Acute flaccid paralysis (AFP) is a lower motor neuron lesion. It is defined as a sudden onset of paralysis or weakness in any part of the body of a child less than 15 years of age. The term “flaccid” indicates the absence of spasticity or other signs of disordered central nervous system motor tracts such as hyperreflexia, clonus, or extensor plantar responses.
AFP mimics poliomyelitis but is rarely due to an infection with polio virus. However, AFP is a marker for poliomyelitis and forms the basis for World Health Organization (WHO) polio surveillance. An AFP case when clinically diagnosed will provide an answer to what caused the paralysis, in which case the child will be tested for possible polio virus infection.
Acute flaccid paralysis is commonly characterized by weakness or paralysis of one limb or one arm. It doesn’t usually affect both limbs at the same time. Children with flaccid paralysis will have reduced muscle tone without any obvious cause such as trauma. The doctor will have to do several investigations to find out the exact cause for your child’s symptoms.
What are the Symptoms of AFP?
Symptoms of Acute Flaccid Paralysis includes
• Paralysis (which has a sudden onset).
• Paresis (weakness).
• Flaccidity of the affected limb or hand (floppiness).
• Inability to sit up, walk or move the affected leg or arm at all.
What causes it?
Causes of AFP can be classified into four, according to their clinical features. They are :
1. Peripheral neuropathy
This is a result of damage to one’s peripheral nerves, often causing weakness, numbness and pain. Examples of diseases that causes peripheral neuropathy which results to AFP includes:
- Guillain-Barre syndrome
- Acute axonal neuropathy
- Neuropathies of infectious diseases (diphtheria, Lyme disease)
- Acute toxic neuropathies (heavy metals, snake toxin)
- Arthropod borne viruses
- Focal mononeuropathy
- Anterior horn cell disease
- Acute anterior poliomyelitis
- Vaccine-associated paralytic polio
- Other neurotropic viruses (eg. enteroviruses and herpesviruses)
- Polymyositis, dermatomyositis
- Corticosteroids and blocking agents
- Mitochondrial diseases (infantile type)
- Post viral myositis
2. Acute Myelopathy
Myelopathy describes any neurologic deficit related to the spinal cord. When due to trauma, it is known as (acute) spinal cord injury and when inflammatory, it is known as myelitis. Disease states that causes myelopathy which results to AFP includes
- Paraspinal abscess
- Vascular malformation with thrombosis/bleeding
- multiple sclerosis
- transverse myelitis
- acute disseminated encephalomyelitis (ADEM)
Ischaemic cord damage
- anterior spinal artery syndrome
- peri-operative complication
3. Systemic Disease
A systemic disease is one that affects a number of organs and tissues or affects the body as a whole. Systemic disease states that features as AFP includes
- Acute porphyria
- Critical illness neuropathy
- Acute myopathy in ICU patients
4. Disorders of neuromuscular transmission
Disorders of neuromuscular transmission that features as AFP includes
- Myasthenia gravis
- Insecticide (organophosphate poisoning)
- Tick bite paralysis
- Snake bite
How is AFP Diagnosed?
Diagnosing AFP can be very challenging because of the several possible causes. Since children with AFP test negative for polio virus in recent years due to intensive glabal childhood vaccination, doctors will have to match your child’s symptoms with the clinical case definition of some of the other known diseases that can cause flaccid paralysis.
A comprehensive history taking and detailed physical examination of your child forms part of the clinical diagnosis of AFP. The doctor will want to be sure whether the flaccid paralysis presented is similar to that caused by the leading suspected conditions such as Guillain-Barre Syndrome, Traumatic neuritis and Transverse myelitis.
Laboratory diagnosis will help ascertain the flaccid paralysis is caused by any of the suspected viral infections including Coxsackie Virus, Poliovirus, Echovirus or other enteroviruses.
How is it Treated?
Treatment and management of AFP is done in the hospital. It is important that you take your child to see a physician immediately you notice any of the symptoms of Acute Flaccid Paralysis for immediate action which may involve determining the cause of the paralysis or weakness.
Depending on the outcome of the doctor’s investigations and laboratory findings, your child will receive the care and treatment required based on what caused the flaccid paralysis.
Massaging and palpating of paralyzed areas are often administered by traditional bone healers but it is worthy of note that due to their inability to carry out laboratory and clinical diagnosis, they may be treating the wrong thing as in the case of poliomyelitis. So it is better that you take your child to the hospital for the best diagnosis and care.
- World Health Organization – Guidelines for Acute Flaccid Paralysis Surveillance Nigeria,
- Centre for Disease Control and Prevention – About Acute Flaccid Myelitis