Aspergillus is a group of saprophytic
moulds world-wide. Only a few of them can cause illness in humans and animals
: Aspergillus fumigatus
(the most frequent), A. flavus, A. niger, A.nidulans,
A terreus.
Most people are naturally immune
to Aspergillus. However, when disease does occur (apergillosis), it takes
several forms.
The type of diseases caused by Aspergillus,
ranged from an "allergy"-type illness to life-threatening generalised
infections. The severity of aspergillosis is determined by various factors but
one of the most important is the status of the immune system of the person.
Allergic bronchopulmonary aspergillosis (ABPA)
This is a condition which produces an
allergy to the spores of the Aspergillus moulds. It is quite common in
asthmatics; up to 20% of asthmatics might get this at some time during their
lives. ABPA is also common in cystic fibrosis patients, as they reach adolescence
and adulthood. The symptoms are similar to those of asthma: intermittent episodes
of feeling unwell, coughing and wheezing. Some patients cough up brown-coloured
plugs of mucus. The diagnosis can be made by X-ray or by sputum, skin and blood
tests. In the long term ABPA can lead to permanent lung damage (fibrosis) if
untreated.
The treatment is with steroids and Itraconazole.
Aspergilloma
Aspergillus grows within a cavity
of the lung, which was previously damaged during an illness such as tuberculosis
or sarcoidosis. The spores penetrate the cavity and germinate, forming a fungal
ball within the cavity. Any lung disease which causes cavities can leave a person
open to developing an aspergilloma.
The person affected may have no symptoms
(especially early on). Weight loss, chronic cough and feeling rundown are common
symptoms later. Coughing of blood (haemoptysis) can occur in up to 50-80% of
affected people.
The diagnosis is made by X-rays, scans of lungs and blood
tests.
Treatment depends on many factors and includes antifungal therapy
or surgical removal.
Aspergillus sinusitis
Aspergillus sinusitis happens
in a similar way to aspergilloma. In those with normal immune systems, stuffiness
of the nose, chronic headache or discomfort in the face is common. Drainage
of the sinus, by surgery, usually cures the problem.
When patients have damaged
immune systems - if, for example they have had leukaemia or have had a bone
marrow transplant- Aspergillus sinusitis is more serious. Since sinusitis
results from invasive aspergillosis (see below). The symptoms include fever,
facial pain, nasal discharge and headaches. The diagnosis is made by finding
the fungus in fluid or tissue from the sinuses and with CT scans. Treatment
with powerful antifungals (e.g. amphotericin) or surgery is essential.
Invasive aspergillosis
Many people with damaged or impaired
immune system die from invasive aspergillosis. Their chances of living are improved
the earlier the diagnosis is made but unfortunately there is no good diagnostic
test. Often treatment has to be started when the condition is only suspected.
Invasive
aspergillosis is usually clinically diagnosed in a person with low defences
such as bone marrow transplant, low white cells after cancer treatment, AIDS
or major burns. There is also a rare inherited condition that gives people low
immunity (chronic granulomatous disease) which puts affected people at risk.
People with invasive aspergillosis usually have a fever and symptoms from the
lungs (cough, chest pain or discomfort or breathlessness) which do not respond
to standard antibiotics. X-rays and scans are usually abnormal and help to localise
the disease. Bronchoscopy (inspection of the inside of the lung with a small
tube inserted via the nose) is often used to help to confirm the diagnosis.
Sometimes
the fungus can transfer from the lung through the blood stream to the brain
and to other organs, including the eye, the heart, the kidneys and the skin.
Usually this is a bad sign as the condition is more severe and the person sicker
with higher risk of death.
Treatment is with antifungal drugs such as amphotericin-B
and/or itraconazole and is difficult. Amphotericin-B has to be given by vein
in large doses. In some patients the treatment can damage kidney and other organs.
Newer forms of amphotericin-B (Amphotec or Amphocil, Abelcet or AmBisome) are
useful, especially when the patient experiences side-effects, as there are less
toxic. Itraconazole is generally given orally (also in large doses, e.g. at
least 400 mg daily). New antifungal drugs (azoles and echinocandins) are presently
launched. The earlier treatment is started the better the chances of survival.
In patients with low numbers of white cells (infection fighters), recovery of
these cells can be important in stopping the growth of the fungus. Sometimes
surgery is also required. Overall, about a third of patients survive invasive
aspergillosis if treated and none survive if they are not treated.
For more information see Aspergillus for Patients