NRE Step 1: Neurology Made Simple – Pass with Precision

Neurology can be hard, but I made it super easy for you! Just read this blog 2 or 3 times, and you’ll understand it. I made everything as simple as possible—you’re going to love it!

1. Huntington’s Disease (HD)

1. What is it?

A brain disorder that causes strange body movements, like dancing movements.

2. How it spreads?

It is a autosomal dominant and runs in families. The problem is on chromosome number 4 with too many CAG repeats in a gene.

3. What is anticipation?

The disease starts earlier and is worse in the next generation. like more it pass will become severe to next generation.

4. What are the Symptoms?

• Memory loss (dementia)
• Slow, jerky movements (chorea)
• Confused thinking (AlOC)
• Sudden falls or fainting

5. What are the tests?

• Genetic test is the gold strandard to confirm
• CT or MRI shows brain shrinking (cerebral atrophy)

6. What is the treatment?

No cure yet. Only supportive care.

2. Parkinson’s Disease

1. What is it?

A movement problem that happens in older age people.

2. Which part is affected?

Substantia nigra is affected which lies in the midbrain, where dopamine decreases that increases acetylcholine (Ach).

3. How to remember?

We use “TRAP” mnemonic to remember Parkinson’s Disease.

• T: Tremor (hand shaking like rolling a pill)
• R: Rigidity (stiff arms/legs, like a cogwheel)
• A: Akinesia (moves slowly)
• P: Posture problem (easy to fall)

4. Other signs

• Tiny handwriting (micrography)
• Memory loss (dementia)

5. Treatment

1. Levodopa + Carbidopa

Mao monoamine oxidase (MAO) andcatechol-o-methyl transferase (COMT) are dopamine antagonist.

2. Selegiline is MAO type B inhibitor means it keeps dopamine to work for long time.
3. Tolcapone and Entacapone = (Ropinirole, Bromocriptine)

• These are COMT inhibitors.
• They help dopamine last longer in the brain.
• Used with other Parkinson’s medicines (like Levodopa).
• They don’t work alone — they are part of combination therapy.

4. For young people Anti-ACh drugs Benztropine, Trihexyphenidyl are given but they have side effects like

• Dry mouth,
• Constipation
• Urine retention
• Dry eyes.

How Levodopa and Carbidopa Work

• Levodopa is the main medicine. It helps make dopamine in the brain.
• If we give Levodopa alone, a body enzyme called dopa decarboxylase enzyme (outside the brain) changes it too early. Carbidopa is added to protect Levodopa in the body.
• Carbidopa stops Levodopa from working before it reaches the brain.
• Carbidopa cannot enter the brain (it stops at the brain barrier).
• Levodopa goes into the brain and then works to fix low dopamine.

Think of it like this:
Carbidopa is a bodyguard that keeps Levodopa safe until it reaches the brain.
Once inside, Levodopa does its job.

3. Neuromuscular Junction Disorders

There are two types of NMJ disorders

1. Myasthenia gravis
2. Lambert-Eaton Syndrome

1.    Myasthenia Gravis

In Myasthenia Gravis, the body makes anti-Ach receptor antibodies that block the Ach (acetylcholine) receptors at the muscles.
This stops the message from the nerve to the muscle, so the muscles become weak.

• In the morning, the person feels okay.
• B y evening, they feel very tired.
• Working or moving makes the weakness worse.

Eye symptoms (ocular signs)

• Ptosis – Drooping eyelids
• Diplopia – Double vision

Linked with

• Thymoma – A tumor in the thymus gland

2.    Lambert-Eaton Syndrome

Calcium is needed to release Ach from Axon. InLambert eaton syndrome anti-calcium channel antibodies are formed and it act on the calcium channel and wont allow to release Ach. Simply no calcium no ach. In morning they are very tired but with movement they become better. There is no ocular symptoms. Small Cell Lung Cancer is linked to Lambert Eaton syndrome.

Small cell lung cancer arise from center of lungs and it produce

• Ectopic ACTH → Causes Cushing’s signs
  • Ectopic ADH → Causes SIADH (low sodium)

Diagnosis

Edrophonium (Tensilon) test and anti-Ach receptor antibodies test to diagnose myasthenia gravis

Edrophonium is given that temporary decreases Ach esterase (ach breaker) and will increase Ach.

Treatment

Pyridostigmine – keeps more Ach in the junction to improve strength

Location of Cell Death According To Disease

• Parkinson’s Disease:
  Substantia nigra is damaged.
  Dopamine goes down, acetylcholine (Ach) goes up.
• Alzheimer’s Disease:
  Affects the temporal lobe.
  Ach and norepinephrine go down.
  Causes memory loss (dementia).
• ALS (Amyotrophic Lateral Sclerosis):
  Destroys nerve cells in the spinal cord.
  Both upper and lower motor nerves are affected.
  Treatment: Riluzole
• Myasthenia Gravis:
  The body blocks Ach receptors → muscles become weak.
• Lambert-Eaton Syndrome:
  The body makes antibodies against calcium channels (Anti-cac).

Tremors (Shaking)

• Older People – Resting Tremor:
  Happens when not moving (resting).
  Often on one side (unilateral).
  Seen in Parkinson’s.
• Younger People – Essential Tremor:
  Happens during movement.
  On both sides (bilateral).
  Often runs in families.
  Treatment: Propranolol

Side Effects:

• Can cause breathing trouble (bronchoconstriction)
  • Can hide signs of low sugar (hypoglycemia)

Do Not Use In:

• Asthma
  • Diabetes
• Fine Tremor:
  Can be caused by Graves’ disease (a thyroid problem).

Meningeal Layers (Brain Coverings)

The brain is covered by 3 protective layers called meninges:

1. Dura mater – outer layer (strongest)
2. Arachnoid mater – middle layer
3. Pia mater – inner layer (touches the brain)

Spaces between layers:

• Epidural space – above the dura mater
• Subdural space – below the dura mater
• Subarachnoid space – below the arachnoid mater

Types of Brain Bleeding (Hemorrhage)

1. Epidural Hematoma

• Blood collects in the epidural space
• Cause: Middle meningeal artery tear (often from skull fracture)
• Lucid interval: Person wakes up then goes unconscious
• CT scan: Looks like a biconvex (lens-shaped) bleed

2. Subdural Hematoma

• Blood collects in the subdural space
• Cause: Bridging veins tear (common in elderly or after trauma)
• Lucid interval: May or may not happen
• CT scan: Looks like a biconcave (crescent) bleed

3. Subarachnoid Hemorrhage (SAH)

• Bleeding collects in the subarachnoid space (Circle of Willis)
• Cause: Rupture of berry aneurysm (small weak spot in artery)
• Most common at: Where Internal Carotid meets Anterior Communicating Artery

Symptoms:

• Sudden severe headache (“worst headache of life”)
• Vomiting, nausea, confusion (ALOC = altered level of consciousness)

Linked to: Autosomal Dominant Polycystic Kidney Disease

Treatment:

• Beta blockers – to control blood pressure
• Calcium channel blockers (CCB) – to prevent vessel spasm

Extra Notes:

• Vertebral artery passes through the foramen magnum (big hole at the base of the skull).
• Internal carotid artery passes through the foramen lacerum (a smaller hole near the base of the skull).

Multiple Sclerosis (MS)

An immune-mediated disease that attacks the central nervous system (CNS) and damages the myelin sheath (the protective covering of nerves).

Key Features

• Age group: 20–40 years
• Gender: More common in females
• Worsens with hot showers
• Improves during pregnancy
• Relapsing-remitting pattern (symptoms come and go)

Symptoms – Remember the mnemonic “SIN“

• S – Scanning speech (broken, choppy speech)
• I – Intention tremor (tremor during movement)
• N – Nystagmus (eye shaking) → can cause diplopia (double vision)

Diagnosis

• Investigation of choice: MRI (shows white matter plaques)
• Diagnostic criteria: McDonald’s Criteria

Treatment

1. First-line: Oral corticosteroids
2. If no response: Plasma exchange (plasmapheresis)
3. If optic neuritis (eye involvement):
   1. Start with IV steroids, then oral steroids, then plasmapheresis

New Therapy

• Ocrelizumab – a monoclonal antibody used in MS treatment           

Guillain-Barré Syndrome (GBS) / Acute Inflammatory Polyneuropathy

A sickness where the body attacks its own nerves (auto immune).
It causes weakness that starts in the legs and moves up (ascending paralysis).

What causes it?

• Often happens after a stomach infection
• Caused by a germ called Campylobacter jejuni

Symptoms

• Starts about 1 week after the infection
• Legs feel weak, then arms
• Reflexes (like knee-jerk) are slow or gone

Diagnosis

• EMG: Shows slow nerve conduction
• Anti-Ganglioside (anti-Schwann) antibodies may be present

Treatment     

• Plasma exchange
• IVIG (good antibodies through a drip)
• Ventilator if diaphragm is affected
• Steroids don’t help

Amyotrophic Lateral Sclerosis (ALS) / Lou Gehrig’s Disease

What is ALS?

ALS is a sickness that hurts the nerves that help your muscles move. These nerves come from the brain and spine.

What happens in ALS?

Two types of nerves stop working:

1. Upper motor nerves – from the brain (UMN)
2. Lower motor nerves – from the spine (LMN)

Signs of Upper Motor Nerve Damage:

• Muscles become stiff (Spastic paralysis)
• Reflexes are too strong (Hyperreflexia)
• Hard to move arms or legs (Hypertonia)

Signs of Lower Motor Nerve Damage:

• Muscles become soft and weak (hypotonia)
• Muscles shrink (muscle atrophy)
• Reflexes are very slow or gone (hyporeflexia)

Other Problems:

• Trouble swallowing food
• Hard to move the tongue

Treatment:

There is no full cure, but a medicine called Riluzole helps slow it down.
Doctors also give care to help with eating and breathing.

Headache

Headache Types

There are 2 main types of headache:

1. Primary Headache – No cause (it happens by itself)
2. Secondary Headache – Has a cause (like fever, injury, infection)

Types of Primary Headaches

1. Cluster Headache

• Pain around the eye (periorbital)
• Red eyes, tears and lacrimation
• Releive in dark places
• Treatment: NSAIDs, Vitamin D3

2. Migraine

• One side of head hurts (unilateral)
• More common in females
• Pain worse with light and noise
• Treatment: NSAIDs, rest in dark room

3. Tension Headache

• Pain gets worse with work/activity
• Better with rest
• Treatment: NSAIDs

What is a seizure?

A seizure happens when brain cells become too active. This can make the body shake or jerk.

• Why do seizures happen?
  • Sometimes because of low or high salts in the body.
  • Sometimes because of genes or unknown reasons.
• What is epilepsy?
  When someone has seizures again and again, it’s called epilepsy.

Types of Seizure

• Partial Seizure (only part of the brain):
  • Simple Seizure: The person is awake with seizure.
  • Complex Seizure: The person is confused or not awake with seizure. Often starts in the temple part of the brain.
• Generalized Seizure (whole brain):
  • Affects both sides of the brain.
  • Person passes out (not awake) with seizure.
  • Tonic-clonic seizure:
    • Person falls, body gets stiff, shakes, back extend and muscle constrict.
    • May bite tongue or pee without knowing.
• Absence Seizure (common in children):
  • Child stares or blanks out for 5–10 seconds.
  • No shaking.

Status Epilepticus (vey long seizure)

• Lasts more than 5 minutes – very dangerous.
• Give benzodiazepines and fosphenytoin.
• May need to ventilate.

How to Find Seizures?

• Test called EEG looks at brain activity.

Treatment

1. Secure the airway so they can breathe.
2. Medicines called antiepileptics help stop seizures.

Medicine Tips

• Phenytoin blocks sodium channel (Na) – helps stop seizures.
• Valproic acid is the liver toxic.
• These medicines can cause low folate:
  • Can lead to spina bifida (a birth problem).
  • Can cause megaloblatic anemia (low blood).
• Phenytoin side effects:
  • Swollen gums (Gingival hyperplasia).
  • megaloblatic Anemia.
  • Also works as a antiarrythemic.
• Best drug for absence seizure:
  • Ethosuximide

What is Dementia?

• Dementia means losing memory and thinking skills slowly, mostly in older people.
• The brain gets weaker over time.

Types of Dementia

Alzheimer’s Disease

• Most common kind.
• Brain gets smaller and ventricles (fluid spaces) get bigger.
• Senile Plaques (bad proteins) build up in the brain.
• Symptoms: Forgetting things, trouble thinking, confusion.
• Medicines: Donepezil, Galantamine.

Normal Pressure Hydrocephalus (NPH)

• Brain’s fluid spaces (ventricles) get bigger, but fluid pressure stays normal.
• Brain may shrink.
• Main signs:
  • Ataxia (Walking problems)
  • Dementia
  • Urinary leaking
• In Alzheimer’s: CSF fluid doesn’t absorb well, ventricles grow.
• In NPH: CSF pressure is normal, but brain shrinks and ventricles still stay big.

Lewy Body Dementia

• Dementia with hallucinations (seeing or hearing things that aren’t real).

Frontotemporal Dementia (Pick’s Disease)

• Affects the front and temporal parts of the brain.
• Causes behavior changes like acting oddly or saying strange things.
• Dementia

Memory Loss (Amnesia)

• Happens suddenly, often after a head injury or stress.

Types of Amnesia:

• Retrograde Amnesia:
  • Can’t remember things before the accident.
• Anterograde Amnesia:
  • Can’t remember things after the accident.

Vascular Dementia

• Second most common type of dementia.
• Happens after many strokes with dementia and multiple infart

Creutzfeldt-Jakob Disease (CJD)

• Demenntia that comes very suddenly.
• Caused by prion proteins (bad proteins) in the brain.

Stroke

• A stroke happens when blood can’t reach the brain.
• Middle cerebral artery is affected that is the branch of internal carotid artery.
• This causes brain damage and problems moving, talking, or seeing.

Types of Stroke:

• Ischemic Stroke (80–85%): A block in the blood vessel.
• Hemorrhagic Stroke (10–15%): A burst in the blood vessel causing bleeding.

Stroke Risk Factors

Things that make stroke more likely remember by this mnemonic ‘LPDS’

• L: Hyper lipidemia High cholesterol
• P: Pressure of blood increase
• D: Diabetes
• S: Smoking

Arteries Affected in Stroke & Symptoms

• MCA (Middle Cerebral Artery) block
  • Half body weakness, trouble speaking, face droops.
  • Use ‘F.A.S.T’ mnemonic:
    • Face: Is it drooping?
    • Arm: Can they lift both arms?
    • Speech: Is speech slurred?
    • Time: Call an ambulance fast!
• PCA (Posterior Cerebral Artery) block
  • Stroke with vision problems.
• ACA (Anterior Cerebral Artery) block
  • Stroke with leg or lower body weakness.

Stroke Treatment

• If patient comes within 4 hours:
  • Give TPA (Thrombolytics – a medicine to break the clot).
• If later than 4 hours:
  • Give Aspirin (stops more clots by blocking TXA2).

Aphasia – Trouble Speaking or Understanding

1. Broca’s Aphasia (Motor/Expressive Aphasia)

• Where in brain: Front part (frontal lobe), MCA area.
• What happens:
  • Person understands what you say.
  • But they can’t speak clearly or make full sentences.
  • They know what they want to say but can’t get the words out.

2. Wernicke’s Aphasia (Sensory/Receptive Aphasia)

• Where in brain: Side part (temporal lobe), MCA area.
• What happens:
  • Person can talk, but the words don’t make sense.
  • They don’t understand what others are saying.

Brain Tumors (Neoplasms)

Types of Brain Tumors

• Primary Tumors (30%)
  • These start in the brain.
• Metastatic Tumors (70%)
  • These come from other parts of the body like:
    • Lungs
    • Breast
    • Kidneys
    • Stomach/Intestines (GI)
    • Skin (Melanoma)

Primary Brain Tumors by Age

In Adults:

• Glioblastoma Multiforme (GBM)
  • Very fast-growing and dangerous.
  • Malignant.
  • Bad outlook (poor prognosis).
• Meningioma
  • Grows slowly.
  • Headache and accidently diagnose.
  • Usually not dangerous (good prognosis).

In Children:

• Astrocytoma
  • Common and may be less severe.
• Medulloblastoma
  • More aggressive.
  • Needs fast treatment.

Acoustic Neuroma (Cranial Nerve 8 Tumor)

• Also called Vestibular Schwannoma.
• Seen in Neurofibromatosis Type 2.
• Affects Cranial Nerve 8, which helps with hearing and balance.

Symptoms:

• Hearing loss on one side.
• Ringing in the ears (tinnitus).
• Feeling dizzy or off balance (vertigo).

Medulloblastoma

• Common in children.
• Grows near the 4th ventricle in a part of the brain called the cerebellar vermis.

Symptoms:

• Blocks fluid in the brain → causes hydrocephalus (CSF buildup).
• Increased pressure in the head – intracranial pressure (causing headache, vomiting).

 Craniopharyngioma

• A tumor found above the pituitary gland (suprasellar area) Supra cellular tumor.
• Often shows calcium spots on X-rays or CT.

Symptoms:

• Calcium deposit on the optic chiasm (vision nerve crossing).
• Causes bitemporal hemianopia (can’t see side vision on both eyes).

Astrocytoma

• A brain tumor made from astrocyte cells.
• Test for marker: GFAP + (Glial Fibrillary Acidic Protein).

Oligodendroglioma

• A tumor made from oligodendrocytes (cells that support brain neurons).
• Usually slow-growing and found in adults.