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ANSWERS TO CASE 24:
Pneumonia
Summary: This 61-year-old woman presents with
Fever, chills, and a productive cough with green sputum
Pulmonary examination revealing rhonchi and decreased breath sounds, with dull-
ness to percussion in bilateral bases
A high white cell count
Medical history significant for diabetes mellitus
Exposure to her grandchildren, who had upper respiratory infections 2 weeks ago
Most likely diagnosis: Community-acquired pneumonia (CAP).
Next diagnostic step: Chest x-ray, sputum Gram stain and culture, and blood
cultures.
Next therapeutic step: Determine whether the patient requires inpatient or outpa-
tient therapy and start antibiotics.
Potential complications: Bacteremia, sepsis, parapneumonic pleural effusion, and
empyema.
ANALYSIS
Objectives
1. Recognize the differential diagnosis of pneumonia. (EPA 1, 2)
2. Be familiar with widely accepted decision-making strategies for the diagnosis
and management of different kinds of pneumonia. (EPA 3, 4)
3. Learn about the treatment and follow-up of pneumonia. (EPA 4, 5, 12)
4. Recognize the effects of comorbid conditions. (EPA 1, 12)
Considerations
This 61-year-old patient presents with a common diagnostic dilemma: productive
cough with green sputum and fever. The first priority for the provider 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 clinician 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
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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 pres-
ence of an infiltrate on chest x-ray, although a 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 adequately rehydrated.
APPROACH TO:
Pneumonia
DEFINITIONS
COMMUNITYACQUIRED PNEUMONIA: Pneumonia that occurs in persons
who are not hospital inpatients or residents of long-term care facilities.
HEALTH CAREASSOCIATED PNEUMONIA: Health care–associated pneumonia (HAP) includes infections that develop in hospitals, nursing homes, skilled
nursing facilities, or other long-term care facilities.
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
Pathophysiology
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 depend 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. 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 CAP is Streptococcus pneumoniae (pneumococcus). Other common bacterial etiologies are Mycoplasma pneumoniae, Haemophilus influenzae, and
Moraxella catarrhalis. Pneumococcal pneumonia classically causes an illness of
acute onset with cough productive of rust-colored sputum, fever, shaking chills,
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and a lobar infiltrate on chest x-ray. Haemophilus 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. HAP is a major source of morbidity, mortality, and prolonged hospitalization. Risk factors include hospitalization within
90days, home infusion therapy, dialysis, and being a resident at a nursing home. The
pathogens found in health care facilities may have multidrug resistance, so the recommended treatments include extended-spectrum antibiotics until the sensitivity of the causative organism is found. Risks for drug-resistant organisms include
being hospitalized for greater than 5 days, antibiotics within the last 90days,
immunosuppression, and high rates of antibiotic resistance in the community. The
causative organisms include the pathogens involved in CAP as well as aerobic gramnegative 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 substantial in most communities. The
risk of HAP can be reduced by giving appropriate vaccinations, smoking cessation,
good nutrition, avoiding intubation when possible, and using contact precautions
(hand hygiene, gloving, and gowning).
Clinical Presentation
History. 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. S. aureus is a common cause of postinfluenza
pneumonia.
Physical Examination. 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.
Imaging. All patients with suspected pneumonia should have a chest x-ray or com-
puted tomography scan. The presence of an infiltrate can confirm the diagnosis.
Absence of an infiltrate on x-ray 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). Outpatient facilities with trained primary
care clinicians are using ultrasound to diagnose pneumonia and pleural effusions
with excellent sensitivity and specificity.
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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 infiltrate appearing like “ground glass” is associated with Pneumo-
cystis jiroveci 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.
Laboratory Values. 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 whether hospitalization is required.
This prediction should be based primarily on mortality and severity prediction
scores. Commonly used prediction scoring systems include the CURB-65 Mortal-
ity Prediction Tool for Patients with CAP and the Pneumonia Severity Index (PSI),
which have approximately 75% sensitivity for need for inpatient care. The PSI tool
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 are assigned. Lowrisk classes can be safely treated as an outpatient; higher risk classes should be
hospitalized with possible admission to the intensive care unit (ICU).
Community-Acquired Pneumonia. The emergence of drug-resistant pneumococci and the development of new antimicrobials have changed the empiric treatment of CAP. 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 beta-lactam (high-dose amoxicillin, amoxicillin/clavulanate, cefpodoxime, or
cefuroxime) plus a macrolide would be recommended.
For hospitalized patients with CAP who do not require ICU treatment, an
intravenous beta-lactam (cefotaxime, ceftriaxone, or ampicillin/sulbactam) and
an intravenous macrolide (erythromycin or azithromycin) are recommended. An
intravenous fluoroquinolone with activity against S. pneumoniae can be substituted.
If it is suitable for the patient to begin outpatient treatment, a follow-up visit to the
office 3 to 4 days later will help to assess response to therapy. Early follow-up chest
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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 Pneumonia. HAPs 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 beta-lactam (pipercillin/tazobactam, cefepime,
imipenem, or meropenem) plus a fluoroquinolone (levofloxacin, moxifloxacin)
and/or an aminoglycoside (amikacin or tobramycin and azithromycin) is advised.
MRSA may require treatment with vancomycin or linezolid.
Steroids. As an adjunct, corticosteroids are also used to reduce rates of complications and hospital days. Intravenous steroids (methylprednisolone) used within
36 hours of presentation can reduce the risk of acute respiratory distress syndrome,
mechanical ventilation, and mortality.
The duration of the treatment is influenced by the severity of illness, the etiologic
agent, the response to therapy, the presence of other medical problems, and complications of the infection. CAP 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 they 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 age 65 years
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 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 midwinter, 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 65years of
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age and older demonstrated the effectiveness of influenza and pneumococcal vaccination at reducing hospitalizations for pneumonia and preventing invasive pneumococcal disease.
CASE CORRELATION
See also Case 19 (Upper Respiratory and Ear Infections) and Case 56
(Wheezing and Asthma).
COMPREHENSION QUESTIONS
24.1 A 17-year-old adolescent male presents to the emergency department with a
temperature of 101°F (38.3°C), a deep nonproductive cough, and generalized malaise for 3 days. He does not recall being around any particular sick
contacts but is around many people in his afterschool job 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. pneumonia
B. Pneumonia caused by P. jiroveci
C. Pneumonia caused by L. pneumophila
D. Pneumonia caused by M. pneumonia
E. Pneumonia caused by H. influenza
24.2 A 35-year-old morbidly obese woman patient is being evaluated in the emergency center from an outlying clinic. She was seen 8 days ago for headache,
fever of 102°F, nonproductive cough, and myalgias, for which she was diagnosed with influenza and prescribed oseltamavir for 5 days. She felt better
after taking the medication initially but now feels she is getting worse. She is
sent to the emergency department for expedited evaluation. She states that
she has had night sweats, chills, shortness of breath, and cough productive of
yellowish-green sputum for 3 days. Today, her vital signs show a temperature
of 104 °F, with a respiratory rate of 30 breaths/min, heart rate of 100 bpm,
and pulse oximetry of 93% on room air. Assuming admission for pneumonia,
which of the following is the best empiric antibiotic treatment for this patient?
A. Continuation of oseltamivir for another week
B. Azithromycin
C. Penicillin
D. Levofloxacin
E. Ceftriaxone with vancomycin
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24.3 A 64-year-old man sees you in the office because of a cough he has had for
the past 4 days and a fever that started last night. He is short of breath and
has significant malaise. He is a nonsmoker and has no history of lung disease. His medical history is significant for type 2 diabetes mellitus, which is
well managed with medications and diet. A physical examination reveals an
alert and mildly ill-appearing man who is speaking in complete sentences.
His temperature is 38.1 °C (100.6 °F), pulse rate 95 beats/min, respiratory
rate 22breaths/min, blood pressure 115/70 mm Hg, and oxygen saturation
97% on room air. His heart has a regular rhythm, and respirations appear
unlabored. He has rhonchi in the left lower lung field but has good air movement overall. A chest radiograph reveals a left lower lobe infiltrate. Which one
of the following is the most appropriate setting for the management of this
patient’s pneumonia?
A. Home with close monitoring
B. An inpatient medical bed without telemetry monitoring
C. An inpatient medical bed with telemetry monitoring
D. An inpatient intensive care bed
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 (answer A, S. pneumonia; answer E, H. influenzae) or
aspiration pneumonia. Legionella (answer C), another atypical pneumonia,
generally is seen in older patients, and usually affected patients have diarrhea,
which this patient did not have. 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 (answer B)
with no prior symptoms.
24.2 E. This patient is most likely suffering from postinfluenza pneumonia, which
is often a bacterial process superimposed on the influenza. 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 (answer D) would be reasonable
for CAP but does not provide good coverage for staph infections. Answer
A (continue osteltamivir) would not be effective and puts the patient at
increased risk for further pulmonary decompensation and possibly death.
Answer B (azithromycin) would be effective for a simple CAP in a healthy
patient. Answer C (penicillin) is no longer used to treat pneumonia due to the
high rate of resistance.
24.3 A. In an outpatient setting, clinical decision tools like the Confusion, Urea,
Respiration, Blood pressure-65 (CURB-65) score are an easy way to assess
risk and should always be used. In this scenario, the patient does not clinically
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appear markedly ill, and his vital signs and physical examination do not fit
any criteria for increased risk. Using the CURB-65, he is not confused (C), we
do not have the BUN value (U), respiratory rate is not > 30 breaths/min (R),
his systolic blood pressure is higher than 90 mm Hg (B), and his age is not 65
or older (65). With possibly 1 point depending on the BUN value, he can be
observed as an outpatient.
CLINICAL PEARLS
» Elderly patients often have fewer or less severe symptoms or atypical pre-
sentations of pneumonia. Consider pneumonia in the differential diagnosis of altered mental status in the elderly.
» Appropriate use of influenza and pneumococcal vaccinations reduce the
risk of pneumonia in susceptible populations. Current 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.
» S. pneumoniae is the most common cause of community acquired
pneumonia (CAP).
» Organisms associated with ventilator associated pneumonia (VAP)
include E. coli, Pseudomonas, Klebsiella, and MRSA.
REFERENCES
Chesnutt AN, Chesnutt MS, Prendergast NT, Prendergast TJ. Pulmonary disorders. In: Papadakis
MA, McPhee SJ, Rabow MW, eds. Current Medical Diagnosis & Treatment 2019. New York, NY:
McGraw Hill; 2019: Chap. 9.
Kaysin A, Viera A. Community acquired pneumonia in adults: diagnosis and management. Am Fam
Physician. 2016;94(9):698-706.
Mandell LA, Wunderink RG. Pneumonia. In: Jameson J, Fauci A, Kasper D, Hauser S, Longo D,
Loscalzo J, eds. Harrison’s Principles of Internal Medicine. 20th ed. New York, NY: McGraw Hill;
2018: Chap. 121. https://accessmedicine-mhmedical-com.evms.idm.oclc.org/content.aspx?bookid
=2129§ionid=184041853 Accessed May 9, 2020.
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.
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CASE 25
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A 38-year-old woman presents to the office with complaints of weight loss,
fatigue, and insomnia of 3 months’ duration. She feels tired most of the time and
frequently does not want to get out of bed. Conversely, she has been staying up
late at night because she cannot fall asleep. She feels she is performing poorly at
work as an administrative assistant and states that she has trouble remembering
things. She does not enjoy going outdoors or being with friends like she used
to and avoids social activities. She denies any recent medication, illicit drug, or
alcohol use. She feels intense guilt regarding past relationships, believing that
it was her fault they failed. She states she has never thought of suicide but has
begun to feel increasingly worthless.
Her vital signs and general physical examination are benign, except she
becomes tearful while discussing her symptoms. Her mental status examination
is significant for depressed mood, psychomotor slowing, and poor concentration.
▶ What is the most likely diagnosis?
▶ What is your next step?
▶ What are important considerations and potential complications of the likely
condition?
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