Aspergillosis - Symptoms, Treatment, Causes, Diagnosis
What is Aspergillosis?
Aspergillosis is the term used to refer to a group of diseases that is caused by a fungus called Aspergillus. The fungi of the gene Aspergillus commonly affect the respiratory system and occur mainly in individuals who have a compromised immune system brought by either the underlying condition or by immunosuppressive drugs.
Aspergillus is a fungus that belongs to phylum Ascomycota and with about 185 known species while 20 species of which are known to be harmful to both human and animals. Most people are exposed to Aspergillus everyday which the spores are inhaled thus gaining an entry into the human body. The spores can be inhaled and affect people from all ages without racial and gender predilection.
The genus Aspergillus commonly affects the respiratory system as the fungus is mainly introduced in the body through inhalation when the spore of the fungi has been inhaled. There are various diseases the fungus Aspergillus can cause and each has their signs and symptoms. There are however, five main clinical syndromes that can result from inhalation of the fungus and these include the following:
Allergic bronchopulmonary aspergillosis or ABPA is common in individuals suffering from asthma and individuals with cystic fibrosis. ABPA leads patient to experience cough and wheezing accompanied with mucous plugs and hemoptysis. Fever and severe headache is also expected and patient will also suffer from general malaise or feeling of being unwell. The onset may also be associated with allergic fungal sinusitis that may lead to chronic sinusitis accompanied by purulent sinus discharge. Steroid dependency may ensue as the symptoms may recur and become progressive and in some cases the patient may become unresponsive to antibacterial treatment.
Aspergilloma causes patient to experience hemoptysis which can be massive and potentially life threatening. The symptoms of cough and fever may be less experienced. Aspergilloma may also occur without symptoms and may only be detected after a procedure of chest X-ray in patient with pre-existing cavitating lung disease. HIV positive patient may also get affected especially those patients who previously suffered from Pneumocystis jirovecii pneumonia. Aspergilloma on the other hand can be benign and may not progress while the mortality is related to the massive development of hemoptysis.
Invasive aspergillosis is an extremely rare occurrence among patients with compromised immune system. It is however prevalent in patients undergoing chemotherapy and patients who underwent organ transplant. Invasive aspergillosis may cause patient to experience cough, fever, and nasal congestion, shortness in breath, pleuritic chest pain and hemoptysis.
Chronic necrotizing pulmonary aspergillosis usually affects patients with mild or moderate immunosuppression. This clinical syndrome of aspergillosis may cause patient to experience fever, cough, anorexia, night sweats and loss of weight. Patient with pneumonia in this syndrome remains unresponsive with antibacterial therapy.
Severe asthma with fungal sensitization is characterized by high fungal sensitivity regardless of treatment in patient suffering from severe asthma. Symptoms of chronic severe asthma regardless of highest form of treatment including steroid treatment are the clinical presentation of severe asthma with fungal sensitization.
The main cause of Aspergillosis is the infection from a fungus of genus Aspergillus. Aspergillus belongs to phylum Ascomycota and which has more than 185 known species and 20 of which are identified to be harmful to humans and animals. Two strains of Aspergillus have been identified to cause Aspergillosis in human. Aspergillus fumigatus is regarded to be extremely dangerous pathogen while the less dangerous is the Aspergillus niger. These two strains of Aspergillus can infect individuals with compromised immune system although healthy individuals may also get affected.
Aspergillus fungus is in a form of mold and is generally present in the environment. These molds can be found both outside and inside homes which make exposure unavoidable with the general population. The fungi in outdoors thrive in decaying plants and leaves, trees, grain crops and in compost. Inside the house or in internal environment, the spores of Aspergillus can be found in insulation, heating ducts and air conditioning and can also be found in certain foods and spices. Places like old hospitals and rundown or old buildings can also be seen with Aspergillus.
Aspergillosis is not a contagious disease that can be passed on from one person to another. The spores of the fungus can be acquired through inhalation where the fungus gain entry to the human body through the respiratory tract after the spores has been inhaled. Individuals with suppressed or compromised immune system either through a disease or immunosuppressant treatment are potentially at high risk for becoming infected. Healthy individuals or those with healthy immune system rarely get Aspergillosis although they are also at risk from everyday exposure to the Aspergillus molds.
Risk factors for developing Aspergillosis include the following:
- Individuals with weak immune system
- Low levels of white blood cell
- People with cavitary lung disease
- Asthmatic individuals or those with cystic fibrosis
- Long-term treatment with corticosteroids
- Rheumatologic lung disease called ankylosing spondylitis
- Patients confined in the hospital
Aspergillosis is rather difficult to diagnose and genus of Aspergillus is also difficult to differentiate with the other molds that are commonly found in the environment. The symptoms of Aspergillosis are also similar with other conditions which make it more difficult to identify.
Healthcare providers or doctors will initially ask for medical history of the patient to determine the risk factor of the patient including the symptoms experienced by the patient.
One or more series of tests may be recommended to diagnose the patient and such test may include the following:
- Sputum test
- Imaging test such as chest X-ray or computerized tomography scan
- Blood tests
- Tissue sample biopsy
The treatment of Aspergillosis depends on the clinical syndrome that developed. Anti-fungal medication is basically the standard treatment for Aspergillosis as it generally treats all types of fungal infection. Invasive aspergillosis is treated with Voriconazole which is the first line of treatment.
Oral corticosteroid is usually prescribed for the treatment of allergic bronchopulmonary aspergillosis and is used in combination with antifungal medication. The goal of this treatment is to inhibit or to prevent the progression of asthma. Surgery on the other hand is indicated for Aspergillosis that developed a fungal mass that results to massive bleeding in the lungs.