Grinker myelinopathy | |
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Other names | Delayed post-hypoxic Encephalopathy, Delayed post-hypoxic Leukoencephalopathy (DPHL), [1] Delayed post-anoxic leukoencephalopathy, [1] Delayed post-anoxic encephalopathy, [1] Delayed post-hypoxic encephalopathy, [1] Delayed neurologic sequelae [1] |
Specialty | Neurology |
Grinker's myelinopathy, also known as anoxic leukoencephalopathy, [2] is a rare disease of the central nervous system. The disease is characterized by a delayed leukoencephalopathy after a hypoxic episode. [2] It is typically, though not necessarily, related to carbon monoxide poisoning or heroin overdose. It occurs in roughly 2.8% of those who experience an acute hypoxic/anoxic episode. [3] Because of the wide range of symptoms and the delay in onset, it is often misdiagnosed as other neuropathologies. Grinker's myelinopathy was originally characterized by Roy R. Grinker in 1925 [4] [5] or 1926, [3] depending on the source.
Following an apparent rehabilitation from a severe episode of prolonged cerebral oxygen deprivation, patients with Grinker's myelinopathy begin to experience massive white matter death that leads to a wide range of neurological dysfunctions ranging from confusion and apathy to Parkinson-like symptoms. [3]
The symptoms have been known to include apathy, dementia, Parkinsonism, agitation, urinary incontinence, and pseudobulbar palsy, among many other neuropsychiatric symptoms. Microscopically, extensive hemispheric demyelination and the degeneration of basal ganglia are observed. [1]
The onset of the symptoms usually occurs several weeks after the initial hypoxic episode. The hypoxic episode is necessarily severe, usually with an arterial oxygen partial pressure less than 40mmHg. [3] Following the severe hypoxia, the patient typically falls unconscious or into a coma, with the exception of cases of carbon monoxide poisoning. [2] [1] If the patient recovers from this unconscious state, usually within 24 hours, it is typically followed by a successful recovery over a few days (generally 4 to 5). After the short recovery, a lucid period is observed, lasting anywhere from 1 to 4 weeks, in which the patient exhibits no symptoms related to the anoxic episode. It is after this period that the degenerative symptoms begin to appear and rapidly grow in severity. [6]
The main cause of the neurological disorders is believed to be demyelination of the cerebral hemispheres, though there is currently no widely accepted consensus on why. The most commonly accepted theories for the cause of demyelination include hypoxia and cerebral edema due to carbon monoxide toxicity, drug overdose, or cerebral blood vessel damage, and a disruption of myelin-producing pathways.
Because carbon monoxide binds to hemoglobin more efficiently than oxygen and lower systemic blood pressure brought upon by an acute anoxic episode in conjunction with carbon monoxide poisoning often leads to cerebral ischemia, a condition where the brain does not receive enough oxygen to satisfy its needs. This results in lesions to a great deal of subcortical cerebral white matter but leaves axons, U-fibers, and perivascular myelin mostly untouched. Support against this theory stems from the ability to replicate these lesions by using nitrogen-induced hypoxia and hypotension in cats [7] and the onset of this disease in individuals who experienced acute hypoxia without carbon monoxide poisoning [1]
Cerebral edema, or unusual swelling of the brain, is commonly caused by anoxic episodes. If it is severe enough, it is known to cause preferential damage to cerebral white matter due to excessive swelling of glial cells while leaving many other tissues unharmed. [6]
This theory suggests that hypoxia and carbon monoxide induce a form of edema resulting in white matter necrosis. Evidence for this theory comes from the observation of pathological lesions mimicking those of carbon monoxide poisoning where hypoxia and dehydration along with too-rapid rehydration have taken place without carbon monoxide present.
The anoxic event is likely to cause damage to cytoplasmic ATP-dependent enzymes in oligodendrocytes. Because many of these enzymes play essential roles in myelin turnover, damage to these enzymes is thought to adversely affect the ability of the body to sustain myelin in white matter, leading to the demyelination of those areas of the brain. The inability to regenerate and remove myelin on certain cells is thought to be responsible for the delay in onset of the disease and for the specificity of the white matter death. [1] [8]
Grinker's myelinopathy is diagnosed by establishing a clinical history of carbon monoxide poisoning, narcotic overdose, myocardial infarction, or other global cerebral hypoxic events. This diagnosis can then be supported by neuroimaging confirmation of broadcast cerebral hemisphere demyelination sparing cerebellar and brainstem tracts. The neuroimaging evidence can also be used to diagnose Grinker's myelinopathy through an elevation in the concentrations of a myelin basic protein in the cerebrospinal fluid . [1] Because this disease shares many of the symptoms with various forms of dementia or hysteria, these possibilities must be eliminated before a diagnosis for Grinker's myelinopathy can be made.
While there are no standard criteria for the diagnosis of Grinker's myelinopathy, neuroimaging can be an important diagnostic tool in ruling out other diagnoses. Magnetic resonance imaging (MRI) or computed tomography (CT) scans can be used to demonstrate a decrease in white matter density in the patient's cerebral hemispheres, with the typical exception of overlying cortices. Unexplained, uniform demyelination of white matter can indicate acute onset Grinker's myelinopathy. [1]
Treatment of Grinker's myelinopathy is still in the experimental stages and is very individualized. Some suggested treatments are early supportive care, rehabilitation therapies, oxygen treatments, and bed rest. Some episodes of Grinker's myelinopathy that progress to comas have no known treatment to reverse the course.
Early supportive care is the anchor of treatment during the first two weeks. Rehabilitation is an important part of the care process and it is important to start the rehabilitation as soon as the patient is able to participate in therapy. Types of therapy include: physical therapy, occupational therapy, speech therapy, and respiratory therapy. These therapies are used to assess the patient's functional status and to develop treatment goals. Each goal is individualized to target the specific neurological impairments to improve the patient's functional abilities.
One way to prevent the likelihood of Grinker's myelinopathy occurring is standard or hyperbaric oxygen after carbon monoxide poisoning. The hyperbaric oxygen treatment eliminates carbon dioxide from the brain, while the standard oxygen treatment normalizes carboxyhemoglobin levels. Another preventative measure one can take is to be on bed rest and abstain from stressful and strenuous procedures for the first 10 days after an extended hypoxic event. Expectation and recognition will also lead to an earlier and more accurate and appropriate use of health care services. [1]
Those patients who survive initial hospitalization are likely to recover from Grinker's Myelinopathy, but may take up to a year or longer. Age seems to be a factor in the time for recovery, as one study indicated that the mean age of patients who recovered within one year was 10 years younger than that of patients who did not. For most patients, a recovery time of 3–6 months is typical. Even after recovering, however, some symptoms may persist, including cognitive deficits or Parkinsonian symptoms that can be treated separately. [1]
Hypoxia is a condition in which the body or a region of the body is deprived of adequate oxygen supply at the tissue level. Hypoxia may be classified as either generalized, affecting the whole body, or local, affecting a region of the body. Although hypoxia is often a pathological condition, variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise.
Adrenoleukodystrophy (ALD) is a disease linked to the X chromosome. It is a result of fatty acid buildup caused by failure of peroxisomal fatty acid beta oxidation which results in the accumulation of very long chain fatty acids in tissues throughout the body. The most severely affected tissues are the myelin in the central nervous system, the adrenal cortex, and the Leydig cells in the testes. The long chain fatty acid buildup causes damage to the myelin sheath of the neurons of the brain, resulting in seizures and hyperactivity. Other symptoms include problems in speaking, listening, and understanding verbal instructions.
Porencephaly is an extremely rare cephalic disorder involving encephalomalacia. It is a neurological disorder of the central nervous system characterized by cysts or cavities within the cerebral hemisphere. Porencephaly was termed by Heschl in 1859 to describe a cavity in the human brain. Derived from Greek roots, the word porencephaly means 'holes in the brain'. The cysts and cavities are more likely to be the result of destructive (encephaloclastic) cause, but can also be from abnormal development (malformative), direct damage, inflammation, or hemorrhage. The cysts and cavities cause a wide range of physiological, physical, and neurological symptoms. Depending on the patient, this disorder may cause only minor neurological problems, without any disruption of intelligence, while others may be severely disabled or die before the second decade of their lives. However, this disorder is far more common within infants, and porencephaly can occur both before or after birth.
Carbon monoxide poisoning typically occurs from breathing in carbon monoxide (CO) at excessive levels. Symptoms are often described as "flu-like" and commonly include headache, dizziness, weakness, vomiting, chest pain, and confusion. Large exposures can result in loss of consciousness, arrhythmias, seizures, or death. The classically described "cherry red skin" rarely occurs. Long-term complications may include chronic fatigue, trouble with memory, and movement problems.
A demyelinating disease refers to any disease affecting the nervous system where the myelin sheath surrounding neurons is damaged. This damage disrupts the transmission of signals through the affected nerves, resulting in a decrease in their conduction ability. Consequently, this reduction in conduction can lead to deficiencies in sensation, movement, cognition, or other functions depending on the nerves affected.
Cerebral hypoxia is a form of hypoxia, specifically involving the brain; when the brain is completely deprived of oxygen, it is called cerebral anoxia. There are four categories of cerebral hypoxia; they are, in order of increasing severity: diffuse cerebral hypoxia (DCH), focal cerebral ischemia, cerebral infarction, and global cerebral ischemia. Prolonged hypoxia induces neuronal cell death via apoptosis, resulting in a hypoxic brain injury.
Leukodystrophies are a group of, usually, inherited disorders, characterized by degeneration of the white matter in the brain. The word leukodystrophy comes from the Greek roots leuko, "white", dys, "abnormal" and troph, "growth". The leukodystrophies are caused by imperfect growth or development of the glial cells which produce the myelin sheath, the fatty insulating covering around nerve fibers. Leukodystrophies may be classified as hypomyelinating or demyelinating diseases, respectively, depending on whether the damage is present before birth or occurs after. Other demyelinating diseases are usually not congenital and have a toxic or autoimmune cause.
Periventricular leukomalacia (PVL) is a form of white-matter brain injury, characterized by the necrosis of white matter near the lateral ventricles. It can affect newborns and fetuses; premature infants are at the greatest risk of neonatal encephalopathy which may lead to this condition. Affected individuals generally exhibit motor control problems or other developmental delays, and they often develop cerebral palsy or epilepsy later in life. The white matter in preterm born children is particularly vulnerable during the third trimester of pregnancy when white matter developing takes place and the myelination process starts around 30 weeks of gestational age.
Experimental autoimmune encephalomyelitis, sometimes experimental allergic encephalomyelitis (EAE), is an animal model of brain inflammation. It is an inflammatory demyelinating disease of the central nervous system (CNS). It is mostly used with rodents and is widely studied as an animal model of the human CNS demyelinating diseases, including multiple sclerosis (MS) and acute disseminated encephalomyelitis (ADEM). EAE is also the prototype for T-cell-mediated autoimmune disease in general.
Intrauterine hypoxia occurs when the fetus is deprived of an adequate supply of oxygen. It may be due to a variety of reasons such as prolapse or occlusion of the umbilical cord, placental infarction, maternal diabetes and maternal smoking. Intrauterine growth restriction may cause or be the result of hypoxia. Intrauterine hypoxia can cause cellular damage that occurs within the central nervous system. This results in an increased mortality rate, including an increased risk of sudden infant death syndrome (SIDS). Oxygen deprivation in the fetus and neonate have been implicated as either a primary or as a contributing risk factor in numerous neurological and neuropsychiatric disorders such as epilepsy, attention deficit hyperactivity disorder, eating disorders and cerebral palsy.
Brain ischemia is a condition in which there is insufficient bloodflow to the brain to meet metabolic demand. This leads to poor oxygen supply or cerebral hypoxia and thus leads to the death of brain tissue or cerebral infarction/ischemic stroke. It is a sub-type of stroke along with subarachnoid hemorrhage and intracerebral hemorrhage.
Toxic leukoencephalopathy is a rare condition that is characterized by progressive damage (-pathy) to white matter (-leuko-) in the brain (-encephalo-), particularly myelin, due to causes such as exposure to substance use, environmental toxins, or chemotherapeutic drugs. The prevalence of this disease is infrequent and often goes unreported, especially in cases resulting from substance use. Magnetic resonance imaging (MRI) is a popular method to study and diagnose the disease. However, even with technological advances, the exact mechanism and underlying pathophysiology of toxic leukoencephalopathy remains unknown and is thought to vary between sources of toxicity. The clinical severity of toxic leukoencephalopathy also varies among patients, exposure time, concentration, and purity of the toxic agent. Some reversibility of the condition has been seen in many cases when the toxic agent is removed.
Baló's concentric sclerosis is a disease in which the white matter of the brain appears damaged in concentric layers, leaving the axis cylinder intact. It was described by József Mátyás Baló who initially named it "leuko-encephalitis periaxialis concentrica" from the previous definition, and it is currently considered one of the borderline forms of multiple sclerosis.
Leukoencephalopathy with vanishing white matter is an autosomal recessive neurological disease. The cause of the disease are mutations in any of the 5 genes encoding subunits of the translation initiation factor eIF2B: EIF2B1, EIF2B2, EIF2B3, EIF2B4, or EIF2B5. The disease belongs to a family of conditions called the Leukodystrophies.
Leukoencephalopathy with neuroaxonal spheroids (LENAS) is an extremely rare kind of leukoencephalopathy and is classified as a neurodegenerative disease. LENAS is a cause of severe and subacute dementia that results from damage to certain areas of the brain. This damage is to a type of brain tissue called white matter and axon damage due to swellings which are termed spheroids.
Neurovirology is an interdisciplinary field which represents a melding of clinical neuroscience, virology, immunology, and molecular biology. The main focus of the field is to study viruses capable of infecting the nervous system. In addition to this, the field studies the use of viruses to trace neuroanatomical pathways, for gene therapy, and to eliminate detrimental populations of neural cells.
Athetoid cerebral palsy, or dyskinetic cerebral palsy, is a type of cerebral palsy primarily associated with damage, like other forms of CP, to the basal ganglia in the form of lesions that occur during brain development due to bilirubin encephalopathy and hypoxic–ischemic brain injury. Unlike spastic or ataxic cerebral palsies, ADCP is characterized by both hypertonia and hypotonia, due to the affected individual's inability to control muscle tone. Clinical diagnosis of ADCP typically occurs within 18 months of birth and is primarily based upon motor function and neuroimaging techniques. While there are no cures for ADCP, some drug therapies as well as speech, occupational therapy, and physical therapy have shown capacity for treating the symptoms.
Hereditary diffuse leukoencephalopathy with spheroids (HDLS) is a rare adult onset autosomal dominant disorder characterized by cerebral white matter degeneration with demyelination and axonal spheroids leading to progressive cognitive and motor dysfunction. Spheroids are axonal swellings with discontinuous or absence of myelin sheaths. It is believed that the disease arises from primary microglial dysfunction that leads to secondary disruption of axonal integrity, neuroaxonal damage, and focal axonal spheroids leading to demyelination. Spheroids in HDLS resemble to some extent those produced by shear stress in a closed head injury with damage to axons, causing them to swell due to blockage of axoplasmic transport. In addition to trauma, axonal spheroids can be found in aged brain, stroke, and in other degenerative diseases. In HDLS, it is uncertain whether demyelination occurs prior to the axonal spheroids or what triggers neurodegeneration after apparently normal brain and white matter development, although genetic deficits suggest that demyelination and axonal pathology may be secondary to microglial dysfunction. The clinical syndrome in patients with HDLS is not specific and it can be mistaken for Alzheimer's disease, frontotemporal dementia, atypical Parkinsonism, multiple sclerosis, or corticobasal degeneration.
Ulegyria is a diagnosis used to describe a specific type of cortical scarring in the deep regions of the sulcus that leads to distortion of the gyri. Ulegyria is identified by its characteristic "mushroom-shaped" gyri, in which scarring causes shrinkage and atrophy in the deep sulcal regions while the surface gyri are spared. This condition is most often caused by hypoxic-ischemic brain injury in the perinatal period. The effects of ulegyria can range in severity, although it is most commonly associated with cerebral palsy, mental retardation and epilepsy. N.C. Bresler was the first to view ulegyria in 1899 and described this abnormal morphology in the brain as “mushroom-gyri." Although ulegyria was first identified in 1899, there is still limited information known or reported about the condition.
Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is disease of the arteries in the brain, which causes tissue loss in the subcortical region of the brain and the destruction of myelin in the CNS. CARASIL is characterized by symptoms such as gait disturbances, hair loss, low back pain, dementia, and stroke. CARASIL is a rare disease, having only been diagnosed in about 50 patients, of which ten have been genetically confirmed. Most cases have been reported in Japan, but Chinese and caucasian individuals have also been diagnosed with the disease. CARASIL is inherited in an autosomal recessive pattern. There is currently no cure for CARASIL. Other names for CARASIL include familial young-adult-onset arteriosclerotic leukoencephalopathy with alopecia and lumbago without arterial hypertension, Nemoto disease and Maeda syndrome.