Pneumonia is a serious respiratory condition characterized by inflammation of the air sacs in one or both lungs. These air sacs, or alveoli, can become filled with pus, fluid, or mucus, making it difficult for oxygen to reach the bloodstream. The disease can range in severity from mild to life-threatening and affects people of all ages, though it is most dangerous in infants, the elderly, and those with weakened immune systems.

Causes

Pneumonia is most commonly caused by infectious agents, which include:

  • Bacteria – such as Streptococcus pneumoniae, Mycoplasma pneumoniae, or Legionella pneumophila

  • Viruses – including influenza, respiratory syncytial virus (RSV), and COVID-19

  • Fungi – such as Pneumocystis jirovecii (especially in immunocompromised individuals)

The specific cause often influences the severity of the illness and the type of treatment required.

Symptoms

Common symptoms of pneumonia include:

  • Persistent cough (with or without mucus)

  • Fever and chills

  • Shortness of breath

  • Chest pain, especially during breathing or coughing

  • Fatigue and weakness

  • Sweating and shivering

  • Rapid heartbeat

  • Nausea or vomiting

In older adults, pneumonia can also cause confusion or a drop in body temperature.

Types

Pneumonia can be classified based on its cause or the setting in which it was acquired:

  • Community-acquired pneumonia (CAP) – contracted outside healthcare settings

  • Hospital-acquired pneumonia (HAP) – developed during a hospital stay

  • Ventilator-associated pneumonia (VAP) – occurs in people using ventilators

  • Aspiration pneumonia – caused by inhaling food, drink, vomit, or saliva

Diagnosis

A healthcare provider may use several methods to diagnose pneumonia:

  • Physical exam – listening to the lungs for abnormal sounds

  • Chest X-ray – to detect the presence and location of infection

  • Blood tests – to identify the type of infection

  • Pulse oximetry – to measure oxygen levels in the blood

  • Sputum test – to identify the organism causing the infection

In some cases, additional tests such as a CT scan or bronchoscopy may be necessary.

Treatment

Treatment depends on the type and severity of pneumonia:

  • Bacterial pneumonia – treated with antibiotics

  • Viral pneumonia – may resolve on its own or be treated with antiviral drugs (e.g., for influenza or COVID-19)

  • Fungal pneumonia – treated with antifungal medications

Supportive care includes:

  • Rest and fluids

  • Fever reducers and pain relievers

  • Oxygen therapy (for severe cases)

Hospitalization may be required for high-risk individuals or severe symptoms.

Risk factors

Several factors can increase the risk of developing pneumonia:

  • Age (infants and elderly)

  • Chronic illnesses (e.g., COPD, asthma, diabetes)

  • Weakened immune system

  • Smoking or heavy alcohol use

  • Recent respiratory infection

  • Being hospitalized or using a ventilator

Complications

If not properly treated, pneumonia can lead to serious complications:

  • Sepsis – a life-threatening reaction to infection

  • Lung abscesses – pus-filled cavities in the lung

  • Pleural effusion – fluid buildup around the lungs

  • Respiratory failure – inability of the lungs to provide sufficient oxygen

Prompt medical attention can greatly reduce the risk of complications.

Prevention

Preventive measures can reduce the likelihood of getting pneumonia:

  • Vaccination – pneumococcal vaccines, flu shots, COVID-19 vaccines

  • Hand hygiene – frequent handwashing with soap and water

  • Healthy lifestyle – eating well, quitting smoking, regular exercise

  • Avoiding sick individuals – especially in high-risk settings

Living with pneumonia

Recovery from pneumonia can take days to weeks, depending on the individual and severity. Rest, hydration, and following the prescribed treatment plan are crucial. For those with recurring infections, long-term management may include lifestyle changes or treatment of underlying conditions.

When to seek help

Seek immediate medical attention if you or someone you care for experiences:

  • Difficulty breathing

  • Chest pain

  • Confusion or bluish skin tone

  • High fever that doesn't respond to medication

  • Symptoms that worsen despite treatment

FAQs

1. Is pneumonia contagious? Some forms, especially viral pneumonia, can be contagious. It spreads through coughs, sneezes, and contaminated surfaces.

2. Can pneumonia come back? Yes, especially in individuals with weakened immunity or chronic conditions.

3. How long does pneumonia last? Mild pneumonia may resolve in 1–2 weeks. Severe cases may take longer and require hospitalization.