sinus infection CT scan preparation

Overview

A sinus infection, also called sinusitis, is when the tissue lining your sinuses becomes swollen and inflamed. Your sinuses are air-filled spaces in the bones around your nose and eyes. A CT scan is a type of X-ray that creates detailed cross-section pictures. For sinus problems, a CT scan can help a doctor see whether the sinus passages are blocked or infected, and guide decisions about treatment. This article explains what sinusitis is, when a CT scan might be needed, and how to prepare for it.

Sinus infections are very common. Most adults have a cold that involves the sinuses several times a year. However, a CT scan for sinusitis is less common and is reserved for situations where more detail is needed.

Sinus infections can affect anyone, but they are more likely in people with allergies, asthma, a weakened immune system, or structural blockages in the nose such as nasal polyps or a deviated septum.

Symptoms

Common symptoms

• Facial pain or pressure around the cheeks, eyes, or forehead
• Nasal congestion or a blocked nose
• Thick nasal discharge that may be yellow or green
• Reduced sense of smell
• Headache
• Cough or sore throat
• Bad breath
• Low-grade fever

Symptoms in children

• Nasal congestion and runny nose
• Cough, especially at night
• Irritability or fussiness
• Trouble sleeping
• Reduced appetite or feeding well

Symptoms in older adults

• Fatigue or low energy
• Confusion or drowsiness, which can be a sign of a more serious infection
• Less obvious facial pain — some older adults only feel unwell or have a cough
• Fever may be absent or mild

Causes

Main causes

• Viral infections, such as the common cold or flu
• Bacterial infections, usually after a viral infection has lasted a long time
• Fungal infections, which are rare and mostly affect people with weakened immune systems
• Allergies that cause swelling and block the sinuses
• Structural problems in the nose, such as a deviated septum or nasal polyps

Risk factors

• Frequent colds or upper respiratory infections
• Allergic rhinitis (hay fever) or asthma
• Smoking or exposure to secondhand smoke
• A weakened immune system
• Nasal polyps or a deviated septum
• Recent air travel or swimming, which can affect sinus pressure

When to see a doctor

See a doctor urgently if:

• Fever or severe pain that is not improving
• Symptoms that last more than 10 days without getting better
• Symptoms that seem to be getting worse after starting to improve
• Any of the urgent or emergency symptoms listed above

Book a routine appointment if:

• You have had more than three sinus infections in one year
• Your symptoms keep coming back or have lasted more than 12 weeks
• You want to discuss long-term management, such as allergy treatment or nasal rinses
• You have a chronic health condition that affects your immune system

Diagnosis

A doctor usually diagnoses sinusitis by asking about your symptoms and examining your nose and face. They may use a light or a small endoscope to look inside your nasal passages. A CT scan is not a routine first step; it is used when the diagnosis is unclear, symptoms are persistent, or the doctor needs to check for complications. Your doctor will arrange the CT scan if it is needed, and you will be given specific instructions on how to prepare.

Tests that may be done

• Clinical examination of the nose, face, and throat
• Nasal endoscopy — a thin, flexible tube with a camera inserted into the nose
• CT scan of the sinuses — a detailed imaging test that shows the sinus passages and surrounding structures
• Allergy testing or immune function tests if infections are recurrent

What to expect at your appointment

For a sinus CT scan, you will lie on a table that slides into a large, ring-shaped scanner. The radiology team may ask you to remove glasses, dentures, hairpins, and any metal objects. You will be given a hospital gown to wear if necessary. You can eat and drink normally unless you are having a contrast dye injection, which is rare for a sinus scan. The scan itself is painless and usually takes around five minutes. You will need to stay still and sometimes hold your breath. Afterward, you can return to your normal activities and drive unless you have had a sedative, which is very unusual for this test. Tell the radiology team beforehand if you are pregnant, may be pregnant, or have any allergies.

Treatment

Treatment for sinus infection focuses on relieving symptoms, helping the sinuses drain, and addressing the underlying cause. Self-care is the first step. Your doctor may discuss other options if your infection is severe, long-lasting, or if the CT scan shows a structural issue. Antibiotics are only used if a bacterial infection is confirmed or strongly suspected — they do not help viral sinusitis.

Self-care at home

• Get plenty of rest to support your immune system
• Drink lots of water or other clear fluids to thin the mucus
• Use a saline (salt water) nasal rinse or spray to keep your nasal passages moist
• Apply a warm cloth to your face to help ease pain and pressure
• Breathe in steam from a warm shower or a bowl of hot water (be careful with hot water)
• Avoid smoking and secondhand smoke

Medical treatments

Depending on your symptoms, your doctor or pharmacist may suggest over-the-counter pain relief, nasal corticosteroid sprays to reduce swelling, or decongestants for short-term use. You may also be offered prescription treatments if an allergy or infection is contributing. Always follow the advice of your healthcare professional and ask if you are unsure. No specific medicine is recommended here because the right option depends on your individual situation.

When is surgery considered?

In rare cases, when sinusitis keeps coming back, or a CT scan shows a blockage such as nasal polyps or a deviated septum, a doctor may recommend a procedure called functional endoscopic sinus surgery (FESS). This operation opens up the sinus drainage pathways to improve airflow and reduce infections.

Living with this condition

If you have chronic (long-term) sinus problems, the key is to understand and manage your triggers. Work with your healthcare team to set up a routine that suits you, such as regular saline rinses, allergy control, and taking any prescribed treatments as advised.

Lifestyle tips

• Use a humidifier at home, especially in dry indoor air
• Avoid smoke, strong perfumes, and air pollutants
• Keep your head slightly elevated when sleeping to help nasal drainage
• Manage allergies with help from your doctor

Diet and exercise

Drinking plenty of water helps keep the mucus thin. A balanced diet with fruits, vegetables, and proteins supports your immune system. Gentle exercise such as walking can help promote drainage and improve your mood, but rest if you feel very unwell or have a fever.

Mental health and emotional wellbeing

Living with chronic sinusitis can be frustrating, tiring, and sometimes embarrassing because of bad breath or constant nasal discharge. It is common to feel low, anxious, or stressed. These feelings are normal, and you should mention them to your doctor so they can support you — there are effective ways to manage both the physical and emotional side of this condition.

Prevention

You cannot always prevent sinus infections, but you can reduce your risk by washing your hands often, avoiding close contact with people who have colds, managing allergies, staying away from tobacco smoke, and keeping your nasal passages moist, especially in dry climates.

Vaccines

Your healthcare provider may recommend routine vaccinations such as the flu vaccine and other standard immunisations, as viral infections can sometimes lead to sinusitis. There is no specific sinusitis vaccine.

Screening programmes

There is no routine screening for sinus infections. If you have frequent or severe episodes, your doctor may look for underlying causes like allergies, immune problems, or structural issues that can be addressed.

Complications

If left untreated

• The infection can spread to nearby tissues, including the tissue around the eye (orbital cellulitis)
• Rarely, infection can spread to the brain or spinal fluid (meningitis)
• Abscess (a pocket of infection) can form in the skull
• Chronic sinusitis can develop, causing long-term symptoms that affect daily life

Long-term outlook

Most sinus infections get better with home care and time. Even when complications do occur, they are treatable when caught early. A CT scan can give your healthcare team a clear picture so they can choose the safest and most effective treatment for you. With proper care, the great majority of people recover fully.

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