Pregnant or breastfeeding women should not consume oregano at doses above those normally found in food.

Zinc: In a few studies of varying quality, patients with cutaneous leishmaniasis were injected with zinc sulfate intralesionally. One study found zinc sulfate was better than meglumine antimoniate (a drug used to treat leishmaniasis) for the first four weeks, but no statistical differences were observed after six weeks. Zinc may decrease the severity of infection and re-infection of S. mansoni, but does not seem to prevent initial infection. More research should be done in this area to examine how zinc affects the S. mansoni life cycle and whether this data can be extrapolated to other species of Schistosoma.

The effects of zinc on the rate of parasitic re-infestation have been examined in children. No significant effect of zinc treatment was found. Due to conflicting results in this area, more research is needed before zinc can be recommended for the treatment of parasites.

Zinc is generally considered safe when taken at the recommended dosages. The recommended daily dose for adult and teenage males is 15mg. The recommended daily dose for adult and teenage females is 12mg. The recommended daily dose for pregnant females is 15mg, and 16-19mg for breastfeeding females. The recommended daily dose for children ages 4-10 is 10mg, and 5-10mg for children 0-3 years old. While zinc appears safe during pregnancy in amounts lower than the established upper intake level, caution should be used since studies cannot rule out the possibility of harm to the fetus.

PREVENTION

Avoid exposure to known allergens.

Do not eat raw or undercooked snails, fish, frogs, slugs, freshwater prawns or other animals that may be contaminated with parasitic worms.

Thoroughly wash all produce to ensure that they are not contaminated with parasitic worms.

AUTHOR INFORMATION

This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

  • Herrin, Vincent. hypereosinophilic Syndrome. eMedicine. http://www.emedicine.com/med/topic1076.htm. Accessed March 16, 2007.
  • Natural Standard: The Authority on Integrative Medicine. http://www.naturalstandard.com. Copyright © 2007. Accessed March 16, 2007.
  • NetDoctor.co.uk. Eosinophilia. http://www.netdoctor.co.uk/diseases/facts/eosinophilia.htm. Accessed March 16, 2007.
  • NYU School of Medicine & NYU Hospitals Center. Eosinophilia. http://www.med.nyu.edu/patientcare/library/article.html?ChunkIID=96970. Accessed March 16, 2007.


Copyright © 2011 Natural Standard (www.naturalstandard.com)
 
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