fever ultrasound explained

Overview

Fever ultrasound is a safe, painless imaging test that uses sound waves to create pictures of the inside of your body. Doctors may use it when you have a fever and the cause is not clear. It helps them look for infections or inflammation in organs such as the liver, gallbladder, kidneys, or in soft tissues and fluid collections.

Doctors use this test quite often when a fever does not go away or has no obvious cause. It is especially common in children with unexplained fever and in people who have recently had surgery.

It can be used for anyone with a fever that needs investigation — from babies and children to older adults. You are more likely to need this test if you have other symptoms like pain, if you have a weakened immune system, or if you have recently been in hospital or had a procedure.

Symptoms

Common symptoms

• Fever or a high temperature
• Chills and shivering
• Body aches and tiredness
• Pain in the belly, back, or side
• Nausea or vomiting

Symptoms in children

• Fever without an obvious cause (no cough, cold, or rash)
• Irritability or unusual drowsiness
• Poor feeding or reduced thirst
• Pulling at the tummy or refusing to move
• Fits (seizures) related to fever

Symptoms in older adults

• Confusion or feeling generally unwell
• Weakness and loss of appetite
• Fever that may be lower than expected
• Pain that is hard to pinpoint
• Changes in behaviour or balance

Causes

Main causes

• An abscess (a pocket of pus), for example in the liver, belly, or under the skin
• Infection in the gallbladder, kidneys, or urinary tract
• Fluid collecting after surgery, such as a seroma or pus collection
• Infection in the lining of the bowel or in deep soft tissue

Risk factors

• Recent surgery or an injury
• A weakened immune system, for example due to illness or certain medicines
• A long stay in hospital, or having a tube or catheter
• Diabetes or other long-term conditions
• Age — being very young or over 65

When to see a doctor

See a doctor urgently if:

• Fever lasting more than 3 days, or more than 24 hours in a baby under 3 months
• Fever together with difficulty breathing, chest pain, or a very fast heartbeat
• Fever after surgery or a recent procedure
• Fever in a baby under 6 months

Book a routine appointment if:

• You or your child feel unwell for more than a week with a fever
• A fever that keeps coming back
• You have a long-term health condition and are concerned

Diagnosis

Fever itself is not a disease, but a sign that your body is fighting something. To find the cause, your doctor will examine you, ask about your symptoms, and may arrange tests. An ultrasound scan can be used as a first imaging test to look for collections of fluid or infected organs.

Tests that may be done

• Ultrasound scan (the 'fever ultrasound')
• Blood tests to check for infection markers
• Urine test to look for a urinary tract infection
• Sometimes a CT scan or MRI if the ultrasound is not clear

What to expect at your appointment

During the ultrasound, a small hand-held device (called a transducer) is moved over your skin with a little gel. It is painless and usually takes between 15 and 30 minutes. You may be asked to hold your breath for a few seconds at a time to get clearer pictures. You can go home afterwards unless you need treatment.

Treatment

Treatment depends on what the ultrasound finds. If it shows an infection, you might need antibiotics or a drainage procedure. If it shows nothing serious, you may just need to rest and stay hydrated.

Self-care at home

• Rest as much as you need
• Drink plenty of fluids, such as water and clear soups
• Keep cool with light bedding and a lukewarm cloth if needed
• Ask your pharmacist about a simple pain reliever that is safe for your age and health

Medical treatments

If the ultrasound finds an infection, your doctor may prescribe antibiotics or other medicines depending on the cause. If the ultrasound shows a collection of pus (abscess), a specialist may drain it with a needle or insert a tube, often guided by ultrasound. If there is a blocked gallbladder or appendicitis, surgery may be needed.

When is surgery considered?

Surgery is only needed if the ultrasound shows a condition that cannot be treated with medicines alone, such as appendicitis, a gallbladder infection, or a large abscess that needs surgical drainage.

Living with this condition

While you are waiting for a diagnosis or recovering, focus on rest and staying hydrated. Take your temperature regularly if advised, and watch for any worsening symptoms.

Lifestyle tips

• Follow your healthcare provider's advice about activity and recovery
• Keep up good hand hygiene to avoid spreading infection
• If you have any drainage tubes, keep the area clean and dry

Diet and exercise

Eat a balanced diet with plenty of fruit, vegetables, and protein to help your body heal. While you have a fever, you may not feel like eating much — that is okay. Focus on drinking enough fluids. When you feel better, gentle activity like walking can help you regain strength.

Mental health and emotional wellbeing

Fever and the tests to find its cause can be worrying. It is normal to feel anxious or overwhelmed. Talk to your healthcare team about any worries, and consider reaching out to a mental health professional if you need extra support.

Prevention

Many infections that cause fever cannot be completely prevented, but you can reduce your risk by washing your hands regularly, staying up to date with recommended vaccines, and avoiding close contact with people who are ill.

Vaccines

Staying up to date with recommended vaccines can help prevent conditions that cause fever, such as flu and some bacterial infections.

Screening programmes

For people with certain conditions (for example, after surgery), your healthcare team may use ultrasound screening to look for fluid collections — this is not routine for everyone.

Complications

If left untreated

• An untreated infection can spread to the bloodstream (sepsis), which is very serious
• An abscess may grow and cause pain, block organs, or burst
• A kidney or bladder infection can damage the kidneys over time

Long-term outlook

The outlook is generally very good. Fever is often short-lived, and when an ultrasound helps find the cause, treatment can start quickly. Most people recover fully with the right care. Even if a serious infection is found, early treatment works well.

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