16873 Cisternogram Scan

Overview

A cisternogram scan is a special imaging test. It shows how the clear fluid that surrounds and cushions your brain and spinal cord — called cerebrospinal fluid, or CSF — moves around. For the scan, a tiny amount of a safe radioactive tracer is put into the fluid in your lower back, usually with a small needle. Pictures are then taken over several hours, or even over a day or two, to watch where the fluid goes. It can help doctors look for a leak of fluid, a build-up of fluid in the brain, or a problem with a shunt (a thin tube that drains extra fluid away from the brain).

It is not a common test. Most people will never need one. It is used when simpler tests, such as a brain scan or a lumbar puncture, have not given a clear answer.

It can be done at almost any age, from children to older adults. It is most often used for people who have clear fluid dripping from the nose or ear, people with walking, memory or bladder changes that may be caused by too much fluid in the brain, and people with a shunt that may not be working properly.

Symptoms

Common symptoms

• Clear, watery fluid dripping from one side of the nose, often worse when bending forward
• Clear fluid coming from an ear, sometimes with hearing changes
• A headache that gets better when lying down and worse when sitting or standing
• Walking that feels unsteady or shuffling
• Memory and thinking changes that have come on slowly
• Needing to pass urine urgently or more often than usual, sometimes with accidents
• Headaches, sickness or drowsiness in someone who already has a shunt

Symptoms in children

• A head that is growing faster than expected in a baby
• Being unusually sleepy, fussy or hard to settle
• Vomiting or poor feeding
• Clear fluid from the nose or ear, especially after a head injury
• Problems with a shunt that was placed earlier

Symptoms in older adults

• Gradual changes in walking, such as a wide or shuffling step
• Memory or thinking changes that are sometimes mistaken for normal ageing
• New bladder urgency or incontinence
• Headaches that change with posture
• Confusion or drowsiness that comes and goes, especially with a shunt

Causes

Main causes

• A leak of cerebrospinal fluid through a small hole in the base of the skull, often after a head injury or surgery, or sometimes with no clear cause
• Too much cerebrospinal fluid in the brain, including a pattern called normal pressure hydrocephalus, which can cause walking, memory and bladder problems
• A shunt that is blocked, broken or draining too much or too little fluid
• A cyst or pocket of fluid in the brain that needs to be checked
• Fluid collecting in the wrong place after brain or spinal surgery

Risk factors

• A recent head injury, even a fairly minor one
• Previous surgery on the brain, skull base, nose or spine
• Having a shunt or other tube placed to drain fluid
• Conditions that raise pressure inside the head, such as some headaches or growths
• Being older, as normal pressure hydrocephalus is more common with age

When to see a doctor

See a doctor urgently if:

• You notice clear fluid dripping from your nose or ear, particularly after a bump to the head
• You have a headache that clearly changes with lying down or standing up
• You or someone you care for is becoming more sleepy, confused or unsteady
• A shunt looks red, swollen or is leaking, or symptoms of a shunt problem come back

Book a routine appointment if:

• Walking, memory or bladder changes that have built up over weeks or months
• Headaches that keep coming back and are not explained
• You have been advised to have a cisternogram and want to understand what it involves
• You have questions about how to prepare for the test or what the results might mean

Diagnosis

A cisternogram is part of the picture, not the whole answer. Your doctor will start by talking with you about your symptoms and examining you, and will usually arrange simpler tests first. The cisternogram is used when those tests leave questions open. It can show whether fluid is leaking, flowing normally, or building up in the brain.

Tests that may be done

• A full conversation about your symptoms and a physical and neurological examination
• A lumbar puncture (a small needle in the lower back) to collect a sample of fluid, and in some cases to measure pressure
• CT or MRI scans of the head, which show the shape of the brain and fluid spaces
• The radionuclide cisternogram itself, where a tiny amount of tracer is injected into the fluid and pictures are taken over hours or a day or two
• Checks on any shunt that is already in place, including how it feels and whether fluid can flow through it
• Eye or ear, nose and throat tests if a leak is suspected

What to expect at your appointment

You will usually be asked to come to the nuclear medicine or imaging department. A doctor will place a small needle in your lower back after numbing the skin, and inject a tiny amount of tracer into the fluid. The needle is then removed and you lie still while the first pictures are taken with a special camera. You may be able to get up, eat and drink between later pictures, which can be spaced over several hours or into the next day. You may be given a small pad to hold against your nose if the team is looking for a leak, so the pad can be checked. The whole process is not painful apart from a brief sting when the needle goes in. Ask the team to explain each step, and tell them straight away if you feel unwell.

Treatment

A cisternogram does not treat anything on its own. The results help your medical team decide what, if anything, needs to be done next. Many people need no treatment at all, or only simple measures, while others may need a small procedure or an adjustment to a shunt.

Self-care at home

• Drink plenty of fluids and eat normally after the test unless you are told otherwise
• Lie down and rest if you develop a headache after the needle in your back, and drink fluids
• Keep the small dressing on your back clean and dry for the first day
• Note down any symptoms that change over the following days, so you can describe them clearly
• Ask when you can drive, go back to work or exercise — it is usually very soon, but check with the team

Medical treatments

Treatment depends entirely on what the scan shows. If a leak is found, your team may first suggest resting, lying flat for a while, drinking plenty of fluids and avoiding heavy lifting, since some leaks close on their own. Some people are offered a procedure to seal the leak or to place a shunt so that fluid drains away safely. If too much fluid is building up, a shunt or a small drainage procedure may help, and some people improve noticeably in walking and thinking. If a shunt is already there and not working well, it may need adjusting or replacing. Your team will explain the choices, the benefits and the risks in a way that fits your situation.

When is surgery considered?

Surgery is only considered when the scan or other tests show a problem that is likely to improve with an operation — for example, sealing a fluid leak that has not settled, or placing or repairing a shunt. Many people never need any surgery. Your doctor will discuss whether the possible benefits outweigh the risks for you.

Living with this condition

Most people go back to normal activities within a day or two of the scan. If you have a fluid leak or a shunt problem, your day-to-day life may need small adjustments while things are sorted out, such as avoiding heavy lifting, bending or straining, and keeping your head at a comfortable level when resting.

Lifestyle tips

• Keep up your usual routine as much as you feel able, with rest when you need it
• Avoid heavy lifting or straining if you have a suspected fluid leak, until you are told it is safe
• Stay well hydrated, particularly in warm weather or after the test
• Take care with head bumps — wear a helmet for cycling or contact sports if you have a shunt
• Keep a simple symptom diary if things change, as this helps your care team

Diet and exercise

There is no special diet for a cisternogram. Eating and drinking normally helps you feel well, and a little gentle activity, such as short walks, is fine once you feel up to it. If you have had a needle in your back, build up slowly over a day or two rather than going straight back to intense exercise. If you have a suspected leak, check with your team before going back to gym work, swimming or contact sports.

Mental health and emotional wellbeing

Tests like this can bring worry, especially when symptoms such as memory changes or unsteadiness have been going on for a while. It is very normal to feel anxious while waiting for results. Talking things through with a partner, friend, or your GP can help, and you are always entitled to ask your team to explain things again in plain words.

Prevention

A cisternogram is a test, so there is nothing to prevent. What you can do is prepare well and reduce the small risks of the test itself: tell the team about any blood-thinning medicines, allergies, pregnancy or breastfeeding, and follow their advice about resting and drinking fluids afterwards. Preventing the problems the scan looks for is a different matter — for example, wearing a helmet and taking care to avoid head injuries, and getting shunt problems checked early rather than waiting.

Screening programmes

There is no routine screening programme for the conditions a cisternogram looks for. The test is only used when your symptoms and other tests suggest it is needed.

Complications

If left untreated

• An untreated fluid leak from around the brain can occasionally let germs in and cause infection, which is serious and needs urgent care
• Ongoing low fluid pressure can cause a persistent headache that makes it hard to work or study
• Fluid building up in the brain can slowly worsen walking, memory and bladder control
• A blocked shunt can cause headaches, sickness and drowsiness, and needs to be checked quickly
• Rarely, long-term raised pressure can affect vision

Long-term outlook

For most people the outlook is good. Many fluid leaks settle by themselves with rest, and problems with fluid build-up or a shunt can usually be managed well once they are found. The cisternogram is simply a way of getting clearer information so that you and your team can choose the right path. If your symptoms change at any point, contact your doctor rather than waiting.

Find support

External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.