Most common cause of death in case of acute poliomyelitis is –
Intercostal muscles paralysis
Convulsion
Cardiac arrest
Respiratory failure
Death is usually due to complications arising from respiratory dysfunction.


Paralytic polio


In less than 1% of infections.
Paralysis is characterized as :


Descending 
Asymmetrical 
Proximal muscles > distal muscles
Non progressive
No sensory involvement 
No autonomic disturbance
Lower motor neuron type


Most common muscle affected -4 Quadriceps
Most common muscle undergoes complete paralysis -4 Tibialis anterior
Most common muscle affected in hand —> Opponens pollicis.
M.C. cause of death ---> Respiratory paralysis 
Following signs can be elicited :


Tripod sign   —>      Child is asked to sit up unassisted. He assumes tripod posture.
Kiss the knee Test           —>         The child cannot kiss his knees due to spine stiffness.
Head drop sign    —>        Hand is placed under the patients shoulder and the trunk is raised. The head lags behind simply.