Acute flaccid paralysis (AFP) is defined as a sudden onset of paralysis/weakness in any part of the body of a child less than 15 years of age. This syndromic reporting strategy, of investigating all AFP cases rather than just “suspected poliomyelitis”, serves many purposes. This case definition also extends to any person of any age with paralytic illness in whom a clinician suspects poliomyelitis. It is a lower motor neuron lesion.
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, a syndrome that encompasses all cases of paralytic poliomyelitis, also is of great public health importance because of its use in surveillance for poliomyelitis in the context of the global polio eradication initiative.
AFP is characterized by weakness or paralysis of one limb or one arm. Flaccid paralysis causes reduced muscle tone without obvious case such as trauma. 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.
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.
Causes of Acute Flaccid Paralysis
Causes of AFP can be classified into four, according to their clinical features as
- Peripheral neuropathy: This is a result of damage to one’s peripheral nerves, often causing weakness, numbness and pain. This weakness is usually noticed in the hands and feet of the affected individual and can also affect other areas of your body. Disease states 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
• Periodic paralyses
• Corticosteroids and blocking agents
• Mitochondrial diseases (infantile type)
• Post viral myositis
- 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
- 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
- Disorders of neuromuscular transmission: Disorders of neuromuscular transmission that features as AFP includes
• Myasthenia gravis
• Insecticide (organophosphate poisoning)
• Tick bite paralysis
• Snake bite
Differential Diagnosis of AFP
AFP is differentially diagnosed according to whether it matches clinical case definition of some known disease conditions or the results of a laboratory analysis. Clinical diagnosis is according to whether the clinician is satisfied that the case presented as Guillain-Barre Syndrome, Traumatic neuritis or Transverse myelitis.
Laboratory diagnosis will ascertain if it is caused by Coxsackie Virus, Poliovirus, Echovirus or other enteroviruses.
Treatment of AFP
Treatment and management of AFP is clinical. Every suspected case of AFP must be reported to the nearest health facility for immediate action which may involve differential diagnosis. Critical care is needed and according to laboratory investigation outcomes, Immune modulatory therapy could be started for rapidly progressive cases and are most effective within the first 10 days. Massaging and palpating of paralyzed areas are often administered by traditional bones 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.
World Health Organization (Guidelines for Acute Flaccid Paralysis Surveillance Nigeria, Revised Edition, November, 2012).