8) CNS Patho

Disorders of the Nervous System

Presenter: Dr. Rozlin Abd. Rahman

Anatomy of the Brain

Key Structures:

Cerebral Cortex: Responsible for higher brain functions such as thought, action, and sensory processing. Divided into lobes: frontal, parietal, occipital, and temporal.
Hypothalamus: Regulates autonomic functions and homeostasis, including temperature, thirst, hunger, and sleep. It also controls the pituitary gland.
Caudate Nucleus: Involved in motor control, learning, and memory. Part of the basal ganglia.
Pituitary Gland: Often termed the "master gland," it regulates hormonal activity in the body, functioning under the hypothalamus.
Thalamus: Acts as a relay station for sensory and motor signals to the cerebral cortex and is involved in sleep and consciousness.
Midbrain: Controls vision, hearing, motor control, sleep/wake, arousal (alertness), and temperature regulation.
Putamen: Involved in regulating movements and influencing various types of learning.
Globus Pallidus: Plays a crucial role in the regulation of voluntary movement.
Amygdala: Essential for emotion regulation, fear responses, and emotional memory.
Optic Chiasm: The crossing point of optic nerve fibers from both eyes, crucial for vision and depth perception.
Hippocampus: Key for memory formation and spatial navigation.
Brain Stem: Controls basic life functions such as heartbeat and breathing.
Cerebellum: Coordinates voluntary movements like posture, balance, and coordination.
Olfactory Bulb: Involved in the sense of smell and processing olfactory information.

Infection and Inflammation of the Nervous System

Types of Infections:

Intracranial Infection: Infections that occur within the skull, affecting brain tissue or membranes.
Meningitis: Inflammation of the protective membranes covering the brain and spinal cord.
Encephalitis: An inflammation of the brain itself, often viral in origin.

Routes of Entry:

Blood-borne spread: Pathogens enter through the bloodstream, affecting the CNS.
Direct inoculation of organisms: Introduction of infectious agents directly into the nervous system, e.g., through injury or surgery.
Local extension of sepsis: Infection spreads from adjacent tissues into the nervous system.
Via the peripheral nervous system: Pathogens can travel along peripheral nerves to reach the CNS.

Meningitis

Definition: Inflammation of the meningeal coverings surrounding the brain and spinal cord, can lead to serious complications if not treated promptly.

Classification:

Pyogenic: Caused by bacteria, leading to intense inflammation.
Aseptic: Often viral, resulting in less severe symptoms compared to pyogenic.
Chronic: Includes tuberculous and cryptococcal meningitis, generally having prolonged symptoms and requiring more complex treatments.

Causes:

Most common: Bacterial (most severe) and viral infections.
Less common causes: Fungal and parasitic infections, physical injury, certain cancers, and reactions to drugs (e.g., NSAIDs).

Pathogens Causing Meningitis

Bacterial Meningitis: Most common form where bacteria release toxins, damaging meningeal cells and inciting immune response; major causative organisms include Neisseria meningitidis and Streptococcus pneumoniae.
Viral Meningitis: Typically less severe; caused by mumps, poliovirus, herpes simplex virus (HSV), and can include arboviral etiology.
Fungal Meningitis: Often seen in immunocompromised patients (e.g., those with AIDS); fungi may include Cryptococcus.

Bacterial Meningitis by Age Group:

Premature Babies and Newborns: Often caused by Group B Streptococci, E. coli.
Older Children: Common organisms include Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae type B.
Adults: Neisseria meningitidis and Streptococcus pneumoniae (responsible for 80% of cases), with increased risk for Listeria monocytogenes in those over 50.

Viral Meningitis

Pathogens: Enterovirus, arboviral infections, influenza, herpes simplex virus type 2, HIV, and rabies virus.
Incubation Period: Typically 3-6 days from exposure.
Duration of Illness: Generally resolves within 7-10 days and is usually less severe than bacterial meningitis.

Symptoms of Meningitis

Central: Severe headache and altered mental status; may progress to confusion or lethargy.
Ears: Increased sensitivity to sound (phonophobia).
Eyes: Light sensitivity (photophobia).
Neck: Stiffness and discomfort, may indicate meningeal irritation.
Systemic: High fever; petechiae may indicate bacterial meningitis (especially meningococcal).

Skin Findings

Non-specific: Ranges from blanching rashes to petechial or purpuric rash indicative of serious conditions such as meningococcal sepsis.

Complications

Potential complications of meningitis include:

Brain abscess: Localized area of infection.
Subdural effusion: Fluid accumulation beneath the dura mater.
Cerebral infarction: Risk of stroke due to compromised blood flow.
Seizures: May occur due to swelling or irritation in the brain.
Hydrocephalus with meningeal fibrosis: Accumulation of CSF can lead to raised intracranial pressure.
Hearing loss: Sensorineural loss due to involvement of cranial nerves.

Tuberculosis (TB) Meningitis

This condition is increasing among AIDS patients, characterized by:

Symptoms: Persistent headache, malaise, mental confusion, and vomiting.
Chronic meningeal inflammation with ranuloma formation and fibrosis → causes hydrocephalus and cranial nerve damage.

Diagnosis of Meningitis

Tests: Include blood cultures, urine culture, and detailed CSF examination.

Lumbar Puncture (LP): Essential to obtain CSF for analysis; helps assess cell count, glucose, and protein levels.
CT Scan of the Head: Rule out contraindications for lumbar puncture, screening for other abnormalities.

Imaging for Diagnosis

Brain CT: Used to rule out hemorrhagic conditions.
Spinal Tap (LP): For laboratory analysis of CSF.
MRI: Sensitive imaging technique especially for changes in the pia and arachnoid mater.

Spinal Fluid Examination

Examines CSF for:

White Blood Cells (WBC): Increased in infections.
Red Blood Cells (RBC): Presence can indicate bleeding or trauma.
Protein Content: Elevated in most infections.
Glucose Levels: Lower in bacterial infections compared to normal levels.
Gram Stain: Useful in identifying bacteria directly during bacterial meningitis.

CSF Appearance in Various Infections

Pyogenic Bacterial Meningitis: Typically appears slightly cloudy, high protein concentration, and low glucose levels.
viral meningitis clear fluid, normal glucose
tuberculosis meningitis yellowish fluid, low glucose
fungal meningitis yellowish and viscous fluid, normal or low glucose

CSF Appearance in Radiographic

initially meninges show vascular congestion, edema and minute hemorrhages

Symptoms Specific to Meningitis:Symptoms can vary significantly based on severity and causative organism; thorough clinical examinations and patient histories are crucial for accurate diagnosis.

Treatment

Bacterial Meningitis: Requires immediate antibiotic administration to manage infection and inflammation effectively.
Viral Meningitis: No specific antiviral treatment; supportive care including hydration and pain management is essential.

Fungal Meningitis: Often necessitates antifungal medications and may require a longer duration of treatment, especially in immunocompromised patients.

Prevention Haemophilus vaccine (HiB vaccine) in children.

• The pneumococcal conjugate vaccine is now a routine childhood immunization.

Encephalitis

Definition: An infection of the brain tissue that can be caused by viral agents such as HSV or arboviruses (chickenpox, small pox, influenza and measles). May be caused by mosquitoes and herpes leading to:

Symptoms: Including headache, malaise, seizure activity, and altered consciousness; symptoms can be severe.
treatment: Treated with antiviral medications
Herpes induced is treated with Acyclovir. Interferes with DNA synthesis and inhibits viral replication
Diagnosis: Confirmed through MRI imaging to assess inflammation or other abnormalities in the brain. Cerebral edema and hemorrhagic lesions.

Vascular Injury

Types of Hemorrhage:

Epidural Hemorrhage: Typically results from trauma, often associated with skull fractures. Immediate intervention is often required. Lucid interval.
Subdural Hemorrhage: Common with blunt trauma, involves tearing of bridging veins.
Usually originates from tearing of bridging veins that pass through the subdural space
between the dura mater & arachnoid meningeal layers
At risk → Elderly → brain atrophy increases stretching of the bridging veins
Becomes clinically evident within hours with non-specific signs (reduced consciousness, headache, vomiting, lethargy, confusion).
re-bleeding is common
Subarachnoid Hemorrhage: Often occurs due to aneurysms; bleeding between the pia and arachnoid membranes can be life-threatening and requires prompt treatment.
Pathogenesis→ involves a congenital defect in the muscle wall of the cerebral arteries → ‘berry aneurysm’
There is an association with adult polycystic kidney disease and hypertension
Presentation: sudden severe headache

Symptoms of hematomas

headaches
agitation
drowsiness
gradual radiograph deficits

Treatment of hematomas

small case: reabsorbed naturally
severe cases: surgical ligation, evacuation of hematoma, drug therapy

CEREBRAL VASCULAR DISEASE: Stroke Overview

Definition: Conditions affecting blood supply to the brain caused by cerebral (thrombosis, embolism, haemorrhage), result in ischemia or hemorrhage, leading to brain damage.

Ischaemic stroke

The thrombus/embolus can occlude a cerebral artery → causes ischaemia
Brain tissue becomes necrotic and degenerates →cerebral infarct.
The myelin sheath material breaks down and the debris resulting from the necrosis of the brain tissue eventually removed by phagocytes leaving an empty space.
No blood leaks into the brain tissue → ischaemic infarct.

Haemorrhagic stroke

More serious type of stroke especially in patients with hypertension
Higher mortality
Bleeding occurs directly into the brain parenchyma
Blood from the burst/ruptured vessel escapes into the brain under high pressure → extensive damage to the brain tissue.
The leaked blood puts too much pressure on brain cells, which damages them.

Symptoms of Stroke

Typical presentations may include sudden onset of:

Weakness: Unilateral, affecting one side of the body.
Trouble Speaking: Slurred speech or inability to communicate.
Vision Problems: Sudden loss of vision in one or both eyes.
Severe Headache: Often described as sudden and intense, sometimes referred to as a "thunderclap" headache.

Risk Factors for Stroke

Notable risk factors include:

Hypertension: Chronic high blood pressure is a leading risk.
Smoking: Increases the risk of clot formation and vessel damage.
Diabetes: Alters blood vessel health.
Obesity: Associated with numerous comorbid conditions that elevate stroke risk.

Imaging Techniques for Strokes

CT Scans: Quick imaging to differentiate between ischemic and hemorrhagic strokes.
MRI: Further evaluation and assessment of brain tissue affected by ischemia.

Transient Ischaemic attack (TIA)

Degenerative & demyelinating diseases

dementia
parkinson’s disease
Multiple sclerosis: A chronic disease that affects the central nervous system, leading to a range of neurological symptoms due to the degeneration of myelin.
Amyotrophic lateral sclerosis (ALS): A progressive neurodegenerative disease that affects motor neurons in the brain and spinal cord, leading to muscle weakness and atrophy.

Brain Tumors

astrocytomas, glioblastoma, metastatic tumors, meningioma

pituitary tumors

other benign tumors

Central neurocytoma: Typically in young adults, site: lateral ventricles:
Schwannoma: arise from the nerve sheath and may compress nerves causing pain, weakness and numbness
Chondroma: Arises from the cartilage, usually at the base of the skul
Gangliocytoma: Occurs in children/young adult and arises from ganglion

Malignant Brain Tumor

astrocytoma
ependymoma
medullablastoma

Metastatic Brain Tumors

Composed of cancer cells that have spread from
its original location
 Most common:
 Breast
 Lungs
 Prostate
 Kidney
 Melanoma
 Treatment is composed of radiation and surgery
if possible

Symptoms of Brain Tumors

Headache
 Nausea and Vomiting
 Lethargy
 Seizures
 Paralysis
 Aphasia
 Blindness
 Deafness
 Abnormal changes in personality & behavior
by location
 Frontal lobe: Weakness, personality changes, speech disturbances
 Parietal lobe: Loss/change in sensation, changes in vision
 Temporal lobe: Seizure, difficulty in understanding, difficulty with language
 Occipital lobe: Changes in vision
 Cerebellum: Abnormal eye movement, loss of coordination, changes in gait, vertigo, hearing loss

Treatment of Brain tumors

surgical resection
radiation therapy

Hydrocephalus

definition: A condition characterized by excessive cerebrospinal fluid (CSF), leading to increased intracranial pressure (ICP).Symptoms: Patients may show enlarged cranial size and distended scalp veins, especially in infancy and childhood

Types of Hydrocephalus

non-communicating
communicating

Radiographic Appearance

Generalized enlargement of the ventricular system

 PA radiograph can reveal separation of the sutures

 CT clearly demonstrates ventricular dilatation

 MRI is more specific in demonstrating the underlying

cause of obstruction or in excluding obstruction

 Ultrasound is useful in utero and in infants

Hydrocephalus Clinical Symptoms

The cranial size is enlarged

 Scalp veins distended

 Skin of scalp thin, fragile and

shiny

 Neck muscles underdeveloped

 Severe cases

 Orbital roofs are depressed

 Eyes displaced downwards

Treatment

Placement of a shunt

Internal jugular, heart or peritoneum

Contains one way valve to prevent backflow of blood into ventricles

 Radiographs taken to verify shunt placement

 CT or MRI done to evaluate

success of treatment

Presenter: Dr. Rozlin Abd. Rahman

Anatomy of the Brain

Key Structures:

Cerebral Cortex: Responsible for higher brain functions such as thought, action, and sensory processing. Divided into lobes: frontal, parietal, occipital, and temporal.
Hypothalamus: Regulates autonomic functions and homeostasis, including temperature, thirst, hunger, and sleep. It also controls the pituitary gland.
Caudate Nucleus: Involved in motor control, learning, and memory. Part of the basal ganglia.
Pituitary Gland: Often termed the "master gland," it regulates hormonal activity in the body, functioning under the hypothalamus.
Thalamus: Acts as a relay station for sensory and motor signals to the cerebral cortex and is involved in sleep and consciousness.
Midbrain: Controls vision, hearing, motor control, sleep/wake, arousal (alertness), and temperature regulation.
Putamen: Involved in regulating movements and influencing various types of learning.
Globus Pallidus: Plays a crucial role in the regulation of voluntary movement.
Amygdala: Essential for emotion regulation, fear responses, and emotional memory.
Optic Chiasm: The crossing point of optic nerve fibers from both eyes, crucial for vision and depth perception.
Hippocampus: Key for memory formation and spatial navigation.
Brain Stem: Controls basic life functions such as heartbeat and breathing.
Cerebellum: Coordinates voluntary movements like posture, balance, and coordination.
Olfactory Bulb: Involved in the sense of smell and processing olfactory information.

Infection and Inflammation of the Nervous System

Types of Infections:

Intracranial Infection: Infections that occur within the skull, affecting brain tissue or membranes.
Meningitis: Inflammation of the protective membranes covering the brain and spinal cord.
Encephalitis: An inflammation of the brain itself, often viral in origin.

Routes of Entry:

Blood-borne spread: Pathogens enter through the bloodstream, affecting the CNS.
Direct inoculation of organisms: Introduction of infectious agents directly into the nervous system, e.g., through injury or surgery.
Local extension of sepsis: Infection spreads from adjacent tissues into the nervous system.
Via the peripheral nervous system: Pathogens can travel along peripheral nerves to reach the CNS.

Meningitis

Definition: Inflammation of the meningeal coverings surrounding the brain and spinal cord, can lead to serious complications if not treated promptly.

Classification:

Pyogenic: Caused by bacteria, leading to intense inflammation.
Aseptic: Often viral, resulting in less severe symptoms compared to pyogenic.
Chronic: Includes tuberculous and cryptococcal meningitis, generally having prolonged symptoms and requiring more complex treatments.

Causes:

Most common: Bacterial (most severe) and viral infections.
Less common causes: Fungal and parasitic infections, physical injury, certain cancers, and reactions to drugs (e.g., NSAIDs).

Pathogens Causing Meningitis

Bacterial Meningitis: Most common form where bacteria release toxins, damaging meningeal cells and inciting immune response; major causative organisms include Neisseria meningitidis and Streptococcus pneumoniae.
Viral Meningitis: Typically less severe; caused by mumps, poliovirus, herpes simplex virus (HSV), and can include arboviral etiology.
Fungal Meningitis: Often seen in immunocompromised patients (e.g., those with AIDS); fungi may include Cryptococcus.

Bacterial Meningitis by Age Group:

Premature Babies and Newborns: Often caused by Group B Streptococci, E. coli.
Older Children: Common organisms include Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae type B.
Adults: Neisseria meningitidis and Streptococcus pneumoniae (responsible for 80% of cases), with increased risk for Listeria monocytogenes in those over 50.

Viral Meningitis

Pathogens: Enterovirus, arboviral infections, influenza, herpes simplex virus type 2, HIV, and rabies virus.
Incubation Period: Typically 3-6 days from exposure.
Duration of Illness: Generally resolves within 7-10 days and is usually less severe than bacterial meningitis.

Symptoms of Meningitis

Central: Severe headache and altered mental status; may progress to confusion or lethargy.
Ears: Increased sensitivity to sound (phonophobia).
Eyes: Light sensitivity (photophobia).
Neck: Stiffness and discomfort, may indicate meningeal irritation.
Systemic: High fever; petechiae may indicate bacterial meningitis (especially meningococcal).

Skin Findings

Non-specific: Ranges from blanching rashes to petechial or purpuric rash indicative of serious conditions such as meningococcal sepsis.

Complications

Potential complications of meningitis include:

Brain abscess: Localized area of infection.
Subdural effusion: Fluid accumulation beneath the dura mater.
Cerebral infarction: Risk of stroke due to compromised blood flow.
Seizures: May occur due to swelling or irritation in the brain.
Hydrocephalus with meningeal fibrosis: Accumulation of CSF can lead to raised intracranial pressure.
Hearing loss: Sensorineural loss due to involvement of cranial nerves.

Tuberculosis (TB) Meningitis

This condition is increasing among AIDS patients, characterized by:

Symptoms: Persistent headache, malaise, mental confusion, and vomiting.

Diagnosis of Meningitis

Tests: Include blood cultures, urine culture, and detailed CSF examination.

Lumbar Puncture (LP): Essential to obtain CSF for analysis; helps assess cell count, glucose, and protein levels.
CT Scan of the Head: Rule out contraindications for lumbar puncture, screening for other abnormalities.

Imaging for Diagnosis

Brain CT: Used to rule out hemorrhagic conditions.
Spinal Tap (LP): For laboratory analysis of CSF.
MRI: Sensitive imaging technique especially for changes in the pia and arachnoid mater.

Spinal Fluid Examination

Examines CSF for:

White Blood Cells (WBC): Increased in infections.
Red Blood Cells (RBC): Presence can indicate bleeding or trauma.
Protein Content: Elevated in most infections.
Glucose Levels: Lower in bacterial infections compared to normal levels.
Gram Stain: Useful in identifying bacteria directly during bacterial meningitis.

CSF Appearance in Various Infections

Pyogenic Bacterial Meningitis: Typically appears slightly cloudy, high protein concentration, and low glucose levels.

Symptoms Specific to Meningitis:Symptoms can vary significantly based on severity and causative organism; thorough clinical examinations and patient histories are crucial for accurate diagnosis.

Treatment

Bacterial Meningitis: Requires immediate antibiotic administration to manage infection and inflammation effectively.
Viral Meningitis: No specific antiviral treatment; supportive care including hydration and pain management is essential.

Encephalitis

Definition: An infection of the brain tissue that can be caused by viral agents such as HSV or arboviruses, leading to:

Symptoms: Including headache, malaise, seizure activity, and altered consciousness; symptoms can be severe.
Diagnosis: Confirmed through MRI imaging to assess inflammation or other abnormalities in the brain.

Vascular Injury

Types of Hemorrhage:

Epidural Hemorrhage: Typically results from trauma, often associated with skull fractures. Immediate intervention is often required.
Subdural Hemorrhage: Common with blunt trauma, involves tearing of bridging veins.
Subarachnoid Hemorrhage: Often occurs due to aneurysms; bleeding between the pia and arachnoid membranes can be life-threatening and requires prompt treatment.

Stroke Overview

Definition: Conditions affecting blood supply to the brain result in ischemia or hemorrhage, leading to brain damage.

Symptoms of Stroke

Typical presentations may include sudden onset of:

Weakness: Unilateral, affecting one side of the body.
Trouble Speaking: Slurred speech or inability to communicate.
Vision Problems: Sudden loss of vision in one or both eyes.
Severe Headache: Often described as sudden and intense, sometimes referred to as a "thunderclap" headache.

Risk Factors for Stroke

Notable risk factors include:

Hypertension: Chronic high blood pressure is a leading risk.
Smoking: Increases the risk of clot formation and vessel damage.
Diabetes: Alters blood vessel health.
Obesity: Associated with numerous comorbid conditions that elevate stroke risk.

Imaging Techniques for Strokes

CT Scans: Quick imaging to differentiate between ischemic and hemorrhagic strokes.
MRI: Further evaluation and assessment of brain tissue affected by ischemia.

Hydrocephalus

Definition: A condition characterized by excessive cerebrospinal fluid (CSF), leading to increased intracranial pressure (ICP).Symptoms: Patients may show enlarged cranial size and distended scalp veins, especially in infancy and childhood.

Treatment of Hydrocephalus

Typically managed by:

Placement of a Shunt: To divert excess CSF and relieve pressure on the brain.

Brain Tumors

Types of Tumors:

Primary Brain Tumors: Less common but associated with poor prognosis; include glioblastomas and medulloblastomas.
Common Pediatric Tumors: Brain tumors frequently seen in children, often requiring specialized treatment protocols.

Symptoms and Treatment of Brain Tumors

Common symptoms may include:

Headache: Often persistent and worsening.
Nausea and Vomiting: Due to increased ICP or irritation of the brain.Treatment Options: May involve surgical resection, chemotherapy, and radiation therapy depending on type, location, and growth rate of the tumor.