Respiratory tract infection

[Munim]

                                                Introduction
The respiratory tract is the whole system that allows you to breathe air into your lungs and back out again.
The passageway that air travels through is divided into two sections:
the upper respiratory tract and the lower respiratory tract:
• The upper respiratory tract includes the nose, throat, voice box (larynx) and upper windpipe (trachea)
• The lower respiratory tract includes bronchi (the two branches the windpipe divides into as it enters the lungs), bronchioles (even smaller branches of air tubes) and alveoli (the tiny air sacs at the end of the bronchioles).

The air that we breathe is full of germs, so infections of the respiratory tract are very common, especially those affecting the upper tract.
Upper respiratory tract infections (URTIs) are usually caused by viruses and are rarely serious.
They include the common cold, tonsillitis, sore throat, sinusitis, laryngitis and croup.
Lower respiratory tract infections (LRTIs) are usually more serious. They affect the breathing tubes (trachea and bronchi) and the lungs. Bronchitis, acute bronchiolitis and pneumonia are all types of LRTI.

                                                Symptoms
A cough is the most common symptom of upper respiratory tract infections. It may linger even after the infections gone, because the swelling in the airways can take a while to settle down.
A cough can take up to three weeks to completely go.
If the infection affects the nose, you will have a stuffy, blocked nose that forces you to breathe through your mouth. In babies, this can make breast or bottle feeding difficult.

Other symptoms include headache, fever, aches and pains.
Symptoms of lower respiratory tract infections are similar. Coughing and bringing up phlegm is most common.
You may also have pain in the chest and a slight fever. Whereas upper respiratory tract infections are usually quite obvious and easy to treat at home, LRTIs need to be diagnosed by a doctor.
                                   
                                                   Causes
Most upper respiratory tract infections are caused by viruses. Each cold you get is caused by a slightly different virus, and once you've fought it off, you are immune (resistant) to that particular virus.

Lower respiratory tract infections are caused by both viruses and bacteria. They may begin with a virus, but if bacteria get into the lower respiratory tract, it can cause more serious problems.
LRTIs are more common in people with a weak immune system, such as older people and those receiving immunosuppressive treatment, for example, cancer patients.

                                                             Diagnosis
Upper respiratory tract infections are usually obvious from the common cough and cold symptoms.
Lower respiratory tract infections are harder to diagnose.
Having a chesty cough does not necessarily mean you have an LRTI. Its best to see your GP if you are concerned LRTIs are diagnosed on the basis of certain breathing sounds heard while the doctor listens to your chest with a stethoscope.
Generally, blood tests or chest X-rays are only carried out if you are not responding to treatment, or your symptoms persist. Analysis of the coughed-up phlegm can tell doctors which germ caused the infection. However, results are not usually available until after treatment has been started, so this is not a routine test
The symptoms of coughs and colds can be eased with over-the-counter remedies. Take a mild painkiller such as paracetamol to relieve headache, fever, and aches and pains (don't give aspirin to children under 16).   
Make sure you drink plenty of fluids if you have a fever, as this helps to prevent dehydration.
You could try a cough medicine to ease coughing, although there is little scientific evidence that they work. Decongestant drops and sprays can help to clear a blocked nose, but check whether they contain paracetamol before taking them in addition to tablets.

When using decongestants, you should take the minimum effective dose. Taking them for a long time can cause side effects such as irritability, palpitations, headache, and insomnia.
If you have angina, high blood pressure or an over-active thyroid, decongestants can increase your chance of stroke, so check with your GP before using them.

Lower respiratory tract infections are generally treated in the same way. Antibiotics are not usually prescribed unless there are clear signs of a bacterial infection.
Antibiotics may be prescribed if you become very unwell, or if you already have an ongoing (chronic) lung disease. They may also be prescribed if a complication develops, such as pneumonia, but this is unlikely if you are otherwise healthy.

If you smoke, it's really important to stop smoking

                                                      Complications
Most respiratory tract infections clear up without complications. However, you should be aware of symptoms that can be a sign of a more serious condition such as pneumonia.
Consult your GP if any of the following develop:
• Fever, wheezing or headaches become worse or severe.
• Fast breathing, shortness of breath, chest pains, or coughing up blood.
• Drowsiness or confusion.
• A cough that lasts longer than 3-4 weeks.
• Recurring URTIs. 

                                                    Prevention
It’s very hard to avoid catching common coughs and colds. The viruses spread in the tiny droplets from coughs and sneezes, so keeping away from obviously infected people can help.
Eating a healthy, balanced diet, exercising regularly, getting enough sleep and managing stress effectively can all help to keep your immune system healthy, so you can fight off infections more easily.

Stop smoking, as smoking irritates the mucous membranes of the nose, sinuses, and lungs, which makes them more susceptible to infections.

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