CAP and Walking Pneumonia

 

Community acquired pneumonia (CAP) and Walking pneumonia

                                 PKGhatak,MD

Pneumonia is an inflammatory condition of the lungs. The name pneumonia has to be qualified further to define it narrowly like viral pneumonia, mycoplasma pneumonia, bronchopneumonia, etc. Infectious agents like viruses, bacteria, and fungus are the most common causes of pneumonia. Other agents like toxic fumes, aspirated stomach acids, drowning, medications, radiation, etc. may also cause pneumonia.

Not all pneumonia is life threatening. Based on the degree of severity of pneumonia, and where the infection is acquired, pneumonia can be put in two separate entities.

 1. Community acquired.

 2. Hospital-acquired pneumonia.

When an otherwise healthy person develops pneumonia, the disease is called Community acquired. Whereas, those patients admitted to hospital for conditions other than pneumonia, subsequently get infected while in hospital, the resulting pneumonia is called hospital acquired pneumonia. Hospital bacteria are generally gram negative and resistant to multiple antibiotics and produce serious complications and deaths.

Walking pneumonia:

Community acquired pneumonia when mild, most patients can be effectively treated outside the hospital with oral antibiotics and common over the counter cold & cough medications. These patients are free to walk around and are not bed confined.

So, doctors have coined this term as walking pneumonia to eliminate fear and concerns of people because in the past, pneumonia was akin to a death sentence, days prior to the availability of sulfonamides and penicillin, like we had experienced with HIV/AIDS before retrovirus medications.

Walking Pneumonia should not be confused with Migratory Pneumonia. In migratory pneumonia, pneumonia walks from one place to another place in the lungs. In Walking pneumonia, the patient walks.

Infectious agents causing CAP.

In 2020 the covid-19 pandemic has taken 20 million lives,( 7 million by official count) worldwide and sickened hundreds of millions. The influenza pandemic in 1918 took 50 million lives. Virus pneumonia is undoubtedly the worst human pathogen. In this article only bacterial pneumonia will be discussed.

Every year in the USA about 5 million cases of CAP are seen; it is the second most common infection requiring hospitalization, on average 650 per 1000,000 population are admitted with CAP.

The health department of every community in corroboration with the CDC keeps a close eye on the prevalent infectious agents causing CAP. CDC provides weekly notification about the common bacteria, the best possible antibiotic to treat CAP and any emerging bacterial resistance to antibiotics.

The most common bacteria causing CAP is Streptococcus pneumoniae followed by Hemophilus influenzae and Moraxella catarrhalis, Mycoplasma pneumoniae, Klebsiella, E. coli, Group A streptococcus, Staphylococcus auras, Legionella, Chlamydia and Coxiella organisms follow.

The mode of infection is by aerosol and droplet; lung infection also occurs from another infection site. 

The symptoms start as a runny nose and scratchy throat. Headaches and a low-grade fever develop in a day or two. Most cases of URI recover in 5 to 7 days, but some may develop chills and temperature elevation of 101 to 103 F followed by the productive cough of yellow sputum, and occasional blood streaking of sputum is seen. Chest wall pain on coughing and rapid breathing is noted. At this stage, most people seek medical attention and are hospitalized.

Blood count shows neutrophilic leukocytosis in most bacterial pneumonia, in severe cases, immature neutrophils may appear in the peripheral blood. Chest x-rays show the location and severity of lung infiltrates. Pulse oximetry may show under saturation specially in COPD patients.

Sputum culture and blood cultures identify the causative bacteria but the results take several days, so rapid antigen tests are used to identify common bacterial infections.

In hospitalized patients, IV antibiotic is administered initially, often empirically based on the prevalence of CAP causing bacteria, till bacteriological confirmation is available. As the condition of the patient improves antibiotic is switched to orally. In addition, inhalation of bronchodilators, and chest physiotherapy may be required in COPD and feeble elderly patients to help to raise sputum.

Complications are rare with early intervention and proper selection of antimicrobial agents. But some of these complications are anticipated.

Plural effusion.

 In streptococcus pneumonia, a small pleura effusion is seen. In general plural, effusion resolves along with pulmonary infiltrates. Occasionally thoracentesis is required for rapid clearing. At times Empyema develops when the pleural effusion is associated with Pseudomonas and Staphylococcus pneumonia.

Lung abscess.

 Lung abscess is a special concern in patients with bronchial obstruction from lung cancer and bronchiectasis. Lung abscess is often due to staphylococcus pneumonia. Anaerobic bacterial pneumonia from aspiration is another important source of lung abscesses.

Delayed clearing of pulmonary infiltrates.

 Delayed clearing of pneumonia is often due to mistakes made in bacterial identification, and secondary infections - specially by fungus or drug resistant bacteria. Preexisting severe lung diseases like pneumoconiosis, emphysema, post lobectomy for cancer are special concerns.

Myocarditis.

 Myocarditis was a serious problem before the antibiotic area, It should not happen nowadays.

Septicemia and multiorgan failure.

Immunosuppressed patients from any cause are carefully watched and treated properly in anticipation of such complications. Cardiovascular support therapy, renal function preservation and adequate oxygenation in all vital organs and the brain are undertaken early.

Prevention.

The cessation of smoking is very important. Annual influenza vaccination of the elderly and COPD should be mandatory. Pneumonia vaccines are available. All are encouraged to take the pneumonia vaccine.

Community acquired pneumonia is an annual event. The problem is increasing due to emerging drug resistant bacteria, cigarette smoking in teenagers and in women and the gradual deterioration of air quality from pollution. Children living in proximity to chemical plants and landfills are specially venerable. It is also a drain for limited medical facilities in rural areas and a great financial burden for the uninsured.

Updated: March 2023.

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