Myoclonus: Causes, Symptoms, Diagnosis, Types, Postanoxic Myoclonus & Treatment Guide

Myoclonus: Causes, Symptoms, Diagnosis, Types, Postanoxic Myoclonus & Treatment Guide

pediagenosis    November 13, 2026    Comment   

 

Myoclonus: Types, Causes, Symptoms, and Postanoxic Myoclonus

What Is Myoclonus?

Myoclonus is a brief, shock-like muscle jerk caused by a sudden muscle contraction or a temporary loss of muscle tone. It can occur in different parts of the body and may originate from various levels of the nervous system, including the cerebral cortex, subcortical structures, brainstem, and spinal cord.

Myoclonus is classified according to its anatomical origin, distribution, etiology, and physiological characteristics. It may occur as an isolated phenomenon, as part of an epileptic disorder, or in association with neurological and neurodegenerative diseases.

Understanding the different types of myoclonus is important for identifying its underlying causes and evaluating associated neurological conditions.

Chorea and Ballism: Symptoms, Causes, Diagnosis, and Treatment

Chorea and Ballism: Symptoms, Causes, Diagnosis, and Treatment

pediagenosis    October 27, 2026    Comment   

CHOREA/BALLISM

Chorea is characterized by random jerky movements jumping from one body part to another. They are irregularly timed, nonrepetitive, and abrupt in character, varying in severity. In mild cases, they may lead to restlessness, intermittent exaggeration of facial expression, or fidgetiness of the hands or toes. In more severe cases, the gait has a dancing quality and limbs exhibiting violent and ballistic movements. It can involve proximal and distal muscles. Patients often attempt to mask such movements by incorporating them into voluntary activities. Ballism can be conceptualized as a severe form of chorea affecting the proximal limb muscles, giving a “throwing” character to the movement. The most common form of ballism is seen in parkinsonian patients with severe levodopa­induced abnormal involuntary movements (dyskinesias) or in patients with contralateral subthalamic lesion (infarct, demyelination). Patients may have difficulties maintaining a sustained posture. When asked to grip the examiner’s hand, pressure cannot be sustained, resulting in the “milkmaid’s grip”; when asked to protrude the tongue, the tongue will pop out, resulting in the “catch fly sign” or “harlequin’s” tongue The bon­bon sign may be present (the tongue moves involuntarily inside the mouth, hitting the inside wall of the cheeks). This latter sign is particularly prominent in patients with drug­induced orolingual chorea (neuroleptic­induced tardive dyskinesia).

Vascular Dementia: Causes, Symptoms, Diagnosis and Treatment

Vascular Dementia: Causes, Symptoms, Diagnosis and Treatment

pediagenosis    October 21, 2026    Comment   

VASCULAR DEMENTIA

Vascular dementia is interesting in that many of those who do have a true vascular dementia are not diagnosed with it, while many who probably do not have a vascular dementia are diagnosed with it. The most straightfor-ward presentations are those in which an individual with normal cognition has a large stroke that causes a combination of cognitive signs, such as aphasia and a memory retrieval problem. If the patient cannot resume their prestroke day-to-day level of function because of these new cognitive deficits, the criteria for vascular dementia are met, but because the stroke so clearly caused the deficits, they are held to simply represent the consequences of a stroke (as opposed to a frank vascular dementia). On the other hand, some patients will present with a gradually progressive dementia, a retention-type memory deficit, no motor signs, no history of sensory or motor changes, and a neuroimaging study that shows subcortical changes that could be consistent with “small vessel cerebrovascular disease.” In the elderly, such patients almost always have the plaques and tangles that are expected in Alzheimer disease. In such cases, despite the neuroimaging changes, it is probably more appropriate to consider Alzheimer disease as the primary etiology. Still, the frequent association between Alzheimer disease and cerebrovascular pathology suggests these conditions may be linked in some way.

Treatable Dementias: Reversible Causes, Symptoms & Treatment

Treatable Dementias: Reversible Causes, Symptoms & Treatment

pediagenosis    October 21, 2026    Comment   

TREATABLE DEMENTIAS

Although in some ways cognitive performance abilities evolve throughout adulthood, many elderly people remain mentally sharp into their ninth and tenth decades. The emergence of uncharacteristic changes in an individual’s cognition that impacts their usual activities should, therefore, trigger an evaluation for possible etiologies.

Normal-Pressure Hydrocephalus: Symptoms, Causes, Diagnosis & Treatment

Normal-Pressure Hydrocephalus: Symptoms, Causes, Diagnosis & Treatment

pediagenosis    October 12, 2026    Comment   

NORMAL-PRESSURE HYDROCEPHALUS

The “plumbing system” of the central nervous system (CNS) operates in a delicate balance. Fluid produced in the choroid plexus of the lateral ventricles circulates through the third ventricle, cerebral aqueduct (of Sylvius), and fourth ventricle. After exiting from the roof of the fourth ventricle, the cerebrospinal fluid (CSF) circulates around the brain within the subarachnoid cisterns, and is ultimately absorbed by the arachnoid granulations into the circulation. If more CSF is produced than is absorbed, the ventricles and subarachnoid space distend with fluid. In the adult, this imbalance leads to enlargement of the ventricles, which then encroach on the normal cerebral white matter, especially frontally.

Tremor: Causes, Symptoms, Types, Diagnosis & Treatment Explained

Tremor: Causes, Symptoms, Types, Diagnosis & Treatment Explained

pediagenosis    July 04, 2026    Comment   

Basal Ganglia and Movement Disorders

Tremor

Tremor is a rhythmic, oscillatory, involuntary movement caused by the alternating activation of agonist and antagonist muscles. The etiology of tremor is diverse and includes hereditary (familial tremor), degenerative (Parkinson disease), metabolic (thyroid, parathyroid, or hepatic disorders and hypoglycemia), toxins (nicotine, mercury, lead, carbon monoxide, manganese, arsenic, toluene), illicit drug use or medication-induced (neuroleptics, tricyclics, lithium, cocaine, alcohol, adrenaline, bronchodilators,  theophylline,  caffeine,  steroids,  valproate, amiodarone, thyroid hormones, vincristine), peripheral neuropathies (Charcot­ Marie ­Tooth disease, RoussyLevy syndrome, complex regional pain syndrome), and psychogenic disorders.

Tics and Tourette Syndrome: Causes, Symptoms, Diagnosis, and Treatment Guide

Tics and Tourette Syndrome: Causes, Symptoms, Diagnosis, and Treatment Guide

pediagenosis    July 02, 2026    Comment   

Tics and Tourette Syndrome

Tics are sudden, rapid, stereotyped, repetitive, non­rhythmic movements or vocalizations affecting discrete muscle groups. Most experts agree and clinical experience dictates that tics are preceded by a sensory component, described by patients as an “urge.” When patients are asked to prevent movements from occurring, an uncomfortable inner sensation builds and an urge to “release” develops, resulting in expression of the tics.

Wilson Disease (Hepatolenticular Degeneration): Symptoms, Causes, Diagnosis, MRI Findings, and Treatment Guide

Wilson Disease (Hepatolenticular Degeneration): Symptoms, Causes, Diagnosis, MRI Findings, and Treatment Guide

pediagenosis    July 02, 2026    Comment   

Also known as hepatolenticular degeneration, Wilson disease is an autosomal recessive disorder that occurs in 1 of 30,000 individuals. The abnormal gene, the ATP7B (adenosine triphosphate) gene, is located on chromosome 13. The defective protein, adenosine triphosphatase (ATPase), is involved in the transport and incorporation of copper into ceruloplasmin and the vesicular compartment near the canalicular membrane for further bile excretion.

MECHANISMS OF MOLECULAR SIGNALING IN NEURONS

MECHANISMS OF MOLECULAR SIGNALING IN NEURONS

pediagenosis    September 30, 2023   

MECHANISMS OF MOLECULAR SIGNALING IN NEURONS

Types of molecular signaling in neurons are shown, including ionotropic receptors (both voltage-gated ion channels and ligand-gated channels) and metabotropic receptors.

HEMATOMAS

HEMATOMAS

pediagenosis    September 26, 2023   

HEMATOMAS

Epidural hematomas occur with trauma or skull fractures that tear meningeal arteries (especially middle meningeal artery branches). Blood from the tear dissects the outer layer of the dura from the skull, forming a space-occupying mass in what was normally only a potential space. 

Major Limbic Forebrain Structures

Major Limbic Forebrain Structures

pediagenosis    April 04, 2023   

The term limbic is derived from limbus, meaning ring. Many of these structures and their pathways in the limbic system form a ring around the diencephalon. They are involved in emotional behavior and individualized interpretations of external and internal stimuli. The hippocampal formation and its major pathway, the fornix, curve into the anterior pole of the diencephalon, forming precommissural (to the septum) and postcommissural (to the hypothalamus) connections in relation to the anterior commissure. The amygdaloid nuclei give rise to several pathways; one, the stria terminalis, extends in a C-shaped course around the diencephalon into the hypothalamus and basal forebrain. The olfactory tract communicates directly with several limbic forebrain areas; it is the only sensory system to entirely bypass the thalamus and terminate directly in cortical and subcortical zones of the telencephalon. Connections from the septal nuclei to the habenula (stria medullaris thalami) connect the limbic forebrain to the brain stem. The amygdaloid nuclei and hippocampus (shaded) are deep to the cortex.

Horizontal Brain Sections Showing The Basal Ganglia

Horizontal Brain Sections Showing The Basal Ganglia

pediagenosis    April 04, 2023   

Two levels of horizontal sections through the forebrain reveal the major anatomical features and the relationships among the basal ganglia, the internal capsule, and the thalamus (schematically shown in the lower illustration). The caudate nucleus is a C-shaped structure that sweeps from the frontal lobe into the temporal lobe; a horizontal section passes through this nucleus in two distinct places (head and tail). The anterior limb, genu, and posterior limb of the internal capsule contain major connections into and out of the cerebral cortex. The head and body of the caudate are medial to the anterior limb, whereas the thalamus is medial to the posterior limb. These relationships are important for understanding imaging studies and for understanding the involvement of specific functional systems in vascular lesions or strokes. The internal and external segments of the globus pallidus are located medial to the putamen. The external capsule, claustrum, extreme capsule, and insular cortex, from medial to lateral, are located lateral to the putamen. The fornix, also a C-shaped bundle, is sectioned in two sites, the crus and the column.

Cells Of The Nervous System I Neurones

Cells Of The Nervous System I Neurones

pediagenosis    March 23, 2023   

Cells Of The Nervous System I: Neurones

There are two major classes of cells in the nervous system: the neuroglial cells and neurones, with the latter making up only 10– 20% of the whole population. The neurones are specialized for excitation and nerve impulse conduction (see Chapters 14, 15 and 17), and communicate with each other by means of the synapse (see Chapter 16) and so act as the structural and functional unit of the nervous system.

The Autonomic Nervous System

The Autonomic Nervous System

pediagenosis    February 08, 2023   

The Autonomic Nervous System.

The autonomic nervous system (ANS) provides the efferent pathway for the involuntary control of most organs, excluding the motor control of skeletal muscle (Chapters 12 and 13). The ANS provides the effector arm for homeostatic reflexes (e.g. control of blood pressure), and allows the integration and modulation of function by central mechanisms in the brain in response to environmental and emotional stimuli (e.g. exercise, thermoregulation, ‘fight or flight’). Figure 7a shows a simplified schematic diagram of the ANS, and Figure 8b its actions on major organs.

Enteric Nervous System

Enteric Nervous System

pediagenosis    February 02, 2023   

Enteric Nervous System

Structure of the enteric nervous system

The enteric nervous system is found in the wall of the gut, primarily the small and large intestine, and is involved with normal gastrointestinal motility and secretory function. It contains about 100 million nerve cell bodies. It is heavily innervated/regulated by the autonomic nervous system but is a separate entity with its own intrinsic circuitry and function. It has no major role in the oesopha- gus and it is less clear what role it fulfils in the stomach.

HYDROCEPHALUS

HYDROCEPHALUS

pediagenosis    January 19, 2023    Comment   

HYDROCEPHALUS

Hydrocephalus results in the enlargement of ventricles. Symptomatic hydrocephalus associated with elevated intracranial pressure results most often from decreased absorption of CSF, or blockage of outflow through the ventricular system (see Plate 1-15). Excess CSF production is quite rare and usually due only to choroid plexus papilloma, a choroid plexus tumor. Enlargement of all CSF spaces, including the ventricles, that is due to brain atrophy, or encephalomalacia, is termed hydrocephalus ex vacuo. The etiology of hydrocephalus can be multifactorial, and the clinical course and management can change throughout the lifetime.

SURGICAL TREATMENT OF HYDROCEPHALUS

SURGICAL TREATMENT OF HYDROCEPHALUS

pediagenosis    January 19, 2023   

SURGICAL TREATMENT OF HYDROCEPHALUS

The treatment of hydrocephalus depends on the etiology and factors such as the patient’s age, comorbidities, and anatomy. When hydrocephalus is secondary to a tumor or cyst blocking CSF outflow pathways, tumor removal or cyst fenestration may suffice. Most patients with communicating or obstructive hydrocephalus, however, require a CSF diversion procedure to compensate for impaired absorption or blockage. Successful CSF diversion procedures can halt progressive ventricular dilation and elevation of intracranial pressure and can frequently lead to improvement in neurologic function. CSF diversion can be accomplished by endoscopic procedures that bypass an obstruction or by insertion of a shunt to move CSF to an alternate site for absorption into the bloodstream.

CEREBRAL PALSY

CEREBRAL PALSY

pediagenosis    January 19, 2023   

CEREBRAL PALSY

The developing brain is sensitive to essential physiologic mechanisms that maintain homeostasis. Regulation of oxygen availability is critical. Historically, cerebral palsy (CP) was used to describe a static, nonprogressive motor disability present at birth secondary to perinatal cerebral hypoxic and traumatic injuries. Currently, CP also encompasses other acquired nonprogressive motor disabilities and is distinct from progressive neurodegenerative processes. Although nonprogressive in the sense of deterioration, CP is not static in evolution. Individuals may display several different types of CP. Cerebral palsy is a descriptive diagnosis rather than an etiologic one. Clinically, CP manifests as motor defects that range in severity, Associated disorders include intellectual disability, epilepsy, visual and hearing difficulties, and orthopedic deformities. Other diagnoses should be excluded before CP is diagnosed.

ESTABLISHING CELLULAR DIVERSITY IN THE EMBRYONIC BRAIN AND SPINAL CORD

ESTABLISHING CELLULAR DIVERSITY IN THE EMBRYONIC BRAIN AND SPINAL CORD

pediagenosis    January 19, 2023    Comment   

ESTABLISHING CELLULAR DIVERSITY IN THE EMBRYONIC BRAIN AND SPINAL CORD

The morphogenetic transformation of the embryonic brain from a neural tube during the early first trimester to an organ that resembles the adult brain by the end of gestation is ultimately driven by ongoing stem cell proliferation, neurogenesis, and differentiation. This “histogenesis” depends on the specification and accumulation of neural stem cells with distinct capacities to generate diverse classes of neurons and glial cells. Subsequently, these stem cells, based on their position in the anterior-posterior as well as posterior-anterior axes of the neural tube and their access to both local and circulating signals, establish identity that is maintained in their postmitotic progeny. Thus the position of neural stem cells is a key determinant of the ultimate organization of each brain region. This relationship can be used to understand the basic adult organization of the entire central nervous system.

GENERATION OF NEURONAL DIVERSITY IN THE SPINAL CORD AND HINDBRAIN

GENERATION OF NEURONAL DIVERSITY IN THE SPINAL CORD AND HINDBRAIN

pediagenosis    January 19, 2023    Comment   

GENERATION OF NEURONAL DIVERSITY IN THE SPINAL CORD AND HINDBRAIN

Morphogenesis ultimately reflects the establishment of distinct cell classes in appropriate numbers and positions throughout the neural tube. In the spinal cord and hindbrain, the basic relationships between neural stem cells and their progeny are well established. These relationships define cell lineages, broadly, for the spinal cord and hindbrain. The key distinctions that establish lineages the range of cell types generated by specific classes of neural stem cells are position in the neural tube of the stem cells and the way in which postmitotic progeny reach their final destination.