10/12/2012 02:02 pm ET Updated Dec 12, 2012

Diagnosing and Treating Fungal Meningitis

As the number of deaths from fungal meningitis mounts, many people want to know how fungal meningitis is diagnosed and treated.

As an infectious disease doctor, it is routine for me to care for patients who come in the hospital with a fever. At first glance it is impossible to tell whether the patient has meningitis, pneumonia or a urine infection.

If a patient has headache, confusion or stiff neck along with the fever then I become suspicious for meningitis. Meningitis is simply an infection of the sac and the sterile fluid that surrounds the brain and the spinal cord. From the clinical presentation, it is impossible to know which type of meningitis a patient has.

One of the most common forms is bacterial meningitis, caused by the same organisms that lead to sinusitis or pneumonia. Viral meningitis is generally less severe and often occurs during the summer months. Tuberculous meningitis occurs often in the developing countries, and fungal meningitis is seen in patients who have a weakened immune system, such as those with cancer or AIDS. It is critically important to know the likely pathogens causing the meningitis because it determines the life-saving treatment regimen.

Diagnosis of meningitis can only be made by a lumbar puncture, also called a spinal tap, where a trained physician places a thin needle in the lower back and draws a sample of fluid surrounding the spinal cord and the brain. If the spinal fluid has many white cells, it is an indication that there is inflammation, possibly due to an infection. If there is a predominance of white cells that are neutrophils, it is indicative of a bacterial meningitis. Other types of cells are suggestive of viral, fungal or TB infection.

The definitive diagnosis of meningitis is made by examining the fluid under a microscope and obtaining a spinal fluid culture. Sometimes a culture may not readily grow a bacteria or a fungus, and so doctors must use clinical judgment and lab results to determine the likely causative agent and give the appropriate treatment.

Public health official have determined that the recent outbreak of meningitis is Tennessee and other states is due to two fungi, aspergillus and exserohilum rostratum, which contaminated some of the 17,000 steroid vials used for injection. These fungi are commonly found in soil and plants. In my practice, while I often see patients who have had a heart or lung transplant with aspergillus infection in the lung, I have never seen a case of aspergillus meningitis, or an infection with the exserohilum rostartum.

For the general public, it is important to know that these fungi don't naturally cause meningitis infections in patients with a normal immune system unless they have been exposed to the tainted injection in the spine. Also, while some types of bacterial meningitis -- like Neisseria meningitidis -- are contagious, most other forms of meningitis, including fungal meningitis, cannot be passes on from person to person.

The treatment for fungal meningitis needs to be promptly started if patients have had a spinal injection and their spinal fluid is suggestive of fungal meningitis. The medicines include voriconazole and lipid amphotericin B. Each medicine has serious side affects, including kidney failure. And even with proper treatment, the prognosis of fungal meningitis is tenuous.

So who should seek medical attention? Any patients who have had a steroid injection after May 21, 2012 and are having symptoms of meningitis or a stroke, as well as patients with back-bone infection or joint infection after steroid injections. Just today at the hospital we were consulted on a patient who had a steroid injection in the back.

Many doctors, including myself, are going through a steep learning curve about the outbreak and better diagnosis and management of fungal meningitis. Likewise, many patients who have previously had any form of steroid injections are very anxious. Most certainly this outbreak of fungal meningitis will be contained, yet it is important for all of us to stay informed.

For more by Manoj Jain, M.D., MPH, click here.

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