Neurology Essentials: Brain, Nerves, and Common Disorders

Neurology: Anatomy and Physiology Fundamentals

Anatomy of the Nervous System

Central Nervous System (CNS)

• Brain: Cerebrum, Diencephalon, Cerebellum, Brain Stem
• Spinal Cord

Peripheral Nervous System (PNS)

• Spinal Nerves
• Peripheral Nerves

Supporting Structures

• Meninges: Membranes surrounding the brain and spinal cord
• Cerebrospinal Fluid (CSF)

Physiology of the Nervous System

Peripheral Nervous System (PNS) Functions

• Autonomic Nervous System:
  • Sympathetic (Adrenergic)
  • Parasympathetic (Cholinergic)
• Somatic Nervous System

Central Nervous System (CNS) Functions

• Cerebrum & Diencephalon: Higher cognitive functions
• Cerebellum: Helps with movement coordination
• Brain Stem: Regulates vital functions like temperature, blood pressure, and heart rate

Common Neurological Signs and Symptoms

• Syncope: Temporary loss of consciousness (passing out)
• Paresthesia: Unusual sensations (e.g., tingling, numbness)
• Motor Dysfunctions: Weakness, paralysis, tremors
• Seizures: Sudden, uncontrolled electrical activity in the brain
• Headaches: Pain in the head or face
• Sensory Disturbances: Altered perception of touch, temperature, pain

Complex Regional Pain Syndrome (CRPS)

CRPS is characterized by a hyperactive sympathetic nervous system, often developing after trauma, immobilization, or non-weight-bearing periods.

Signs and Symptoms of CRPS

• Severe pain
• Hypersensitivity to touch
• Swelling
• Increased skin temperature

As CRPS progresses, it can lead to:

• Atrophy of affected limbs
• Decreased circulation

CRPS Treatment

• Opioid medications (among other treatments)

Amyotrophic Lateral Sclerosis (ALS)

ALS is a progressive neurodegenerative disease characterized by the degeneration of efferent neurons, which control motor function. Its etiology is currently unknown.

ALS Signs and Symptoms

• Progressive muscle weakness
• Spasticity
• Hyperreflexia

Unfortunately, ALS often leads to death within approximately three years of diagnosis.

Muscular Dystrophy

Muscular Dystrophy refers to a group of genetic diseases that cause progressive atrophy of muscles without direct neural involvement.

Types of Muscular Dystrophy

• Pseudohypertrophic Muscular Dystrophy: Often seen in childhood.
• Duchenne Muscular Dystrophy: A common and severe form.

Multiple Sclerosis (MS)

Multiple Sclerosis is a chronic disease characterized by the demyelination of nerves within the Central Nervous System (CNS), disrupting communication between the brain and body.

Spina Bifida

Spina Bifida is a congenital defect resulting from the incomplete formation of the neural tube during embryonic development.

Cerebral Palsy

Cerebral Palsy is a group of disorders that affect movement and muscle tone or posture. It is caused by brain injury occurring during birth or early childhood.

Stroke and Transient Ischemic Attack

A stroke is a sudden neurological deficit resulting from impaired circulation to the brain.

Types of Stroke

• Ischemic Stroke: Caused by a blockage in a blood vessel.
• Hemorrhagic Stroke: Caused by bleeding in the brain.

Transient Ischemic Attack (TIA)

Also known as a "mini-stroke," a TIA is a temporary episode of neurological dysfunction caused by a brief interruption in blood flow to the brain.

Stroke Diagnosis

Diagnosis often involves:

• FAST Test: Face drooping, Arm weakness, Speech difficulty, Time to call emergency services.
• Imaging: CT scans and MRI scans.

Cerebral Aneurysm

A cerebral aneurysm is a weak or thin spot in a blood vessel in the brain that balloons out and fills with blood. Rupture of an aneurysm is a common cause of hemorrhagic stroke.

Cerebral Aneurysm Signs and Symptoms

• Severe headache
• Vision changes
• Pupillary dysfunction

Types of Neurovascular Headaches

• Migraines: Characterized by severe, throbbing pain, often accompanied by nausea and sensitivity to light and sound.
• Cluster Headaches: Intense, piercing pain typically occurring in cycles, often affecting one side of the head or around the eye at specific times.
• Toxic Headaches: Caused by exposure to certain poisons or severe dehydration.

Seizure Disorders

Seizure disorders are characterized by sudden, temporary electromechanical cerebral dysfunction.

Types of Seizures

• Partial (Focal) Seizures: Electrical activity changes are localized to a specific area of the brain.
• Generalized Seizures: Involve widespread electrical activity across both hemispheres of the brain.

Seizure Incidence

• Single seizure incidence: 1-30% of the population.
• Recurrent seizures (Epilepsy): Approximately 1% of the population.

Epilepsy: Causes, Types, and Phases

Epilepsy is a chronic neurological disorder characterized by recurrent, unprovoked seizures. It is one of the most common causes of seizures.

Epilepsy Treatment

• Anticonvulsant medications are the primary treatment.

Types of Epileptic Seizures

• Absence Seizures: Formerly known as "petit mal" seizures, characterized by brief periods of staring or unresponsiveness.
• Tonic-Clonic Seizures: Formerly known as "grand mal" seizures, involving stiffening (tonic phase) followed by rhythmic jerking (clonic phase).

Phases of a Seizure

• Aura: A warning sensation that precedes a seizure.
• Ictal Phase: The actual seizure event.
• Postictal State: The period of recovery immediately following a seizure.

Meningitis: Inflammation of the Meninges

Meningitis is an inflammation of the meninges, the protective membranes surrounding the brain and spinal cord, typically caused by bacterial or viral infection.

Bacterial Meningitis

Bacterial meningitis is the most severe and acute form of meningitis, often life-threatening. It can be transmitted through respiratory and throat secretions.

Bacterial Meningitis Signs and Symptoms

• High fever
• Severe headache
• Stiff neck (nuchal rigidity)

Viral Meningitis

Viral meningitis is the most common and generally less severe form of meningitis. It is often transmitted through direct contact with respiratory fluids, such as kissing.

Viral Meningitis Signs and Symptoms

• High fever
• Headache
• Stiff neck