Clinical features

Acute Poliomyelitis

In 95% of cases of acute poliomyelitis the infection is asymptomatic or of a very minor nature. Symptoms include sore throat, fever, nausea, vomiting, abdominal pain, muscle pains etc. that are indistinguishable from the common symptoms of other viral infections.

If the nervous system is attacked by the virus, headache and stiffness of the neck, back and legs with painful spasms develop. In 1% of cases paralysis of muscles occurs and worsens over some days. Classically certain groups of muscles are affected in an asymmetrical pattern. The lower limbs are affected more often than the upper limbs, and one leg or one part of the leg may be involved while the other leg is spared. The affected muscles are weak and floppy (flaccid) and paralysed.

In a very small number of cases the virus also attacks the motor nerve cells controlling the muscles of the face, throat, tongue and of respiration. The ability to swallow, speak and breathe becomes affected. This is known as bulbar polio and may be fatal in some cases. Artificial ventilation is necessary to sustain life when paralysis of respiratory muscles is severe.

Late Effects of Polio and the Post Polio Syndrome

There is a wide spectrum of clinical presentations in people who experience late deterioration, and these depends in part on the nature and extent of the residual disabilities. The clinical features include:-

• Increasing muscle weakness, wasting, pain and fatigue in affected muscles and limbs, and, in some cases, of other muscles.
• Decreased physical stamina and increased feelings of fatigue
• Osteoporosis causing pain and propensity to fractures
• Insomnia and sleep apnoea
• Severe degenerative arthritis in the joints of weak or paralysed limbs leading to more pain, deformity, instability and restricted movement.
• Development of arthritis in joints of non-paralysed limbs due to overuse or spinal deformity.
• Severe degenerative arthritis in the spine, especially the neck; progressive scoliosis of the spine.
• Increased pressure on nerves causing pain, sensory symptoms such as parathesiae and numbness and further impairment of movement
• Pressure on the spinal cord leading to limb weakness and sensory symptoms.
• Development of obesity and general lack of physical fitness due to poor mobility and difficulty in exercising.
• Increasing chest wall deformity leading to shortness of breath and propensity to chest infections
• Increasing respiratory difficulty causing shortness of breath. This may lead to a requirement to use a ventilator at night and/or for short periods in the day, and for those already using ventilators to use them for longer periods.
• Difficulty in swallowing may worsen and predispose to chest infections due to aspiration
• Other common medical conditions that develop in middle age such as diabetes and heart disease that causes additional functional restrictions.
• Symptoms of depression and anxiety may exacerbate physical problems subsequent to the development of new or increasing functional restrictions

Amended June 2008