Acute Flaccid Myelitis

What is Acute Flaccid Myelitis?

Acute Flaccid Myelitis (AFM) is a rare but potentially serious neurological disorder, particularly affecting children. Characterized by sudden onset of flaccid muscle weakness, this condition often occurs following viral infections and affects the motor nerve cells of the spinal cord. If you are curious about the causes and treatment methods of this very serious disease and would like to have detailed information, you can take a look at our content. We wish you all healthy days and good reading.

What Causes Acute Flaccid Myelitis?

Acute Flaccid Myelitis (AFM) is a neurological condition that most commonly develops following viral infections, and the underlying cause is inflammatory damage affecting the motor neurons of the spinal cord. Enteroviruses, in particular, are among the factors most strongly associated with the development of AFM; these viruses can trigger an immune response, leading to damage in the anterior horn cells of the spinal cord. As a result, motor signals to the muscles are disrupted, causing sudden onset of flaccid muscle weakness. In some cases, the virus directly affects nerve tissue, while in others, an excessive or abnormal immune response is considered the primary mechanism of nerve damage. On the other hand, rarely, bacterial infections, toxic exposures, or other inflammatory processes may also contribute to a similar clinical picture. However, current scientific data indicate that AFM is mostly a disease that develops after infection, resulting from the interaction between the immune and nervous systems.

Who Does AFM Affect?

Acute Flaccid Myelitis (AFM) is a rare neurological disease that can affect people of all ages, but most commonly affects children. Preschool and school-aged children are particularly at risk; the main reason for this is that their immune systems are not yet fully mature and they are more susceptible to viral infections. In addition, individuals with weakened immune systems, those with chronic illnesses, or those with a history of severe infections may also be at increased risk of developing AFM. Although rare, adolescents and adults can also be affected by AFM; however, the incidence in these groups is lower compared to children. In conclusion, AFM is a serious neurological condition that requires careful clinical follow-up, especially in childhood, but can occur in all age groups.

How Common Is Acute Flaccid Myelitis?

Acute Flaccid Myelitis (AFM) is a neurological disease that is quite rare in the community but can have serious clinical consequences. Therefore, its prevalence is very low in the general population, with fewer than one case per million reported annually in most countries. Furthermore, while AFM cases generally occur sporadically, they may increase in clusters in some years, particularly during the fall months. These increases are thought to be associated with periods of increased circulation of viral infections, primarily enteroviruses.

Acute Flaccid Myelitis (AFM) Symptoms

Acute flaccid myelitis has many different symptoms. These symptoms vary from person to person, and not every symptom is seen in every patient. Therefore, if you think you are experiencing one or more of the symptoms listed below, you should seek immediate medical attention. At this point, the symptoms of acute flaccid myelitis are as follows:

• Sudden onset of flaccid (flask) muscle weakness in the arms and/or legs
• Significant decrease in muscle tone and weakening or loss of reflexes
• Extremity involvement, usually asymmetrical
• Weakness in the neck muscles and difficulty holding the head upright
• Difficulty swallowing (dysphagia) and speech disorders (dysarthria)
• Weakness in the facial muscles or facial paralysis
• Limited eye movement and drooping eyelids
• Shortness of breath or respiratory failure due to involvement of the respiratory muscles
• A history of fever, upper respiratory tract infection, fatigue, or muscle pain prior to onset

Acute Flaccid Myelitis (AFM) Diagnostic Process

The Acute Flaccid Myelitis (AFM) diagnostic process requires a detailed clinical evaluation and advanced investigations in conjunction with the patient's history of sudden onset of flaccid muscle weakness. Therefore, diagnosis begins primarily with a neurological examination, during which muscle strength, muscle tone, reflexes, and the distribution of involvement are carefully assessed. Magnetic resonance imaging (MRI) is one of the most critical steps in the diagnostic process for suspected cases of AFM; demonstrating lesions affecting the spinal cord, particularly the anterior horn cells, supports the diagnosis. In addition, cerebrospinal fluid (CSF) analysis via lumbar puncture is performed to investigate signs of inflammation and evaluate possible infectious agents. Ultimately, the diagnosis of AFM is made by evaluating clinical findings, imaging results, and laboratory data together; early diagnosis directly affects the course and management of the disease.

Treatment Methods for Acute Flaccid Myelitis

There are six different treatment methods for acute flaccid myelitis, which vary depending on the individual. These are: Nerve Transfer with Microsurgery, Cross Facial Nerve Graft, Free Muscle Transfer, Masseter Muscle Transfer, Temporalis Muscle Flap, and Free Temporalis Tendon Transfer (MIT-3). These treatment methods vary depending on the severity of the acute flaccid myelitis the person has experienced. Therefore, the treatment method is determined after a detailed analysis. If we examine the treatment methods closely;

• Nerve Transfer with Microsurgery

In this method, a healthy motor nerve capable of replacing the dysfunctional facial nerve is transferred to the target muscle group using microsurgical techniques. Following AFM, if permanent damage has developed in the motor nerves that stimulate the facial muscles, the aim is to prevent muscle atrophy by applying the treatment in the early or mid-term. The goal of nerve transfer with microsurgery is to restore nerve transmission to the muscles and regain voluntary facial movements.

• Cross Facial Nerve Graft

In the cross facial nerve graft technique, a nerve graft taken from the healthy side of the facial nerve is transferred to the paralyzed side to stimulate the mimic muscles again. Thus, it is preferred in cases of unilateral permanent facial paralysis associated with AFM to restore natural and symmetrical facial expressions. This requires a two-stage surgical plan and is supported by long-term rehabilitation.

• Free Muscle Transfer

Free muscle transfer is a technique that involves micro-surgical transplantation of living muscle tissue taken from another part of the body (usually the thigh) to replace facial muscles that have completely lost their function. In this context, the free muscle transfer procedure is performed on patients with muscle loss due to long-term denervation following AFM. Additionally, the transferred muscle is connected to an appropriate motor nerve to restore active facial expressions.

• Masseter Muscle Transfer

In this method, the masseter muscle, one of the chewing muscles, is repositioned to enable smiling and corner of the mouth movements. Thus, it is an option that allows for functional results to be achieved in a relatively shorter time in patients with facial paralysis associated with AFM where nerve recovery is not possible. Masseter muscle transfer is particularly effective in correcting drooping of the corner of the mouth.

• Temporalis Muscle Flap

In the temporalis muscle flap technique, the temporalis muscle in the temple region is rotated and used to take over the function of the facial mimic muscles. This technique is preferred in patients with severe facial muscle weakness after AFM who are not suitable for nerve repair. At the same time, thanks to the strong structure of the muscle, mouth corner movements and facial symmetry can be significantly improved.

• Temporalis Tendon Transfer (MIT-3)

The MIT-3 technique involves transferring the tendon of the temporalis muscle to the corner of the mouth using minimally invasive methods. In cases of chronic facial paralysis associated with AFM, this technique aims to restore functional smiling movement with less surgical trauma. Additionally, in temporalis tendon transfer treatment, natural-looking facial expressions can be achieved by providing learned muscle activation in conjunction with the rehabilitation process.

Precautions to Take Before Treatment for Acute Flaccid Myelitis

There are several points to consider before starting treatment for acute flaccid myelitis. Paying attention to these points will ensure better results from acute flaccid myelitis treatment. At this point, the factors you should consider before treatment for acute flaccid myelitis are as follows:

• The onset time, course, and accompanying infection history of sudden muscle weakness should be evaluated in detail.
• A neurological examination should clearly reveal muscle strength, muscle tone, reflexes, and the distribution of involvement.
• Magnetic resonance imaging (MRI) should confirm spinal cord involvement, particularly assessing whether anterior horn cells are affected.
• Guillain-Barré syndrome, transverse myelitis, and other neuromuscular diseases must be ruled out in the differential diagnosis.
• Respiratory functions should be closely monitored, considering the risk of involvement of the respiratory muscles.
• Swallowing and speech functions should be evaluated to determine the risk of aspiration.
• Lumbar puncture and necessary laboratory tests should be performed to investigate infectious and inflammatory causes.
• The patient's age, general health status, and comorbidities should be considered before treatment planning.
• It should be remembered that the treatment process requires a multidisciplinary approach (neurology, intensive care, physical therapy, and rehabilitation).
• The patient and their family should be informed about the course of the disease, possible complications, and the duration of the treatment process.

Things to Consider After Acute Flaccid Myelitis Treatment

Just as before acute flaccid myelitis treatment, there are many points to consider after acute flaccid myelitis treatment. This ensures maximum effectiveness from acute flaccid myelitis treatment and helps achieve the desired results. In this context, the following are important considerations after surgery:

• Muscle strength, reflexes, and changes in motor functions should be assessed neurologically at regular intervals.
• Physical therapy and rehabilitation programs should be continued long-term and regularly.
• Respiratory function should continue to be closely monitored in patients with affected respiratory muscles.
• Speech and swallowing therapy should not be neglected in individuals with impaired swallowing and speech functions.
• Appropriate positioning and exercises should be applied to prevent joint stiffness, muscle shortening, and deformity development.
• The level of independence in activities of daily living should be assessed, and assistive devices should be planned if necessary.
• Immunity status and general health should be monitored for infections.
• Psychosocial support should be provided to help the patient and family adapt to the long recovery process.
• Advanced rehabilitation and reconstructive treatment options should be evaluated in cases of permanent motor loss.
• Regular physician check-ups should be maintained in accordance with the clinical course.