Other fungal infections

From WebHealth

Contents 1 Other fungal infections 2 Chromomycosis 3 Phaeohyphomycosis 4 Mucormycosis

[edit] Other fungal infections

Introduction:

There are other, perhaps less known fungal infections that can occur in people with a normal immune system such as chromomycosis. On the other hand AIDS patients or those who have a weak immune system like cancer patients or patients who had transplants and are on immunosuppressants, can develop otherwise rare fungal diseases such as mucormycosis or phaeohyphomycosis.

Choose from these other fungal infections:

Introduction

Chromomycosis

Mucormycosis

Phaeohyphomycosis

[edit] Chromomycosis

Introduction:

Chromomycosis is a rare fungal infection of the skin of patients with a normal immune system. It happens usually in the tropics or subtropics. The entry into the body occurs through small skin wounds in the feet, lower legs or other skin areas. As the fungi that cause chromomycosis contain melanin, which is pigment laden, the skin eruptions containing the fungi also appear dark and pigmented. A number of different species such as Bipolaris, Cladosporium, Phialophora and many others cause chromomycosis.

Signs and symptoms:

The initially isolated skin lesion enlarge, ulcerate, multiply and for between 4 and 15 years stay locally confined to an extremity or a regional area of skin. Here is a picture of a male with chromomycosis of the lower leg.

The underlying lymph vessels and lymph glands get also infected and this can lead to edematous swelling of the regional area. The affected skin is very itchy. Scratching only helps to infect the neighboring skin. Eventually cauliflower like skin surface develops that is pigmented compared to the normal skin. Bacterial superinfection of scratched open lesions can complicate the clinical picture.

Diagnostic tests:

The diagnosis can be difficult and culture methods and biopsy and histological analysis are the only reliable means to confirm the clinical suspicion. A skin specialist likely should be consulted.

Treatment:

Itraconazole (brand name: Sporanox) is the treatment of choice, but will not heal all of the cases. The specialist may use other agents such as flucytosine (brand name: Ancobon) as additional therapy. If antifungal therapy does not lead to a cure, the physician may have to use surgical excision as an additional mode of therapy.

Infections overview

Fungal infections

Other fungal infections

[edit] Phaeohyphomycosis

If the skin infection described under "chromomycosis" is invading from a local infection into the rest of the body, this is called a phaeohyphomycosis. This is happening a lot more in immunocompromized patients such as in the presence of AIDS, or in poorly controlled diabetics or patients with cancer.

Phaeohyphomycosis -- what's that?

Step 1: the roots. "pheo" or "phaeo-" is a term originating from the Greek word "phaios" meaning dun, dusky or brown."Hyphomycosis" has its roots in the Greek "hyphe" meaning web and "mykes" meaning fungus. Hyphomycetes is a species of imperfect fungi that can multiply in the skin (to be contrasted with imperfect yeast infections such as monilia).

Step 2: putting it together. "Phaeohyphomycosis" is a fungus infection with incomplete fungi that form spores and hyphae that are pigmented, dark brown or black. Most authorities use the term "chromomycosis" for localized infections of the skin with these pigmented species and the term "phaeohyphomycosis" for infections of other tissues than the skin with this fungus (see text).

With phaeohyphomycosis the pigmented fungi spread to other parts of the body, likely either through the lymphatic system or through the circulatory system. This way chronic festering infections of the sinus cavities, bones, joints, lungs, heart valves (=endocarditis), brain (=brain abscess) or the meningeal membranes (=meningitis) can occur. Also, there can be nodules or abscesses can show up under the skin, in regional lymph glands of infected skin or organs. Even internal bleeding can happen when a local abscess erodes a major blood vessel. Systemic spread like this is facilitated when the immune system is weak such as in AIDS patients or in patients with cancer or diabetes out of control.

Signs and symptoms:

Here is a picture of a child with this condition.

Depending on what organ system is involved, the symptoms change. For instance, with involvement of the heart valves, such as in endocarditis, depending on the severity there will be circulatory symptoms with signs of congestive heart failure such as cyanosis (bluish skin discoloration), shortness of breath, weakness etc. With a lung lesions there might be a cough, shortness of breath and chest pains. X-rays would show lesions that would be followed up with further investigations such as bronchoscopy or lung biopsy.

Diagnostic tests:

Biopsies of diseased tissue are sent to the pathologist who will use special melanin staining techniques to diagnose this condition. Ultrasonic tests, CT or MRI scan testing as well as regular x-rays are all helpful in assessing the extent of the disease.

Infections overview

Fungal infections

Other fungal infections

[edit] Mucormycosis

This fungal infection is characterized by irregular shapes of hyphae (thread like structures) that can be caused by a number of rare fungi (species of Rhizomucor, Rhizopus and others). It happens mostly in patients whose immune system is compromised such as in AIDS patients, patients with poorly controlled diabetes in ketoacidosis, with kidney failure or in patients who receive high doses of corticosteroids or other immunosuppressive therapy.

The most common form of mucormycosis is an infection inside the nose that spreads to the sinuses and through the bone into the base of the brain cavity. Associated with this can be excruciating pain deep underneath the face and in the bones of the sinuses. Headaches, fever, and a breakdown of the palate bone on top of the roof of the mouth cavity are some of the possible and more common symptoms. There can be a pussy nasal discharge, swelling around the eye socket with bone destruction of the bones behind and around the eye. Here is a picture of mucormycosis. Superinfection with bacteria can lead to more dangerous cellulitis around the eye, which very quickly will spread into the meningeal membranes and cause meningitis. Occasionally the initial lesions are found in the lungs, the skin or the GI tract.

The diagnosis of this condition is very difficult and the physician must have a high index of suspicion. The only positive tests are histological examination of tissue biopsy samples by an experienced histopathologist. The characteristic irregularly shaped hyphae are what make the diagnosis. Cultures are not reliable and there is presently no reliable blood test antibody titer. Treatment is also difficult, as the only reliable drug that helps is intravenous amphotericin B, but this will not reach avascular abscessed areas. This means then that affected areas that do not have a lot of blood vessels need to be surgically explored and any infected material should be excised until the vascular margin is reached. The remainder of the disease should then be amenable to the intravenous amphotericin B. Other oral antifungal antibiotics have not been found to be of benefit (Ref. 1, p. 1223 and 1225).

Infections overview

Fungal infections

Other fungal infections

References:

1.The Merck Manual, 7^th edition, by M. H. Beer s et al., Whitehouse Station, N.J., 1999. Chapter 158.

2.The Merck Manual, 7^th edition, by M. H. Beers et al., Whitehouse Station, N.J., 1999. Chapter 113.

3. The Merck Manual, 7^th edition, by M. H. Beers et al., Whitehouse Station, N.J., 1999. Chapter 164.

4.David Heymann, MD, Editor: Control of Communicable Diseases Manual, 18th Edition, 2004, American Public Health Association.