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Can dehydration cause a mini stroke?

Dehydration linked to worsening stroke conditions

Date: February 12, 2015 Source: American Heart Association Summary: Patients who are dehydrated and suffer a stroke have worse short-term outcomes than those patients who are well-hydrated at the time of their stroke. Dehydrated patients had nearly a four times higher risk of worsening compared to patients who were adequately hydrated at the time of their stroke. Being well hydrated at the time of a stroke is associated with better outcomes. Share:


People who are well hydrated at the time of their stroke have a greater chance of better recovery compared to people who are dehydrated, according to research presented at the American Stroke Association’s International Stroke Conference 2015.

Researchers gathered baseline lab measurements and MRI scans on ischemic (clot-caused) stroke patients admitted to the Comprehensive Stroke Center at Johns Hopkins Hospital between July 2013 and April 2014. Hydration levels were evaluated based on two well-accepted measurements — BUN/creatinine ratio, which shows how well the kidneys work; and urine specific gravity, which tests urine concentration.

After evaluating 168 ischemic stroke patients, researchers found almost half of them were dehydrated when admitted to the hospital for stroke.

Researchers also found:

  • Stroke condition worsened or stayed the same in 42 percent of dehydrated patients, compared to only 17 percent of hydrated patients.
  • Dehydrated stroke patients also had about a four times higher risk of their conditions worsening than hydrated patients.

«Perhaps we should be giving more fluids to patients after stroke…but that’s not what providers consistently do,» said Mona Bahouth, M.D., lead researcher and stroke fellow at Johns Hopkins Hospital in Baltimore, Maryland.

Current hospital protocols advise caution administering fluids during a stroke because patients could also have heart problems. The main concern is that overloading patients with heart problems with water may lead to volume overload and fluid backing up to the lungs. Doctors don’t suggest drinking water while having a stroke because it could cause choking.

«Previous studies suggest that about 60 percent of people are dehydrated at the time of stroke» said Bahouth. «Perhaps there is opportunity for intervention for this group of patients using simple hydration strategies.»

There was little difference in hydration levels across patients’ race, gender, ethnicity or diabetes status. Patients with kidney failure were not included in this study. The scientists tracked patients’ daily stroke severity based on their NIHSS scores, a measure of patients’ neurological health. They also used MRI scans to calculate the volume of brain lesions caused by stroke. Even after researchers factored out the effects of age, initial NIHSS score, lesion volume and blood sugar levels, results still pointed to dehydration negatively impacting the patients’ conditions. However, they point out that since there was no intervention in this study, there still may be differences in the types of people who came in dehydrated as opposed to well-hydrated.

«It’s not clear why proper hydration at the time of stroke is linked to better stroke outcomes. It’s possible that dehydration causes blood to be thicker causing it to flow less easily to the brain through the narrowed or blocked blood vessels. Larger studies will determine whether hydrating stroke patients may be an inexpensive and accessible intervention to improve outcomes,» Bahouth said. «The beauty here lies in the simplicity of this potential treatment. Rehydration is cheap and can be given to people even in the most remote locations.»

Co-authors are Argye Hillis, M.D., and Rebecca Gottesman, M.D., Ph.D.

The study was funded by the National Institutes of Health.

Treatment — Stroke

The specific treatments recommended depend on whether a stroke is caused by:

  • a blood clot blocking the flow of blood to the brain (ischaemic stroke)
  • bleeding in or around the brain (haemorrhagic stroke)

Treatment usually involves taking 1 or more different medicines, although some people may also need surgery.

Treating ischaemic strokes

If you have had an ischaemic stroke, a combination of medicines to treat the condition and prevent it happening again is usually recommended.

Some of these medicines need to be taken immediately and only for a short time, while others may only be started once the stroke has been treated and may need to be taken long term.

Thrombolysis – «clot buster» medicine

Ischaemic strokes can often be treated using injections of a medicine called alteplase, which dissolves blood clots and restores blood flow to the brain.

This use of «clot-busting» medicine is known as thrombolysis.

Alteplase is most effective if started as soon as possible after the stroke occurs – and certainly within 4.5 hours.

It’s not generally recommended if more than 4.5 hours have passed, as it’s not clear how beneficial it is when used after this time.

Before alteplase can be used, it’s very important that a brain scan is done to confirm a diagnosis of an ischaemic stroke.

This is because the medicine can make the bleeding that occurs in haemorrhagic strokes worse.


A small number of severe ischaemic strokes can be treated by an emergency procedure called a thrombectomy.

This removes blood clots and helps restore blood flow to the brain.

Thrombectomy is only effective at treating ischaemic strokes caused by a blood clot in a large artery in the brain.

It’s most effective when started as soon as possible after a stroke.

The procedure involves inserting a catheter into an artery, often in the groin. A small device is passed through the catheter into the artery in the brain.

The blood clot can then be removed using the device, or through suction. The procedure can be done under local anaesthetic or general anaesthetic.

Aspirin and other antiplatelets

Most people will be given aspirin straight after having an ischaemic stroke. As well as being a painkiller, aspirin is an antiplatelet, which reduces the chances of another clot forming.

Other antiplatelet medicines may be used later, such as clopidogrel and dipyridamole.


Some people may be offered an anticoagulant to help reduce their risk of developing new blood clots in the future.

Anticoagulants prevent blood clots by changing the chemical composition of the blood in a way that prevents clots from forming.

Warfarin, apixaban, dabigatran, edoxaban and rivaroxaban are examples of anticoagulants for long-term use.

There are also a number of anticoagulants called heparins, which can only be given by injection and are used short term.

Anticoagulants may be offered if you:

  • have a type of irregular heartbeat called atrial fibrillation, which can cause blood clots
  • have a history of blood clots
  • develop a blood clot in your leg veins (deep vein thrombosis (DVT)) because a stroke has left you unable to move one of your legs

Blood pressure medicines

If your blood pressure is too high, you may be offered medicines to lower it.

Medicines that are commonly used include:

  • thiazide diuretics
  • angiotensin-converting enzyme (ACE) inhibitors
  • calcium channel blockers
  • beta blockers
  • alpha-blockers


You’ll usually be advised to take a medicine known as a statin.

Statins reduce the level of cholesterol in your blood by blocking a chemical (enzyme) in the liver that produces cholesterol.

You may be offered a statin even if your cholesterol level is not particularly high, as it may help reduce your risk of stroke whatever your cholesterol level is.

Carotid endarterectomy

Some ischaemic strokes are caused by narrowing of an artery in the neck called the carotid artery, which carries blood to the brain.

The narrowing, known as carotid stenosis, is caused by a build-up of fatty plaques.

If the carotid stenosis is very severe, surgery may be used to unblock the artery. This is called a carotid endarterectomy.

It involves the surgeon making a cut (incision) in your neck to open up the carotid artery and remove the fatty deposits.

Treating haemorrhagic strokes

As with ischaemic strokes, some people who have had a haemorrhagic stroke will also be offered medicine to lower their blood pressure and prevent further strokes.

If you were taking anticoagulants before you had your stroke, you may also need treatment to reverse the effects of the medicine and reduce your risk of further bleeding.


Occasionally, emergency surgery may be needed to remove any blood from the brain and repair any burst blood vessels. This is usually done using a surgical procedure known as a craniotomy.

During a craniotomy, a section of the skull is removed to allow the surgeon access to the source of the bleeding.

The surgeon will repair any damaged blood vessels and ensure there are no blood clots present that may restrict the blood flow to the brain.

After the bleeding has been stopped, the piece of bone removed from the skull is replaced, often by an artificial metal plate.

Surgery for hydrocephalus

Surgery can also be done to treat a complication of haemorrhagic strokes called hydrocephalus.

This is where damage resulting from a stroke causes cerebrospinal fluid to build up in the cavities (ventricles) of the brain, causing symptoms such as headaches, sickness, drowsiness, vomiting and loss of balance.

Hydrocephalus can be treated by putting a tube called a shunt into the brain to allow the fluid to drain.

Supportive treatments

You may need further short-term treatment to help manage some of the problems that can affect people who have had a stroke.

For example, you may require:

  • a feeding tube inserted into your stomach through your nose (nasogastric tube) to provide nutrition if you have difficulty swallowing (dysphagia)
  • nutritional supplements if you’re malnourished
  • fluids given directly into a vein (intravenously) if you’re at risk of dehydration
  • oxygen through a nasal tube or face mask if you have low levels of oxygen in your blood
  • compression stockings to prevent blood clots in the legs (DVT)

Page last reviewed: 13 September 2022
Next review due: 13 September 2025

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Transient Global Amnesia

Transient global amnesia (TGA) causes sudden short-term memory loss that resolves on its own within 24 hours. Even though the condition is harmless, it’s important to seek immediate medical care if you or a loved one experience sudden memory loss to be sure there’s not a more serious underlying cause.

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What is transient global amnesia (TGA)?

Transient global amnesia (TGA) is a rare medical condition in which you experience a sudden episode of memory loss.

During a TGA episode, you can’t form new memories (a condition called anterograde amnesia), and you have difficulty recalling recent memories (a condition called retrograde amnesia). “Transient” means passing. Transient global amnesia episodes usually last no more than several hours. In rare cases, they last up to 24 hours.

People with TGA remember who they are and can remember their friends and family members. They can still perform complex daily tasks, such as cooking or driving. They also retain their language and social interaction skills. However, during a TGA episode, they may not know where they are or the day or time.

Even though researchers have been studying transient global amnesia for over 50 years, they’re still not sure what causes it or why it happens.

Who does transient global amnesia affect?

Transient global amnesia mainly affects people between the ages of 50 and 80 (75% of cases). It rarely affects people younger than 40.

Some studies suggest that people who have a history of the following health conditions may be more at risk for developing transient global amnesia:

  • Heart disease.
  • Migraine.
  • Hyperlipidemia (high cholesterol).

How common is transient global amnesia?

Transient global amnesia is rare. It affects about 5 to 10 people per 100,000 per year in the general U.S. population.

For people aged 50 and older, it affects 23 to 32 people per 100,000 a year.

Symptoms and Causes

What are the symptoms of transient global amnesia?

The main sign of transient global amnesia is a sudden inability to form new memories. Some people also can’t recall memories from hours or days ago or longer in the past.

People experiencing a TGA episode may:

  • Appear disoriented and confused.
  • Repeatedly ask the same questions, especially about the date, time and their location.

People experiencing TGA do not:

  • Lose consciousness.
  • Have other neurological or cognitive symptoms, such as loss of language or issues moving.
  • Wake up with TGA. It happens later in the day.

Other symptoms that can occur with TGA include:

  • Headache.
  • Nausea and vomiting.
  • Dizziness.
  • Anxiety.

In most cases, TGA episodes last one to 10 hours (six hours is average). In rare cases, symptoms may persist for up to 24 hours.

Memory problems that develop gradually or last for more than a day aren’t part of TGA and are likely related to other causes.

What causes transient global amnesia?

Researchers don’t know the exact cause of transient global amnesia (TGA). But they believe it’s due to a temporary issue in your hippocampus — the part of your brain that plays a significant role in learning and memory.

Some research suggests that TGA results from a lack of sufficient blood flow (ischemia) or oxygen flow (hypoxia) to your brain. Other research suggests that TGA may be related to seizure activity in your brain.

Certain situations may trigger TGA, including:

  • Physical exertion.
  • Emotional or psychological stress.
  • Sudden immersion in cold or hot water.
  • Pain.
  • Sexual intercourse.
  • Performing the Valsalva maneuver. This is a breathing technique you purposely perform as part of a medical test or to slow a rapid heart rate. It involves closing your mouth and pinching your nose and bearing down as if you’re having a bowel movement.

One type of TGA — benign transient amnesia after substance ingestion — results from any of the following:

  • Excessive alcohol consumption.
  • Using large doses of barbiturates (sedative and sleep-inducing drugs).
  • Using several recreational drugs.
  • Using small doses of benzodiazepines (drugs that treat anxiety, insomnia and seizures).

If you or a loved one has symptoms of sudden memory loss, you should go to the hospital as soon as possible to be sure there’s not a potentially life-threatening condition causing it.

Diagnosis and Tests

How is transient global amnesia diagnosed?

There’s no diagnostic test for transient global amnesia. Instead, healthcare providers rule out all other possible causes of amnesia before diagnosing TGA.

To rule out other causes, a provider will perform a physical exam and check your vital signs. They may also perform a neurological exam.

They may order imaging tests and certain blood tests, such as:

  • Comprehensive metabolic panel.
  • Drug test (toxicology screen).

Management and Treatment

How is transient global amnesia treated?

There’s no treatment for transient global amnesia. The condition resolves on its own within 24 hours — your memory function will return to its normal state.

Your healthcare team will likely recommend staying in the hospital until the amnesia goes away to be sure there isn’t an underlying medical cause and you don’t develop additional symptoms.

Outlook / Prognosis

What are the long-term effects of transient global amnesia?

There are usually no long-term issues related to transient global amnesia. In most cases, people experiencing TGA recover completely. When the episode is over, they can form new memories, but they won’t remember what happened during the episode. Any other recent memories generally return within 24 hours.

In rare cases, transient global results in longer-lasting memory issues. This issue generally occurs only for people who have repeated episodes. Recurring transient global amnesia episodes are rare — less than 10% of people who experience TGA have another episode.

Frequently Asked Questions

Is TGA a mini stroke?

Transient global amnesia (TGA) isn’t a mini stroke (transient ischemic attack). Even though the conditions share a word in their name and both have symptoms that come on suddenly, they’re different conditions.

Sudden memory loss is the main — and generally only — sign of TGA. Mini strokes have the same symptoms as strokes, such as:

  • Difficulty seeing from one or both eyes.
  • Numbness or weakness in your face, arms or legs, especially on one side.
  • Severe headache.

If stroke symptoms appear, it’s very important to go to the emergency room to get immediate medical help.

Does TGA lead to dementia?

In the majority of cases, transient global amnesia doesn’t cause long-term memory problems, like those seen in dementia. However, you could develop dementia for other reasons.

A note from Cleveland Clinic

It’s important to take your loved one to the hospital as soon as possible if they’re suddenly unable to form new memories and are asking repeated questions about where they are and what time it is. While it can be frightening, the good news is that transient global amnesia (TGA) is harmless and resolves within 24 hours. However, sudden memory issues could be a sign of a more serious medical condition, so it’s essential to get evaluated by medical professionals.

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