Pneumonia is a common lung infection caused by a bacteria, virus, fungi, or aspiration of stomach contents. Pneumonia and its symptoms can vary from mild to severe and the treatment is based on symptomatology, etiology and site of care. A major goal of therapy is the identification and treatment of the infecting organism. As such, antimicrobials are a mainstay of treatment. Supportive respiratory care and the prevention of systemic spread of the organism are vital. Acute pneumonia may be caused by a wide variety of pathogens. Appropriate drug selection is dependent on the suspected causative pathogen and its antibiotic susceptibility.
Most healthy people recover from pneumonia in one to three weeks with supportive care. Improving the outcomes of patients with community-acquired pneumonia (CAP) – defined as pneumonia acquired outside a hospital or long-term care facility – has been the focus of many different organizational efforts. Community acquired pneumonia, together with influenza, remains the seventh leading cause of death in the United States. Site-of-care decisions (e.g., hospital vs. outpatient, intensive care unit [ICU] vs. medical unit) are important guidelines for the aggressiveness of treatment and prognosis.
Outpatient treatment
Almost all of the major decisions regarding management of pneumonia, including diagnostic and treatment issues revolve around the initial assessment of severity. The decision to admit the patient is the most costly issue in the management of pneumonia. Some reasons for avoiding unnecessary admissions are that patients at low risk who are treated in the outpatient setting are able to resume normal activity sooner than those who are hospitalized. Hospitalization also increases the risk of thromboembolic events and superinfection by more virulent or resistant hospital bacteria. Patients at low risk without signs of respiratory compromise or co-morbid factors should be treated as an outpatient.
Most people can be treated at home with supportive care such as:
– Increasing fluid intake
– Obtaining adequate sleep and rest
– Using cough and expectant medication as needed
– Controlling of fever with nonsteroidal anti-inflammatory drugs (NSAIDs), or acetaminophen. DO NOT give aspirin to children!
– Controlling of body aches and pain with the cautious use of pain medication, if not relieved by NSAID’s
– Utilizing a humidifier or vaporizer
– Taking antibiotics or antivirals as prescribed
The ability to safely and reliably take oral medication and the availability of outpatient support is paramount to the rapid recovery of these patients. Antibiotic choices in the outpatient setting should be driven by the presence of patient risk factors, including recent exposure to antibiotics, chronic diseases, and local trends in antibiotic resistance. The majority of antibiotics released in the past several decades for CAP makes the choice of antibiotics potentially overwhelming. Selection of antimicrobial regimens for empirical therapy is based on prediction of the most likely pathogen(s) and knowledge of local susceptibility patterns. Recommendations are generally for a class of antibiotics rather than a specific drug, unless outcome data clearly favor one drug. Because overall efficacy remains good for many classes of agents, the more potent drugs are given preference because of their benefit in decreasing the risk of antibiotic resistance. Other factors for considerations of specific antibiotics include pharmacokinetics/pharmacodynamics, compliance, safety, and cost.
Typical bacterial pathogens that cause CAP include Streptococcus pneumonia, Haemophilus influenza, and Moraxella catarrhalis and account for approximately 85% of CAP cases. Aspiration pneumonia is the only form of CAP caused by multiple pathogens (e.g., aerobic/anaerobic oral organisms). Klebsiella pneumonia CAP occurs primarily in persons with chronic alcoholism and Staphylococcal aureus may cause CAP in patients with influenza. Despite advances in antimicrobial therapy, rates of mortality due to bacterial pneumonia have not decreased significantly since penicillin became routinely available.
Outpatient antimicrobial guidelines
Healthy patients with no risk factors for drug-resistance may be prescribed:
Azithromycin – 500 mg PO one dose, then 250 mg PO daily for 4 d or extended-release 2 g PO as a single dose or
Clarithromycin – 500 mg PO bid or extended-release 1000 mg PO q24h or
Doxycycline – 100 mg PO bid – weak choice
In immunized children, amoxicillin 90mg/kg/day in 2 doses or 45mg/kg/day in 3 doses.
If antibiotics administered within 3 months:
Azithromycin or clarithromycin plus amoxicillin 1 g PO q8h or amoxicillin-clavulanate 2 g PO q12h or
Respiratory fluoroquinolone (levofloxacin 750 mg PO daily or moxifloxacin 400 mg PO daily)
If comorbidities are present e.g., alcoholism, cystic fibrosis, COPD, IV drug use, post-influenza, immunocompromised, diabetes mellitus, lung/liver/renal diseases:
Levofloxacin (Levaquin)750 mg PO q24h or
Moxifloxacin (Avelox) 400 mg PO q24h or
Combination of a beta-lactam ( amoxicillin 1 g PO q8h or amoxicillin-clavulanate 2 g PO q12h or ceftriaxone 1g IV/IM q24h or cefuroxime 500 mg PO BID) plus a macrolide (azithromycin or clarithromycin)
Therapy should be maintained for a minimum of 5 to 7 days. Longer duration of therapy may be needed if initial therapy was ineffective or complications arise. Pneumonia that does not respond to treatment poses a clinical dilemma. If patients do not improve within 72 hours, an organism that is not susceptible or is resistant to the initial antibiotic regimen should be considered. Lack of response may also be secondary to a complication such as empyema or abscess formation. Antibiotics should not be changed within the first 72 hours unless marked clinical deterioration occurs or the causative organism is identified.
Inpatient treatments
Treatment modalities for severe viral and bacterial pneumonias include:
Analgesics or opioids to relieve sometimes severe chest discomfort
Antipyretics
Intravenous fluids (and, conversely, diuretics) if indicated
Appropriate antibiotic/antiviral therapy based on suspected pathogen or positive identification
Monitoring – Pulse oximetry with or without cardiac monitoring
Oxygen supplementation
Respiratory therapy, including treatment with bronchodilators and, perhaps, N -acetylcysteine in selected patients
Pulmonary toilet including active suction of secretions, chest physiotherapy, positioning, and incentive spirometry
Mechanical ventilator or CPAP support with patients in respiratory failure due to bilateral pneumonia or acute respiratory distress syndrome (ARDS)
Vasopressors for the treatment of septic shock
Corticosteroids in severe cases of shock
Full body support may include proper hydration, nutrition, and range of motion, bladder and bowel hygiene
Not all pneumonias are community acquired. The development of hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) bring their own challenges. Short-course antibiotic therapy is recommended for most patients with HAP or VAP regardless of microbial etiology, which is rarely isolated. Traditionally, nosocomial pneumonias are treated for 7-14 days. These regimens should be based on the local profile of organisms associated with hospital-acquired pneumonia (HAP) and their antibiotic sensitivities. In cases of HAP and VAP, antibiotics should be administered by either extended or continuous infusion. Dosing needs to be based on antibiotic blood levels and should also be weight-based, when applicable.
The use of inhaled antibiotic therapy should be generally limited to cases of VAP produced by gram-negative bacilli that are sensitive only to aminoglycosides, colistin, or polymyxin B. These antibiotics should also be administered systemically and renal functions closely observed.
Drug-resistant S pneumoniae have become increasingly common worldwide, but have been decreasing in the United States due to vigilance and decreased use of antibiotics. MRSA should be covered empirically in patients in units having 10-20 percent known cases. The preferred antibiotics for treatment of MRSA infections include vancomycin and linezolid.
Viral pneumonia
Viral causes of pneumonia make up about 30% of all pneumonias in the United States today. Influenza, respiratory syncytial virus (RSV), adenoviruses, rhinoviruses, herpes, measles and chickenpox can all lead to the development of viral pneumonia. The use of oseltamivir, zanamivir, and peramivir is not recommended for patients with uncomplicated influenza but may be used to reduce viral shedding in hospitalized patients, patients in communal living, or for influenza pneumonia. For optimal treatment, medications should be prescribed within 36 hours of the onset of symptoms. Most influenza pneumonias are treated with supportive outpatient care and education on prevention of spreading the virus.
Ribavirin is commonly used in the treatment of RSV to limit the spread of viruses. RSV is most commonly seen in children. Varicella pneumonia is almost always serious enough to require inpatient hospital care and treatment with acyclovir either through an IV or orally. Inpatient treatment includes the basics of supportive care and decreasing pulmonary and potentially septic complications.
The newest recognized form of viral pneumonia is in patients with known exposure to poultry; this has been named the H5N1 virus. In patients with suspected H5N1 infection, droplet precautions and careful respiratory infection control measures should be used until an H5N1 infection is ruled out. Patients with suspected H5N1 infection should be treated with oseltamivir and antibacterial agents targeting S. pneumoniae and S. aureus, the most common causes of secondary bacterial pneumonia in viral pneumonia patients.
Post-treatment information
Whether a patient with pneumonia is treated in an outpatient setting or hospitalized, arranging adequate follow-up evaluations is mandatory. The patient should also be instructed to return promptly if their condition deteriorates or does not improve. Patients should have a follow-up chest radiograph in four to six weeks to ensure resolution of consolidation, effusion or bronchiectasis. Computed tomography (CT) scanning may be of benefit in cases with persistent changes on radiograph.
Vaccination programs for children, at risk adults and the elderly have aided in the prevention of pneumonias. Education on handwashing and respiratory etiquette, and decreasing exposure or inhalation of irritants may further reduce the incidence of pneumonia.
References:
http://emedicine.medscape.com/
Pneumonia. (2016). Retrieved from http://www.who.int/en/news-room/fact-sheets/detail/pneumonia.
Recent Comments