Signs, Symptoms, and Complications - Increased respiratory rate - Foul-smelling sputum - Hemoptysis - Fever - Complications such as exudative pleural effusion, empyema, and lung abscesses

Causes and Risk Factors - Defective swallowing mechanism - Neurological diseases - Injuries impairing swallowing or consciousness - Impaired consciousness due to anaesthesia or medical conditions - Poor oral hygiene leading to bacterial colonization - Impaired swallowing - Neurologic conditions affecting swallow mechanism - Anatomical changes in the chest - Altered mental status - Bacterial colonization - Ethnicity - Other factors like age, gender, diabetes, malnutrition, medication use, and respiratory conditions

Bacteria - Common aerobic bacteria: Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, Pseudomonas aeruginosa, Klebsiella - Anaerobic bacteria: Bacteroides, Prevotella, Fusobacterium, Peptostreptococcus - Anaerobic coverage is typically included in treatment regardless of culture results

Pathophysiology and Diagnosis - Aspiration defined as inhalation of oropharyngeal or gastric contents into the lungs - Complications: chemical pneumonitis, aspiration pneumonia, airway obstruction - Severity of chemical pneumonitis depends on pH and quantity of aspirate - Location of aspiration is often gravity dependent, with right middle and lower lung lobes most commonly affected - Chest x-ray is typically performed to detect pneumonia, including aspiration pneumonia - Findings on chest x-ray can support the diagnosis of aspiration pneumonia - Sputum cultures are not used for diagnosing aspiration pneumonia - Clinical symptoms and physical exam findings can increase suspicion of aspiration pneumonia - Lung biopsy specimens can diagnose aspiration pneumonia caused by food particles or other substances - Differentiation from Chemical Pneumonitis - Chemical pneumonitis and aspiration pneumonia have similar findings but require different management - Chemical pneumonitis is caused by damage to the inner layer of lung tissue - Inflammation triggers fluid influx in chemical pneumonitis - Treatment of chemical pneumonitis involves removal of inflammatory fluid and supportive measures - Antibiotics are reserved for chemical pneumonitis complicated by bacterial infection

Prevention, Treatment, and Prognosis - Oral hygiene practices can decrease the incidence and severity of aspiration pneumonia - Reduction of oral bacteria through antimicrobial use and dental professional interventions is beneficial - Post-pyloric feeding may reduce the risk of aspiration pneumonia in critically ill patients with feeding tubes - Training and assistance in swallowing can reduce episodes of aspiration pneumonia - Identifying conditions causing upper gastrointestinal dysfunction before surgery is essential in preventing aspiration - Adjusting the patient's posture and suctioning oropharyngeal contents are initial treatment steps - Humidified oxygen and elevated head end of the bed are recommended for patients not intubated - Antibiotics are the main treatment for aspiration pneumonia - Broad antibiotic coverage is necessary due to diverse types of bacteria causing the infection - Drainage of fluid within the lungs may aid in the healing process - Alteration of dietary regimens and head positioning can be recommended for dysphagia patients - Thickening liquids may decrease aspiration but increase the risk of delayed aspiration - Clinical interventions' impact on reducing pneumonia incidence is relatively unknown - Aspiration pneumonia is associated with increased in-hospital mortality compared to other forms of pneumonia - Individuals diagnosed with aspiration pneumonia have an increased risk of future episodes and higher mortality rates