- What is Aspergillosis
- Statistics on Aspergillosis
- Risk Factors for Aspergillosis
- Progression of Aspergillosis
- Symptoms of Aspergillosis
- Clinical Examination of Aspergillosis
- How is Aspergillosis Diagnosed?
- Prognosis of Aspergillosis
- How is Aspergillosis Treated?
- Aspergillosis References
What is Aspergillosis
Aspergillosis is an infection, a growth, or an allergic response caused by the Aspergillus fungus. Aspergillus are common in the soil and decaying vegetation.
Colonisation of parts of the body by Aspergillus fungus is common. Certain sites are involved more commonly than others, including the:
- Central nervous system;
- Ears; and
- Urinary tract, including bladder and urethra.
Although the above listed may be involved, Aspergillus primarily affects the lungs. It causes four main syndromes, including allergic bronchopulmonary aspergillosis (ABPA), chronic necrotising aspergillus pneumonia, aspergilloma, and invasive aspergillosis.
Statistics on Aspergillosis
Aspergillosis is common in the community. Depending on which type of aspergillosis, the figures vary. However it is fair to say that aspergillosis is common in patients whose immune system is affected. This include those with HIV infection, and on medications that suppress immune system in transplant patients.
Other vulnerable groups include:
- Cancer patients undergoing chemotherapy; and
- Intensive care unit patients on multiple antibiotics.
Risk Factors for Aspergillosis
Because of the abundance of Aspergillus organisms in the environment, exposure to their spores is a frequent event. However, disease development due to fungi invasion occurs primarily in the state where there is reduced immunity. Any factors that lead to this will predispose the individuals to aspergillosis. This includes:
- Neutropenia (low white cell count that is important to fight infection);
- Corticosteroid use;
- HIV infection;
- Allogenic stem cell transplant recipients;
- Graft versus host disease;
- Solid tumours.
Progression of Aspergillosis
Aspergillosis occur in many organs in the body. With invasive aspergillosis, significant mortality ensues. However with other clinical diseases of aspergillosis, some will resolve spontaneously with suitable drugs, and some will go onto a chronic ‘on and off’ course of disease progression.
Sometimes chronic aspergillus pneumonia (infection of the lung tissue by aspergillus fungi) can lead to severe complications such as diminished pulmonary function, and eventually death. The reason for this is the disease often remains undiagnosed and elusive.
Symptoms of Aspergillosis
Aspergillosis generally causes a sudden, worsening infection where the symptoms depend on the site involved.
Lung involvement is the most common presentation of aspergillosis. Major symptoms include fever that is unresponsive to antibiotics, chest pain, cough (sometimes associated with coughing out blood). Sometimes a slower course of disease progression may occur, leading to chronic cough, coughing up blood, and slight fever.
Below are the sites involved with associated symptoms:
- Sinuses: congestion of the nose, fever, facial pain and around the eye. If the disease becomes more severe, the disease might cause blurry vision, protrusion of the eyeballs, and watery conjunctivae.
- Trachea and bronchi: these are the windpipes that connect to the lungs. Involvement will cause shortness of breath, cough and wheezing.
- Heart: fever, floating blood clot in the blood stream leading to further complications.
- Eyes: eye pain and visual changes.
- Cornea: cornea is the transparent front part of the eyeball. Involvement will cause severe pain, red eye, stinging pain upon gazing at light, change in vision and watery discharge from the eye.
- Skin: typically starts off with trauma to the skin. If aspergillosis occurs on the skin, the wound will rapidly ulcerate and enlarge at varying rates.
- Gut: this is rare. Involvement can cause sudden, severe pain in the tummy and fever.
Clinical Examination of Aspergillosis
A general, thorough examination will be carried out on patients with any medical condition. Aspergillosis produces signs which are very non-specific, including fever, wheezing, reduced expansion of the lungs, fingernails changes and sounds in the lungs. Other diagnoses will usually be considered first. Also the signs that could be found on examination depends upon involvement of different sites.
How is Aspergillosis Diagnosed?
Because the patient is usually immunocompromised and diagnosis of aspergillosis is difficult if it involves internal organs, the usual routine blood tests will be done, including:
- Full blood count;
- Urea and electrolytes;
- Liver function test;
- Coagulation studies.
There is no simple way of diagnosing aspergillosis. However the following are usually done:
- Sputum (phlegm) microscopy, culture and sensitivity;
- Tissue sample biopsy (removal of tissue for further evaluation using laboratory techniques): this is more useful in skin, cornea and lung;
- Serum galactomannan antigen detection: galactomannan is a constituent secreted by Aspergillus hyphae during growth. Early detection of serum galactomannan has been used as a diagnostic test for aspergillosis;
- Polymerase chain reaction: this involves identifying the DNA in the blood;
- Imaging: because the lungs are usually involved, x-ray or CT scan of the chest are routinely done as part of the investigation for aspergillosis.
Prognosis of Aspergillosis
Because aspergillosis can present in many ways, their prognoses differ as well. The one with the worst prognosis is invasive pulmonary aspergillosis. Also the prognosis depends on the underlying condition the patient has, for example a person during terminal HIV disease with AIDS would have a worse prognoses than those being treated in intensive care unit.
How is Aspergillosis Treated?
There are 3 components in the treatment of aspergillosis:
- Reduction of underlying risk factors;
- Medical treatment; and
- Surgical treatment.
Reversal of underlying risk factors
This intend to improve the immune system of the patient. The current treatment option is to use granulocyte colony-stimulating factor (G-CSF) and interferon gamma to boost the body immune system. However this has not been uniformly successful.
Antifungal drugs are the mainstay of treatment in terms of pharmacological options for aspergillosis. These drugs include conventional and liposomal amphotericin B, voriconazole, traconazole, and the newer agent called caspofungin (an echinocandin). If treatment is not successful or the the disease is aggressive, combination medications can be administered. The duration of therapy depends on many factors, including disease site, host’s underlying disease, and response to the therapy.
Surgery can be used as diagnostic biopsy of the involved site. Sometimes surgical excision of the cavity can be performed in patients with single pulmonary lesion.
- Aspergillosis [online]. New York, NY: DoctorFungus; 2005 [cited 30 September 2005]. Available from: URL link
- Harman EM. Aspergillosis [online]. Omaha, NE; eMedicine; 2005 [cited 30 September 2005]. Available from: URL link
- Sugar AM. Clinical features and diagnosis of invasive aspergillosis [online]. Waltham, MA: UpToDate; 2005 [cited 30 September 2005]. Available from: URL link
- Sugar AM. Treatment of invasive aspergillosis [online]. Waltham, MA: UpToDate; 2005 [cited 30 September 2005]. Available from: URL link