Signs and symptoms

Pneumonia

Pneumonia is an inflammatory condition of the lung—especially affecting the microscopic air sacs (alveoli)—associated with fever, chest symptoms, and a lack of air space (consolidation) on a chest X-ray. Pneumonia is typically caused by an infection but there are a number of other causes. Infectious agents include: bacteria, viruses, fungi, and parasites.

Typical symptoms include cough, chest pain, fever, and difficulty breathing. Diagnostic tools include x-rays and examination of the sputum. Vaccines to prevent certain types of pneumonia are available. Treatment depends on the underlying cause with presumed bacterial pneumonia being treated with antibiotics.

Although pneumonia was regarded by William Osler in the 19th century as "the captain of the men of death", the advent of antibiotic therapy and vaccines in the 20th century have seen radical improvements in survival outcomes. Nevertheless, in the third world, and among the very old, the very young and the chronically ill, pneumonia remains a leading cause of death.

Classification

Pneumonitis refers to lung inflammation; pneumonia refers to pneumonitis, usually due to infection but sometimes non infectious, that has the additional feature of pulmonary consolidation. Pneumonia can be classified in several ways. It is most commonly classified by where or how it was acquired (community-acquired, aspiration, healthcare-associated, hospital-acquired, and ventilator-associated pneumonia), but may also be classified by the area of lung affected (lobar pneumonia, bronchial pneumonia and acute interstitial pneumonia), or by the causative organism. Pneumonia in children may additionally be classified based on signs and symptoms as non-severe, severe, or very severe.

Signs and symptoms

People with infectious pneumonia often have a productive cough, fever accompanied by shaking chills, shortness of breath, sharp or stabbing chest pain during deep breaths, confusion, and an increased respiratory rate. In the elderly, confusion may be the most prominent symptom. The typical symptoms in children under five are fever, cough, and fast or difficult breathing.Fever, however, is not very specific, as it occurs in many other common illnesses, and may be absent in those with severe disease or malnutrition. Additionally, a cough is frequently absent in children less than 2 months old. More severe symptoms may include: central cyanosis, decreased thirst, convulsions, persistent vomiting, or a decreased level of consciousness.

Some causes of pneumonia are associated with classic, but non-specific, clinical characteristics. Pneumonia caused by Legionella may occur with abdominal pain, diarrhea, or confusion, while pneumonia caused by Streptococcus pneumoniae is associated with rusty colored sputum, and pneumonia caused by Klebsiella may have bloody sputum often described as "currant jelly".

Physical examination may sometimes reveal low blood pressure, a high heart rate, or a low oxygen saturation. Examination of the chest may be normal, but may show decreased chest expansion on the affected side. Harsh breath sounds from the larger airways that are transmitted through the inflamed lung are termed bronchial breathing, and are heard 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.^[10] Struggling to breathe, confusion, and blue-tinged skin are signs of a medical emergency.

Diagnosis

Pneumonia is typically diagnosed based on a combination of physical signs and a chest X-ray. Confirming the underlying cause can be difficult, however, with no definitive test able to distinguish between bacterial and not-bacterial origin. The World Health Organization has defined pneumonia in children clinically based on a either a cough or difficulty breathing and a rapid respiratory rate, chest indrawing, or a decreased level of consciousness. A rapid respiratory rate is defined as greater than 60 breaths per minute in children under 2 months old, 50 breaths per minute in children two months to one year old, or greater than 40 breaths per minute in children one to five years old. In children, an increased respiratory rate and lower chest indrawing are more sensitive than hearing chest crackles with a stethoscope.

In adults investigations are generally not needed in mild cases as if all vital signs and auscultation are normal the risk of pneumonia is very low. In those requiring admission to a hospital, pulse oximetry, chest radiography, and blood tests including a complete blood count, serum electrolytes, C-reactive protein, and possibly liver function tests are recommended.^[25] The diagnosis of influenza-like illness can be made based on presenting signs and symptoms however verification of an influenza infection requires testing. Thus treatment is frequently based on the presence of influenza in the community or a rapid influenza test.

Prevention

Prevention includes vaccination, environmental measures, and appropriately treating other diseases.

Vaccination

Vaccination is effective for preventing certain bacterial and viral pneumonias in both children and adults.

Дата добавления: 2015-11-14