By Dorothy Brooks
The CDC is advising frontline providers of a potential surge in cases of acute flaccid myelitis (AFM), a rare, polio-like complication of certain enteroviruses. Concurrently, there are concerns about the re-emergence of poliomyelitis.
New York has declared a state of emergency after a young adult tested positive for poliomyelitis in Rockland County, the first case of the illness discovered in the United States in decades. Further, evidence of circulating poliovirus has been found in wastewater samples from at least three counties in New York, indicating there is local transmission.
Health officials believe the case of poliomyelitis, the paralytic form of polio, probably originated from overseas. Perhaps more importantly, the officials note poliovirus is highly contagious, and they are urging frontline providers to consider polio on the differential diagnosis for any patient who presents with a sudden onset of limb weakness.
Of course, AFM must be considered in such cases as well, particularly given the fact severe respiratory illnesses are causing an increase in pediatric hospitalizations across the country, a development that often signals an increase in cases of AFM. However, there are some key differences between these two illnesses.
At this point, frontline providers likely are familiar with the presentation of AFM, as there has been a number of outbreaks of the illness in young children in recent years. However, given that poliomyelitis has suddenly reappeared, the CDC recently hosted a briefing for clinicians on what they know about the recent case in New York, how a case typically presents, and what kind of testing is required to pin down an accurate diagnosis.1
Emily Lutterloh, MD, MPH, director of the division of epidemiology for the New York Department of Health, explained her division became aware the poliovirus had been detected in a stool sample in July.
“The patient was an unimmunized, immunocompetent young adult who had developed fever, neck stiffness, back pain, abdominal pain, and constipation,” she noted. “Then, over the next few days [the patient] developed lower extremity weakness, and about two days after the weakness began, [the patient] presented to an emergency department and was admitted to the hospital with flaccid weakness. After a stay of several days, the patient was discharged to a rehabilitation facility.”
Interestingly, the specimen sample from this patient had been submitted as part of routine surveillance for AFM. “The clinicians caring for the patient were aware of an advisory that had been disseminated by the [New York] Department of Health in late June that was reminding healthcare providers to submit specimens for cases of AFM,” Lutterloh said. “That’s what led to the submission of specimens in this case and the fortuitous [early] detection of poliovirus.”
The case set off alarms throughout the state. There is an ongoing outreach effort to ensure healthcare providers are aware of the case and can provide continuing assistance in conducting surveillance. Public health authorities also have acted swiftly to drive up immunization rates among children and adults who have not been vaccinated against polio or have not completed the series of recommended shots.
“We’ve also recommended boosters for a very narrow group of individuals who are a high risk of exposures, such as those in contact with our case and certain healthcare workers who might care for polio patients,” Lutterloh said.
It is important to note not all patients infected with poliovirus suffer from the limb weakness exhibited by the case identified in New York. In fact, Farrell Tobolowsky, DO, MS, clinical task force lead for the 2022 polio response at the CDC, noted paralytic polio occurs in less than 1% of infections, and that the proportion of patients with paralysis varies based on what serotype of the virus is involved.1
“For this reason, one case of paralytic polio indicates an outbreak, and there are likely many infected, with about 25% who have a mild clinical illness, and the majority — or about 75% — who have an asymptomatic infection,” she said.
Typically, for nonparalytic polio, it takes three to six days following exposure to develop signs or symptoms. However, it can take up to 21 days for paralytic polio to present. “Poliovirus is a highly infectious pathogen and can spread very easily,” Tobolowsky said. “Generally, person-to-person spread occurs via the fecal-oral route; however, it can spread less commonly through the oral-to-oral route.”
Tobolowsky indicated patients with poliovirus are most infectious during the days immediately before and after symptom onset. However, she noted patients can shed the virus in their stool for three to six weeks — and sometimes longer. “Even those with asymptomatic or mild infection can shed the virus,” she said.
There are key signs and symptoms clinicians should consider when evaluating a patient with limb weakness, noted Janell Routh, MD, MHS, incident manager for the 2022 New York polio response from the CDC.1 “Most patients have a preceding illness before the onset of acute flaccid limb weakness. The illness is often gastrointestinal in nature, which may include symptoms of fever, sore throat, abdominal pain, muscle aches, and malaise,” she said. “This preceding illness may occur one to three weeks before the development of limb weakness, [and] weakness onset is often accompanied by a recurring fever, neck or back pain, and pain in the affected limbs.”
Routh explained the onset of weakness is rapid, taking place over the course of a just a few hours or days. More specifically, she noted the affected limbs tend to be flopping rather than spastic. While this aspect is observed in cases of AFM as well as paralytic polio, there are some differences between the two illnesses in presentation. “For paralytic polio, weakness is usually in the lower extremities and is often asymmetric. This is in contrast to acute flaccid myelitis, where although we see that same asymmetry, it is mostly the upper extremities that are affected in that disease,” Routh said.
Also, with polio, there may be drooping eyelids or struggling eye movement, facial droop, difficulty swallowing, and slurred speech. “It is definitely important to note these symptoms because they can signal respiratory impairment, and these findings might present with a weak or hoarse cry in infants,” she indicated.
When taking a medical history, providers should include questions about recent travel and vaccination status. “Red flags are recent international travel to areas where poliovirus is circulating within the incubation period of seven to 21 days or exposure to someone who has been infected with poliovirus,” Routh said. “When I walk into an examination room with a child who has acute flaccid weakness, that first question out of my mouth should be ‘does that patient have the full complement of recommended polio vaccinations?’”
Routh advised clinicians to note any gastrointestinal symptoms that occurred with or without fever before the onset of limb weakness. Also, ask about any difficulties with respect to breathing or shortness of breath. This could indicate the illness has affected the bulbar region of the brain, which controls many involuntary functions. “Young children or parents may not describe limb impairment as actual weakness, so it is definitely important to ask questions about limb function,” Routh stressed.
For instance, ask whether patients have lost their age-appropriate ability to feed or dress themselves or throw a ball. Also ask the patient whether he or she stumbles or falls when walking or trying to squat.
Clinicians should evaluate strength in both proximal and distal muscle groups. These are most often affected by paralytic polio and can be missed when examining a patient. In particular, Routh noted clinicians should evaluate the shoulders, hips, and trunk muscle groups.2
When assessing a patient with acute flaccid paralysis, note there could be multiple causes. For example, acute cord compression, transverse myelitis, spinal stroke, Guillain-Barré syndrome, and other illnesses that affect the spine and motor neurons.
“A careful medical history, neurologic examination, lab testing, and MRI of the brain and spine can help guide diagnosis. [Testing] should be done together with specialists in both infectious disease and neurology,” Routh said.
Regarding neuroimaging, Routh advised ordering an MRI with and without contrast for the entire spine and brain using the highest Tesla scanner available. These images can be helpful in pinpointing hyperintense lesions in the gray matter that are indications of poliomyelitis.
For laboratory testing, Routh recommended collecting cerebrospinal fluid, serum, and both nasopharyngeal and oropharyngeal swabs as quickly as possible. “In-house enterovirus testing on a multiplex assay is an important first step for many of those specimen types, but it won’t detect stool enteroviruses which are the gold standard for polio,” she said.
When poliovirus is suspected, collect two whole stool and two oropharyngeal swabs that are taken at least 24 hours apart during the first 14 days following the onset of limb weakness.3 “All specimens should be routed through the state or local health department for initial enterovirus testing, and then will be sent to the CDC for confirmation,” Routh said.
Routh stressed it is critical to report any suspected cases to public health authorities. However, such reporting should not delay appropriate patient management. She said patients with acute flaccid weakness should be hospitalized for the diagnostic workup as well as the monitoring of respiratory status because the progression of weakness can be quite rapid.
While there are no FDA-approved medications for treating polio myelitis, early initiation of rehabilitation has proven helpful in patients with AFM.
If poliovirus is suspected, isolate the patient in a room with a private bathroom, if possible, while the diagnostic workup is completed. Routh noted healthcare providers should use standard and contact precautions while interacting with suspected poliovirus patients. In cases when respiratory distress prompts the need for intervention, providers should consider droplet precautions.
Finally, Routh stressed only healthcare personnel and lab workers with evidence of complete polio vaccination should work with suspected poliovirus patients. “The CDC does have booster recommendations for certain groups. A single lifetime booster is recommended for lab and healthcare providers who handle specimens that might contain polioviruses, and for healthcare providers who are treating patients who could have polio,” she said.
RESOURCE
• Centers for Disease Control and Prevention. Severe respiratory illnesses associated with rhinoviruses and/or enteroviruses including EV-D68 — Multistate, 2022. Sept. 9, 2022.
REFERENCES
1. Centers for Disease Control and Prevention. Polio in New York: How to recognize and report polio, and reinforce routine childhood polio vaccination. Sept. 1, 2022.
2. Centers for Disease Control and Prevention. Acute flaccid myelitis. Evaluating proximal muscle weakness. Page last reviewed July 1, 2022.
3. Centers for Disease Control and Prevention. Acute flaccid myelitis. Specimen collection instructions. Page last reviewed July 1, 2022.
The CDC is advising frontline providers of a potential surge in cases of acute flaccid myelitis (AFM), a rare, polio-like complication of certain enteroviruses. Concurrently, there are concerns about the re-emergence of poliomyelitis.
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