Description

Mucormycosis is a collection of fungal and mold diseases in dogs including pythiosis, zygomycosis, and lagenidiosis that affect the gastrointestinal tract and skin.

Signs and symptoms

Mucormycosis frequently involves the sinuses, brain, or lungs as the sites of infection. While oral or cerebral Mucormycosis are the most common types of the disease, this infection can also manifest in the gastrointestinal tract, skin, and in other organ systems.  In rare cases, the maxilla may be affected by Mucormycosis.  The rich vascularity of maxillofacial areas usually prevents fungal infections, although more prevalent fungi, such as those responsible for Mucormycosis, can often overcome this difficulty.

There are several key signs which point towards Mucormycosis. One such sign is fungal invasion into the vascular network which results in thrombosis and death of surrounding tissue by loss of blood supply.  If the disease involves the brain then symptoms may include a one-sided headache behind the eyes, facial pain, fevers, nasal stuffiness that progresses to black discharge, and acute sinusitis along with swelling of the eye.  Affected skin may appear relatively normal during the earliest stages of infection. This skin quickly progresses to an erythemic (reddening, occasionally with edema) stage, before eventually turning black due to necrosis.  In other forms of Mucormycosis, such as pulmonary, cutaneous, or disseminated Mucormycosis, symptoms may also include dyspnea (difficulty breathing), and persistent cough; in cases of necrosis, symptoms include nausea and vomiting, coughing blood, and abdominal pain.

Diagnosis

As swabs of tissue or discharge are generally unreliable, the diagnosis of Mucormycosis tends to be established by a biopsy specimen of the involved tissue.

Treatment

If Mucormycosis is suspected, prompt amphotericin B therapy should be administered due to the rapid spread and mortality rate of the disease. Amphotericin B (which works by damaging the cell walls of the fungi) is usually administered for a further 4–6 weeks after initial therapy begins to ensure eradication of the infection. Posaconazole has been shown to be effective against Mucormycosis, perhaps more so than amphotericin B, but has not yet replaced it as the standard of care.

After administration of either amphotericin B or Posaconazole, surgical removal of the "fungus ball" is indicated. The disease must be monitored carefully for any signs of reemergence.

Surgical therapy can be very drastic, and in some cases of Rhinocerebral disease removal of infected brain tissue may be required. In some cases surgery may be disfiguring because it may involve removal of the palate, nasal cavity, or eye structures.  Surgery may be extended to more than one operation.  It has been hypothesised that hyperbaric oxygen may be beneficial as an adjunctive therapy because higher oxygen pressure increases the ability of neutrophils to kill the organism.

Prognosis

In most cases, the prognosis of Mucormycosis is poor and has varied mortality rates depending on its form and severity. In the rhinocerebral form, the mortality rate is between 30% and 70%, whereas disseminated Mucormycosis presents with the highest mortality rate in an otherwise healthy patient, with a mortality rate of up to 90%.  Patients with AIDS have a mortality rate of almost 100%.  Possible complications of Mucormycosis include the partial loss of neurological function, blindness and clotting of brain or lung vessels.

Wikipedia and GNU

The content of this entry is from the Wikipedia article "Mucormycosis" licensed under the GNU Free Documentation License.