Posts Tagged ‘Poliomyelitis’
Polio, or infantile paralysis, is primarily a childhood disease caused by a virus that destroys nerve cell bodies in the anterior horn of the spinal cord, especially in the cervical and lumbar swellings. This degenerative disease is characterized by fever, headache, stiffness and severe pain in the head and back, and the loss of some somatic reflexes. Muscle paralysis follows within several weeks, and finally the muscles atrophy. The death follows that if the virus invades the respiratory and vasomotor nuclei in the medulla or anterior horn cells of control of respiratory muscles. Polio has been effectively controlled by vaccination.
Antibiotics, especially given early in the disease, are very effective against bacterial causes of pneumonia. Erythromycin and tetracycline improve recovery time for symptoms of mycoplasma pneumonia, but do not eliminate the organisms. Amantadine and acyclovir may be helpful against certain viral pneumonias. Because many bacterial pneumonias occur in patients who are first infected with influenza, annual vaccination against influenza can decrease the risk of pneumonia in some patients, particularly the elderly and people with chronic diseases . A specific vaccine against Streptococcus pneumoniae is very protective, and should be administered to patients with chronic diseases. Patients who have decreased immune resistance, and therefore may be at risk of infection by Pneumocystis carinii, are often put on regular medication trimethoprim sulfa and / or inhaled pentamidine to prevent Pneumocystis pneumonia.
WORLD OF MICROBIOLOGY AND IMMUNOLOGY Poliomyelitis and polio – The Invading Organism Causes Symptoms
The invading organism causes symptoms, in part, by provoking an immune response in the lungs too exuberant. Small blood vessels in the lungs become leaking, and protein-rich fluid seeps into the alveoli. This results in less functional area for the exchange of carbon dioxide into oxygen. The patient becomes relatively oxygen deprived, while retaining potentially damaging carbon dioxide. The patient breathes faster, in an effort to bring more oxygen and blow up more carbon dioxide. Mucus production is increased, and capillary leak may shade the mucus with blood. Mucus clogs the fact further decrease the efficiency of gas exchange in the lungs. The alveoli fill further with fluid and debris from the large number of white blood cells being produced to fight infection. Consolidation, a feature of bacterial pneumonias, occurs when the alveoli, which are normally hollow air spaces within the lung, instead become solid, due to quantities of fluid and debris. Viral pneumonias and mycoplasma pneumonias do not result in the consolidation. These types of pneumonia primarily infect the cell walls and lung parenchyma. The diagnosis is largely based on the patient report of symptoms, combined with examination of the chest. Listening with a stethoscope will reveal abnormal sounds, and tapping the back of the patient can get up to a thump if the alveoli are filled with fluid and debris. Laboratory diagnosis can be made of some bacterial pneumonias by staining sputum with special chemicals and looking under a microscope. The identification of the specific type of bacteria may require the sputum culture. X-ray examination of the chest may reveal certain abnormal changes associated with pneumonia. Localized shadows obscuring areas of the lung may indicate a bacterial pneumonia, while streaky or patchy appearing changes in the X-ray image may indicate viral or mycoplasma pneumonia. These changes on x-ray, however, are known to lag in time behind the patient's actual symptoms.
ach contents with their resident bacteria), as well as diabetes, sickle cell anemia, lymphoma, leukemia, and emphysema. Pneumonia is one of the most frequent infectious complications of all types of surgery. Many drugs used during and after surgery can increase the risk of aspiration, impair the cough reflex, and cause a patient to underfill their lungs with air. Pain after surgery also discourages a patient to breathe deeply and cough effectively. The list of organisms that can cause pneumonia is very large, and includes almost every class of infecting organism: viruses, bacteria, bacteria-like organisms, fungi and parasites. Different organisms are more frequently encountered by different age groups. In addition, other host characteristics may place individuals at increased risk of infection by particular types of organizations. Viruses, especially respiratory syncytial virus, parainfluenza and influenza virus, and adenovirus, cause the majority of pneumonias in young children. Pneumonia in older children and young adults is often caused by the bacterium Mycoplasma pneumoniae type. Adults are most often infected by bacteria. The parasite Pneumocystis carinii is an extremely important cause of pneumonia in patients with immune problems, such as patients treated for cancer with chemotherapy or AIDS patients. People who have reason to come into contact with bird droppings, such as poultry workers, are at risk for pneumonia caused by Chlamydia psittaci the parasite. A very large, serious outbreak of pneumonia occurred in 1976, when many people attending an American Legion convention were infected by a previously unknown, which was attributed to air conditioning units in the conference hotel . Pneumonia is suspected in any patient who has fever, cough, breathing chest pain, shortness of breath, and increased. Fever with a shaking chill is even more suspect, and many patients cough up clumps of mucus that may appear streaked with pus or blood. The results of severe pneumonia in the signs of oxygen deprivation, including the blue appearance of the nails.
Acute poliomyelitis is very rare these days in the UK, because of effective vaccination program. Rare cases are usually the result of primary vaccination or "booster" insufficient. It remains a serious problem in some other parts of the world. After infection gastroenterology, the virus settles in the lower motor neurons. Paralysis follows, which is often uneven and asymmetrical in the body. When the infection was very severe in the central nervous system, the lower motor neurons do not recover and the paralysis is permanent. Some damage to motor neurons is less complete, and often it is the recovery of muscle function after several weeks. Permanently affected muscles remain wasted and areflexic. Herpes zoster infections of herpes zoster or shingles infections, have been described in Chapters 8, 9 and 13. The virus enters cells probably dorsal root ganglia in childhood when the chickenpox infection, and remains there as a kind of dormancy. Later in life, as a result of certain disorders of immunological surveillance, the virus becomes active and causes shingles. Herpes simplex infections, cold sores around the mouth and nose are the most common clinical manifestations of herpes simplex virus type 1 infection. A state similar to that in dormant herpes zoster infections occur here, with the herpes simplex virus resident in the trigeminal ganglion. Altered immune status that accompanies another viral infection allows the virus herpes simplex to activate in the ganglion, and cause the rash on the trigeminal territory. In the case of herpes simplex virus type 2 infections, the site of latent infection is the dorsal root ganglia in the sacral region, and led to the reactivation of genital herpes, in which ulcerative vesicular lesions occur in the urogenital tract and the perineum.
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Spinal muscular atrophy Brachial plexopathies Genetic or acquired neuropathies Disorders of neuromuscular junction Myopathies Muscular dystrophies Central nervous system: spinal cord Friedreich’s ataxia Congenital muscular dystrophies Mitochondrial encephalomyopathies Myotonic dystrophy type I evaluation, particularly a difference between upper and lower extremities, manifesting with signs of weakness, spasticity, incoordination, disproportionate tendon reflexes, or extensor toe responses. Concave curves to the left, multiple, or complex curves predict higher risk of underlying neurological disorders. Sensory examination should focus on uncovering features of a sensory level, suspended sensory deficit of spinothalamic modalities suggestive of a syrinx, or local sensory deficits characteristic of radiculopathy. Scoliosis is a common early feature of Friedreich’s ataxia, where diffuse areflexia, extensor toe responses, and abnormal Romberg testing are prominent. Abnormalities of bowel or bladder function should be evaluated with examination of sacral reflexes. Ancillary tests that might be of value include EMG and somatosensory evoked potentials; the latter may be useful as preoperative baseline studies for interoperative monitoring. Spinal cord MRI studies are invaluable in investigating a possible mass or syrinx; in occasional circumstances as, for example when metal rods preclude MR imaging, CT or standard myelography may also have a role. Orthopedic evaluation entails inspection for symmetry in standing and forward bending, and determination of whether the curvature is fixed or flexible. Spine radiographs are obtained with standing posterior–anterior and lateral films; if the child is unable to stand, they are obtained in anterior–posterior seated or supine positions. Curvatures are named for the side and region of the convexity, measured Table 2 Musculoskeletal and Genetic Causes of Scoliosis Musculoskeletal disorders Rheumatoid arthritis Leg length discrepancy Injury to vertebrae Infection of vertebrae Tumors of vertebrae
Genetic testing NCV/EMG Laboratory Imaging Biopsy Poliomyelitis is a viral infection that causes the death of motor neurons in the spinal cord and brainstem. During the acute phase of the infection, the virus may infect the cortex, thalamus, hypothalamus, reticular formation, brainstem motor and vestibular nuclei, cerebellar nuclei, and motor neurons of the anterior and lateral horns of the spinal cord, causing an inflammatory reaction. Death of motor neurons may result, leading to muscle atrophy. The motor neurons that survive recover fully and may reinnervate denervated muscle. Paralytic poliomyelitis is characterized by an initial period of muscle pain and spasms, followed by muscle weakness that peaks in severity by one week after the onset of symptoms. Patients do not experience sensory impairment, but may complain of paresthesias. Bulbar symptoms occur in some patients and include dysphagia, dysarthria, hiccups, and respiratory weakness leading to anxiety and restlessness. In adults, bulbar disease is found in conjunction with spinal disease, but children may present with a pure bulbar poliomyelitis. Urinary retention is common during the acute phase. Patients may also complain of neck and back stiffness and pain, from meningeal inflammation. Muscle weakness is asymmetric and typically proximal. Lumbar segments are usually more severely affected, with trunk muscles being largely spared. Tendon reflexes may be initially brisk, but become diminished or absent. Muscles progressively and permanently atrophy over a period of 2–3 months. Loss of bulbar motor neurons occurs in some patients and can lead to paralysis of the facial muscles , pharynx, larynx, tongue, and mastication muscles. If infection strikes the reticular formation, severe respiratory and autonomic impairment may result. Breathing and swallowing difficulties, as well as loss of vasomotor control, are serious risks for mortality and warrant intensive life support. Acute poliomyelitis is caused by infection with one of three forms of enterovirus, a single-stranded, encapsilated RNA virus in the picornavirus family. Enteroviruses spread by fecal-oral transmission. Rare cases have been attribut Anatomy Symptoms Signs Pathogenesis Acute poliomyelitis Minor or abortive poliomyelitis Non-paralytic or preparalytic poliomyelitis Paralytic poliomyelitis ed to live attenuated virus in the polio vaccine. The replication phase takes place 1–3 weeks post-infection in the pharynx and lower gastrointestinal tract. Secretion of the virus occurs in the saliva and feces. The severity of infection is variable, and can be classified into several categories: Most patients are asymptomatic, or exhibit pharyngitis or gastroenteritis. After this initial phase, up to 5% of infected patients may show signs of nervous system involvement. Nervous system involvement is preceded by a flu-like set of symptoms, including fever, headache, muscle aches, pharyngitis, anorexia, nausea, and vomiting. Neurological signs and symptoms include restlessness, irritability, and signs of meningitis . This situation may then proceed to paralytic poliomyelitis. Paralytic poliomyelitis develops in only 1–2% of infected patients, anywhere from 4 days to 5 weeks following initial infection. Factors believed to predispose a patient to paralytic disease include muscle damage from recent strenuous exercise or muscle injections, increased age, tonsillectomy, weakened B-cell function, and pregnancy. Acute paralytic poliomyelitis causes fatal respi Fig. 4. Postpolio syndrome, with polio in early infancy. A and B Foot deformity reveas early onset. C Very often involvement of the lower limbs is asymmetric ratory or cardiovascular problems in 5–10% of cases, or as high as 60% of cases with bulbar involvement. Encephalitic poliomyelitis is extremely rare and has a high mortality associated with autonomic dysfunction. Patients present with confusion and agitation, which may progress to stupor and coma. Post-polio syndrome occurs 10 years or longer after the initial polio infection, and is characterized by slowly progressive, asymmetric increases in weakness and muscle atrophy . Patients may complain of joint and muscle pain, and fatigue. PPS is not caused by the virus itself. It is believed that surviving motor neurons that have reinnervated muscle fibers become incapable of maintaining all the connections in their enlarged motor units, and begin to lose some connections. Some clinicians have suggested that excessive exercise aimed at keeping diseased muscles strong leads to this “burn-out”, but studies show that the primary associative factor for PPS is the severity of disease during the acute phase of the infection. PPS may lead to weakness in muscle groups previously thought to be unaffected, but typically these muscles were originally affected and the patient developed sufficient strength and adaptation to mask the deficits until the onset of PPS. Laboratory: Virus recovery from stool cultures during the first 2–3 weeks of disease is considered diagnostic for poliomyelitis. Virus may also be detected in throat washings, and occasionally from CSF or blood. CBC may show increased white count. CSF pressure may be increased. Neutrophils, and then lymphocytes, may be found in the CSF prior to neurological impairment. Slight to severe protein elevation with normal glucose may be detected. EMG: Early on, there is decreased recruitment and interference, with decreased motor unit action potential amplitudes. In 2–4 weeks, fibrillations will develop, with possible fasciculations. Over time, reinnervation will lead to polyphasic motor units. Nerve conduction velocities and sensory studies are normal. Imaging: Inflammation of the anterior spinal cord may be detected with MRI. Post-polio syndrome: The diagnosis of PPS is by exclusion of other conditions and demonstration of progressive weakness over time. Encephalitis caused by echovirus or coxsackie virus Meningitis Guillain-Barre syndrome Motor polyneuropathies Acute transverse myelitis Encephalitic poliomyelitis Post-polio syndrome Diagnosis Differential diagnosis Therapy Vaccination programs have tremendously decreased the incidence of poliomyelitis in developed countries. However, rare cases are still reported in countries with good vaccine programs, frequently in isolated cultures that reject modern medical care. In countries without adequate vaccination, poliomyelitis is still common. Once a patient has poliomyelitis, the only treatment is supportive therapy. This includes physical therapy to prevent contractures and joint ankylosis, prosthetic devices, and respiratory/swallowing therapy to minimize pulmonary complications like aspiration and atelectasis. Some clinicians recommend that patients with PPS minimize their activity, but studies suggest that exercise is beneficial for PPS, too. Respiratory failure can be caused by central depression, weakness of the respiratory muscles, or other complications associated with airway obstruction. Cardiovascular collapse may also occur from infection of the brainstem. These situations require intensive care with artificial ventilation. During the acute phase of polio paralysis, the mortality rate is fairly low . Patients requiring ventilation during this period usually recover over a period of several months, during which the respiratory muscles become reinnervated and hypertrophic. Continued dependence on artificial ventilation is uncommon. In general, the prognosis for polio patients is good. Patients that later develop PPS will experience slowly worsening weakness. This does not usually cause increased disability or mortality, although deterioration of respiratory function is a rare possibility. Dalakas MC The post-polio syndrome as an evolved clinical entity. Definition and clinical description. Annals of the New York Academy of Science 753: 68–80 Mulder DW Clinical observations on acute poliomyelitis. Annals of the New York Academy of Science 753: 1–10 Price RW, Plum F Poliomyelitis. In: Handbook of clinical neurology, vol. 32, pp 2091–2092 Rowland LP Viral infections of the nervous system: syndrome of acute anterior poliomyelitis. In: Merritt neurology, 10th edn. pp 764–767 Trojan DA, et al Predictive factors for post-poliomyelitis syndrome. Arch Phys Med Rehab 75: 770–777 Prognosis References Bulbospinal muscular atrophy Genetic testing NCV/EMG Laboratory Imaging Biopsy Bulbospinal muscular atrophy , or Kennedy’s syndrome, affects the lower motor neurons found in the brainstem cranial nerve motor nuclei and the anterior horns of the spinal cord. On autopsy, patients with BSMA show mild atrophy of the brainstem and spinal cord. Muscle atrophy is also present, with signs of denervation and reinnervation. The mean onset for BSMA is 30 years . Patients exhibit symmetrical weakness that progresses slowly over many years, and typically do not need canes or walkers until they are in their fifties or sixties. Facial, tongue, and proximal weakness are typical at presentation. Dysphagia, dysarthria, and masseter weakness are commonly observed. As BSMA only affects lower motor neurons, there are no upper motor neuron signs. Tendon reflexes are reduced or absent. Fasciculations are common in the face . Vibratory sensation may be reduced, and patients often show a mild postural tremor. Gynecomastia occurs in 50% of patients . BSMA is an X-linked recessive disorder, caused by a tri-nucleotide repeat expansion in the first exon of the androgen receptor gene on chromosome Xq11–12. It is unknown how disruption of the androgen receptor in this way leads to specific loss of lower motor neurons, as there are other mutations in Fig. 5. Kennedy’s syndrome. A Pt with gynecomastia. B Presence of tonque atrophy Anatomy Symptoms Signs Pathogenesis Diagnosis Differential diagnosis Therapy Prognosis References this gene that cause testicular feminization but have no affects on motor neurons. Genetic: Patients with appropriate signs and symptoms are diagnosed by positive genetic testing. Laboratory: As muscles are chronically denervated, creatine kinase levels are elevated . A muscle biopsy is frequently performed and shows evidence of denervation. EMG: Chronic denervation is also demonstrated by EMG. ALS: BSMA has no upper motor neuron signs, distinguishing it from ALS. Currently, the only treatment is supportive care when the muscle weakness becomes problematic. The number of CAG repeats present in the gene directly correlates with the age of onset and severity of the disease Dubovitz V Disorders of the lower motor neurons: the spinal muscular atrophies. In: Muscle disorders in childhood, 2nd edn. Saunders, London, pp 325–369 Wang CH, Carter TA, Gilliam TC Molecular and genetic basis of the spinal muscular atrophies. In: Rosenberg RN, Pruisner SB, DiMauro S, Barchi RL The molecular and genetic basis of neurological disease, 2nd edn. Butterworth-Heinemann, Boston, pp 787– 796 General disease finder This overview will help to find neuromuscular disease patterns in the different sections Cushing‘s disease: steroid myopathy Addison’s disease: general muscle weakness Periodic paralysis Tetanic muscles CN: VII Polyneuropathies: inflammatory, immune mediated, treatment related Myopathies: inflammatory, treatment related
Inflammatory/immune mediated: Dermatoand polymyositis Neoplastic: Jugular foramen tumor, metastasis Meningeal carcinomatosis Iatrogenic: Operations of trachea and esophagus, thoracotomy, mediastinoscopy, mediastinal tumors, thyroid surgery Trauma Fractures that affect the jugular foramen . Hyperextension neck injuries are also sometimes associated with injury to these nerves at the craniocervical junction. Other: Familial hypertrophic polyneuropathy