The Florida Health Department has been busy this summer, with this year’s fourth reported case of primary amebic meningoencephalitis (PAM) striking an undisclosed patient. PAM is an infection caused by a parasitic amoeba known as Naegleria fowleri, a parasite that thrives in warm freshwater environments. Florida, known for its subtropical climate and wetland ecosystem, has been the home of several Naegleria fowleri-related cases in the past few years. The infection is often deadly, taking the lives of several patients between 2014-2016. Most reported cases of the infection were sourced back to a singular activity: swimming in warm, stagnant water. The amoeba enters the body through the nose or mouth, where it enters the brain and damages the tissue.
The symptoms of PAM closely resemble those of meningitis, occurring up to nine days after initial exposure. The first wave of symptoms include headache, nausea, vomiting, and fever – but are followed by hallucinations and seizures if left untreated. Those unfortunate enough to become infected have died anywhere between one and eighteen days after symptoms appeared, making early detection and treatment imperative to survival.
Because this deadly infection presents similarly to meningitis and other infections, there are a number of ways to accurately detect the presence of Naegleria fowleri in the brain and cerebrospinal fluid (CSF). The amoeba is often visible under a microscope when pathologists are looking at a sample of infected CSF. The organism can be strained and singularly identified for confirmation. Another common method is through antigen detection, were Naegleria fowleri’s antibodies are used with another type of antibody that catalyzes a glowing reaction when held under specific types of light. The third most widely used method is through cultures. Through observation of Naegleria cultures (CPT 87081), pathologists can take biopsied or scraped tissue and isolate the parasites in a growth plate with bacteria. The bacteria will serve as food for the parasite, and this screening process will cause detection by visualization.
Billable ICD-10 code to specify the diagnosis of PAM is B60.2.
Once PAM is detected, treatment must be immediate to maximize chances of patient survival. In 2013, a drug was used to save the lives of two patients who had been afflicted by the parasitic infection. Impavido, also known as Miltefosine, is an anti-parasitic that was previously only able to be obtained by the Centers for Disease Control. In March, the drug was green-lighted to treat other similar infections since its acquisition by pharmaceutical company Profounda Inc.
Miltefosine is the standard of treatment in PAM patients, after being used on Kali Hardig, the Arkansas teenager whose survival set the precedent of PAM treatment in 2013. Treatment for Hardig included a medically induced coma to lower her body temperature, while awaiting the arrival of the expensive drug, which sells for around $16,000 per pack. Considering the lengthy period of time on which patients need to remain on Miltefosine (28 days), this treatment can be quite costly.