Pneumonia is an inflammatory condition of the lung, especially of the alveoli (microscopic air sacs in the lungs) or when the lungs fill with fluid (called consolidation and exudation). There are many causes, of which infection is the most common. Infecting agents can be bacteria,viruses, fungi, or parasites. Chemical burns or physical injury to the lungs can also produce pneumonia.
Typical symptoms include cough, chest pain, fever, and difficulty in breathing. Diagnostic tools include x-rays and examination of the sputum. Treatment depends on the cause of pneumonia; bacterial pneumonia is treated with antibiotics.
Pneumonia is a common disease that occurs in all age groups. It is a leading cause of death among the young, the old, and the chronically ill. Vaccines to prevent certain types of pneumonia are available. The prognosis depends on the type of pneumonia, the treatment, any complications, and the person's underlying health.
Sign and symptom:
People with infectious pneumonia often have a cough producing greenish or yellow sputum orphlegm and a high fever that may be accompanied by shaking chills. Shortness of breath is also common, as is sharp or stabbing chest pain during deep breaths or coughs. Less frequent symptoms of pneumonia include coughing up blood, headaches, sweaty and clammy skin, loss of appetite, fatigue, blueness of the skin, nausea, vomiting, mood swings, and joint pains or muscle aches. Some forms of pneumonia can cause specific symptoms. Pneumonia caused byLegionella may cause abdominal pain and diarrhea, while pneumonia caused by tuberculosis orPneumocystis may cause only weight loss and night sweats. Symptoms in the elderly can include new or worsening confusion (delirium) or may experience unsteadiness, leading to falls. Infants with pneumonia may have many of the symptoms above, but in many cases they are simply sleepy or have a decreased appetite.
Physical examination may reveal signs of illness including fever or sometimes low body temperature, anincreased respiratory rate, low blood pressure, a high heart rate, or a low oxygen saturation, which is the amount of oxygen in the blood as indicated by either pulse oximetry or blood gas analysis. Struggling to breathe, confusion, and blue-tinged skinare signs of a medical emergency.
Findings from physical examination of the lungs may be normal, but often show decreased expansion of the chest on the affected side. Harsher sounds from the larger airways transmitted through the inflamed lung are heard as bronchial breathing on auscultation with a stethoscope.Rales (or crackles) may be heard over the affected area during inspiration. Percussion may be dulled over the affected lung, and increased rather than decreased vocal resonance distinguishes pneumonia from a pleural effusion. Because some of these signs are subjective, physical examination alone is insufficient to diagnose or rule out pneumonia
Pneumonia can be due to microorganisms, irritants or unknown causes. When pneumonias are grouped this way, infectious causes are the most common.
The symptoms of infectious pneumonia are caused by the invasion of the lungs bymicroorganisms and by the immune system's response to the infection. Although more than one hundred strains of microorganism can cause pneumonia, only a few are responsible for most cases. The most common causes of pneumonia are viruses and bacteria. Less common causes of infectious pneumonia are fungi and parasites.
If pneumonia is suspected on the basis of symptoms and findings from physical examination, further investigations are needed to confirm the diagnosis. Information from a chest X-ray and blood tests are helpful, and sputum cultures in some cases. The chest X-ray is typically used for diagnosis in hospitals and some clinics with X-ray facilities. However, in a community setting (general practice), pneumonia is usually diagnosed based on symptoms and physical examination alone. Diagnosing pneumonia can be difficult in some people, especially those who have other illnesses. Occasionally a chest CT scan or other tests may be needed to distinguish pneumonia from other illnesses.