 Title page of Encephalitis Lethargica, Economo, 1931 | |
| Deaths | 20% mortality |
|---|---|
The encephalitis lethargica epidemic lasted from around 1918 to 1930. [1] The cause is still unknown. [2] Though the cause was once attributed to the coinciding Spanish flu epidemic, modern research has disputed this claim. [3] The mortality was as high as 20% [4]
Encephalitis lethargica is a neurological syndrome that cause lethargy, a “mask like” face, excessive blood in the meninges, and other general neurological symptoms. [5] Officially recognized as its own condition in 1917, it is believed to have exist far longer in human history. [5] It is known to cause post-encephalitic parkinsonism. [3] Despite often being considered a condition of the past, cases still occur.[ citation needed ]
Neurologist Constantin von Economo published a paper in April 1917 on some cases he encountered in the winter months of 1916 and 1917. [3] These patients, despite their various previous diagnoses, had a similar pattern of symptoms. This led him to suggest a novel disease, which he named Encephalitis lethargica. [3] In France, physician René Cruchet was encountering similar patterns, and published his findings within a few days of Constantin von Economo. Following these two reports, many more cases were reported, first in Europe, but quickly spreading around the globe. [3] The epidemic peaked between 1920 and 1929, [1] with an estimated million people diagnosed with Encephalitis lethargica during the epidemic period. [5]
The causes of encephalitis lethargica are still unknown. [3] Though the connection to the Spanish flu epidemic is often made, the encephalitis outbreak did begin slightly earlier. However, this cannot disprove the claim, simply point out that not all of the existing evidence lines up. [3]
In the aftermath of the epidemic, many cases of post-encephalitic parkinsonism were reported. This condition was distinctive from idiopathic Parkinson's disease, as it occurs in younger patients than typical idiopathic Parkinson's disease, and lacks the "pill-rolling tremor" of idiopathic Parkinson's disease. [3]
Encephalitis is inflammation of the brain. The severity can be variable with symptoms including reduction or alteration in consciousness, headache, fever, confusion, a stiff neck, and vomiting. Complications may include seizures, hallucinations, trouble speaking, memory problems, and problems with hearing.
Parkinsonism is a clinical syndrome characterized by tremor, bradykinesia, rigidity, and postural instability. These are the four motor symptoms found in Parkinson's disease (PD) – after which it is named – dementia with Lewy bodies (DLB), Parkinson's disease dementia (PDD), and many other conditions. This set of symptoms occurs in a wide range of conditions and may have many causes, including neurodegenerative conditions, drugs, toxins, metabolic diseases, and neurological conditions other than PD.
Rapid eye movement sleep behavior disorder or REM behavior disorder (RBD) is a sleep disorder in which people act out their dreams. It involves abnormal behavior during the sleep phase with rapid eye movement (REM) sleep. The major feature of RBD is loss of muscle atonia during otherwise intact REM sleep. The loss of motor inhibition leads to sleep behaviors ranging from simple limb twitches to more complex integrated movements that can be violent or result in injury to either the individual or their bedmates.
Encephalitis lethargica is an atypical form of encephalitis. Also known as "sleeping sickness" or "sleepy sickness", it was first described in 1917 by neurologist Constantin von Economo and pathologist Jean-René Cruchet. The disease attacks the brain, leaving some victims in a statue-like condition, speechless and motionless. Between 1915 and 1926, an epidemic of encephalitis lethargica spread around the world. The exact number of people infected is unknown, but it is estimated that more than one million people contracted the disease during the epidemic, which directly caused more than 500,000 deaths. Most of those who survived never returned to their pre-morbid vigour.
Hypersomnia is a neurological disorder of excessive time spent sleeping or excessive sleepiness. It can have many possible causes and can cause distress and problems with functioning. In the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), hypersomnolence, of which there are several subtypes, appears under sleep-wake disorders.
Alexander disease is a very rare autosomal dominant leukodystrophy, which are neurological conditions caused by anomalies in the myelin which protects nerve fibers in the brain. The most common type is the infantile form that usually begins during the first two years of life. Symptoms include mental and physical developmental delays, followed by the loss of developmental milestones, an abnormal increase in head size and seizures. The juvenile form of Alexander disease has an onset between the ages of 2 and 13 years. These children may have excessive vomiting, difficulty swallowing and speaking, poor coordination, and loss of motor control. Adult-onset forms of Alexander disease are less common. The symptoms sometimes mimic those of Parkinson’s disease or multiple sclerosis, or may present primarily as a psychiatric disorder.
Progressive supranuclear palsy (PSP) is a late-onset neurodegenerative disease involving the gradual deterioration and death of specific volumes of the brain. The condition leads to symptoms including loss of balance, slowing of movement, difficulty moving the eyes, and cognitive impairment. PSP may be mistaken for other types of neurodegeneration such as Parkinson's disease, frontotemporal dementia and Alzheimer's disease. The cause of the condition is uncertain, but involves the accumulation of tau protein within the brain. Medications such as levodopa and amantadine may be useful in some cases.
Post-encephalitic parkinsonism is a disease believed to be caused by a viral illness that triggers degeneration of the nerve cells in the substantia nigra. Overall, this degeneration leads to clinical parkinsonism.
Rasmussen's encephalitis is a rare inflammatory neurological disease, characterized by frequent and severe seizures, loss of motor skills and speech, hemiparesis, encephalitis, and dementia. The illness affects a single cerebral hemisphere and generally occurs in children under the age of 15.
Viral encephalitis is inflammation of the brain parenchyma, called encephalitis, by a virus. The different forms of viral encephalitis are called viral encephalitides. It is the most common type of encephalitis and often occurs with viral meningitis. Encephalitic viruses first cause infection and replicate outside of the central nervous system (CNS), most reaching the CNS through the circulatory system and a minority from nerve endings toward the CNS. Once in the brain, the virus and the host's inflammatory response disrupt neural function, leading to illness and complications, many of which frequently are neurological in nature, such as impaired motor skills and altered behavior.
Klazomania refers to compulsive shouting; it has features resembling the complex tics such as echolalia, palilalia and coprolalia seen in tic disorders, but has been seen in people with encephalitis lethargica, alcohol use disorder, and carbon monoxide poisoning. It was first reported by L. Benedek in 1925 in a patient with postencephalitic parkinsonism. Little is known about the condition, and few cases have been reported.
Limbic encephalitis is a form of encephalitis, a disease characterized by inflammation of the brain. Limbic encephalitis is caused by autoimmunity: an abnormal state where the body produces antibodies against itself. Some cases are associated with cancer and some are not. Although the disease is known as "limbic" encephalitis, it is seldom limited to the limbic system and post-mortem studies usually show involvement of other parts of the brain. The disease was first described by Brierley and others in 1960 as a series of three cases. The link to cancer was first noted in 1968 and confirmed by later investigators.
Constantin Freiherr von Economo was an Austrian psychiatrist and neurologist of Romanian origin. He is mostly known for his discovery of encephalitis lethargica and his atlas of cytoarchitectonics of the cerebral cortex.
Bradyphrenia is the slowness of thought common to many disorders of the brain. Disorders characterized by bradyphrenia include Parkinson's disease and forms of schizophrenia consequently causing a delayed response and fatigue. Patients with bradyphrenia may describe or may manifest slowed thought processes, evidenced by increased latency of response and also involve severe memory impairment and poor motor control. The word 'bradyphrenia' originates from the ancient Greek meaning 'slow mind.'
A neurological disorder is any disorder of the nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord or other nerves can result in a range of symptoms. Examples of symptoms include paralysis, muscle weakness, poor coordination, loss of sensation, seizures, confusion, pain, tauopathies, and altered levels of consciousness. There are many recognized neurological disorders, some relatively common, but many rare. They may be assessed by neurological examination, and studied and treated within the specialties of neurology and clinical neuropsychology.
Herpes simplex encephalitis (HSE), or simply herpes encephalitis, is encephalitis due to herpes simplex virus. It is estimated to affect at least 1 in 500,000 individuals per year, and some studies suggest an incidence rate of 5.9 cases per 100,000 live births.
Camptocormia, also known as bent spine syndrome (BSS), is a symptom of a multitude of diseases that is most commonly seen in the elderly. It is identified by an abnormal thoracolumbar spinal flexion, which is a forward bending of the lower joints of the spine, occurring in a standing position. In order to be classified as BSS, the anterior flexion must be of 45 degrees anteriorly. This classification differentiates it from a similar syndrome known as kyphosis. Although camptocormia is a symptom of many diseases, there are two common origins: neurological and muscular. Camptocormia is treated by alleviating the underlying condition causing it through therapeutic measures or lifestyle changes.
Anti-NMDA receptor encephalitis is a type of brain inflammation caused by antibodies. Early symptoms may include fever, headache, and feeling tired. This is then typically followed by psychosis which presents with false beliefs (delusions) and seeing or hearing things that others do not see or hear (hallucinations). People are also often agitated or confused. Over time, seizures, decreased breathing, and blood pressure and heart rate variability typically occur. In some cases, patients may develop catatonia.
Bickerstaff brainstem encephalitis is a rare inflammatory disorder of the central nervous system, first described by Edwin Bickerstaff in 1951. It may also affect the peripheral nervous system, and has features in common with both Miller Fisher syndrome and Guillain–Barré syndrome.
Anti-Hu associated encephalitis, also known as Anti-ANNA1 associated encephalitis, is an uncommon form of brain inflammation that is associated with an underlying cancer. It can cause psychiatric symptoms such as depression, anxiety, and hallucinations. It can also produce neurological symptoms such as confusion, memory loss, weakness, sensory loss, pain, seizures, and problems coordinating the movement of the body.