Laxatives And Hida Scans: What's The Connection?

A hepatobiliary iminodiacetic acid (HIDA) scan is a type of nuclear imaging test used to diagnose problems with the gallbladder, liver, bile ducts, and small intestine. It involves injecting a radioactive tracer into a person's vein and tracking its movement through the body using a special camera. The procedure typically takes between one and four hours. As laxatives are used to treat constipation by encouraging bowel movements, it is reasonable to consider their potential impact on the accuracy of a HIDA scan.

What is a HIDA scan?

A hepatobiliary iminodiacetic acid (HIDA) scan, also known as cholescintigraphy or hepatobiliary scintigraphy, is a type of nuclear imaging test. It allows healthcare providers to examine the bile ducts, gallbladder, and liver.

During the test, a tracer containing a small amount of radioactive material is injected into the patient's blood. The tracer travels through the bloodstream, and images are captured to show how it moves through the body. This procedure gives healthcare providers a picture of how the gallbladder and liver are functioning. The test typically takes about an hour to complete, but can take up to four hours in some cases.

A HIDA scan can be used for several purposes, including:

• Diagnosing problems with the gallbladder
• Determining how the liver excretes bile
• Following the path of bile as it leaves the liver and enters the small intestine
• Assessing the outcome of a liver transplant
• Finding the cause of abdominal pain, particularly on the right side
• Uncovering the cause of jaundice, or a yellowish hue to the skin

The test can help diagnose various conditions, including:

• Biliary atresia or other congenital bile duct conditions
• Leaks or complications in the biliary system, such as fistulas
• Inflammation of the gallbladder (cholecystitis)
• Blockage of the bile duct
• Sphincter of Oddi dysfunction, which can cause severe stomach pain

A HIDA scan is a non-invasive procedure that gives healthcare providers valuable information about the biliary system, particularly the gallbladder. It is a useful test to help diagnose conditions in the liver, gallbladder, bile ducts, and small intestine.

How to prepare for a HIDA scan

A hepatobiliary iminodiacetic acid (HIDA) scan is a type of nuclear imaging test that lets healthcare providers look at the bile ducts, gallbladder, and liver. Here are some detailed instructions on how to prepare for a HIDA scan:

Fasting

You will need to stop eating any solid foods for about 4-12 hours before the test. You may be allowed to drink clear liquids, but always check with your doctor. You may also drink water during this fasting period.

Medication

You can take your regular medications with a sip of water, except for any opioid or morphine-based pain medication. If you have taken a medication containing bismuth, such as Pepto-Bismol, in the days before the scan, be sure to inform your doctor. You may be given a drug to take at home before the test.

Clothing

The imaging room can be chilly, so dress in warm, comfortable clothing without metal buttons, snaps, or buckles. You will need to remove any metal objects such as jewellery, belt buckles, coins, and keys.

Appointment

Arrive at the hospital or clinic 10-15 minutes before your scheduled appointment. Bring a list of your medications, x-rays, CT scans, or other pertinent test results with you. You will need to check in at the Radiology department.

Pregnancy and Breastfeeding

If there is a chance that you are pregnant, you should inform your doctor or the radiology staff before the test. Breastfeeding women should also inform their doctor, as they will be advised to avoid feeding their infant for several days following the scan.

What to expect during a HIDA scan

Before the test, you will be asked to fill out some forms and answer questions about any medications you are taking and any previous surgeries, especially in the abdomen area. If you are female, you will be asked about the possibility of pregnancy and the date of your last menstrual period.

During the test, you will lie on your back on a table and a technician will inject a tracer containing a small amount of radioactive material into your arm. You may feel some pressure or a cold sensation. In some cases, other drugs may be injected, such as Kinevac (sincalide) or cholecystokinin, which activates the gallbladder, or morphine, which helps guide the tracer to the gallbladder. It is important to stay still during the test so that clear images can be captured. The technician will move a gamma camera over your abdomen to follow the tracer as it moves through your body, which typically takes between one and four hours.

After the test, there are usually no special instructions to follow. You should not experience any side effects, and the radioactivity of the tracer only lasts for a few hours. Drinking plenty of water will help speed up the passing of the tracer from your body. If you received morphine, you should not drive and will need someone to pick you up.

Side effects and risks of a HIDA scan

A HIDA scan is considered a safe procedure with minimal side effects and risks. However, as with any medical procedure, there are some potential adverse effects that patients should be aware of. Here is some detailed information about the possible side effects and risks associated with a HIDA scan:

Side Effects:

• Allergic Reaction: Although rare, there is a possibility of an allergic reaction to the medications or substances used during the scan, including the radioactive tracer.
• Bruising: Some individuals may experience bruising at the site where the tracer or other medications were injected.
• Rash: A rash may develop at the injection site, along with the bruising and swelling.

Risks:

• Radiation Exposure: While the amount of radiation exposure during a HIDA scan is minimal, individuals are exposed to a small amount of radiation. This is a typical risk associated with any type of nuclear imaging test.
• Pregnancy and Breastfeeding: HIDA scans are generally not performed on pregnant individuals due to potential risks to the fetus. Breastfeeding women are advised to avoid feeding their infants for several days after the scan to ensure the complete elimination of the radioactive tracer from their system.
• Medication Interactions: It is crucial to inform your healthcare provider about any medications or supplements you are taking, as certain drugs can interfere with the accuracy of the HIDA scan results.
• Metal Objects: Metal objects, including jewelry and piercings, can interfere with the imaging process. Therefore, patients are usually instructed to remove any metal objects before the scan.

Overall, the benefits of a HIDA scan typically outweigh the risks for non-pregnant individuals. However, it is always important to discuss any concerns with your healthcare provider and follow their instructions for preparation and aftercare.

Interpreting the results of a HIDA scan

A normal result means that the tracer moved freely from the liver into the gallbladder and small intestine. This suggests that the gallbladder is functioning correctly and is of average size and shape.

If the tracer moves slowly through the body, this could indicate an obstruction or blockage in the gallbladder or bile duct, or suggest suboptimal liver function.

If there is no sign of the tracer in the gallbladder, this can indicate acute inflammation of the gallbladder (acute cholecystitis) or a blockage.

Low gallbladder ejection fraction suggests chronic inflammation of the gallbladder (chronic cholecystitis).

If the tracer is detected in other parts of the body, this suggests a leak in the bile ducts.

A doctor will use these results, along with other tests and a patient's symptoms, to make a diagnosis.

Frequently asked questions