POLIOMYELITIS
Dr .Ghazi F.Haji Cardiologist AL-Kindy Medical collageThese viruses have a propensity for the nervous system, especially the anterior horn cells of the spinal cord and cranial nerve motor neurones. The virus causes a lymphocytic meningitis and infects the grey matter of the spinal cord, brain stem and cortex.
Poliomyelitis is found world-wide but its incidence has decreased dramatically following improvements in sanitation, hygiene and the widespread use of polio vaccines.
AETIOLOGY AND PATHOLOGY
The disease is caused by one of three polioviruses, which are a subgroup of the enteroviruses.It is much less common in developed countries following the widespread use of oral vaccines but is still a problem in the developing world. Infection usually occurs through the nasopharynx. Spread is usually via the faeco-oral route, as the virus is excreted in the faeces.
CLINICAL FEATURES
The incubation period is 7-14 days.Figure :illustrates the various features of the infection.
CONT.Many patients recover fully after the initial phase of a few days of mild fever and headache.
In others, after a week of well-being, there is recurrence of pyrexia, headache and meningism. Weakness may start later in one muscle group and can progress to widespread paresis. Respiratory failure may supervene if intercostal muscles are paralysed or the medullary motor nuclei are involved.
INVESTIGATIONS
The CSF shows a lymphocytic pleocytosis, a rise in protein and a normal sugar content.Poliomyelitis virus may be cultured from CSF and stool.
MANAGEMENTIn the early stages, bed rest is imperative because exercise appears to worsen the paralysis or precipitate it.
At the onset of respiratory difficulties, a tracheostomy and ventilation are required. Subsequent treatment is by physiotherapy and orthopaedic measures.