Sunday, November 21, 2010

Aspergillus


Aspergillus is a fungus that commonly grows on rotting vegetation. Some people with asthma are allergic to Aspergillus and develop allergic bronchopulmonary aspergillosis (ABPA). The symptoms include wheezing and blood-stained sputum.

Some people with asthma are allergic to the fungal spores. These can trigger an asthma attack if inhaled. Some people will develop a condition known as allergic bronchopulmonary aspergillosis (ABPA), in which asthma worsens significantly, as a result of increased lung inflammation.

In rare cases, a person may suffer serious lung or other organ infection with this fungus. Some severely ill people, or those whose resistance is lowered because they are taking medications which suppress their immune system, may be affected.

The structure of the lungs
The lungs are inside the chest, protected by the ribcage and wrapped in a membrane called the pleura. The windpipe (trachea) splits into two tubes, called bronchi, that service one lung each. The bronchi divide into smaller tubes called bronchioles, which ultimately branch into even smaller air sacs called alveoli. Each alveolus has a fine mesh of capillaries. This is where the exchange of oxygen and carbon dioxide takes place. A person with asthma who is allergic to Aspergillus will have spasms of the bronchioles, which causes breathlessness and wheezing.

Allergens and asthma
Nine out of 10 people with asthma find their symptoms worsen when they are exposed to certain triggers or allergens. An allergen is any substance that causes an overzealous response from the immune system, which treats the non-poisonous substance as if were poisonous. People with asthma are allergic to different triggers, such as cigarette smoke, wood smoke, pollen, dust mite or Aspergillus spores.

Men and women with asthma who are aged 20 to 40 years are most commonly affected. People with cystic fibrosis are also vulnerable. Treatment options include medications and avoiding exposure to the fungus whenever possible.

Symptoms
Symptoms of allergic bronchopulmonary aspergillosis include:

* Wheezing
* Breathlessness
* Significant worsening of asthma symptoms
* A productive cough with brown mucus or mucus plugs
* Coughing up blood
* Loss of appetite
* Fever
* General malaise.

Complications of ABPA
Some of the complications of untreated allergic bronchopulmonary aspergillosis include:

* Haemoptysis - the irritated and inflamed airways can bleed and bloodstained phlegm is coughed up.
* Bronchiectasis - recurring bouts of inflammation eventually damage the bronchiolar walls.
* Atelectasis - this involves varying degrees of lung tissue collapse.
* Respiratory failure - the airways become obstructed, or a severe asthma attack squeezes the airways closed. This is a medical emergency.

Diagnosis methods
ABPA is diagnosed using a number of tests, including:

* Chest x-rays - to check for the presence of fluid in the lungs and for any abnormalities, such as enlarged, stretched or damaged airways. CT scans may also be used.
* Skin test - the skin is pricked and a tiny amount of the allergen is introduced. A person who is allergic to Aspergillus will experience swelling, itching and reddening of the site, usually within 20 minutes. However, the skin reaction may take as long as eight hours to develop in some people.
* Blood tests - antibodies are special proteins of the immune system that are tailor-made to counter specific antigens. Blood tests check for the presence of Aspergillus antibodies (Aspergillus precipitins). These precipitins bind with the spores and form tiny solids. Around half of all people with ABPA have elevated levels of immunoglobulin E, or IgE, which is a type of blood protein that prompts allergic reactions.
* Sputum tests - Aspergillus spores are sometimes visible in the person’s mucus when viewed under a microscope. The spores can be cultured from the mucus and positively identified using special dyes.

Treatment options
There is no cure for ABPA. The condition is managed with corticosteroids taken orally or with puffers. Antifungal medications generally have no effect. People with ABPA should be monitored regularly to make sure their condition is successfully managed.

Monitoring may include checking antibody levels and evaluating the airflow capacity of the lungs. People with asthma are generally advised to avoid their known triggers whenever possible. However, Aspergillus is a particularly common fungus. People with ABPA should try to stay away from marshes, forests, bogs, compost heaps and other areas where vegetation is known to be rotting.

Tuesday, November 9, 2010

Leukodystrophy

Leukodystrophy refers to progressive degeneration of the white matter of the brain due to imperfect growth or development of the myelin sheath, the fatty covering that acts as an insulator around nerve fiber. Myelin, which lends its color to the white matter of the brain, is a complex substance made up of at least ten different chemicals. The leukodystrophies are a group of disorders that are caused by genetic defects in how myelin produces or metabolizes these chemicals. Each of the leukodystrophies is the result of a defect in the gene that controls one (and only one) of the chemicals. Specific leukodystrophies include metachromatic leukodystrophy, Krabbé disease, adrenoleukodystrophy, Pelizaeus-Merzbacher disease, Canavan disease, Childhood Ataxia with Central Nervous System Hypomyelination or CACH (also known as Vanishing White Matter Disease), Alexander disease, Refsum disease, and cerebrotendinous xanthomatosis. The most common symptom of a leukodystrophy disease is a gradual decline in an infant or child who previously appeared well. Progressive loss may appear in body tone, movements, gait, speech, ability to eat, vision, hearing, and behavior. There is often a slowdown in mental and physical development. Symptoms vary according to the specific type of leukodystrophy, and may be difficult to recognize in the early stages of the disease.

Treatment for most of the leukodystrophies is symptomatic and supportive, and may include medications, physical, occupational, and speech therapies; and nutritional, educational, and recreational programs. Bone marrow transplantation is showing promise for a few of the leukodystrophies.

The prognosis for the leukodystrophies varies according to the specific type of leukodystrophy.

Monday, November 1, 2010

Seborrheic dermatitis

Seborrheic dermatitis is a common, inflammatory skin condition that causes flaky, white to yellowish scales to form on oily areas such as the scalp or inside the ear. It can occur with or without reddened skin.

Cradle cap is the term used when seborrheic dermatitis affects the scalp of infants.

Causes

Seborrheic dermatitis is thought to be due to a combination of an over production of skin oil and irritation from a yeast called malessizia.

Seborrheic dermatitis appears to run in families. Stress, fatigue, weather extremes, oily skin, infrequent shampoos or skin cleaning, use of lotions that contain alcohol, skin disorders (such as acne), or obesity may increase the risk.

Neurologic conditions, including Parkinson's disease, head injury, and stroke may be associated with seborrheic dermatitis. Human immunodeficiency virus (HIV) has also been linked to increased cases of seborrheic dermatitis.

Symptoms

Seborrheic dermatitis can occur on many different body areas. Typically it forms where the skin is oily or greasy. Commonly affected areas include the scalp, eyebrows, eyelids, creases of the nose, lips, behind the ears, in the external ear, and along skin folds on the middle of the body.

Seborrheic dermatitis in infants, also called cradle cap, is a harmless, temporary condition. It appears as thick, crusty, yellow or brown scales over the child's scalp. Similar scales may also be found on the eyelids, ear, around the nose, and in the groin. Cradle cap may be seen in newborns and small children up to age 3 .

Cradle cap is not contagious, nor is it caused by poor hygiene. It is not an allergy, and it is not dangerous. Cradle cap may or may not itch. If it itches, excessive scratching of the area may cause additional inflammation, and breaks in skin may cause mild infections or bleeding.

In general, symptoms of seborrheic dermatitis include:

* Skin lesions
* Plaques over large area
* Greasy, oily areas of skin
* Skin scales -- white and flaking, or yellowish, oily, and adherent -- "dandruff"
* Itching -- may become more itchy if infected
* Mild redness
* Hair loss

Exams and Tests

The diagnosis is based on the appearance and location of the skin lesions.

Treatment

You can treat flaking and dryness with over-the-counter dandruff or medicated shampoos. Shampoo the hair vigorously and frequently (preferably daily). Loosen scales with the fingers, scrub for at least 5 minutes, and rinse thoroughly. Active ingredients in these shampoos include salicylic acid, coal tar, zinc, resorcin, ketoconazole, or selenium.

Shampoos or lotions containing selenium, ketoconazole, or corticosteroids may be prescribed for severe cases. To apply shampoos, part the hair into small sections, apply to a small area at a time, and massage into the skin. If on face or chest, apply medicated lotion twice per day.

Seborrheic dermatitis may improve in the summer, especially after outdoor activities.

For infants with cradle cap:

1. Massage your baby's scalp gently with your fingers or a soft brush to loosen the scales and improve scalp circulation.
2. Give your child daily, gentle shampoos with a mild soap while scales are present. After scales have disappeared, you may reduce shampoos to twice weekly.
3. Be sure to rinse off all soap.
4. Brush your child's hair with a clean, soft brush after each shampoo and several times during the day.
5. If scales do not easily loosen and wash off, apply some mineral oil to the baby's scalp and wrap warm, wet cloths around his head for up to an hour before shampooing. Then, shampoo as directed above. Remember that your baby loses a lot of heat through his scalp. If you use warm, wet cloths with the mineral oil, check frequently to be sure that the cloths have not become cold. Cold, wet cloths could drastically reduce your baby's temperature.
6. If the scales continue to be a problem or concern, or if you child seems uncomfortable or scratches his scalp, contact your physician. He may prescribe a cream or lotion to apply to your baby's scalp several times a day.

Outlook (Prognosis)

Seborrheic dermatitis is a chronic (life-long) condition that can be controlled with treatment. It often has extended inactive periods followed by flare-ups.
Possible Complications

* Psychological distress, low self esteem, embarrassment
* Secondary bacterial or fungal infections

When to Contact a Medical Professional

Call for an appointment with your health care provider if seborrheic dermatitis symptoms do not respond to self-care or over-the-counter treatments.

Also call if patches of seborrheic dermatitis drain fluid or pus, form crusts, or become very red or painful.

Prevention

The severity of seborrheic dermatitis can be lessened by controlling the risk factors and by paying careful attention to skin care.

Alternative Names

Dandruff; Seborrheic eczema; Cradle cap