Aspiration Pneumonia: Causes symptoms and Treatment

Aspiration is the act of bringing foreign material into the lungs and is described as the accidental inhalation of either oropharyngeal or stomach contents into the lower respiratory tract. Numerous symptoms may result from this, depending on the amount and type of aspirated material, how frequently it occurs, and a variety of other factors that predispose the patient to aspiration and alter the reaction.

Highlights

• Aspiration pneumonia refers to a lung infection caused by accidental inhalation of any content other than air.
•  Common causes of aspiration pneumonia include impaired coughing, excessive consumption of alcohol, gastroesophageal reflux disease, etc.
• Streptococci, Staphylococci, Pseudomonas, and Fusobacterium are common pathogens in aspiration pneumonia.
• Treatment of aspiration pneumonia is mediated by antibiotics and humidified oxygen.

What is aspiration pneumonia?

The term aspiration pneumonia (Figure 1) is derived from two words: aspiration means accidental inhalation of any content other than air which can be food, drink, saliva, gastric content, germs, toxins, and even small foreign particles, while pneumonia refers to the inflammation and infection of lungs. Aspiration pneumonia is also known as anaerobic pneumonia or necrotizing pneumonia.

Figure 1. Aspiration pneumonia.

It is characterized by inhalational acute lung damage, leading to inflammation, irritation, and localized infection. Whereas aspiration pneumonitis is the medical term used to describe the inhalational acute lung damage caused by aspirated material, but it is characterized by inflammation and irritation only; no infection occurs in this case.

How does aspiration pneumonia occur?

Aspiration pneumonia often occurs when you have a weakened immune system, and the aspirated material contains a lot of disease-causing germs. Even normal healthy adults can aspirate food or drink, but a regular gag reflex action or coughing mediated by mucociliary mechanism and alveolar macrophages (part of the innate immune response) effectively block particles’ entry into the lungs, thus preventing pneumonia.

On the contrary, people with impaired coughing and failure of the natural defense system of the lungs have increased chances of aspiration pneumonia. This impairment can be due to throat cancer, neurological disorders, excessive consumption of alcohol, esophageal disorders, medical conditions like Parkinson’s disease or myasthenia gravis, use of sedative drugs or anesthesia, and dental problems such as chewing or swallowing. Other conditions that might increase the chances of aspiration pneumonia include head trauma, gastroesophageal reflux disease, pseudobulbar palsy, tracheostomy, protracted vomiting, stroke, drug overdose, intracranial masses, and dementia.
Although Streptococci, Staphylococcus aureus, Hemophilus, and Gram-negative bacilli are frequently involved in community-acquired pneumonia, the occurrence of aspiration pneumonia largely depends on the type and source of aspirated material. A recent study found 49% Gram-negative bacilli cases in 95 aspiration pneumonia patients, followed by 16% anaerobes of the genera Fusobacterium, Bacteroides, and Peptostreptococcus. Similarly, the Gram-negative organism Pseudomonas aeruginosa must also be considered in the case of nosocomial aspiration pneumonia.

Signs and Symptoms

Colored phlegm, crackling noise, and high fever are the three common signs of aspiration pneumonia, whereas symptoms may include:
Difficulty breathing: The aspirated material may get stuck in the windpipe and cause difficulty in breathing.
Fatigue: In some cases, shortness of breath may cause oxygen depletion in the body, resulting in tiredness and muscle fatigue.
Chest pain
Wheezing: It is a shrill whistle you hear when your airways are partially blocked.
Excessive sweating
Slightly blue skin: Body parts with depleted oxygen supply may turn light blue.
High fever: The pneumonitis caused by aspiration pneumonia may increase body temperature.

Diagnosis

To diagnose aspiration pneumonia, your healthcare provider will first conduct a physical examination based on identifying signs such as crackling noise, rapid heart rate, and decreased airflow to the lungs. Other tests may include chest X-ray, sputum culturing, blood culturing, CBC (Complete Blood Count), ABGs (arterial blood gases) test, bronchoscopy, and chest CT scan (computed tomography scan).

Treatment

The treatment of aspiration pneumonia varies greatly, depending upon the patient’s overall health and severity of symptoms. If a person has difficulty swallowing, a nasogastric tube is placed through the nose into the stomach to feed the patient. In others, humidified oxygen is administered, and oxygen saturation is regularly monitored. Patients are transferred to mechanical ventilation if the oxygen level drops to a hypoxic condition. Similarly, bronchoscopy is performed to clear the secretion from the lungs and to obtain bronchoalveolar lavage samples for bacterial analysis. The antibiotics of choice are ampicillin-sulbactam or a combination therapy based on metronidazole and amoxicillin. In patients with penicillin allergy, clindamycin is prescribed. Similarly, vancomycin and piperacillin-tazobactam are most widely used to control antibiotic-resistant Gram-negative bacteria and Gram-positive S. aureus infections.