by Jeremy Mikolai, ND, and Martin Milner, ND

Introduction

Infections of the respiratory system commonly present to the outpatient primary care setting. The first decision for the primary care provider is to determine the appropriate setting for treatment, in hospital or outpatient.¹ The second decision is to initiate empiric therapy with or without an initial work-up for the microbial cause of the infection. In the outpatient setting, many cases of respiratory infection are amenable to naturopathic treatment as an alternative to the conventional standard of care. Where necessary, the standard of care treatment should be initiated without hesitation, yet in these circumstances naturopathic treatment may make an excellent adjunct to conventional care and may improve outcomes.

The world over, pneumonia is the most important infectious cause of death in children. Liu et al. (2012) analyzed global mortality figures from 2010 and determined that, of the 7.6 million children annually who do not reach their fifth birthday, two-thirds of them die from infectious causes; pneumonia is the leading cause of infection and death among them.² In America, the combination of pneumonia and influenza remains the eighth leading cause of death, annually. This makes it the most common infection-related cause of mortality.³

Acute respiratory illnesses may be as routine and self-limited as the common cold or as complicated and life threatening as multilobar pneumonia with multiple or drug-resistant organisms. While many cases of acute respiratory infection in adults are mild, no provider or patient can afford to miss a case that is complicated, becomes complicated, or requires hospitalization. Therefore, the clinical evaluation and assessment of acute respiratory illness, with a focus on community-acquired pneumonia, demands some attention.

Classifications of Pneumonia

Pneumonias are typically divided into categories based on the location of their transmission. There is a high correlation between where the infection is contracted and what the infectious agent is likely to be. The current classification of infectious pneumonias include community-acquired (CAP), hospital-acquired (HAP), ventilator-associated (VAP), and health-care-associated (HCAP).⁴ We will address CAP almost exclusively in this article, as it is the category most commonly encountered in ambulatory primary care. Bacteria are the most common causes of CAP and have traditionally been divided into “typical” and “atypical” groups. While this distinction is still used, distinguishing between the two on clinical grounds is often not possible.^1,5 Evidence indicates that physician judgment is moderately good at ruling out a diagnosis of pneumonia, yet there is an ever-increasing opportunity for us to utilize evidence-based clinical decision-making tools and prediction rules to improve upon this.⁶

Community-Acquired Pneumonia

CAP is an infection of the lung parenchyma that is not acquired in a hospital, long-term care facility, or other recent exposure to the health care system. Typical CAP is caused by the gram-positive airway bacterium Streptococcus pneumonia or by Group A strep, Haemophilus influenzae, Staphylococcus aureus, Moraxella catarrhalis, aerobic gram-negative bacteria, and anaerobes. Atypical causes of CAP include numerous respiratory viruses, Mycoplasma pneumoniae, Chlamydophila pneumoniae, C. psittaci, and Legionella species.⁵

Very often, CAP microbial etiologies are not identified (44%-69%); the most frequently isolated etiologic agent is S. pneumoniae (6%-14%). Viral causes of CAP appear to make up 3% to 15% of cases in the outpatient setting, while Mycoplasma and Chlamydophila account for 5% to 17% and 2% to 14% of identified etiologies, respectively.^7-9 When treating CAP empirically, it is therefore important to cover the most common atypical organisms, as their individual incidence is similar to that of viral causes and their combined probability exceeds viral likelihood severalfold.¹⁰

History and Physical Evaluation of CAP

The interview of a patient with suspected pneumonia should include questions about animal exposures (especially birds), occupation, recent travel (domestic and international), and sexual history.¹ This information is important in the decision-making process about the likelihood of involvement of particular microbes and the appropriate laboratory evaluations to be made.

There are no individual clinical findings or combination of findings that can predict the diagnosis of pneumonia with certainty. Cough and sputum production, pleuritic chest pain, tachypnea (rapid breathing), tachycardia (rapid pulse), dyspnea (shortness of breath), fever, chills, and rigor (a single shaking chill) are common signs and symptoms seen in the setting of CAP. While fever may be present in 75% to 80% of positive cases, chills in 40% to 50%, tachypnea (over 24 breaths per minute) in 45% to 70%, and chest pain in 30%, none of these findings are sensitive enough to rule out the disease in their absence. Pneumonia can present with a protean constellation of symptoms; even gastrointestinal involvement is common as diarrhea, nausea, and vomiting may be among the complaints at the initial evaluation.^1,11,12

Tachypnea has a positive likelihood ratio of 3.5 (LR+ = 3.5), for the prediction of CAP in adults when the breathing rate is over 24 per minute. Moreover, it is an important sign of pneumonia in the elderly.¹² Up to 70% of those over 65 years old with CAP will demonstrate tachypnea. Confusion or functional mental status change and weakness are also important clinical signs of CAP in the older population.¹³ While the absence of fever and absence of sputum production significantly reduce the likelihood of CAP in adult patients, these indicators are unreliable in the older adult population, which tends toward fewer febrile events, in general, and often presents a subtler picture of CAP.^7,14

Rales or crackles are present upon pulmonary auscultation in most patients with CAP; signs of lung consolidation are present in about one-third of patients. Of the potential signs, egophony (LR+ = 2.0-8.6), bronchial breath sounds (LR+ = 3.5), dullness to percussion (LR+ = 2.2-4.3), and decreased breath sounds (LR+ = 2.3-2.5) have the best likelihood ratios for predicting the presence of consolidation. Asymmetric breath sounds, increased fremitus, and pleural rubs are very specific for the presence of consolidation, but are often absent clinically.^1,14,15

Pulse oximetry should be performed in all patients suspected for CAP. Often a 3- to 5-minute exercise desaturation challenge can unmask important information that may not be obvious during a resting pulse oximetry measurement. Even in the setting of a normal resting measurement, it is abnormal for patients to lose 5% or more from their oxygen saturation reading during exertion.¹⁶ Completing a pulse oximetry oxygen desaturation challenge in the office is a simple and straightforward procedure; we believe that the procedure should be used routinely.