Neuromuscular Disorders Overview

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Questions and Answers

What is the consequence of ischemia on pyruvic acid's role in the Krebs cycle?

Pyruvic acid is oxidized efficiently.

Pyruvic acid is converted into glucose.

Pyruvic acid forms carbon dioxide.

Pyruvic acid is not included in the Krebs cycle. (correct)

What effect does an increase in lactate have during brain ischemia?

It causes lactate-dependent intracellular acidosis. (correct)

It raises the intracellular pH.

It decreases calcium ion influx.

It enhances energy production.

Which enzyme's system is disrupted due to energy deficit in ischemia?

Calcium-dependent protein kinase.

Lactate dehydrogenase.

Cyclic AMP phosphodiesterase.

Na+/K+-ATPase enzyme system. (correct)

What happens to potassium and sodium ions during the metabolic disturbances associated with ischemia?

K+ passively exits the cell, and Na+ influx increases. Signup and view all the answers

What role does calcium play during acute focal cerebral ischemia?

It enters the cell through charge-sensitive channels. Signup and view all the answers

What is a likely consequence of excessive nitric oxide synthesis during ischemia?

Increased oxidative stress reactions. Signup and view all the answers

What distinguishes fibrillation from fasciculations?

Fibrillation can only be detected through electromyography. Signup and view all the answers

Which condition is characterized by rapid, involuntary, stereotyped jerks of muscle groups?

Tick Signup and view all the answers

Which of the following is a characteristic of chorea?

Random, fast, irregular violent contractions Signup and view all the answers

What type of muscle movement is characterized by rhythmic involuntary trembling?

Tremor Signup and view all the answers

What is the main characteristic of athetosis?

Slow, wormlike pretentious movements Signup and view all the answers

What is the primary feature of epilepsy as a neurological condition?

Repeated convulsive seizures Signup and view all the answers

Which statement accurately describes the epileptogenic focus?

It consists of a group of neurons that generates excessive discharges. Signup and view all the answers

What common feature do tics and tremors share?

Both are involuntary muscle movements. Signup and view all the answers

What type of movements are associated with tremors?

Rhythmic and involuntary Signup and view all the answers

What characterizes brain edema primarily?

Increased volume of water inside cells Signup and view all the answers

Which form of edema is primarily associated with swelling of astrocytes?

Cytotoxic edema Signup and view all the answers

What mediators contribute to vasogenic edema?

Glutamate and kinins Signup and view all the answers

What is a potential consequence of increased intracranial pressure due to edema?

Dislocation and wedging of the brain Signup and view all the answers

Which type of stroke is particularly predisposed to hemorrhagic transformation?

Cardioembolic stroke Signup and view all the answers

What occurs as a result of fibrinolysis of the embolus in stroke treatment?

Restoration of blood flow through ischemic arteries Signup and view all the answers

What is one consequence of the breakdown of the blood-brain barrier during vasogenic edema?

Increased permeability allowing protein molecules to enter brain tissue Signup and view all the answers

Hemorrhagic transformation after a stroke is most likely associated with which of the following?

Reperfusion therapy Signup and view all the answers

What triggers cytotoxic edema in the brain?

Pathobiochemical reactions following ischemia Signup and view all the answers

What is one primary function of the astrocytes during cytotoxic edema?

Release of excitatory amino acids Signup and view all the answers

What is the primary cause of meningitis?

Bacteria, viruses, fungi, and other agents Signup and view all the answers

Which of the following is true about neurodegenerative diseases?

They progress slowly and involve the death of nerve cells. Signup and view all the answers

What is meningism?

Presence of meningeal symptoms without inflammation Signup and view all the answers

What characterizes meningococcemia?

Septicemia with massive death of meningococci Signup and view all the answers

What is a common non-specific symptom associated with neuroinfections?

Fever Signup and view all the answers

Which of the following is NOT considered a type of neuroinfection?

Diabetes mellitus Signup and view all the answers

Which neurotransmitter imbalance is indicative of neurodegenerative diseases?

Imbalance in synthesis and isolation of neurotransmitters Signup and view all the answers

What is the main transmission method for meningococcus infection?

Airborne transmission through respiratory droplets Signup and view all the answers

Neurotuberculosis is characterized by an infection primarily targeting which system?

Nervous system Signup and view all the answers

Which type of neurodegenerative disease is characterized by a gradual degeneration of motor control?

Parkinson's disease Signup and view all the answers

What is microcirculatory microembolization?

A naturally occurring phenomenon or one induced by medical interventions like revascularization. Signup and view all the answers

Which processes are activated in brain tissue after a stroke to promote recovery?

Angiogenesis, synaptogenesis, and neurogenesis Signup and view all the answers

What determines the growth and branching of neurons and synaptogenesis during recovery?

The level and completeness of neurotrophic factors and regulators Signup and view all the answers

What are the zones that form alongside the nuclear zone of irreversible brain damage after a stroke?

Zones of plasticity and secondary replacement of lost functions Signup and view all the answers

What happens to energy supply in neurons during ischemia?

Anaerobic glycolysis dominates due to oxygen deprivation. Signup and view all the answers

How much ATP is produced from one glucose molecule during anaerobic glycolysis compared to normal conditions?

2 ATP during anaerobic and 38 ATP during aerobic conditions Signup and view all the answers

Which factors influence the severity of recovery processes after a stroke?

Neurotrophic factors, membrane modulators, and endogenous regulators Signup and view all the answers

What term describes the phenomenon of new associative connections forming in the brain after an injury?

Neuroplasticity Signup and view all the answers

What effect does ischemia have on metabolic processes in the brain?

It promotes anaerobic glycolysis, reducing energy output. Signup and view all the answers

What role do gangliosides play after a stroke?

They serve as modulators of membrane functional states. Signup and view all the answers

Study Notes

Fasciculations

Involuntary twitching of muscle fibers, visible to the naked eye.
Caused by spontaneous contraction of a muscle fiber group.

Fibrillation

Involuntary contractions of individual muscle fibers (myofibrils).
Undetectable visually, only measurable by electromyography.

Tick

Rapid involuntary jerking of a single muscle or muscle group.
Usually associated with extrapyramidal system dysfunction, encephalitis, intoxication, and certain mental disorders.

Tremor

Rhythmic, involuntary trembling of limbs, eyelids, fingers, or torso.
Caused by muscle contractions.

Chorea

Rapid, irregular, violent muscle contractions of various groups.

Athetosis

Slow, wormlike, involuntary movements.
Results from simultaneous activation of agonist and antagonist muscles.
Primarily affects distal extremities like fingers and toes.

Epilepsy

Chronic brain disease characterized by repeated convulsive seizures.
Seizures disrupt motor, sensory, autonomic, mental, and cognitive functions.
Caused by excessive neuronal discharges.
Pathogenesis originates from spontaneous membrane instability of neurons in the cerebral cortex leading to paroxysmal depolarization shift on the cell membrane.
An epileptogenic focus is a region of local brain damage responsible for pathological excitation of surrounding neurons, triggering focal amplified and synchronous discharges, and potentially forming a functionally active epileptic focus.
An epileptic focus is a collection of interconnected neurons with abnormal electrogenesis that generates excessive neuronal discharges, leading to hypersynchronization of surrounding neurons.

Neuroinfections

Infectious diseases affecting the human nervous system.
Possess specific manifestations due to the infectious agent and non-specific syndromes associated with the body's response to the disease.
Includes meningitis, encephalitis, myelitis, brain abscess, poliomyelitis, rabies, neurotuberculosis, neurosyphilis, nervous system disorders in AIDS, parasitic diseases, prion diseases.

Meningitis

Purulent or serous inflammation of the brain and/or spinal cord.
Caused by bacteria, viruses, fungi, and other agents.
Typically refers to inflammation of the pia mater.
Characterized by meningeal symptoms and inflammatory changes in the cerebrospinal fluid.

Meningism

Irritation of the brain or spinal cord membranes causing meningeal symptoms without liquorological signs of inflammation.

Meningococcus (Neisseria meningitidis)

Aerobic gram-negative diplococcus that causes meningococcal infection.
Can lead to nasopharyngeal mucosa infection (nasopharyngitis), cerebral membrane infection (meningitis), and septicemia.
Spreads hematogenously.
Anthroponosis (human-to-human transmission).

Meningococcemia

Generalized form of meningococcal infection.
Characterized by bacteremia with massive meningococcal death.
Manifested by acute septicemia with infectious-toxic shock and thrombohemorrhagic syndrome development.

Neurodegenerative Diseases

Slowly progressing diseases, either hereditary or acquired, affecting the central nervous system (CNS).
Different etiologies and pathogenesis.
Based on degeneration and death of nerve cells within specific CNS structures.
Disrupts connections within the CNS.
Imbalances the synthesis and isolation of neurotransmitters.
Leads to memory impairment, coordination difficulties, and cognitive decline.

Brain Edema

Swelling of the apical dendrites and lysis of neurons.
Develops a few hours post-stroke, peaking on the 2nd-4th day.
Characterized by increased intracellular water content, primarily in glial cells.
"Edema-swelling of the brain" term is used instead of "edema".
Intracellular edema-swelling of astrocytes is the primary form of cytotoxic edema.
Observed following ischemia, triggering pathobiochemical reactions of secondary neuronal damage, realizing cytotoxic and excitotoxic effects.

Cytotoxic Edema

Based on primary damage to cell membranes and cell cytoplasm.
Astrocytic edema causes increased release of excitatory amino acids from swollen astrocytes.

Vasogenic Edema

Develops alongside cytotoxic edema.
Involves vascular factors and mediators: kinins, glutamate, free fatty acids, prostaglandins, and thromboxanes.
Increase in permeability of microvessel walls allows protein molecules and blood plasma components to pass through the blood-brain barrier (BBB) into the brain's tissue spaces.
Increases intercellular fluid osmolarity and damages cell membranes, disrupting neural functions.

Brain Edema Effects

Increases brain volume.
Elevates intracranial pressure.
Leads to possible dislocation, wedging of the brain, and vital function impairment.

Hemorrhagic Transformation (HT) of Brain Infarction

Frequency and probability of HT development correlates with stroke's pathogenesis, localization, and volume of brain damage.
Cardioembolic strokes and extensive ischemic damage zones have a higher predisposition to HT.
Can result from reperfusion therapy for stroke.
Fibrinolysis of the embolus restores blood flow, increasing diapedesis in the infarct zone and secondary intracranial hemorrhages.
Two types of hemorrhages: hemorrhagic infarction and infarction-hematoma (parenchymal hematoma).

Microcirculatory Microembolization

Can develop independently in ischemic stroke (natural microembolization).
Can be caused or aggravated by revascularization interventions (pharmacological or mechanical).

Reparative Processes After Stroke

Brain tissue activates for recovery.
Increased expression of specific genes and related proteins indicates enhanced regenerative and reparative processes, neural tissue plasticity, and formation of new connections.
Processes include angiogenesis, neurogenesis, and synaptogenesis.
Processes are interdependent and remodel the brain, leading to improved neurological functions.
Severity of recovery is influenced by neurotrophic factors, membrane and receptor modulators, endogenous regulators (neuropeptides).
Their formation levels determine neuron process growth, branching, and synaptogenesis.

Reparative Process Regularity

Zones of brain plasticity and secondary replacement of lost functions form next to irreversible tissue damage.
Hypermetabolism zones form in symmetrical regions of the opposite hemisphere.

Ischemic (Pathobiochemical) Cascade Stages

Energy Supply Disturbances:
- Decreased cerebral blood flow (CBF) dramatically reduces aerobic glycolysis, normally supplying 95% of the brain's energy.
- Metabolism shifts to anaerobic glycolysis, producing only 2 ATP molecules per glucose molecule (1/19th of aerobic glycolysis).
- Ischemia halts pyruvate acid (PVA) inclusion in the Krebs cycle.
- Accumulating PVA is converted into lactic acid instead of being oxidized.
- Increased lactate leads to pH decrease to 6.4-6.7 and intracellular acidosis.
- Energy deficit and acidosis disrupt metabolic reactions and ion transport as the Na+/K+-ATP-azic enzyme system is compromised.
- This causes passive outflow of potassium (K+) from the cell and influx of sodium (Na+) and chloride (Cl-) into the cell, further increasing water entry and contributing to edema.
- Cell membrane depolarization opens calcium channels, allowing calcium (Ca2+) influx.

Acute Focal Cerebral Ischemia Cascade

Energy deficit
Lactic acidosis
Active ion transport disorders
Glutamate excitotoxicity
Accumulation of Ca2+ inside the cell
Activation of intracellular enzymes
Excessive synthesis of nitric oxide
Activation of oxidative stress reactions

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Description

Explore the various neuromuscular disorders including fasciculations, fibrillation, and tremors. This quiz provides insights into symptoms, causes, and effects of different involuntary muscle contractions. Understand the complexities of conditions such as epilepsy and chorea.