Lung abscess

lung abscess is a pus-filled cavity in the lung surrounded by inflamed tissue and caused by an infection. A common mechanism is aspiration of stomach contents by vomiting and aspiration of part of the vomitus with all the bacteria from the pharynx, or gastrointestinal tract. Infections and neoplasms are the most common causes. The formation of multiple small (<2 cm) abscesses is occasionally referred to as necrotizing pneumonia or lung gangrene. Before the availability of antibiotics, the etiology of a typical abscess was complications after oral surgical procedures (ie, tonsillectomy), resulting in aspiration of infected material into the lungs. Both lung abscess and necrotizing pneumonia are manifestations of a similar pathologic process. The process is usually surrounded by a fibrous reaction, forming the abscess wall. Multiple small abscess formation may occur and is sometimes referred to as necrotising pneumonia. In children, the most vulnerable patients are those with weakened immune systems, malnutrition , or blunt injuries to the chest.
Lung Abscess is defined as a localized suppurative necrotizing collection occurring within the pulmonary parenchyma. Acute abscesses are less than 4-6 weeks old, whereas chronic abscesses are of longer duration. Several processes, either respiratory or systemic, can lead to abscess formation. Most abscesses are primary, meaning they result from necrosis in an existing parenchymal process (usually an infectious pneumonia). Lung abscesses can be classified based on the duration and the likely etiology. Aspiration into the lungs may be due to impaired normal swallowing mechanisms, esophageal disorders (e.g., acid Reflux ), altered consciousness levels, or absent gag reflex. Signs and symptoms usually begin at least 2 weeks before presentation and include cough, hemoptysis, fever, chills, night sweats, anorexia, pleuritic chest pain, and weight loss. The availability of effective antibiotic therapy for primary lung abscess has drastically modified the natural history of the disease and diminished the role of surgery. A pneumonitis develops which progresses to abscess formation over a period of 1–2 weeks.

Causes of Lung Abscess

The comman causes of Lung Abscess include the following :

• A lung abscess is usually caused by bacteria that normally live in the mouth or throat and that are inhaled into the lungs, resulting in an infection.
• Choking/near-drowning/ aspiration.
• Individuals with an inability to protect their airways because of an absent gag reflex, such as during coma, loss of consciousness, or general anesthesia and sedation.
• Severe periodontal disease.
• The remaining cases are caused by a mixture of anaerobic and aerobic (air breathing) bacteria.
• An abscess may occur secondary to carcinoma of the bronchus; the bronchial obstruction causes postobstructive pneumonia, which may lead to abscess formation.
• Stroke / cerebral palsy /cognitive impairment/impaired consciousness leading to increased risk of aspiration.

Symptoms of Lung Abscess

Some sign and symptoms related to Lung Abscess are as follows :

• The patient usually is sick for several weeks or months with a lack of appetite and the resulting weight loss.
• Cough with foul smelling sputum.
• Coughing pus.
• Poor dental hygiene is common.
• Chills and fever.
• Sweating.
• Productive cough.
• Rapid pulse ( heart rate).
• Foul-smelling cough.
• Bluish discoloration of the skin caused by lack of oxygen.

Treatment of Lung Abscess

Here is list of the methods for treating Lung Abscess:

• Lung abscess is treated with a combination of antibiotic drugs, oxygen therapy, and surgery.
• Penicillin intravenously.
• Cefoxitin is a second-generation cephalosporin that has gram-positive, gram-negative, and anaerobic coverage. This agent may be used when a polymicrobial infection is suspected as cause of lung abscess.
• Clindamycin intravenously.
• Standard treatment of an anaerobic lung infection is clindamycin (600 mg IV q8h followed by 150-300 mg PO qid).
• Patients may receive special antibiotics to treat organisms that may live in the mouth.
• Surgery is very rarely required for patients with uncomplicated lung abscesses.