🫁 Pneumonia in Adults: Warning Signs & When to Seek Emergency Care

Pneumonia is an infection of the lungs that can range from mild to life‑threatening. The air sacs (alveoli) fill with fluid and pus, making it hard to breathe and limiting the oxygen that reaches your bloodstream. While most healthy adults recover with treatment, pneumonia remains a leading cause of death, especially among the elderly and those with weakened immune systems. Dr. Ravi Sishir Reddy explains the key symptoms that distinguish pneumonia from a common cold or bronchitis, the most common causes, and the warning signs that demand immediate medical care.

1. What Is Pneumonia?

Pneumonia is an acute infection of the lung parenchyma — the deep part of the lung where oxygen and carbon dioxide are exchanged. When you breathe in, air travels through the bronchi into millions of tiny air sacs called alveoli. In pneumonia, these alveoli become inflamed and fill with fluid, white blood cells, and debris. This consolidation of lung tissue makes the lungs stiff, reduces the surface area for gas exchange, and causes the hallmark symptoms of cough, fever, and difficulty breathing. Pneumonia can affect just one lobe of one lung (lobar pneumonia) or be scattered throughout both lungs (bronchopneumonia or interstitial pneumonia).

2. What Causes Pneumonia?

Pneumonia can be caused by bacteria, viruses, or (less commonly) fungi. The most common pathogens include:

• Streptococcus pneumoniae (pneumococcus): The most common bacterial cause of community‑acquired pneumonia. It often starts after a viral respiratory infection and causes a classic lobar pneumonia with high fever, shaking chills, and rust‑coloured sputum. The pneumococcal vaccine protects against the most dangerous strains.
• Haemophilus influenzae: Common in patients with COPD and smokers.
• Mycoplasma pneumoniae: A cause of "walking pneumonia" — a milder but persistent form that often affects younger adults, with a dry hacking cough, low‑grade fever, and fatigue. It does not respond to penicillins but can be treated with macrolides (azithromycin) or tetracyclines (doxycycline).
• Respiratory viruses: Influenza, SARS‑CoV‑2 (COVID‑19), RSV, and adenoviruses can all cause primary viral pneumonia, which may be severe in its own right and also predispose to secondary bacterial pneumonia.
• Legionella pneumophila: Causes Legionnaires' disease — a severe pneumonia often associated with contaminated water sources (air conditioners, cooling towers).
• Aspiration pneumonia: Occurs when food, liquid, or stomach contents are inhaled into the lungs. It is more common in people with swallowing difficulties (stroke, dementia, alcohol intoxication) and involves mixed bacteria from the mouth and gut.
• Fungal pneumonia: Rare in people with normal immune systems; affects immunocompromised patients (HIV/AIDS, organ transplant, on chemotherapy). Pneumocystis jirovecii is a classic cause in advanced HIV.

3. Warning Signs of Pneumonia in Adults

Pneumonia can present differently depending on the cause and the patient, but the classic constellation of symptoms includes:

• Cough with phlegm (sputum): The cough is often productive from the beginning. The sputum may be yellow, green, rust‑coloured (classic for pneumococcal pneumonia), or even blood‑streaked. A dry cough may be present early in viral or atypical pneumonia.
• High fever with shaking chills (rigors): Bacterial pneumonia typically causes a sudden high fever (often 102°F–105°F / 39°C–40.5°C) with intense, teeth‑chattering shivering. Sweating is profuse when the fever breaks.
• Pleuritic chest pain: A sharp, stabbing pain that worsens with deep breathing, coughing, or sneezing. This indicates that the inflammation has spread to the pleura (the outer lining of the lung), a condition called pleurisy. The patient may splint (hold) the affected side of the chest and breathe shallowly to avoid pain.
• Shortness of breath (dyspnea): As the alveoli fill with fluid, the lungs become stiff, and it takes more effort to breathe. The patient may breathe rapidly and feel like they cannot get enough air. In severe cases, the lips or fingertips may turn bluish (cyanosis), indicating dangerously low oxygen levels.
• Generalised symptoms: Severe fatigue, muscle aches, headache, loss of appetite, and confusion — especially in the elderly, who may not present with typical fever or cough but rather with sudden confusion, a fall, or a decline in functional status.

4. How Is Pneumonia Diagnosed?

• Chest X‑ray: The most important diagnostic test. It shows areas of consolidation (white patches) where the airspaces are filled with fluid. It helps confirm the diagnosis and determine the extent and location of the infection.
• Pulse oximetry: A clip placed on the finger measures the oxygen saturation in the blood. A reading below 92‑94% indicates that the pneumonia is interfering with oxygen exchange and may require hospitalisation for supplemental oxygen.
• Blood tests: A complete blood count often shows a high white blood cell count (leukocytosis) in bacterial pneumonia. Inflammatory markers (CRP, procalcitonin) help distinguish bacterial from viral pneumonia. Blood cultures are taken in hospitalised patients to identify the specific organism.
• Sputum culture and Gram stain: A sample of coughed‑up sputum is examined under a microscope and cultured to identify the causative bacteria and their antibiotic sensitivities. This is more useful in severe cases.
• Urine antigen tests: Rapid tests for Streptococcus pneumoniae and Legionella from a urine sample, available in some settings.

5. Treatment: Antibiotics, Supportive Care, and Hospitalisation

Treatment depends on the severity, the suspected pathogen, and the patient's underlying health:

• Mild community‑acquired pneumonia in an otherwise healthy adult can often be treated at home with oral antibiotics (e.g., amoxicillin, doxycycline, or a macrolide like azithromycin, depending on the likely pathogen and local resistance patterns). Complete the full course, even if you start to feel better after 2‑3 days.
• Moderate to severe pneumonia requires hospitalisation for intravenous antibiotics (such as ceftriaxone plus azithromycin or a respiratory fluoroquinolone like levofloxacin), supplemental oxygen if needed, and close monitoring.
• Supportive care: Paracetamol or ibuprofen for fever and pleuritic pain. Adequate hydration — drink water, soups, and herbal teas. Cough suppressants are generally not recommended, as coughing helps clear the infected material from the lungs. In severe cases, corticosteroids (dexamethasone) may be used to reduce the inflammatory storm, particularly in severe COVID‑19 pneumonia.
• ICU admission: For patients with respiratory failure, septic shock, or multi‑organ dysfunction. Mechanical ventilation may be required.

6. When to Go to the Emergency Room Immediately

Dr. Reddy emphasises that the following are emergency warning signs of severe pneumonia:

• Severe shortness of breath at rest, or breathing faster than 30 breaths per minute.
• Bluish discolouration of the lips, tongue, or fingertips (cyanosis).
• Confusion, disorientation, or extreme drowsiness — especially in older adults.
• Systolic blood pressure below 90 mmHg or a feeling of extreme dizziness and fainting on standing (signs of septic shock).
• Very high fever (>104°F / 40°C) unresponsive to antipyretics.
• Severe chest pain that prevents you from breathing deeply.

7. Preventing Pneumonia: Vaccination and Healthy Habits

• Pneumococcal vaccine: Two types — PCV13 (Prevnar 13) and PPSV23 (Pneumovax 23). They protect against the most common and dangerous strains of Streptococcus pneumoniae. The CDC recommends both vaccines, given at different times, for all adults aged 65 and older, and for younger adults with certain chronic medical conditions (diabetes, heart disease, COPD, kidney disease, immunocompromised states). Discuss the appropriate schedule with your doctor.
• Annual influenza vaccine: Influenza is a major cause of primary viral pneumonia and predisposes to secondary bacterial pneumonia. The flu vaccine significantly reduces this risk.
• COVID‑19 vaccination: Protects against severe COVID‑19 pneumonia.
• Smoking cessation: Smoking damages the lung's natural defence mechanisms (cilia, immune cells) and is a major risk factor for pneumonia.
• Good hand hygiene: Reduces the transmission of respiratory viruses and bacteria.
• Manage chronic conditions: Good control of diabetes, COPD, asthma, and heart failure reduces susceptibility to infections.