Acute Flaccid Paralysis results from spinal cord inflammation. Medication cannot treat Acute Flaccid Paralysis symptoms and causes. Learn more at Meri Sehat.

Acute Flaccid Paralysis

PNS SHIFA

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Syed Intisar Hussain

Overview

Acute flaccid paralysis (AFP) is a clinical syndrome with several infectious and non-infectious causes. It is characterized by sudden and rapid onset of weakness, in one or more limbs, in children less than 15 years of age.

In Pakistan, AFP occurs at a rate of approximately 8 cases per year per 100,000 children under 15 years of age<a href="#accordion">[1]</a>. <a href="https://merisehat.pk/disease/polio">Poliomyelitis</a> was once the most common cause of AFP. However, with the illness reaching the brink of elimination, other causes have increased in incidence. According to a Pakistani study, Guillain-Barr&eacute; syndrome (GBS) has become the most common cause of AFP in the &lt;15 years population of Punjab<a href="#accordion">[2]</a>. In Pakistan, environmental surveillance of AFP is a part of the polio eradication campaign<a href="#accordion">[1]</a>. Pakistan continues to be one of the only two countries where the wild polio virus exists.&nbsp;

AFP is an &#39;umbrella&#39; term for various diseases such as poliomyelitis, Guillain-Barr&eacute; syndrome, muscle disorders, acute transverse myelitis, and acute traumatic myelitis. As the name implies, AFP causes reduced muscle tone (flaccid) in affected children. Other common symptoms include fever, muscle atrophy, respiratory muscle weakness, difficulty swallowing, tingling of the palms and soles of the feet, cramps, sensory loss, and loss of bladder control.&nbsp;

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Diagnosis of AFP is often made clinically; however, fecal samples are also collected from children for viral culture. Two samples, 24 hours apart, are collected immediately after the onset of illness and two weeks after paralysis. There is no treatment for the syndrome and mostly involves supportive therapy.&nbsp;&nbsp;

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As per Pakistan&#39;s health ministry, acute flaccid paralysis is a Priority Disease, and its presence should be notified to authorities immediately.&nbsp; 
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<h4>Recent Outbreak</h4>

Between January 2018 and January 2019, the UK experienced a surge in cases of acute flaccid paralysis<a href="#accordion">[3]</a>. A total of 40 AFP cases occurred during this period. The cases peaked in October, parallel to an increased enterovirus D68 (EV-D68) activity. Moreover, the majority of the cases in 2018 occurred among young children. Non-polio enteroviruses, especially EV-D68, were found in most of the cases. Polio virus was not detected in any of the samples.&nbsp;

22 of the patients reported respiratory symptoms before limb weakness. As a result of their illness, they either required intensive care unit (ICU) admission or assisted ventilation. Furthermore, health authorities also reported 9 cases of acute flaccid myelitis (AFM) during the outbreak.&nbsp; 
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Acute flaccid myelitis (AFM) is a subset of AFP and has caused outbreaks across the United Kingdom and the United States in the past. A confirmed case of AFP is defined as a rapid onset of flaccid paralysis or weakness of one or more limbs, accompanied by an MRI revealing spinal cord lesions in the gray matter of one or more spinal segments. On the other hand, the presence of acute limb weakness and cerebrospinal fluid (CSF) showing pleocytosis (white blood cell count &gt; 5 cells/mm3) is considered a probable case of AFM. According to the US Centers for Disease Control and Infection (CDC), more than 90% of AFM cases occur in infants<a href="#accordion">[4]</a>.&nbsp;

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In 2014, more than 100 US pediatric patients, younger than 22 years of age, began to develop sudden limb weakness. Their MRI scans revealed inflammation in the grey matter of the spinal cord. The cases peaked between August and November, coinciding with an enterovirus-D68 (EV-68) outbreak in the country. Although researchers initially suspected poliomyelitis, it was soon ruled out and the new condition became to be known as acute flaccid myelitis. Since then, the CDC has reported 682 confirmed cases of AFM<a href="#accordion">[5]</a>. As of 3rd June, 4 confirmed cases from across 2 states have come forward.&nbsp;

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Furthermore, with cases occurring across North America, Asia, Europe, Australia, and Africa, AFM is now considered a global disease. 
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Signs And Symptoms

AFM is characterized by the sudden onset of limb weakness with reduced muscle tone and reflexes. Before limb weakness, people report fever and respiratory symptoms such as cough, runny nose (rhinorrhea), or pharyngitis. Moreover, along with limb weakness, individuals experience symptoms such as: 
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<ul>
	<li>Facial droop or weakness (facial paralysis)</li>
	<li>Drooping eyelids</li>
	<li>Difficulty moving eyes</li>
	<li>Difficulty swallowing (dysphagia)</li>
	<li>Slurred speech (dysarthria)</li>
	<li>Pain in the neck, back, and legs</li>
	<li>Numbness and tingling sensation</li>
	<li>Inability to urinate 
	&nbsp;</li>
</ul>

In severe cases, people can develop paralysis of limbs, respiratory failure, and blood pressure problems.&nbsp; 
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Causes

The neurological condition results from an inflammation of the spinal cord. The death of anterior horn cells within the gray matter of the spinal cord causes reduced muscle tone and weakness in the affected limb. Although the exact cause remains unclear, a majority of cases in AFM outbreaks have shown the presence of enteroviruses, in particular, non-polio enteroviruses D68 and 71. EV-68 typically causes respiratory symptoms; however, the virus can also invade the brain and cause neurological symptoms. On the other hand, enterovirus A71 is responsible for hand-foot-mouth disease. Moreover, other viruses such as West Nile virus, flavivirus, herpesvirus, poliovirus, and adenoviruses can also cause AFM. 
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Diagnosis

Since the symptoms of AFM are similar to other neurological diseases such as transverse myelitis and <a href="https://merisehat.pk/disease/guillain-barre-syndrome-108">Guillain-Barr&eacute; syndrome (GBS)</a>, it is difficult to diagnose the illness. Besides taking a complete history, the doctor performs a physical exam, focusing on muscle tone and reflexes. Investigations such as an MRI scan of the brain and spinal cord, lumbar puncture, and nerve conduction test are also conducted. Moreover, stool and respiratory samples are often collected for viral cultures.&nbsp;

MRI scans allow researchers to look for spinal cord lesions and lumbar picture helps assess the presence of white blood cells in the cerebrospinal fluid. On the other hand, nerve conduction studies help assess nerve speed and muscles&#39; response to messages from the nerves. However, they are only conducted in case one is suspecting GBS or other neuromuscular disorder. 
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Treatment

There is no treatment for AFM and supportive therapy is mostly given to help rehabilitate the child. Neurologists, physiotherapists, and occupational therapists may work together to improve long-term outcomes for the patient. While some people do report an improvement after a year, muscle weakness continues to persist in people. Moreover, people with respiratory weakness often require long-term ventilatory support.&nbsp;&nbsp;

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In some cases, doctors may prescribe antivirals for infection and corticosteroids to reduce inflammation. Other options include immunoglobulins from healthy donors and plasma exchange. However, there is no evidence of these interventions improve health outcomes for patients. 
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Since viral infections are largely responsible for causing acute flaccid myelitis, prevention strategies are mostly aimed at good hygiene practices. These include washing hands with soap and water, avoiding contact with sick individuals, and wearing a mask in case of respiratory symptoms. Furthermore, sick individuals should stay home to prevent the spread of illness. 
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Key Points

<ul>
	<li>Acute flaccid paralysis (AFP) is an umbrella term for multiple diseases such as poliomyelitis, Guillain-Barr&eacute; syndrome, muscle disorders, acute transverse myelitis, and acute traumatic myelitis. It has several infectious and non-infectious causes.</li>
	<li>AFP is a notifiable priority disease in Pakistan; thus, health authorities should be alerted immediately after a case is suspected or confirmed.&nbsp;</li>
	<li>Acute flaccid myelitis (AFM) is a subset of AFP and is characterized by sudden onset of limb weakness, along with MRI findings of spinal cord lesions within the gray matter of the spinal segments.&nbsp;</li>
	<li>Although the exact cause of AFM remains unclear, a majority of the outbreaks across Europe, the US, and Asia have found evidence of enterovirus-68 infection in affected individuals.</li>
	<li>Treatment of AFM is largely supportive and is meant to rehabilitate patients. 
	&nbsp;</li>
</ul>

[1] O'Reilly, K. M. et al., 2018. Population sensitivity of acute flaccid paralysis and environmental surveillance for serotype 1 poliovirus in Pakistan: an observational study. BMC Infectious Diseases.

[2] Ali, S., Rehman, M. Z. u. & Sultan, T., 2016. Spectrum of acute flaccid paralysis in children. Pakistan Journal of Neurological Sciences (PJNS), 11(4).

[3] The United Kingdom Acute Flaccid Paralysis (AFP) Task Force, 2019. An increase in reports of acute flaccid paralysis (AFP) in the United Kingdom, 1 January 2018–21 January 2019: early findings. Euro surveillance, 24(6).