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  • Topic: Poliomyelitis, Polio vaccine, Nervous system
  • Pages : 9 (2349 words )
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  • Published : March 12, 2013
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• Also known as: Polio; Infantile paralysis or Heine-Medin’s disease • is a viral disease that can affect nerves and lead to paralysis • a disease caused by infection with the poliovirus. The virus spreads by direct person-to-person contact, by contact with infected mucus or phlegm from the nose or mouth, or by contact with infected feces. • Usually affected are infants

• High risk are children below 10 years old


The causative agent: LEGIO DEBILITANS VIRUS which has 3 strains. Three serotypes of poliovirus have been identified—poliovirus type 1 (PV1 - Brunhilde), type 2 (PV2 -Lansing), and type 3 (PV3 -Leon)—each with a slightly different capsid protein. All three are extremely virulent and produce the same disease symptoms. PV1 is the most commonly encountered form, and the one most closely associated with paralysis. Symptoms

There are three basic patterns of polio infection: subclinical infections, nonparalytic, and paralytic. Approximately 95% of infections are subclinical infections, which may not have symptoms. SUBCLINICAL INFECTION

• General discomfort or uneasiness (malaise)
• Headache
• Red throat
• Slight fever
• Sore throat
• Vomiting
People with subclinical polio infection might not have symptoms, or their symptoms may last 72 hours or less. Clinical poliomyelitis affects the central nervous system (brain and spinal cord), and is divided into nonparalytic and paralytic forms. It may occur after recovery from a subclinical infection. NONPARALYTIC POLIOMYELITIS

• Back pain or backache
• Diarrhea
• Excessive tiredness, fatigue
• Headache
• Irritability
• Leg pain (calf muscles)
• Moderate fever
• Muscle stiffness
• Muscle tenderness and spasm in any area of the body
• Neck pain and stiffness
• Pain in front part of neck
• Pain or stiffness of the back, arms, legs, abdomen
• Skin rash or lesion with pain
• Vomiting

Symptoms usually last 1 - 2 weeks.
• Abnormal sensations (but not loss of sensation) in an area • Bloated feeling in abdomen
• Breathing difficulty
• Constipation
• Difficulty beginning to urinate
• Drooling
• Fever 5 - 7 days before other symptoms
• Headache
• Irritability or poor temper control
• Muscle contractions or muscle spasms in the calf, neck, or back • Muscle pain
• Muscle weakness, asymmetrical (only on one side or worse on one side) o Location depends on where the spinal cord is affected o Progresses to paralysis
o Rapid onset
• Sensitivity to touch; mild touch may be painful
• Stiff neck and back
• Swallowing difficulty
Paralytic polio

Spinal polio is the most common form, characterized by asymmetric paralysis that most often involves the legs. Bulbar polio leads to weakness of muscles innervated by cranial nerves. Bulbospinal polio is a combination of bulbar and spinal paralysis. In around 1% of infections, poliovirus spreads along certain nerve fiber pathways, preferentially replicating in and destroying motor neurons within the spinal cord, brain stem, or motor cortex. This leads to the development of paralytic poliomyelitis, the various forms of which (spinal, bulbar, and bulbospinal) vary only with the amount of neuronal damage and inflammation that occurs, and the region of the CNS that is affected. The destruction of neuronal cells produces lesions within the spinal ganglia; these may also occur in the reticular formation, vestibular nuclei, cerebellar vermis, and deep cerebellar nuclei. Inflammation associated with nerve cell destruction often alters the colour and appearance of the gray matter in the spinal column, causing it to appear reddish and swollen. Other destructive changes associated with paralytic disease occur in the forebrain region, specifically the hypothalamus and thalamus. The...
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