Blackouts & fits

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A blackout is the sudden loss or near loss of consciousness and may be accompanied by dizziness, vertigo, headache or (if due to a fit/convulsion) shaking of the limbs and incontinence.


The most common cause is a simple faint which is the body's protective mechanism to ensure a sufficient blood supply gets to the brain. However HIV may affect the nerves that control blood pressure and result in dizziness or near blackouts when standing or sitting up quickly (postural hypotension). Some people with HIV get damage to the adrenal glands, usually caused by CMV, which reduces the production of corticosteroid hormones. Lack of these hormones is another important cause of postural hypotension.

A potentially more serious cause is a fit or convulsion as this might indicate an acute problem in the brain such as an infection or abscess, possibly a result of toxoplasmosis.

What to do

If a blackout has occurred it is important to tell a doctor or, if the cause is definitely a fit, to get medical advice urgently. It is useful to talk to anyone who witnessed the blackout to find out exactly what happened as this may help to determine the cause.

If the blackout was due to postural hypotension then treatment and advice can be given to help cope with this. If the hypotension is caused by adrenal damage, the treatment consists of hydrocortisone and fludrocortisone, normally given continuously to replace what the body normally produces. Doses will need to be increased at times when the patient has active infections.

Other possible causes of blackouts such as toxoplasmosis require specific investigation and treatment.

Community Consensus Statement on Access to HIV Treatment and its Use for Prevention

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We can end HIV soon if people have equal access to HIV drugs as treatment and as PrEP, and have free choice over whether to take them.

Launched today, the Community Consensus Statement is a basic set of principles aimed at making sure that happens.

The Community Consensus Statement is a joint initiative of AVAC, EATG, MSMGF, GNP+, HIV i-Base, the International HIV/AIDS Alliance, ITPC and NAM/aidsmap

This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.

NAM’s information is intended to support, rather than replace, consultation with a healthcare professional. Talk to your doctor or another member of your healthcare team for advice tailored to your situation.