Flaccid Myelitis Diagnosis and Evaluation

Liv Hospital provides advanced MRI imaging and pediatric neurological assessment for early and accurate Flaccid Myelitis diagnosis.

How Is Acute Flaccid Myelitis (AFM) Diagnosed?

Diagnosing Acute Flaccid Myelitis (AFM) is a race against time. Because the condition progresses rapidly and mimics several other neurological emergencies, a swift and precise evaluation is mandatory. The diagnosis is often "comprehensive," meaning it relies on a combination of clinical physical findings, advanced neuroimaging, and laboratory analysis of various bodily fluids.

At Liv Hospital, we utilize an accelerated diagnostic protocol for children presenting with sudden-onset weakness. The "gold standard" for confirming AFM is the identification of specific lesions within the gray matter of the spinal cord. 

Detailed Clinical History and "The Viral Timeline"

The evaluation begins with a meticulous reconstruction of the days and weeks leading up to the weakness. Clinicians look for a "biphasic" illness pattern: a mild respiratory or gastrointestinal illness followed by a brief period of recovery, then the sudden onset of paralysis. Identifying the specific timing of the fever and cough helps narrow down the likely viral trigger, such as Enterovirus D68.

A specialized pediatric neurologist assesses the child’s motor system. Key findings for AFM include:

• Hypotonia: Checking for "floppiness" in the limbs.
• Diminished Reflexes: Using a reflex hammer to confirm the absence of deep tendon reflexes (areflexia).
• Cranial Nerve Check: Evaluating eye movements, facial symmetry, and the gag reflex to see if the brainstem is involved.

High-Resolution MRI (3-Tesla MRI)

Magnetic Resonance Imaging is the most critical tool in the diagnosis of AFM.

• The Signature Finding: The MRI must show a longitudinal lesion (inflammation) restricted primarily to the gray matter (the "butterfly" shape in the center of the spinal cord).
• Extent of Damage: The scan helps determine how many segments of the spinal cord are affected, which predicts the severity of the paralysis and the risk of respiratory failure.

Lumbar Puncture (Cerebrospinal Fluid Analysis)

A sample of the fluid surrounding the brain and spinal cord (CSF) is collected via a needle in the lower back.

• Pleocytosis: In AFM, the CSF typically shows an increased white blood cell count (lymphocytes), indicating active inflammation.
• Protein Levels: Unlike in Guillain-Barré Syndrome, protein levels in AFM are usually normal or only slightly elevated.

These tests measure the electrical activity of muscles and the speed of nerve signals.

• Lower Motor Neuron Pattern: In AFM, the nerves outside the spinal cord may look normal, but the muscles show signs of "denervation." This confirms that the problem is located within the spinal cord’s motor neurons rather than the peripheral nerves or the muscles themselves.

Viral Pathogen Testing (PCR)

To identify the trigger, samples are taken from multiple sites:

• Respiratory Swabs: Testing the nose and throat for enteroviruses and rhinoviruses.
• Stool Samples: Enteroviruses are often shed in the stool long after they have cleared the respiratory tract.
• Blood and CSF: While viruses are rarely found directly in the spinal fluid in AFM, testing is done to rule out other infections like West Nile Virus.

Differential Diagnosis: Ruling Out GBS

Guillain-Barré Syndrome (GBS) is the most common condition confused with AFM.

• The Difference: GBS usually presents with symmetrical weakness and sensory loss (numbness), whereas AFM is often asymmetrical and focuses almost exclusively on motor weakness. The MRI and EMG results are the primary tools used to tell them apart.

Ruling Out Transverse Myelitis (TM)

Transverse Myelitis involves inflammation across the entire width of the spinal cord (both white and gray matter).

• Distinction: TM patients usually have a "sensory level" (a line on the body below which they feel nothing) and significant bladder/bowel dysfunction early on. AFM is much more selective, targeting only the motor cells.

Brainstem Imaging

If the child has difficulty swallowing, slurred speech, or drooping eyelids, the MRI is extended to the brainstem.

• Encephalitis Check: Clinicians look for lesions in the pons or medulla, which can indicate a more severe form of the disease that puts the child at risk for sudden respiratory arrest.

Respiratory Functional Assessment

If the weakness involves the neck or upper arms, the child’s breathing capacity is tested.

• Vital Capacity: Using a spirometer to measure how much air the child can exhale. A drop in these numbers can indicate that the spinal cord damage is affecting the nerves that control the diaphragm.

Why Choose Liv Hospital for AFM Diagnosis?

At Liv Hospital, we follow a “Zero Delay” approach. Our 3-Tesla MRI technology provides high-resolution spinal cord imaging, helping detect the characteristic lesions of Acute Flaccid Myelitis.
Pediatric neurologists and neuroradiologists work together for rapid, accurate diagnosis, while ensuring clear communication with families at every step.