Pneumonia: Underestimated And Overlooked

13. February 2018

Pneumonia is a condition often overlooked by doctors. Patients benefit from taking antibiotics even in mild cases. In order to promptly distinguish pneumonia from other infections, one should pay attention to certain points in everyday clinical practice.

The world’s number one causes of death from infections is so-called CAP, ie community-acquired pneumonia. The spectrum ranges from- conditions that are easily treatable by the family doctor to medical emergencies with high lethality. It is important that acute progress of this illness be recognised promptly. Yet many a case can go undetected.

Many patients are unaware

Assistant Professor Dr. Lutz P. Breitling of the German Cancer Research Center Heidelberg arrived at this very conclusion. Together with colleagues he analysed data from the ESTHER study over a period of ten years. Between 2000 and 2002, 9,949 subjects were recruited aged 50 to 75. Doctors offered them routine health check-ups as part of the study. Breitling was able to assume that his participants had not suffered acute symptoms, otherwise they would have needed more urgent medical attention. Auscultation was part of the program. In addition, doctors recorded the living habits of all participants. Further examinations took place after two, five, eight and eleven years.


X-ray of a lobar pneumonia in the left upper lobe © Hellerhoff, Wikipedia

The result: In the cohort, a total of 435 instances of pneumonia occurred, which corresponds to a ten-year incidence of 4.5 percent. The distribution was surprising. 128 cases were addressed by the participants themselves (for instance as previous illnesses), 131 were recognised by the study doctor in a check-up (without the patient having been aware of it) and 176 were confirmed by both the participant and the doctor.

In general, the prospective observational study shows associations but no causalities. Breitling identified age, smoking and heart failure as independent risk factors. A correlation with diabetes mellitus was not statistically significant. Using these results, physicians might be better able to identify high-risk groups. Diagnosing itself is not quite so easy.

Diagnosis: difficult

Pneumonia patients often have a general feeling of illness, they feel weak and have a fever. Headache, muscle and joint pain, cough, purulent sputum or shortness of breath are further symptoms. However these symptoms have little interpretative weight, because they match those of a number of diseases. An examination often reveals dyspnoea with an elevated respiratory rate.

Other indications include tachycardia and hypotension, abnormalities when percussing and rattling noises when auscultating. Assistant Professor Arne Schneidewind from University Hospital Bonn (Germany) indicates in a lecture however that the positive predictive value of these symptoms is below 50 percent. His recommendation: “In view of this, a chest X-ray should also be sought in the outpatient department if CAP is suspected”.

One option employed by doctors to easily determine risk is the CRB-65 index. The CRB-65 index is a measure of the severity of pneumonia and consists of four criteria:

  • confusion (loss of orientation)
  • respiratory rate (breath rate) ≥ 30/min
  • blood pressure; diastolic ≤ 60 mmHg or systolic < 90 mmHg
  • age ≥ 65 years

This in turn results in three risk groups:

  • 0 points according to CRB-65 correlates to total mortality of one percent. Patients can be treated on an outpatient basis.
  • With 1 to 2 points lethality increases up to eight percent. Patients should be referred to the hospital for further clarification.
  • If 3 to 4 points is the result, an immediate inpatient – possibly intensive care – therapy is required. For patients in this group the total mortality rate can be as high as 31 percent.

CRB-56-Index © SlideShare

Mild cases are easily overlooked

In practice, the classification of pneumonia based on the CRB-65 criteria is not always easy. “Acute uncomplicated respiratory tract infections are among the most common acute diseases in primary care, and a large proportion of them are treated with antibiotics”, Professor Dr Michael Moore of the University of Southampton says. A Cochrane review shows that patients with a clearly defined bronchitis diagnosis hardly benefit from these medications. In contrast, doctors overlook up to two thirds of all pneumonia cases in patients where symptoms are less pronounced.

Jolien Teepe from the University Medical Center Utrecht found out that this group of pneumonia patients with few symptoms also benefits from antibiotics. She enrolled 2,055 patients with acute cough in a randomised controlled trial. Of these, 20 were excluded because no X-rays of sufficient quality were available. Radiologically discernible pneumonia was present with 56 out of 1,885 people (3 percent). These were randomly assigned to two groups: taking amoxicillin (n = 23) or placebo (n = 33). Under verum the symptoms improved significantly faster than they did with the medication substitute. The difference was 5 versus 8 days. Symptoms were in particular less severe at the beginning of the illness, compared to the placebo group.

“Patients with radiologically proven, clinically unnoticeable pneumonia benefit from antibiotic treatment in terms of symptom duration and symptom severity”, Teepe summarises. “This suggests that it is worth the effort to identify even milder and less clear cases in primary care”.

When are antibiotics useful?

Moore does not deny that antibiotics are relevant in the clinical treatment of pneumonia. He fears however that GPs, when deceived by signs of what is really more likely to be acute bronchitis of viral origin, would still pull out their prescription pad. In order to help doctors make a quick decision, the researcher has evaluated almost 29,000 patient records, including 720 chest X-ray examinations. In all cases, there was evidence of infection. With 115 patients, pneumonia was confirmed to be the correct diagnosis. In addition, extensive records on vital parameters were available. Antibiotics should therefore be prescribed with the following warning symptoms:

  • Body temperatures over 37.8 degrees Celsius
  • crackling noises in the lungs
  • a pulse of over 100 beats per minute
  • blood oxygen saturation below 95 percent

Sonal N. Shah is interested in similar issues, especially those involving children. She works at Boston Children’s Hospital and Harvard Medical School Boston. Her team evaluated 23 prospective cohort studies involving a total of 13,833 children ranging from one month to 21 years of age. In all cases, in addition to detailed clinical findings, an X-ray of the thorax was available. Although no single symptom reliably distinguishes pneumonia from other respiratory illnesses, hypoxia and difficulty in breathing provide possible indications. Tachypnoea and auscultatory findings are less useful.

Neither Moore nor Shah when employing their criteria can exclude the possibility of pneumonia beyond any doubt. They see the added value of their screenings in that they can quickly identify low-risk or high-risk patients in contexts such as general medicine.

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DocCheck Team

Dear PhD Ljubomir Marcov, Thank you for you question. The study period was from 2000-2010 as stated here: “From 2000 to 2002, nearly 10 000 persons aged 50 to 75 were recruited into the prospective ESTHER cohort study while visiting their family physician for a check-up. The mean duration of follow-up was 10.6 years.” You can find further information through this link: Best wishes, Your DocCheck Team.

#2 |
PhD Ljubomir Marcov
PhD Ljubomir Marcov

Which is the study period of 10 years-2000 to 2002 or 2000 to 2010?

#1 |

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