Complications

Overview

A complication is a new health problem that happens because of another illness, a treatment, or a medical procedure. It is not the same as a symptom. A symptom is what you feel because of the illness itself. A complication is a separate problem that develops on top of it. For example, a chest infection can be the illness, and a build-up of fluid in the lungs can be a complication of it. Some complications are mild and pass quickly. Others are more serious and need medical care. Understanding what to watch for helps you get help early, when problems are usually easier to treat.

Yes, complications are common. Most people recover well, and many complications are mild. Because complications can happen with almost any illness — from a simple wound to a long-term condition like diabetes or heart disease — healthcare services see them every day. Being aware of them is a normal part of looking after your health, not a sign that something has gone wrong.

Anyone can develop a complication, but some people are at higher risk. This includes older adults, babies and young children, people with long-term conditions (such as diabetes, heart disease, kidney disease or lung disease), people whose immune system is weaker, people who smoke, people who are very underweight or overweight, people living with poor nutrition or dehydration, and people who have limited access to healthcare. Having a higher risk does not mean you will definitely have a complication — it simply means it is worth being a little more watchful.

Symptoms

Common symptoms

• New symptoms that appear on top of your existing illness, or symptoms that suddenly get worse
• A fever, or a temperature that keeps coming back
• Pain that increases instead of slowly improving
• Feeling more tired or weak than expected for your illness
• Breathlessness, a new cough, or a change in your breathing
• Feeling sick, being sick, or not being able to keep food or drink down
• A wound that becomes red, hot, swollen, more painful, or starts to leak pus
• Swelling in an arm or leg, especially if it is only on one side
• Unusual bleeding, bruising, or a rash that does not fade when pressed
• New confusion, dizziness, or difficulty concentrating
• Losing weight without trying, or a big drop in appetite

Symptoms in children

• Not feeding well, or refusing feeds and drinks
• Fewer wet nappies or dry nappies, which can be a sign of dehydration
• Being much sleepier than usual, or hard to wake
• A high temperature that does not settle, or a child who feels floppy
• Fast or noisy breathing, or sucking in between the ribs
• A rash that does not fade when you press a glass against it
• Being unusually unsettled, or crying in a way that cannot be comforted
• A bulging or sunken soft spot on a baby's head

Symptoms in older adults

• Sudden confusion or a change in someone's usual thinking or behaviour — this can be the first sign of infection
• Falls, or a new difficulty walking or moving about
• New incontinence, or trouble getting to the toilet in time
• Loss of appetite, or drinking much less than usual
• Pressure sores, or red, sore skin over bony areas
• Becoming withdrawn, sleepy, or less able to do everyday tasks
• Dehydration, which can cause dizziness and weakness
• A temperature that is low rather than high — in older adults, infection does not always cause a fever

Causes

Main causes

• The original illness getting worse or spreading to another part of the body
• A new infection, especially after a viral illness, a wound, or surgery
• Long periods of immobility, such as staying in bed, which can lead to clots or chest infections
• Side effects of a treatment or medicine, including treatments that lower the body's defences
• A delay in getting a diagnosis or starting treatment
• Poor nutrition or not drinking enough, which slows healing
• A weakened immune system that finds it harder to fight off infection
• Problems with how an organ is working, such as the heart, kidneys or lungs, caused by the stress of illness

Risk factors

• Being older, or being a baby or young child
• Long-term conditions such as diabetes, heart disease, kidney disease, lung disease or liver disease
• A weakened immune system, whether from illness or from treatment
• Smoking
• Being very overweight or very underweight
• Poor diet or ongoing dehydration
• Not finishing a course of treatment, or not following advice about rest and recovery
• Taking several medicines at once, which can interact
• Limited access to healthcare, or waiting a long time before seeking help

When to see a doctor

See a doctor urgently if:

• You have any of the emergency or same-day warning signs listed above
• Your symptoms are getting worse rather than slowly better
• You have a fever along with feeling very unwell
• A wound looks infected, or is not healing as expected
• You cannot keep fluids down, or you feel dizzy and light-headed
• You are caring for someone whose behaviour or alertness has suddenly changed

Book a routine appointment if:

• Your symptoms are not improving after a week or two, or after the time your doctor expected
• You keep getting infections, or infections that take a long time to clear
• You have a long-term condition and want to review how to spot problems early
• You are unsure whether a new symptom is part of your illness or something separate
• You want to talk through your treatment plan, or ask about side effects

Diagnosis

A doctor or nurse will usually start by asking what has been happening: when your symptoms began, how they have changed, what illness or treatment you already have, and what medicines you take. They will check your temperature, pulse, blood pressure, breathing and oxygen levels, and examine the part of the body that is causing problems. From there, they will decide whether any tests are needed. There is no single test for complications — the tests depend entirely on what the doctor suspects.

Tests that may be done

• Blood tests to look for infection, inflammation, or how well organs such as the kidneys and liver are working
• Urine tests to check for infection or other problems
• Swabs or samples from a wound, throat or other area to look for the cause of an infection
• Imaging such as an X-ray, ultrasound or scan to look inside the body
• A heart tracing (electrocardiogram) if there are chest symptoms or an irregular heartbeat
• Monitoring of oxygen levels and breathing
• Review of your medicines to check whether any are contributing to your symptoms

What to expect at your appointment

Most of these checks are quick and can be done at your local surgery, a clinic, or a hospital outpatient department. Some tests give results the same day; others take a few days. Your healthcare team should explain what they are looking for and when you will hear back. If you have not heard anything within the time they told you, it is fine to follow up. Write down your questions beforehand — it is easy to forget them in the moment — and ask a relative or friend to come with you if that helps.

Treatment

Treatment for a complication depends on what the complication is and what caused it. Usually, the aim is twofold: to treat the new problem and to keep treating the original illness. Your healthcare team will talk you through the options, the expected benefits and any risks, and agree a plan with you. Many complications can be managed with medicines, rest and monitoring. Others need closer observation in hospital.

Self-care at home

• Take any prescribed medicines exactly as your healthcare team explains, and finish courses as advised
• Rest, but move around gently as soon as you are able — short walks help prevent clots and chest problems
• Drink regularly, and watch for signs of dehydration such as dark urine or a dry mouth
• Keep any wound clean and covered as advised, and check it daily
• Keep a simple note of your symptoms, temperature and how you feel, so you can describe changes clearly
• Attend follow-up appointments, even if you feel better
• Ask your pharmacist or doctor before starting any new medicine, including ones you buy over the counter or herbal remedies
• Avoid smoking and keep rooms well aired to help your breathing and healing

Medical treatments

Doctors may treat a complication with medicines — for example, medicines to fight infection, to ease pain or fever, to thin the blood when there is a clot risk, or to support an organ that is under strain. They may also use treatments such as oxygen, fluids given through a drip, or physiotherapy to help clear the chest. Which approach is used depends on the type of complication and how serious it is. Your team will explain the plan, how long treatment is likely to last, and what to watch for. Always ask your doctor or pharmacist if you are unsure why something has been prescribed, or if you notice a new symptom after starting it.

When is surgery considered?

Surgery or another procedure is only needed for some complications — for example, to drain a collection of pus, to repair a wound, to remove a blockage, or to treat a problem inside the body that medicines cannot fix. Most complications do not need an operation. If one is suggested, your team will explain why, what it involves, what the recovery is like, and what the alternatives are.

Living with this condition

Recovering from a complication often takes longer than people expect, and progress is rarely in a straight line. Give yourself permission to do a little less for a while. Set small, realistic goals, such as getting dressed each day or taking a short walk. Accept help with shopping, cooking or childcare if it is offered. Keep important information in one place — appointment dates, medicine lists, and the phone number of your doctor or clinic — so it is easy to find when you need it.

Lifestyle tips

• Build gentle movement into each day, increasing slowly as you feel stronger
• Protect your sleep — rest is when the body repairs itself
• Keep up to date with recommended vaccinations for your age and health conditions
• Wash your hands regularly to reduce the chance of new infections
• Ask for help early rather than waiting until you feel much worse
• Keep a list of your medicines and bring it to every appointment
• Stay connected with friends and family, even if it is just a short phone call

Diet and exercise

Eating well and moving gently both support healing. Try to have regular meals that include a source of protein (such as beans, eggs, fish, meat or dairy), plenty of vegetables and fruit, and enough fluids through the day. If your appetite is poor, small snacks more often can be easier than large meals. For exercise, start with what feels comfortable — walking around the house, then a short walk outside, then a little further as your strength returns. If you have a long-term condition, ask your healthcare team what level of activity is safe for you. Stop and rest if you feel chest pain, very breathless, or dizzy.

Mental health and emotional wellbeing

Being unwell and then dealing with a complication can be frightening, frustrating and tiring. It is very common to feel anxious, low, or worried about the future. These feelings usually ease as you recover, but they deserve attention too. Talk to someone you trust, and mention how you are feeling to your doctor or nurse — support is available and asking for it is a sign of strength. If at any point you have thoughts of harming yourself, please contact your local emergency number or a crisis support line in your country straight away. You do not have to cope alone.

Prevention

Not all complications can be prevented, but many can be made less likely. The most effective steps are usually simple: get treatment for the original illness early, take medicines as prescribed, keep follow-up appointments, eat and drink well, move around as soon as you are able, and know the warning signs so you can act quickly. If you have a long-term condition, regular reviews help keep it well controlled, which lowers the chance of problems developing.

Vaccines

Keeping up to date with the vaccinations recommended for your age and health conditions is one of the simplest ways to prevent certain infections and the complications they can cause. Your doctor, nurse or pharmacist can tell you which vaccinations are recommended for you and when they are due.

Screening programmes

Routine health checks and screening programmes are designed to pick up problems early, before they cause complications. These vary between countries and by age and risk. Ask your healthcare provider which checks and screenings are recommended for you, and keep track of when your next one is due.

Complications

If left untreated

• The underlying illness may get worse, spreading or causing more damage
• An infection can spread into the blood, which is a serious condition needing emergency care
• Permanent damage to organs such as the heart, lungs, kidneys or nerves
• Longer recovery time, and a greater chance of needing hospital care
• Loss of mobility, strength or independence, especially in older adults
• Ongoing pain, fatigue, or difficulty with everyday tasks
• Effects on mood, sleep and quality of life

Long-term outlook

The outlook for most complications is good, particularly when they are recognised and treated early. Many people recover fully, and some find that going through a complication helps them understand their health better and know what to watch for in future. Recovery may take time and may not always follow a straight path — good days and harder days are both normal. Your healthcare team is there to adjust the plan as you go. If you are worried at any point, reach out; getting advice early is one of the most helpful things you can do.

Find support

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