Pneumonia

Essentials

• This article deals with pneumonia in adults. A separate article is available on pneumonia in children Pneumonia in Children.
• Pneumonia should be considered as a possible diagnosis in a patient who presents with an acute illness with principal symptoms of cough, fever, deteriorating general condition and, particularly in the elderly, confusion and worsening of an underlying disease.
• The signs and symptoms are very similar in pneumonia and acute bronchitis but are usually more severe in pneumonia. The two conditions are different degrees of severity of the same disease process.
• The diagnosis of pneumonia is based on a chest x-ray.
• Pneumonia should initially be assumed to be a bacterial disease, and any treatment prescribed must be effective against pneumococcal infection.
  • In outpatient care, amoxicillin is the first choice antimicrobial drug (for patients with penicillin allergy doxycycline, for patients with severe symptoms either moxifloxacin or levofloxacin).
  • In hospital care, the first choice is intravenous cefuroxime or penicillin G (for patients with penicillin allergy moxifloxacin or levofloxacin).
  • As extensive use of fluoroquinolones involves the risk of problem microbes becoming more common, there must be clear proof of penicillin allergy.
• A repeat x-ray should not be taken sooner than 6-8 weeks after recovery. No repeat x-ray is needed if the patient is below 50 years of age, non-smoking, and the response to treatment is good. A repeat x-ray must always be taken if the clinical symptoms have not improved within 1-2 weeks.

Aetiology

• The most common causative pathogen of community-acquired pneumonia is Streptococcus pneumoniae, followed by Mycoplasma pneumoniae, Chlamydophila pneumoniae and Haemophilus influenzae.
• It is not possible to identify the causative organism on the basis of clinical presentation.
• In 30-35% of patients, a viral infection can be detected by a nucleic acid detection test. In these cases, the disease is usually a mixed infection.
• The microbial aetiology depends essentially on whether the patient contracted the infection in or out of hospital and whether predisposing aetiological factors are present, e.g. possibility of aspiration, chronic pulmonary disease, immunosuppressive therapy or surgery.

Symptoms and findings

• Common signs and symptoms of an acute lower respiratory tract infection include
  • cough
  • purulent sputum
  • fever (often higher than 38.0°C; may be absent in an elderly patient)
  • dyspnoea
  • wheezing
  • chest pain.
• Pneumonia should be suspected if, in addition to the above symptoms
  • the illness has affected the patient's general health
  • the symptoms have emerged rapidly
  • the symptoms of respiratory tract infection have worsened again
  • the patient has additional risk factors (age, underlying medical conditions).
• In the elderly, confusion, abdominal symptoms, overall poor health or worsening of an underlying disease may be the most prominent symptoms. Fever is absent in up to every third patient over 65 years with pneumonia.
• Auscultation usually reveals fine crackles or crepitations, but the auscultation findings may also be normal (in one in three patients).

Diagnosis

• Pneumonia is likely and antimicrobial treatment should be started if clinical findings are clear (CRP > 100 mg/l, oxygen saturation HASH(0x2fcf4d8) 96%, respiration rate HASH(0x2fd7118) 16/min).

• A definite pneumonia diagnosis is based on chest x-ray. Whenever pneumonia is suspected a chest x-ray is indicated, provided that the investigation is feasible and within reasonable reach. Suggestive evidence regarding some other, possible lung disease is obtained at the same time.
• Lack of infiltrates does not exclude pneumonia if the clinical picture and laboratory findings suggest it.

Differential diagnosis

• Diseases to be considered in the differential diagnosis of pneumonia are presented in table T1.

Antimicrobial treatment

• The choice of antimicrobial treatment in community-acquired pneumonia is presented in tables T2 and T3.

• Any treatment prescribed must be effective against pneumococcal infection. Other causative agents must be considered if there are clinical or epidemiological reasons to suspect their presence. Pneumococcal infection cannot be definitely excluded even during epidemics clearly caused by Mycoplasma or Chlamydophila pneumoniae.
• The first dose of oral medication should be given in the doctor's office already.
• If the patient's condition does not improve with the first-line drug within 2-4 days, antimicrobial medication that is effective against Chlamydophila pneumoniae and Mycoplasma should be added to the regimen.
• Parenteral antimicrobials are indicated for patients whose general condition has deteriorated or who have a concomitant disease that affects the immune system. After intravenous medication, drugs that are used for the treatment of pneumonia at home should be used.
  • Aspiration pneumonia is treated on a hospital ward with the same principles as community-acquired pneumonia. If treatment response is poor and there is a strong suspicion of aspiration, metronidazole may be combined to the antimicrobial treatment.
• Cefalexin is not recommended as first-line treatment in uncomplicated pneumonia because its spectrum is too broad and its efficacy against pneumococci is inferior to that of amoxicillin. It can, however, be considered in a patient with penicillin allergy for further antimicrobial treatment after intravenous administration at a minimum dose of 750 mg 3 times daily.
• Ciprofloxacin is not suitable in community-acquired pneumonia as it is not sufficiently effective against pneumococci.
• Levofloxacin and moxifloxacin are also effective against pneumococci. However, they should be reserved for patients with reliably, through careful history taking, confirmed penicillin allergy and for use should the resistance of pneumococci against penicillin increase.
  • Widespread use of these drugs would also jeopardise the treatment of urinary tract infections and infections caused by Gram-negative bacteria.
• As 10-15% of pneumococci are resistant to the macrolides, use of macrolides alone is not recommended. Country/region-specific differences may exist in the level of resistance to antimicrobials.

Other treatment

• Assess the need for oxygen therapy (pulse oximetry, blood gas analysis) in inpatients.
• Treat any dehydration.
• Avoid unnecessary antipyretic and antitussive medication.
• Treat underlying diseases (heart failure, diabetes).

Indications for hospital treatment

• Choice of the place of treatment is principally based on the assessed severity of the pneumonia and the facilities available to carry out the planned treatment.
  • Successful outcome of home care depends on the home circumstances and the availability of help with daily activities if the patient's performance capacity is impaired.
• In pneumonia with rapid onset (symptoms developing within a few hours), the patient should always be quickly referred to hospital because of suspected pneumococcal disease.
  • In patients aged 50 years or less, respiratory rate HASH(0x2fd7118) 20/min and oxygen saturation HASH(0x2fcf4d8) 92% are suggestive of severe disease.
  • Moreover, a CRP concentration of more than 100 mg/l may be a sign of severe or quickly progressing pneumonia.
• A severe pneumonia should be suspected and the need for hospital treatment considered if the patient has
  • any of the following signs of severe pneumonia:
    • confusion or reduced level of consciousness
    • respiratory rate 20/min or higher
    • systolic blood pressure below 90 mmHg
    • pulse rate over 105/min
    • body temperature < 36°C or > 38.5°C
    • blood leucocyte count < 3 × 10⁹ /l or > 15 × 10⁹ /l.
  • severe underlying disease (severe pulmonary disease, cancer, hepatic, renal or cardiac failure, cerebrovascular disorder or immunosuppression [prednisone dose 10 mg/day or more] or other immunodeficiency)
  • extensive changes in several pulmonary lobes or in both lungs
  • poor general condition without the findings described above.
• Hospitalisation may be indicated in pneumonia with mild symptoms if the patient presents with any of the following:
  • vomiting which prevents the intake of medication
  • dyspnoea and other complications
  • problems with differential diagnosis
  • severe primary disease
  • immunosuppression
  • unsatisfactory home situation.

Follow-up

• It is difficult to predict the course of pneumonia. Regardless of the chosen treatment, follow-up must be arranged for all patients, as well as the possibility of seeking examination and treatment again if recovery does not proceed as expected.
• In inpatients, intravenous administration is changed to oral medication as soon as the patient is haemodynamically stable, there are clinical signs of recovery and the patient is able to swallow medication .
• Antimicrobial treatment should continue for 5 to 7 days, at least. Treatment can usually be discontinued after 10 days. Medication must not be withdrawn before the patient has had 2-3 days without fever.
• Treatment response is evaluated after 2-3 days. The evaluation is based on the clinical picture. CRP concentration starts to decrease only after 3-4 days.
• If there is no response to antimicrobial treatment, the following questions should be dealt with:
  • are there signs of a complication; or does the patient possibly have some other disease resembling pneumonia;
  • does the treatment cover Chlamydia pneumoniae and Mycoplasma?
• Consider any complications in hospitalised or very ill patients (pleural effusion Pleural Effusions and Thoracentesis, empyema, pulmonary abscess). Do not hesitate to consult a specialist.
• A repeat x-ray is indicated in patients over 50 and smokers but no sooner than 6-8 weeks from the end of treatment because any changes in the chest x-ray disappear slowly. A repeat x-ray is always indicated no later than after 2 weeks if the symptoms have not improved significantly by that time.
• Recovery often takes a long time, and sick leave must be extended accordingly.

Prevention

• Risk groups must receive influenza vaccination.
• Pneumococcal conjugate vaccine prevents severe pneumococcal diseases and pneumonia. It is recommended for all persons who have previously had community-acquired pneumonia requiring hospitalization and for persons who are at great risk of acquiring a severe pneumococcal infection or a complication associated with such an infection.
  • These include e.g. patients who have
    • chronic cardiac or pulmonary disease
    • diabetes
    • liver failure
    • removed or non-functioning spleen
    • HIV infection or other immunodeficiency
    • undergone organ or tissue transplantation
    • permanent systemic glucocorticoid or other immunosuppressive medication
    • age at least 65 years
    • permanent place in a care institution.
  • The vaccine is administered in one dose. No revaccinations are required.
• Smoking cessation Smoking Cessation
• Hand hygiene