Systemic mycoses – symptoms and diagnosis

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Fungi are common in the human environment and in some circumstances become a dangerous pathogen that is difficult to eliminate. Mycoses, especially systemic, i.e. affecting one or more organs, are a real challenge for modern medicine. They are difficult to recognize, even more difficult to cure. Meanwhile, over the past 20 years, there has been a steady increase in systemic fungal infections and the emergence of drug-resistant or new, previously rare strains. Mortality from fungal infections is also steadily increasing.

Risk groups of systemic fungal infections

The increase in the incidence of mycoses is due to the growing number immunocompromised patients or damaged immune system. People most at risk of developing mycosis are HIV-positive people, people with AIDS, organ or bone marrow transplants, people taking immunosuppressants, cancer patients, receiving chemotherapy, enteral nutrition, diabetes and abdominal surgery. Also, the widespread, long-term use of antibiotics promotes the development of mycosis.

Fungal infections – Candida, Aspergillus

So far, we have known 250 species of mushrooms, of which more than 200 causes human infections. The vast majority of these infections are opportunistic, that is, they are caused by fungi that are pathogenic only in immunocompromised people. In healthy people, fungi are rendered harmless by cells of the immune system: macrophages and lymphocytes. The disease is most often caused by fungi of the genus Candida (about 60-80 percent of infections) i Aspergillus.

Mold fungi, including Aspergillus, enter the body through inhalation of air. Systemic fungal infections can affect one or more organs, taking the form of a generalized infection with fungemia, i.e. the presence of the pathogen in the blood. Mortality in systemic fungal infections reaches 30-70 percent. Aspergillus infections develop almost exclusively in severely immunocompromised patients.

Candida is an etiological factor of invasive infections in immunocompromised patients as well as in patients without immune disorders, for example, who have undergone abdominal surgery, long-term intensive care units and enteral nutrition.

Candida causes infections with a very broad spectrum, ranging from harmless mucosal surface to multi-organ systems that pose a threat to the patient’s life. In healthy people, the proper condition of the mucosa and immune mechanisms effectively protect against fungal colonization. Damage to the continuity and function of mucous membranes, disturbances in the immune response and destruction of the physiological bacterial flora favor the colonization of the mucous membranes by Candida, and then the spread of the infection to the blood, organs and deeper tissues. In recent years, the frequency of infections caused by other types of fungi, including Fusarium, Trichosporon, and Scedosporium, has been increasing.

One of the varieties of fungal infection is cryptococcosis. It is caused by fungi belonging to the genus Cryptococcus. There are over 30 different species in this group, but most human and animal infections are caused by the presence of Cryptococcus neoformans or Cryptococcus gattii. Cryptococcus fungi live in soil all over the world, and infection most often occurs through inhalation of air containing fungal spores. In people with a weakened immune system, the fungus can spread from the lungs to other organs of the body and cause chronic infections, such as the central nervous system.

Symptoms of systemic mycoses

To the earliest clinical symptoms of systemic fungal infections it should be a fever. Persistence of fever in patients treated with antibiotics for a long time, especially with compromised immunity, should raise the suspicion of mycosis. Systemic fungal infections can manifest themselves, inter alia, in fungemia (blood poisoning), pneumonia, inflammation of the meninges, eyeball, endocarditis, liver and kidneys. In the case of lung infections, a common symptom is also a dry cough, pain, and hemoptysis. Sometimes, however, infections can proceed without developing a fever. Therefore, in any case suspicion of mycosis there is a need for additional research to help determine the etiological factor.

Diagnosis of fungal infections

In the diagnosis of fungal infections, microscopic examinations, microbiological or serological methods (detection of antigens and antibodies) are used. Imaging tests, such as x-rays of the lungs, are helpful in suspecting a fungal infection. A sensitive method is computed tomography, which often shows the presence of lesions typical of mycoses, despite the correct radiological image. In recent years, methods of molecular biology (genetic testing) have also been increasingly used in the diagnosis of fungal infections.

The clinical symptoms of systemic fungal infections are not very characteristic, they resemble infections caused by the presence of viruses or bacteria. The first problem is the difficulty in obtaining the right material for research. Samples should be taken depending on the symptoms and location of the infection, the most common are: blood, sputum, urine, feces, swabs, tissue specimens or cerebrospinal fluid. Then, the test material is cultivated, often for a long time, even up to several weeks.

Another problem in interpreting the obtained results is the common presence of fungi in the environment, which favors accidental contamination of the samples and false-positive results. At the same time, in spite of the existing fungal infection, it is often not possible to cultivate the fungi from cultures. It is estimated that positive cultures is only obtained in up to 50 percent of patients with confirmed mycosis. Therefore, microbiological analyzes should be supplemented with molecular or serological methods.

Known mycosis is treated with available antifungal drugs and, where possible, by enhancing natural immunity. Prophylactic measures include the careful use of antibiotics, only in those cases when it is really necessary.

Also read:

  1. A breakthrough in the treatment of systemic mycoses
  2. Skin mycosis – symptoms, treatment
  3. Antifungal diet – how to help the body fight mycosis?

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