Spinal cord lesions

Introduction Spinal cord anterior horn lesions are manifestations of polio. Polio is an acute infectious disease caused by poliovirus. Under the electron microscope, the virus was observed to have a small spherical shape with a diameter of 24 to 30 nm and a circular particle shape. It contains a single-stranded ribonucleic acid with a nucleic acid content of 20% to 30%. The viral nucleocapsid consists of 32 shells, each containing four structural proteins, VP1 to VP4. VP1 has a specific affinity for human cell membrane receptors and is associated with the pathogenicity and toxicity of the virus.

Cause

The poliomyelitis virus is an enterovirus genus of the picornavirus family. Under the electron microscope, the virus was observed to have a small spherical shape with a diameter of 24 to 30 nm and a circular particle shape. It contains a single-stranded ribonucleic acid with a nucleic acid content of 20% to 30%. The viral nucleocapsid consists of 32 shells, each containing four structural proteins, VP1 to VP4. VP1 has a specific affinity for human cell membrane receptors and is associated with the pathogenicity and toxicity of the virus.

1. Resistance Poliovirus is insensitive to all known antibiotics and chemotherapeutic drugs and can tolerate chemical disinfectants of general concentrations, such as 70% ethanol and 5% phenolic soap. 0.3% formaldehyde, 0.1 mmol/L hydrochloric acid and (0.3-0.5) x 10-6 residual chlorine can be quickly inactivated, but can be protected in the presence of organic matter. It can be completely inactivated by heating to 56 ° C for 30 min, but it can be stored for several years in a frozen environment, for several weeks in a 4 ° C refrigerator, and for several days at room temperature. Sensitive to ultraviolet light, dryness and heat. It can survive for months in water, feces and milk. Magnesium chloride can enhance the resistance of the virus to temperature, so it is widely used to preserve live attenuated vaccines.

2. Antigenic properties The serum neutralization test can be divided into three serotypes I, II and III. Each serotype virus has two type-specific antigens, one is a D (dense) antigen, which is present in the mature virion, and the virus containing the D antigen is sufficiently infectious and antigenic; the other is C ( The coreless antigen is present in the pre-shell of the virus, and the virus containing the C antigen is an empty shell particle lacking RNA, and is not infectious. Under the action of neutralizing antibodies, D antigenicity can be converted to C antigenicity, losing the ability to reinfect cells. Heating the inactivated virus loses VP4 and ribonucleic acid and becomes a viral particle containing the C antigen. The natural D antigen and the heated C antigen can be detected by a precipitation reaction and a complement binding assay.

3. Host range and virulence Humans are the natural host and storage host of poliovirus, and both monkeys and orangutans are susceptible animals. The virus binds to cell surface specific receptors and is taken up into the cells, replicating in the cytoplasm, and releasing inhibitors to inhibit the synthesis of host cell RNA and proteins.

The natural poliovirus is called a wild strain, and the virus strain that has been attenuated in the laboratory is called a vaccine strain. Vaccine strains can only cause spasms when injected directly into the monkey central nervous system, but not to human nerve cells. Vaccine strain viruses, particularly type III viruses, can be mutated into toxic intermediates when transmitted in humans. The most reliable method for identifying wild strains and vaccine strains is to perform nucleic acid sequence analysis.

an examination

Related inspection

Spinal MRI examination of poliovirus antibodies

(A), the performance of the lower motor neuron, because the anterior horn cells are widely distributed, so it is less common.

(B), muscle atrophy is obvious.

(C), there may be fasciculation.

(D), muscle tension is reduced.

(5), the reflex is slow or disappears.

(6) There is no sensory disturbance. Found in polio, progressive spinal muscular atrophy.

Differential diagnosis

Differential diagnosis of anterior horn lesions:

1. The frustration type should be differentiated from upper respiratory tract infections caused by influenza and other viruses. Identification can be based on epidemiological data in conjunction with laboratory tests, particularly as a result of virus isolation from the pharynx.

2. Innocent type should be associated with other viruses (Coxsackie virus, Echo virus, Epstein-Barr virus, Mumps virus, Lymphocytic choriomeningitis virus, Japanese encephalitis virus) infection caused by meningitis Phase differentiation of suppurative meningitis, tuberculous meningitis, fungal meningitis, and meningococcal leptospirosis. Identification with other viral meningitis depends on virus isolation and serological testing. Identification of meningitis caused by other pathogens can be identified by reference to their clinical characteristics, cerebrospinal fluid examination, effects of specific treatment, and pathogenic examination.

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