Preliminary Guidelines for the Diagnosis and Treatment of Human Neuroangiostrongyliasis (Rat Lungworm Disease) in Hawai’i
Authors: Clinical Subcommittee* of the Hawaii Governor’s Joint Task Force on Rat Lungworm Disease
From Hawaii Department of Health Press Release:
Preliminary Guidelines for the Diagnosis and Treatment of Human Neuroangiostrongyliasis (Rat Lungworm Disease) in Hawaii
August 29, 2018
The Clinical Subcommittee of the Hawaii Governor’s Joint Task Force on Rat Lungworm Disease has published its report, “Preliminary Guidelines for the Diagnosis and Treatment of Human Neuroangiostrongyliasis (Rat Lungworm Disease) in Hawaii”. The full document can be read here; below are the key points of the report.
- Clinicians in Hawaii should have a high index of suspicion for neuroangiostrongyliasis.
- Suspect cases should be discussed with the Department of Health (DOH) Disease Investigation Branch (DIB) at the earliest opportunity to facilitate prompt, accurate diagnosis and appropriate patient management. Call (808) 586-4586 for the Disease Reporting Line.
- Typical symptoms in adults include severe headaches, neck stiffness, nausea, paresthesias, and limb pains. Highly suggestive symptoms include migratory hyperesthesias, cranial nerve abnormalities, ataxia, and focal neurologic findings which are migratory or do not follow a dermatomal distribution.
- Typical symptoms in children include fever, abdominal pain, vomiting, irritability, poor appetite, muscle weakness, fatigue, and lethargy.
- Lumbar puncture (LP) is an essential part of the evaluation of suspected neuroangiostrongyliasis. It is a low-risk procedure and has therapeutic benefits, including relief of headaches, nausea, and vomiting.
- A presumptive diagnosis of neuroangiostrongyliasis requires all three of the following:
- A history of suggestive symptoms and signs,
- Evidence of eosinophilic meningitis in the cerebrospinal fluid (CSF), and
- An exposure history, which includes residence in or recent travel to an endemic area.
- Eosinophilic meningitis is the hallmark of the disease and is defined as the presence of 10 or more eosinophils per μL of CSF and/or eosinophils accounting for more than 10% of CSF white blood cells when there are at least 6 total WBC per μL in CSF.
- CSF eosinophil counts may be absent or low early in the course of the disease, requiring repeat LPs if neuroangiostrongyliasis is still suspected.
- Real-time polymerase chain reaction (RTi-PCR) of CSF for A. cantonensis DNA is the best way to confirm the infection and is available in Hawaii through the DIB or from the Centers for Disease Control and Prevention (CDC) for the rest of the United States.
- CSF RTi-PCR may be negative in the early stages of infection.
- Repeat LP and testing is indicated if neuroangiostrongyliasis is still suspected.
- Baseline studies should include a complete blood count (CBC) with differential, serum electrolytes, liver function tests, renal function tests, blood glucose, urinalysis, and chest x-ray.
- Peripheral eosinophil counts of ≥ 500 cells/μL are often present during the course of the illness but may be absent.
- Magnetic resonance imaging (MRI) of the brain, although not required, may be helpful in diagnosing suspected neuroangiostrongyliasis. Focused MRI of the spine may be appropriate if indicated by clinical presentation.
- Serological tests for antibodies against A. cantonensis in the serum or CSF are not recommended for the diagnosis of neuroangiostrongyliasis.
- High dose corticosteroids have been shown to improve clinical outcomes. Start corticosteroids as soon as a presumptive diagnosis of neuroangiostrongyliasis is made and assuming no contraindications.
- Individuals with diabetes or glucose intolerance should be closely monitored.
- Modifications to the patient’s diabetes medications may be needed.
- The addition of albendazole, an anthelminthic drug, may provide additional benefits, although there is limited evidence of this in humans.
- If albendazole is used, combine with corticosteroids to blunt any possible increase in the inflammatory response to dying worms.
- Careful clinical monitoring is recommended in all patients, and specialist consultation (e.g., infectious disease, neurology, etc.) may be advisable.
- Pain management may require early consultation with a pain specialist.