Cryptococcosis is one of the most important fungal infections in humans. It is caused by the fungus Cryptococcus neoformans and poses a serious risk, especially to immunocompromised individuals.
What is cryptococcosis?
Cryptococcus neoformans is a yeast fungus that has a thick capsule of polysaccharides that protects it from environmental influences. In particular, this prevents phagocytosis by granulocytes and macrophages. Melanin is also incorporated into the cell wall, which prevents damage caused by oxidation products from macrophages. Cryptococcosis is an opportunistic infection, which means that especially immunocompromised people are affected by Cryptococcus neoformans. AIDS patients, for example, whose body’s defense system is so weakened that it can no longer fight off the pathogen, are frequently affected. For this reason, cryptococcosis is also counted among the AIDS-defining diseases. Rarely, it occurs in people with suppressed immune systems due to organ transplantation or after chemotherapy. However, it can also manifest in individuals without predisposing conditions.
Causes
The causative agent, Cryptococcus neoformans, is usually found in soil rich in inorganic substances. In addition, cryptococci also occur on cereals and on grasses. Birds eat the fungus-colonized grass blades as well as seeds and then excrete them. Therefore, bird droppings are a strong source of infection. In humans, the pathogen usually uses the respiratory tract as a portal of entry. Ingestion occurs through inhalation of contaminated dusts. Once Cryptococcus neoformans has reached the lungs, granulomas form in the lungs, which can also remain asymptomatic. Especially in patients with a weakened immune system, the infection often spreads to other organs via the bloodstream after a short time. Infection of the central nervous system, i.e. the brain and spinal cord, is feared. Cryptococci have a strong affinity for this. They initially multiply there and in turn form granulomas. The course becomes critical when cryptococcal meningoencephalitis, i.e. inflammation of the brain and meninges caused by Crytococcus neoformans, occurs. Cryptococcus can also affect the skin, but this is rarely seen.
Symptoms, complaints, and signs
Regarding the course of cryptococcal infection, it can be said that it often does not cause visible symptoms in the primary stage. This stage is called a clinically inapparent state. However, as it progresses, a chronic progressive fungal infection may develop, which means that the disease becomes progressively worse. In particular, cryptococcosis becomes threatening from the time it enters the bloodstream. From this point on, the secondary stage is present. The pathogen reaches all parenchymatous organs via the bloodstream, so that symptoms of organ damage occur. Bones as well as joints can also be affected, which manifests itself in functional disorders and pain. In addition, Cryptococcus neoformans settles preferentially in the central nervous system. The acute meningoencephalitis triggered by it manifests itself, among other things, by headaches, mental abnormalities and a general feeling of illness. It can also develop into chronic meningitis. Furthermore, skin changes of all kinds can occur. This occurs in a relatively unspecific form, so that it is not possible to clearly conclude the cause from the skin condition. In most cases, cryptococcoses affect the entire body. However, they may also remain localized to a single region, which is particularly common when the infection is due to a single injury.
Diagnosis and course of disease
Microscopy is suitable for diagnostic detection of cryptococcosis. For this purpose, a CSF sediment is obtained. This is done by removing cerebrospinal fluid from the patient. The CSF is then centrifuged, filtered and sedimented in the laboratory so that the solid portion can be obtained. It contains cells and possibly also microorganisms such as Cryptococcus neoformans. The CSF sediment is now stained using India ink. Due to their distinctive capsule, the fungal cells of the cryptococci have the property of displacing the ink around them, so that a bright halo is created in their vicinity. This allows them to be identified without a doubt.Other options for detecting Cryptococcus neoformans include an antigen test, which can be performed using CSF, urine and serum samples, and cultural detection. However, the latter takes about five days, so it is used less frequently. Sabouraud agar is best suited for cultivation. Because Cryptococcus neoformans is capable of special metabolic activities such as the degradation of urea, it can be clearly distinguished from other yeast species in culture.
Complications
Cryptococcosis, also named Busse-Buschke disease, is an infection caused by the fungal pathogen Cryptococcus neoformans. The pathogens are found on grass blades and seeds, which are ingested by birds, mostly pigeons, by eating them and are excreted in their droppings. The pathogens become airborne through the dried feces and are unknowingly inhaled into the lungs, where they develop granulomas. At the beginning, the infection appears inconspicuous. Only in the course do different forms of complications develop. Those affected with a weakened immune system and HIV patients are particularly at risk, as the pathogen can more easily spread to other organs and spread. As soon as cryptococcosis has established itself in the central nervous system, fever attacks, severe headaches, joint pain, reduced vision and hearing, and impaired consciousness occur. If prompt medical attention is not arranged, the brain can become inflamed and progress to chronic meningitis. In some cases, cryptococcosis may affect only a wounded area of the skin and cause an unpleasant dermatologic reaction. The diagnosis of the symptom is made microscopically. After clarification, a drug triple combination of different liquid preparations is administered for a period of four to eight weeks. Male patients, however, receive lifelong fluconazole therapy, because the fungal pathogen always settles in the prostate gland as a complication and reactivates from there.
When should you see a doctor?
If symptoms such as headaches or a general feeling of illness are noticed over a longer period of time that cannot be attributed to any particular trigger, the affected person should go to the doctor. The signs of illness indicate a serious disease, which must be diagnosed in any case and treated if necessary. If the causative condition is cryptococcosis, further visits to the doctor are indicated. If there are signs of chronic meningitis, the disease may already be advanced. A visit to the doctor is necessary if chronic nausea, migraine and increasing malaise are noticed. Noticeable skin changes also require clarification by a physician. Anyone who notices warning signs of cryptococcosis after contact with possibly infected animals should also consult the doctor. At the latest when fever and circulatory problems occur, the disease must be diagnosed and treated immediately. In addition to the family doctor, an internist or a specialist can be consulted. In the event of a medical emergency, emergency medical treatment is necessary in any case.
Treatment and therapy
Effective therapy for cryptococcosis is very important, since CNS infestation in particular can become causative of major problems. In addition, the pathogen has the ability to persist in certain tissues such as the prostate. If this happens, reactivation of the cryptococcal infection is possible, which sometimes takes a more serious course. For this reason, a lifelong prophylactic intake of medication should also be considered, especially in persons with immunosuppression. In principle, cryptococcosis is treated with a triple therapy consisting of fluorocytosine, amphotericin B and fluconazole. These drugs must be taken for a period of four to eight weeks. Because the drugs are liquid-permeable, they can easily cross the blood–brain barrier and thus can be used to treat meningoencephalitis.
Outlook and prognosis
The prognosis for patients with cryptococcosis has now improved somewhat. This yeast infection almost always occurs in people whose immune systems are already compromised. Most of those affected – known or not yet diagnosed – suffer from the immune deficiency AIDS. People with organ transplants and cancer patients are also at risk of contracting cryptococcosis.In the latter, Hodgkin’s lymphoma or the various forms of leukemia are usually the cause of the favoring immune deficiency. Healthy people are only affected to a small extent. Problematic for the diagnosis is that the onset of the infection is mostly asymptomatic. Therefore, cryptococcosis is usually already far advanced when it is discovered. Cryptococcal meningitis is often fatal. Usually, the healthy organism can successfully fight cryptococci. But in the case of an immunodeficiency, this is no longer possible. Therefore, early detection and treatment of the potentially fatal trigger is essential. Only with rapid treatment can the prognosis for cryptococcosis be improved. However, if it occurs in the terminal stage of leukemia or Hodgkin’s lymphoma, patients usually have no chance. The underlying disease, the degree of its progression and the degree of immunodeficiency define how good or bad the prognosis is. In healthy people, the infection can almost always be treated successfully.
Prevention
Cryptococcosis can be prevented by avoiding infectious agents. An important step in reducing the incidence of this disease is to control any pigeon infestations in cities, as bird excrement is one of the main sources of infection.
Follow-up
In most cases, there are few to no special aftercare measures available to the person affected by cryptococcosis. However, the infection should be detected and treated by a physician at a very early stage to prevent further complications or other symptoms. Affected persons should therefore see a doctor at the first signs and symptoms of the disease so that a rapid diagnosis can be made. Most of those affected are dependent on taking various medications. The doctor’s instructions should always be followed, and a doctor should be contacted first if there are any questions or if anything is unclear. It is also important to ensure that the medication is taken regularly and in the correct dosage so that the symptoms can be permanently alleviated. A regular visit to the doctor is also very important in order to detect further damage at an early stage. Also the contact to other patients of cryptococcosis can be useful thereby, in order to exchange over treatment successes and complaints.
What you can do yourself
Treatment of cryptococcosis focuses on the causes of the fungal infection. Affected persons can support the therapy by taking some measures. First and foremost, sparing is important. Individuals suffering from cryptococcosis are particularly susceptible to further infections and should avoid sports activities and contact with other people if possible. If necessary, the diet must also be changed. A healthy and balanced diet containing all the necessary vitamins and minerals has proven to be effective. Sick people should also drink plenty of fluids, ideally herbal teas or juice spritzers, to expel the viruses as quickly as possible. Furthermore, stimulants should be avoided. Alcohol and cigarettes in particular have a very negative effect on a fungal infection and should therefore be avoided. In addition to these general measures, which primarily counteract the causative disease, targeted action can be taken against the individual symptoms. Fresh air and cooling compresses help with recurring headaches. Naturopathy offers soothing essential oils that prevent tension headaches and reduce stress. If accompanied by a general feeling of illness, a doctor must be consulted. Cryptococcus patients require extensive medical supervision in any case.