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Nervous system


Central nervous system disorders
Central and peripheral nervous system disorders
Peripheral nervous system disorders
Autonomic nervous system disorders
Nervous system pathology review



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High Yield Notes
6 pages


8 flashcards

USMLE® Step 1 style questions USMLE

2 questions

A 30-year-old woman comes to the emergency department due to right-sided tingling and weakness, as well as a severe headache. She says she started experiencing problems with her vision two hours ago, followed by tingling in her right hand. After this, she began experiencing weakness in her right hand, which progressively extended to her right arm and face, as well as a severe, unilateral throbbing headache that is still ongoing. Her medical history is significant for migraines, but mentions that this time it “feels different.” She is otherwise healthy and takes no medications. Her temperature is 37.1°C (98.8°F), pulse is 85/min, and blood pressure is 135/85 mmHg. Physical examination shows 4/5 muscle strength on the right side compared to 5/5 on the left, as well as mildly reduced sensation on the right side. Ophthalmologic examination shows decreased vision and central scotoma in the right eye. Computed tomography is obtained and shows no abnormalities. Which of the following is the most likely diagnosis?  

External References

Headaches are a type of terrible pain in the head and neck, and there are two main types.

The first are called primary headaches, and they’re more common. These are chronic or recurrent headaches, that account for over 90% of all headaches.

Some examples, are migraine headaches, tension headaches, and cluster headaches.

The second type are called secondary headaches, and these are acute headaches from a specific underlying cause like a serious head injury or a brain tumor.

So normally, throughout the body, there are special neurons that act as pain receptors.

These neurons convert a painful stimulus into an electrical signal that conveys the feeling of “pain” to the brain.

The brain itself does not have pain receptors, but nearby tissues in the head and neck like the blood vessels, meninges, and muscles do have pain receptors.

These pain receptors might be stimulated by a variety of things such as blood vessel spasm like in vasculitis, increased pressure like from a tumor, inflammation like in meningitis, or increased muscle tension like in temporomandibular disorder.

That helps explain the pain in secondary headaches.

Now, in primary headaches the exact mechanisms are unknown.

Tension headaches are the most common primary headache.

It’s called a tension headache because it feels like a band squeezing down on the head applying constant pressure or tension on it.

The pain is mild to moderate, can last a few hours, and usually there are no associated symptoms.

Tension headaches are usually triggered by stress, lack of sleep, and dehydration - imagine being late to work after a night of drinking heavily and not sleeping much.

Migraines are the second most common primary headache.

They’re often preceded by symptoms like irritability, depression, and fatigue that can begin hours to days before the headache itself.

Sometimes there can be an aura where people experience strange smells, lights, visual disturbances, or even hallucinations before the onset of the migraine.

The migraine itself usually feels like a pounding or pulsating, typically localized to one side of the head and can last from hours to days.

As if this was not bad enough, these headaches tend to come with nausea and vomiting, irritability, and pain or discomfort with lights, sounds, and smells called photophobia, phonophobia, and osmophobia, respectively.

During childhood, individuals can have nausea and vomiting without the headaches; and that’s called an abdominal migraine.

After a migraine is over, it can leave people feeling sore at the location of the pain and generally fatigued.

To remember the main features of migraines, you can use the mnemonic POUND, where P stands for pulsatile headache, O stands for one-day duration, U stands for unilateral, N for nausea, and D for disabling.

Although the underlying mechanism causing migraines isn’t well understood, there are some clues.

Concentrations of the neurotransmitter, serotonin, increase during the aura, triggering vasoconstriction, and then decrease to lower-than-normal levels during the migraine attack, triggering vasodilation. This change in the blood vessel size may be a trigger for pain receptors, causing the headache.


A migraine is a type of headache that presents with recurrent episodes of (usually) unilateral, throbbing headaches. It may be accompanied by sensitivity to light, nausea and vomiting, and a preference for a quiet environment.

Sometimes there can be an aura where people experience strange smells, lights, visual disturbances, or even hallucinations before the onset of the migraine. The cause of migraine is not yet known, but it is believed to have a genetic predisposition, and risk factors such as alcohol, hormonal changes in women, fasting, disorganized sleeping patterns, etc.

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  6. "Primary headaches during lifespan" The Journal of Headache and Pain (2019)
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