Pneumonia Case File

Pneumonia Case File

Eugene C. Toy MD, Donald Briscoe, MD, FA  AFP, Bruce Britton, MD, Joel J. Heidelbaugh, MD, FA  AFP, FACG

Case 24

A 61-year-old woman presents to the emergency room (ER) complaining of cough for 2 weeks. The cough is productive of green sputum and is associated with sweating, shaking chills, and fever up to 102°F (38.8°C). She was exposed to her grandchildren who were told that they had upper respiratory infections 2 weeks ago but now are fine. Her past medical history is significant for diabetes for 10 years, which is under good control using oral hypoglycemics. She denies tobacco, alcohol, or drug use. On examination, she looks ill and in distress, with continuous coughing and chills. Her blood pressure is 100/80 mm Hg, her pulse is 110 beats/min, her temperature is 101°F (38.3°C), her respirations are 24 breaths/min, and her oxygen saturation is 97% on room air. Examination of the head and neck is unremarkable. Her lungs have rhonchi and decreased breath sounds, with dullness to percussion in bilateral bases. Her heart is tachycardic but regular. Her extremities are without signs of cyanosis or edema. The remainder of her examination is normal. A complete blood count (CBC) shows a high white blood cell (WBC) count of 17,000 cells/mm3, with a differential of 85% neutrophils and 20% lymphocytes. Her blood sugar is 120 mg/dl.

⯈ What is the most likely diagnosis?

⯈ What is your next diagnostic step?

⯈ What is the next step in therapy?

⯈ What are potential complications to this condition?

ANSWER TO CASE 24:

Pneumonia

Summary: This is a 61-year-old woman with fever, chills, and productive cough. She has an abnormal pulmonary examination and is found to have a high white cell count. Her significant medical history is diabetes mellitus.

• Most likely diagnosis: Community-acquired pneumonia.
• Next diagnostic step: Chest x-ray, sputum Gram stain and culture, and blood cultures.
• Next therapeutic step: Determine whether the patient requires in-patient or out-patient therapy and start antibiotics.
• Potential complications: Bacteremia, sepsis, parapneumonic pleural effusion, and empyema.

ANALYSIS

Objectives

1. Recognize the differential diagnosis of pneumonia.
2. Be familiar with widely accepted decision-making strategies for the diagnosis and management of different kinds of pneumonia.
3. Learn about the treatment and follow-up of pneumonia.
4. Recognize the effects of comorbid conditions.

Considerations

This 61-year-old patient presents with a common diagnostic dilemma: productive cough with green sputum and fever. The first priority for the physician is to assess whether the patient is more ill than the complaint would indicate. Helpful clues to the patient's overall condition include a toxic appearance, using accessory muscles to breathe, and low oxygen saturation. Tachycardia, hypotension, and altered mental status are signs of more critical illness. Cardiopulmonary stabilization must always be addressed.

Fortunately, this patient does not have those alarming symptoms. If a patient has respiratory distress, the physician may need to check arterial blood gases. If the patient has low oxygen saturation, give oxygen by nasal cannula and then proceed to your history and physical examination.

The most common etiology of cough is an upper respiratory tract infection. This patient has several features that make pneumonia more likely, including her age, cough with green sputum, fever with chills, and exposure to close contacts with respiratory infections. The gold standard for diagnosis of pneumonia is the presence of an infiltrate on chest x-ray, although normal x-ray does not exclude the diagnosis. X-rays may be normal early in the course of disease and a patient who is dehydrated may not demonstrate an infiltrate until the patient is adequately rehydrated.

Approach To:

Pneumonia

DEFINITIONS

PNEUMONIA: Infection of lung parenchyma caused by agents that include bacteria, viruses, fungi, and parasites.

PNEUMONITIS: An inflammation of the lungs from a variety of noninfectious causes such as chemicals, blood, radiation, and autoimmune processes.

CLINICAL APPROACH

Bronchitis and pneumonia represent a continuum of lower respiratory infection. The extent of involvement of adjacent lung parenchyma determines whether there is an infiltrate on x-ray.

Pneumonia is defined as an infection of lung parenchyma caused by agents that include bacteria, viruses, fungi, and parasites. It should be distinguished from pneumonitis, which is an inflammation of the lungs from a variety of noninfectious causes such as chemicals, blood, radiation, and autoimmune processes. The occurrence and severity of pneumonia depends on both the state of the body's defense mechanism against infection and the characteristics of the infectious agent. The most common mechanism triggering pneumonia is upper airway colonization by potentially pathogenic organisms that are subsequently aspirated. The type of organism involved depends, in part, on host characteristics.

Community-Acquired Pneumonia

Pneumonia that occurs in persons who are not hospital in-patients or residents of long-term care facilities is defined as community acquired. Community-acquired pneumonias can be either viral or bacterial in etiology, and both can range from a mild to severe presentation. Common viral causes of pneumonia include influenza A and B, adenoviruses, respiratory syncytial viruses, and parainfluenza viruses. The most common bacterial cause of community-acquired pneumonia is Streptococcus pneumoniae (pneumococcus). Other common bacterial etiologies are Mycoplasma pneumoniae, Haemophilus influenzae, and Moraxella cararrhalis. Pneumococcal pneumonia classically causes an illness of acute onset with cough productive of rust-colored sputum, fever, shaking chills, and a lobar infiltrate on chest x-ray. H influenzae is often seen in patients with underlying chronic obstructive pulmonary disease.

M pneumoniae, Chlamydia pneumoniae, and Legionella pneumophila are bacteria that cause what is classified as "atypical" pneumonia. Atypical pneumonia is also caused by several different viruses. The typical pneumonia organisms are more common in the very young and in the older patient. Atypical pneumonias occur more commonly in adolescent or young adult patients. Atypical organisms tend to cause bilateral, diffuse infiltrates, rather than focal, lobar infiltrates, on x-ray.

Health-Care-Associated Pneumonia

Health-care-associated pneumonia includes infections that develop in hospitals, nursing homes, skilled nursing facilities, or other long-term care facilities. The pathogens found in these types of facilities may have multidrug resistance, so the recommended treatments may include extended spectrum antibiotics until sensitivity of causative organism is found. Health-care-associated pneumonia is a major source of morbidity, mortality, and prolonged hospitalization. Risk factors include hospitalization within 90 days, home infusion therapy, dialysis, and being a resident at a nursing home. Risks for drug-resistant organisms include being hospitalized for more than 5 days, antibiotics within the last 90 days, immunosuppresion, and high rates of antibiotic resistance in the community. The causative organisms include the pathogens involved in community-acquired pneumonia as well as aerobic gram negative bacteria (Pseudomonas, Klebsiella, Acinetobacter) and gram-positive cocci such as Staphylococcus aureus. The incidence of drug-resistant organisms, such as methicillin-resistant S aureus (MRSA), is increasing. Avoiding intubation when possible, using oropharyngeal intubation as opposed to nasopharyngeal intubation, keeping the head of the patient's bed elevated during tube feedings, and utilizing infection control techniques, such as careful hand washing and use of alcohol-based hand disinfectants, can reduce risks.

Diagnosis

Patient history in cases of pneumonia commonly includes the symptoms of productive cough, fever, pleuritic chest pain, and dyspnea. The symptoms can be very nonspecific in the very old and very young. In young children, rapid breathing is commonly seen; in the elderly, pneumonia may present as altered mental status.

Sometimes, the history may assist in determining the specific organism involved. An abrupt onset or abruptly worsening illness is seen frequently in pneumococcal pneumonia. Legionella often causes diarrhea, hyponatremia, and elevated liver enzymes along with pneumonia in older patients. S aureus is a common cause of postinfluenza pneumonia.

Physical examination findings can include fever, tachycardia, tachypnea, hypotension, and reduced oxygen saturation. Auscultation of the lungs may reveal rhonchi or rales. Egophony (E to A change) can be a sign of focal lung consolidation, and dullness to percussion may be the result of a pulmonary effusion.

All patients with suspected pneumonia should have a chest x-ray. The presence of an infiltrate can confirm the diagnosis. Absence of an infiltrate does not rule out pneumonia as a diagnosis. A chest x-ray can also identify a pleural effusion, which may be a complication of pneumonia (parapneumonic effusion).

Specific x-ray findings may also lead to consideration of certain etiologic agents or types of pneumonia. As noted previously, lobar infiltrates are more common with typical infections and diffuse infiltrates are more likely with atypical infections. A bilateral, "ground glass" -appearing infiltrate is associated with Pneumocystis jiroveci (formerly known as Pneumocystis carinii) infections, which are seen most often in patients with AIDS. Apical consolidation may be seen with tuberculosis. Pneumonia caused by the aspiration of gastrointestinal contents commonly is seen in the right lower lobe because of the branching of the bronchial tree.

Other testing indicated in patients with pneumonia includes a CBC and a chemistry panel. Specific microbiologic diagnosis is possible with blood or sputum cultures. Cultures have a low sensitivity (many false negatives), but a positive culture can help to guide treatment. Legionella can be confirmed in suspected cases by urine antigen testing.

Treatment

When pneumonia is diagnosed, the initial decision to be made is whether the patient can be treated safely as an outpatient or is hospitalization required. This prediction should be based primarily on mortality and severity prediction scores. Commonly used prediction scoring systems include the CURB-65 mortality prediction tool for patients with community-acquired pneumonia, and the pneumonia severity index (PSI/PORT score), which is the most validated risk assessment tool. It assigns patients to a risk category based on their age, comorbid illnesses, specific examination, and laboratory findings. High-risk comorbidities include neoplastic disease, liver disease, renal disease, congestive heart failure, and diabetes. Physical examination findings taken into consideration are tachypnea, fever, hypotension, tachycardia, and altered mental status. Laboratory findings include a low pH, low serum sodium, low hematocrit, low oxygen saturation, high glucose, high blood urea nitrogen (BUN), and pleural effusion on x-ray. Based on the patient's demographics and individual findings, a risk class and mortality risk is assigned. Low-risk classes (classes 1 and 2) can be safely treated as an outpatient; higher-risk classes (classes 3, 4, and 5) should be hospitalized.

The emergence of drug-resistant pneumococci and the development of new antimicrobials have changed the empiric treatment of community-acquired pneumonia. In healthy persons suitable for outpatient treatment, a macrolide ( clarithromycin or azithromycin) or doxycycline is recommended empiric therapy. If the patient has chronic comorbidities such as diabetes or heart and lung disease, treatments with fluoroquinolones (levofloxacin, moxifloxacin) or the combination of a β-lactam (high-dose amoxicillin, amoxicillin/ clavulanate, cefpodoxime, or cefuroxime) plus a macrolide would be recommended.

For hospitalized patients with community-acquired pneumonia who do not require intensive care unit (ICU) treatment, an intravenous β-lactam ( cefotaxime, ceftriaxone, or ampicillin/sulbactam) and an intravenous macrolide (erythromycin or azithromycin) are recommended. An IV fluoroquinolone with activity against S pneumoniae can be substituted. If the patient is suitable to begin outpatient treatment, the follow-up visit to the office 3 to 4 days later will help to assess response to therapy. Early follow-up chest x-rays are mandatory in those who fail to show clinical improvement by 5 to 7 days, as bronchogenic carcinoma can present with the picture of a typical pneumonia.

Health-care-associated pneumonias require broader antibiotic coverage of the likely pathogens, many of which have developed multiple-drug resistance.

If Pseudomonas is considered a likely cause, such as in a patient with immunocompromise or recent hospitalization with intubation, treatment with an antipneumococcal and antipseudomonal β-lactam (piperacillin/tazobactam, cefepime, imipenem, or meropenem) plus a fluoroquinolone (levofloxacin, moxifloxacin) and/or an aminoglycoside (amikacin or tobramycin and azithromycin) is advised. Methicillin-resistant S aureus may require treatment with vancomycin.

The duration of the treatment is influenced by the severity of illness, the etiologic agent, response to therapy, the presence of other medical problems, and complications of the infection. Community-acquired pneumonia therapy lasts from 5 to 10 days or until the patient is afebrile for at least 72 hours. Two to three weeks of therapy is appropriate for hospital-acquired pneumonias caused by S aureus, Pseudomonas aeruginosa, Klebsiella, anaerobes, M pneumoniae, C pneumoniae, or Legionella species.

Complications

Bacteremia occurs in approximately 25% to 30% of patients with pneumococcal pneumonia. Mortality rates for patients with bacteremia range from 20% to 30%, but can be as high as 60% in the elderly. Parapneumonic pleural effusion develops in 40% of hospitalized patients with pneumococcal pneumonia. Fewer than 5% of cases progress to empyema. If more than a minimal amount of fluid is present, as evidenced by significant blunting of the costophrenic angle on x-ray, it may be necessary to perform a thoracentesis with Gram stain and culture of the pleural fluid. The presence of an empyema usually requires drainage with a chest tube or surgical procedure.

Prevention

Pneumococcal vaccine is recommended for all persons aged 65 and older, all adults with chronic cardiopulmonary diseases, cigarette smokers, and all immunocompromised persons. In addition to the traditional immunization with the 23-valent pneumococcal polysaccharide vaccine for all adults aged 65 and older, the Advisory Committee on Immunization Practices (ACIP) now recommends routine use of the 13-valent pneumococcal conjugate vaccine in a series with the original 23-valent vaccination. Revaccinate 5 years after the initial dose in patients known to be immunocompromised or without a functioning spleen.

Influenza vaccination is recommended in the late fall and winter months for all individuals aged 6 months and older. The association between influenza virus infection and pneumonia is well recognized. The number of cases of invasive pneumococcal disease from influenza peaks in mid-winter, when influenza is prevalent. Influenza virus infection can lead to a secondary pneumonia by facilitating bacterial colonization and impairing host defense mechanisms. S aureus is the most common causative organism in these cases. A prospective study of patients of 65 years and older demonstrated the effectiveness of influenza and pneumococcal vaccination at reducing hospitalizations for pneumonia and at preventing invasive pneumococcal disease.

CASE CORRELATION

• See also Case 2 (Dyspnea, COPD) and Case 19 (Upper Respiratory Infections).

COMPREHENSION QUESTIONS

24.1 A 17-year-old adolescent boy presents to the ER with a temperature of 101.0°F (38.3°C), a deep nonproductive cough, and generalized malaise for 3 days. He doesn't recall being around any particular sick contacts but is around many people in his after-school job in sales and at school. He states that he never had the chicken pox and is unaware of what immunizations he received as a child. He was diagnosed at age 12 with leukemia but has since been healthy. He is worried that his cancer may no longer be in remission. A chest x-ray reveals bilateral, diffuse infiltrates. Which of the following is the most likely cause of illness?

A. Pneumonia caused by S pneumoniae

B. Pneumonia caused by P jiroveci

C. Pneumonia caused by L pneumophila

D. Pneumonia caused by M pneumoniae

E. Pneumonia caused by H influenzae

24.2 A 35-year-old morbidly obese woman returns to clinic with sudden onset of night sweats, chills, shortness of breath, and cough productive of yellowish green sputum. Her vital signs show a temperature of 104.0°F, with a respiratory rate of 30 breaths/min, heart rate of 100 beats/min, pulse oximetry is 93% on room air. She was seen 8 days ago for headache, fever of 102.0°F, nonproductive cough, and myalgias. She was prescribed a dose of oseltamivir for 5 days. She felt better after taking the medication initially but now feels she is getting worse. She is sent to the emergency room for expedited evaluation. Assuming admission for pneumonia, which of the following is the best empiric antibiotic treatment for this patient?

A. A 14-day trial of oseltamivir

B. Azithromycin

C. Penicillin

D. Levofloxacin

E. Ceftriaxone with vancomycin

24.3 A 76-year-old widowed man who lives alone presents to clinic with increasing shortness of breath and chest pain at rest for the past 2 weeks. He has had chronic hypertension and coronary artery disease (CAD) for 20 years for which he takes hydrochlorothiazide (HCTZ), enalapril, and aspirin 81 mg daily. Other medical problems include hyperlipidemia, peripheral vascular disease, and gastroesophageal reflux disease (GERD) which are controlled by lovastatin, warfarin, and omeprazole. Two years ago, he suffered a cerebrovascular accident that was localized to the brain stem. He now has dysphagia and is noted to cough frequently at night. He has no cough at present and has not been able to take his temperature at home. Which of the following is the best next step?

A. Upper endoscopy

B. Removal of angiotensin-converting enzyme (ACE) inhibitor

C. Nitroglycerine patch

D. Chest radiograph

ANSWERS

24.1 D. Bilateral, diffuse infiltrates are more likely to be seen in patients with pneumonia caused by atypical agents, such as Mycoplasma, than in patients with typical pneumonia or aspiration pneumonia. Legionella, another atypical pneumonia, usually is in older patients and the patient did not have diarrhea. It is more likely that the patient contracted an atypical pneumonia than having a relapse of leukemia with such profound immunodeficiency as to have contracted a Pneumocystis infection, with no prior symptoms.

24.2 E. This patient is most likely suffering from postinfluenza pneumonia. Due to the higher risk of mortality associated with morbid obesity and some vital signs indicating risk of sepsis, this patient should be evaluated quickly for possible admission. If admitted for pneumonia, antibiotic coverage should cover for Pneumococcus and S aureus. Levofloxacin would be reasonable for community-acquired pneumonia but does not provide good coverage for staph infections.

24.3 D. This patient most likely has aspiration pneumonia. With impairment of the gag reflex after cerebrovascular accident (CVA), he is more likely to aspirate during sleep, indicated by his cough. His GERD is well controlled by medication, so upper endoscopy is not warranted at this time. Nitroglycerine patches may be indicated if he described symptoms more related to angina. An ACE inhibitor would cause a cough unrelated to the time of day.

CLINICAL PEARLS

⯈ Elderly patients often have fewer or less-severe symptoms or atypical presentations of pneumonia. Consider pneumonia in the differential diagnosis of altered mental status in the elderly.

⯈ Appropriate use of influenza and pneumococcal vaccination reduces the risk of pneumonia in susceptible populations. New vaccination guidelines now recommend both the 23-valent and 13-valent pneumococcal vaccines given in series to all patients 65 and older.

⯈ Consider the diagnosis of empyema in patients with pneumonia and a pleural effusion, especially if the patients continue to have fever despite appropriate antibiotic therapy.

REFERENCES

Chesnutt MS, Prendergast TJ. Pulmonary disorders. In: Papadakis MA, McPhee SJ, Rabow MW, eds. Current Medical Diagnosis & Treatment 2015. New York, NY: McGraw-Hill; 2014. 

Mandell LA, Wunderink RG. Pneumonia. In: Kasper D, Fauci A, Hauser S, et al., eds. Harrison's Principles of Internal Medicine. 19th ed. New York, NY: McGraw-Hill; 2015. Available at: http:// accessmedicine.mhmedical.com. Accessed May 25, 2015. 

Marrie TJ. Pneumonia. In: Halter JB, Ouslander JG, T inetti ME, Studenski S, High KP, Asthana S, eds. Hazzard's Geriatric Medicine and Gerontology. 6th ed. New York, NY: McGraw-Hill; 2009. 

Tomczyk S, Bennett NM, Stoecker C, et al. Use of PCV-13 and PPSV-23 vaccine among adults aged 65 and older: recommendations of the Advisory Committee on Immunization Practices (ACIP) . MMWR Morb Mortal Wkly Rep. 2014:63(37):822-825. 

Watkins RR, Lemonovich TL. Diagnosis and management of community-acquired pneumonia in adults. Am Fam Physician. 2011 Jun 1;83(11):1299-1306.

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