Mucormycosis: symptoms, risk factors, diagnosis and treatment

Mucormycosis is an infection caused by a group of moulds called Mucorales. Patient.info explains that Rhizopus species are the most common cause, with other genera occurring less often. These moulds live in the environment and are not a problem for most people. MedlinePlus says they are often found in decaying organic matter such as spoiled bread, fruit and vegetables, as well as soil and compost, and that most people come into contact with the fungus in the environment.

The infection happens when the immune defences are weakened. Patient.info describes how the spores grow, and the fungal threads invade blood vessels and produce tissue death (infarction), which is why the disease can be fast-moving and destructive. Severe infection of the facial sinuses can extend into the brain.

Patient.info notes that less common forms are pulmonary (lung), cutaneous (skin) and gastrointestinal infections. It describes the condition as very rare but often unrecognised, and says that invasive fungal infections have long been a problem in people with weakened immunity, with the incidence of mucormycosis having increased over the last decade.

Patient.info also notes that, extremely rarely, trauma and contaminated medical supplies over wounds have been associated with cutaneous disease in people who are not immunosuppressed, but not the disseminated form.

Mucormycosis is overwhelmingly a problem of impaired immunity or severe underlying illness rather than of healthy people. Patient.info lists the following as risk factors, and MedlinePlus gives a similar list.

• Poorly controlled diabetes mellitus, especially diabetic ketoacidosis.

• Steroid use, and the use of other medicines that suppress the immune system.

• Neutropenia (a low neutrophil count), especially with blood cancers such as leukaemia and lymphoma.

• AIDS, kidney failure, and organ or stem cell transplantation.

• Iron overload, burns, malnutrition and extremes of age.

• Intravenous drug use, and use of voriconazole for prophylaxis or treatment of aspergillosis.

Symptoms depend on which part of the body is involved. Patient.info says that fever is usual and that the course is often fulminant, meaning rapid, with considerable tissue death.

MedlinePlus advises that people with weakened immune systems and immune disorders, including diabetes, should seek medical attention if they develop fever, headache, sinus pain, eye swelling or other symptoms of the kind listed above. In the UK, that means contacting your GP or NHS 111 promptly, and going to A&E or calling 999 if there are severe symptoms such as swelling around the eye with loss of vision, confusion or drowsiness, breathlessness or collapse.

People who are known to be at higher risk, for example during chemotherapy, after a transplant or with poorly controlled diabetes, are usually given a route to contact their specialist team directly. If you have such a contact, use it.

A blocked nose or sinus pain is very common and almost always due to an ordinary cause. It is the combination of a vulnerable immune system with symptoms such as black discharge, facial swelling or eye changes that makes this diagnosis worth considering.

Because the early symptoms are non-specific, mucormycosis can be difficult to diagnose, and Patient.info describes the diagnosis as often unrecognised. Both Patient.info and MedlinePlus state that a biopsy is central: a small piece of tissue is removed and examined in the laboratory to demonstrate the fungal threads and invasion into the tissue. Patient.info adds that hyphae must be shown in order to start treatment swiftly, and that culture is also needed to identify the species but takes longer.

Imaging helps to show how far the infection has spread. Patient.info notes that both CT and MRI are useful for the skull, sinuses and brain, with CT better for bone and MRI better for brain and soft tissue, and that chest and abdominal CT are used when disease in those areas is suspected. Blood tests assess kidney function, blood sugar control and iron status, because these affect both the risk and the treatment.

Patient.info lists other conditions that can look similar, including anthrax, bacterial cellulitis, cavernous sinus thrombosis, aspergillosis, a rapidly growing orbital tumour, pulmonary embolism and bowel obstruction, which is one reason specialist assessment is needed.

Patient.info sets out the general principles of treatment as early diagnosis and starting treatment promptly, reversing the underlying problem where possible, surgical removal of dead tissue, and antifungal medicine. Reversing the underlying problem means, for example, correcting poor diabetes control, reducing immunosuppressant medicines where possible and stopping deferoxamine.

Surgery to remove dead and infected tissue is described by both sources as an important part of treatment. MedlinePlus says that it should be done right away, that it can lead to disfigurement because it may involve removal of parts of the palate, nose or eye, and that without such surgery the chance of survival is greatly decreased. Patient.info adds that surgery can be destructive and may need to be repeated.

The main antifungal medicine is amphotericin B, given through a vein. Patient.info describes high-dose liposomal amphotericin B for at least 4 to 6 weeks as the usual primary therapy, and notes that it can affect the kidneys, so kidney function is monitored. MedlinePlus says that once the infection is under control, treatment may be switched to a medicine such as posaconazole or isavuconazole.

Mucormycosis has a serious outlook. Patient.info says mortality is at least 50%, higher for lung and gut disease because of late diagnosis, and higher again in transplant patients. MedlinePlus says the risk of death depends on the area of the body involved and on overall health. These figures describe published series of often very ill people; they cannot predict an individual outcome, and a specialist team can explain what applies to a particular person.

People who survive sinus and brain infection may need extensive reconstruction. Patient.info notes that treatment in this form often requires extensive and sometimes disfiguring facial surgery. Possible complications listed by MedlinePlus include blindness if the optic nerve is involved, blocked blood vessels in the brain or lungs, and nerve damage.

Prevention largely means looking after the conditions that raise the risk. MedlinePlus says that because the fungi are widespread, the best way to prevent infection is to improve control of the illnesses associated with mucormycosis, for example blood sugar control in diabetes.

Patient.info stresses that recognition is essential for early and effective treatment, and lists black discharge from the nose or palate, double vision or restricted eye movements and visual field defects, in a person with a predisposing factor such as diabetes, cancer or a disorder of iron metabolism, as the points to consider the diagnosis.