How to choose the right treatment for community-acquired pneumonia

Community-acquired pneumonia (CAP) is still a common respiratory infection and a regular reason for acute admissions of patients. CAP remains a significant burden, despite modern antibiotics and preventative measures.

So, while pneumonia can be successfully managed in primary care settings (as most respiratory tract infections are), a group of the sickest patients will present to hospitals as emergency admissions, some of whom will need to be managed in intensive care.

The relevance of this is equally high for commissioners of care as it is for providers: hospital care is relatively expensive when compared with community care; intensive care is particularly so.

Who is at risk?

The key risk factors for CAP are age; pre-existing respiratory diseases (such as asthma or bronchitis); smoking; and other co-morbid illnesses such as diabetes.

CAP can affect the old and the young. It can be severe in the young, although older people who have respiratory compromise of various kinds are particularly vulnerable. There remains a significant burden both of CAP disease and of associated mortality. CAP mortality in the community is much lower for the obvious reason: patients suitable for treatment in those settings are far less sick.

Stopping smoking is a hugely important intervention in preventing CAP, as is vaccination for pneumococcal disease – which is the main but not the only pathogen which causes CAP.

Delivering the optimal outcomes of care and reducing mortality and hospital length of stay in cases of CAP will be affected by what initial choices clinicians make, and how quickly they make them. Understanding the severity of the disease is crucial to choosing the best treatment.

It’s particularly important that patients are started on the most appropriate antibiotics quickly. The first four hours when a patient presents with severe CAP are critical.

Picking the right treatment is a determining factor of health outcomes and potential mortality. It is important to improve clinicians’ knowledge of the right antibiotics for a patient with CAP in both primary and secondary care; but we should be most interested in optimising treatment for acutely-ill patients. In the most sick patients, using the right treatment quickly can be literally a matter of life or death.

The early warning signs of CAP risk in acute settings vary by age of patient. In younger patients, the diagnosis of CAP as opposed to other diseases that cause respiratory distress can be relatively straightforward provided that the clinical team can get a good history because the patient is not too ill or confused.

Accurate diagnosis can become harder as patients get older, either since they may be confused or because other conditions that are more prevalent in older people can mask or cover pneumonia.

Other clinical conditions can cause build-up of fluid in the lungs, such as heart failure. This can be one of the main difficulties in making the right diagnosis: older patients are more likely to have heart disease, and it can become harder to say whether the heart disease or pneumonia is the cause (and the cause can be a bit of both).

The effect of pneumonia on the lungs is similar to a sponge being filled with fluid: the lung should be filled with air, and excess fluid in the lungs compromises the lung’s ability to take in oxygen and get rid of CO2.

As well as fluid in the lungs, hospital clinicians should look for other signs, including cough (which may be productive of phlegm or mucous); shivering and shaking; reporting generally feeling unwell; and possibly pain on the in-breath (indicating inflamed lining of the lung).

One of the main tools used to optimise diagnosis of and care for CAP in the acute setting is scoring for severity of infection is the commonly used CURB65 score. Its name derives from the acronym of:

• Confusion of new onset (defined as an abbreviated mental test score of eight or less)
• Urea greater than 7 mmol/l (19 mg/dL)
• Respiratory rate of 30 breaths per minute or greater
• Blood pressure less than 90 mmHg systolic or diastolic blood pressure 60 mmHg or less
• 65, standing for those aged 65 or older.

The CURB65 score helps determine levels of risk and need for care in relation to the severity of infection: this influences which antibiotic and route of administration should be chosen.

For less severely-ill patients, penicillin-derived oral antibiotics such as amoxicillin or co-amoxiclav can be used (with or without a macrolide antibiotic such as clarithromycin).

For the more severely ill patient, co-amoxiclav should be used intravenously rather than orally (with or without a macrolide antibiotic such as clarithromycin), and alternatives include fluoroquinolones such as intravenous/oral moxifloxacin. Patients with serious CAP must be intensively monitored, to check breathing rate and adequate oxygenation.

To successfully treat CAP, clinicians must ascertain that the infection is present, using a range of tests, which recently have expanded to include serum procalcitonin measurement. If serum procalcitonin is normal then infection is very unlikely. As procalcitonin levels fall, this indicates that CAP is being successfully treated.

This laboratory test is a useful adjunct to the sequence of care: initial assessment of patients: is the disease present? if so, what is the severity?; choice of treatment thereafter. All stages need to happen in a timely fashion. The crucial first four hours of care can be a key determinant of outcome.

Commissioning updated care pathways for CAP

Both commissioners and providers should focus on relatively easy wins available to improve CAP care, which don’t require great upfront investment. Every NHS trust should have a guideline policy on CAP treatment: trusts and indeed commissioners could review a sample of cases for their proximity to optimal care – the right assessment; getting diagnosed and treated as quickly as possible; optimal antibiotic choice.

Current care pathways should be reviewed, to ensure their awareness of recent best practice. Other key areas include staff education, and driving optimal assessment of at-risk patients for CAP every time.

Commissioners and providers who want to measure results in improving CAP treatment and diagnosis clinically and cost-effectively should monitor lengths of stay; CAP mortality; and adherence to treatment guidelines.

Some resources may be necessary to improve care. Commissioners and providers should ask whether the new tests for CAP such as procalcitonin are available; and if so, are they available 24/7? These may require “pump-priming” funding before they demonstrate a return on investment (for example, via reduced unnecessary antibiotic prescribing).

Providers and commissioners should also beware of focusing purely on drug acquisition costs. Looking only at cost may miss whether an appropriate newer or more expensive antibiotic has better outcomes. In terms of total cost to the health system, using the cheapest antibiotic could be misleading if it is associated with higher whole-system costs of morbidity and / or mortality.