|Types of polio
Spinal Paralytic poliomyelitis: In this the motor neurons in the anterior horns of spinal cord are affected. Paralysis is usually asymmetrical, predominantly involves proximal muscle with pain and tenderness. Most commonly it affects the leg. Extent of weakness can vary from a single muscle group to complete tetraparesis.
Bulbar Paralytic poliomyelitis: It occurs due to damage to the medulla, pons and midbrain with dysfunction of the cranial nerve nuclei and respiratory and vasomotor regulating centres in the medulla. It can lead to respiratory muscle failure, distress of respiratory control, dysphagia, dysphonia and dysarthria. Cardiovascular, sweating and gut mobility disturbances may occur.
Bulbospinal paralytic poliomyelitis: It is also known as respiratory poliomyelitis. It has symptoms both of spinal cord and bulbar poliomyelitis. It affects the part of spinal cord C3 to C5 segments and causes paralysis of the diaphragm. Dysphagia and respiratory failure follow.
Polio encephalitis: There is inflammation of motor neurons within the brain stem, motor cortex and the spinal cord. It leads to the stiffness of back and neck, muscle cramps, headaches and paraesthesias. Paralysis occurs within 10 days after symptoms develop progress in 2 to 3 days and complete by the time fever subsides.
There are many symptoms of polio and not everyone will experience all of the symptoms. They symptoms vary according to the type of polio the individual has. In mild polio, some of the symptoms are: headache, nausea, vomiting, general discomfort or a slight fever for up to three days. In nonparalytic polio (aseptic meningitis): the symptoms are similar to mild cases, with the addition of moderate fever, stiff neck and back, fatigue and muscle pain. The symptoms for polio and paralytic polio different. Individuals with paralytic polio experience tremor, muscle weakness, fever, stiffness, constipation, muscle pain and spasms, and difficulty swallowing.
The disease may be staged as:-
Stage 1: Acute stage of paralysis: : it begins with fever and headache, followed by neck stiffness and meningitis. Muscles are painful and tender. Paralysis soon follows and reaches its maximum in 2-3 days. Limbs are weak and there may be difficulty with breathing and swallowing. If the patient does not succumb to respiratory failure, pain and pyrexia subsides after 7-10 days and the patient enters the convalescent stage.
Stage 2: Recovery/convalescent stage: : This stage is prolonged. The return of muscle power is most noticeable during the first 6 months, but there may be continuing improvement for up to 2 years.
Stage 3: Residual paralysis: : Some cases do not progress beyond the early stage of meningeal irritation. In others, however recovery is incomplete and the patient is left with some degree of asymmetric flaccid paralysis or muscle weakness.