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Three Part Question

In [adults with suspected pneumonia], is [history and physical examination alone] adequate to [make a diagnosis of pneumonia?]

Clinical Scenario

A 25 year-old man presents with a fever and cough productive of yellowish sputum. You take a history and examine the patient. You wonder whether it is possible to rule in or rule out pneumonia without the need for a chest x-ray, to save time, money and radiation.

Search Strategy

Medline 1950 to December 7, 2008 using the OVID interface.
(exp pneumonia/ or pneumonia.mp)

AND(exp radiography, thoracic/ OR ((exp thorax/ OR chest.mp OR thora*.mp) AND (exp x-rays/ OR xray*.mp OR radiogra*.mp)))

AND (exp physical examination/ OR ((clinical or physical) AND (exam* or sign*)).mp)

AND (exp diagnosis/ OR diagnos*.mp)

Limit to Humans and English

Search Outcome

727 papers were identified. Nine were relevant to the three part question, two of which were included in the systematic review. [4] Seven papers have therefore been summarized in the table.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
O'Brien 2006 USA	350 adults in outpatients and the ED, with acute respiratory symptoms and positive chest radiographic results were enrolled as positive cases. An equal number of age-matched controls with acute respiratory symptoms but negative radiographic results were included.	Prospective, blinded study. Physicians recorded clinical indicators before obtaining chest radiographs. Chest radiographs were interpreted by radiologists blinded to the clinical findings.	Sensitivity of clinical diagnosis	95%	1. Physician’s clinical judgement determined which patients require chest radiographs rather than established predetermined guidelines so that the findings would best reflect current practice patterns. 2. Classification of patients with acute respiratory symptoms and equivocal radiographic findings as positive cases. 3. Lack of validation of the prediction rule (needs to be interpreted with caution)
			Specificity of clinical diagnosis	46%
			Odds ratio	24.9
Lieberman et al 2003 Israel	250 ambulatory patients with febrile respiratory tract infections who attended their primary care physician or the emergency department.	Prospective clinical study. Chest radiographs read by pulmonologist and radiologist were blinded to clinical data and assessments of the patient.	Sensitivity of diagnosis	74% (49-90%)	1. Chest radiograph used as gold standard can be insensitive and nonspecific 2. Wide variety of practice may occur between different physicians 3. No mention on what the clinical indicators for the diagnosis was. 4. Physicians were not blinded to the study.
			Specificity of diagnosis	84% (78-88%)
			Negative predictive value compared to chest x-ray	97% (94-99%)
			Positive predictive value compared to chest x-ray	27% (16-42%)
Hopstaken et al 2003 Netherlands	246 patients who presented to their GP with signs and symptoms of LRTI. GPs recorded extensive medical history and performed physical examination.	Prospective clinical study. Chest radiographs of the patients made on the third day after inclusion which were read by radiologists blinded to the clinical status formed the gold standard.	Dyspnoea	Odds Ratio 0.7 (95% CI 0.3-1.6 ) PPV 12.2% NPV 83.6%	1. There may be interobserver variation in clinical findings. 2. Chest radiograph used as a standard reference may be insensitive and non-specific.
			Recent cough	Odds Ratio 3.8 (95% CI 1.0-13.8) PPV 36.4% NPV 86.9%
			Fever	Odds Ratio 1.8 (95% CI 1.1-5.4) PPV 17.6% NPV 89.2%
			Diarrhoea	Odds Ratio 3.5 (95% CI 1.2-10.0) PPV 31.6%
			Sputum purulence	Odds Ratio (95% CI ) PPV NPV
			Auscultation abnormality	Odds Ratio 2.0 (95% CI 0.6-6.9%) PPV 14.2% NPV 92.3%
			Crackles	Odds Ratio 1.5 (95% CI 0.7-3.7) PPV 18.0% NPV 87.6%
			Respiration rate >20/min	Odds Ratio 0.8 (95% CI 0.1-6.8) PPV 11.1% NPV 86.8%
			Percussion dullness	Odds Ratio 4.5 PPV - NPV 100%
			Bronchial breathing	Odds Ratio 1.4 (95% CI 0.7-3.4) PPV 17.2% NPV 87.8%
Okimoto et al 2006 Japan	Okimoto et al, 2006, Japan 79 outpatients presenting with at least one of following clinical features of pneumonia: fever, cough, sputum, chest pain, dyspnoea and coarse crackles and who underwent CXR to detect pneumonia were examined retrospectively. Retrospective case study of adult patients with one of the recognized clinical features of pneumonia such as fever, cough, sputum, chest pain, dyspnoea or coarse crackles and who underwent CXR. Sensitivity of the four clinical features ( fever, cough, sputum and coarse crackles) 91.7% 1. Small sample size 2. Chest x-ray as gold standard which can be insensitive and nonspecific 3. The study states that the chest x-rays were read by one or more physicians to confirm the presence or absence of pneumonia. Having only one physician may introduce inaccuracies. 4. No mention of blinding.	Retrospective case study of adult patients with one of the recognized clinical features of pneumonia such as fever, cough, sputum, chest pain, dyspnoea or coarse crackles and who underwent CXR.	Sensitivity of the four clinical features ( fever, cough, sputum and coarse crackles)	91.7%	1. Small sample size 2. Chest x-ray as gold standard which can be insensitive and nonspecific 3. The study states that the chest x-rays were read by one or more physicians to confirm the presence or absence of pneumonia. Having only one physician may introduce inaccuracies. 4. No mention of blinding.
			Specificity of the four clinical features ( fever, cough, sputum and coarse crackles)	92.7%
Graffelman et al 2007 Netherlands	145 adult patients with signs and symptoms of lower respiratory tract infection who attended a primary care physician.	Prospective clinical study. After inclusion of the patients in the study, investigators visited the patients within 24 hours for further history, physical examination and investigations. Chest X-rays were also taken later and results were confirmed by two radiologists. Six different prediction rules from 5 studies were applied to determine their usefulness compared with the chest x-ray as the gold standard.	Predictive Values of the 6 models using signs and symptoms:		1. Possible bias in the setting. Some of the studies were held in different places such as the US and Spain where the organization of medical care is different from the Netherlands. Selection bias could have been introduced because there were different prerequisites for the inclusion of patients. 2. Chest radiography was used as the standard reference to confirm the diagnosis but it may be insensitive and nonspecific. 3. Treatment may have influenced results because how quickly antibiotic use affected radiological findings remains unclear. Nearly all patients in the patients were treated with antibiotics.
			Singal	PPV (95% CI) - NPV (95% CI) 80% (73%-87%)
			Heckerling	PPV (95% CI) 24%(11%-38%) NPV (95% CI) 85% (77%-93%)
			Melbye	PPV (95% CI) 17%(6%-36%) NPV (95% CI) 79% (70%-a6%)
			Gonzalez Ortiz	PPV (95% CI) 23% (15%-31 %) NPV (95% CI) 88%(74%-100%)
			Hopstaken I	PPV (95% CI) 43% (17%-69%) NPV (95% CI) 83% (76%-90%)
			Hopstaken II	PPV (95% CI) 47%(23%-71%) NPV (95% CI) 84%(77%-91%)
Metlay et al 2003 USA	Systematic review on studies of patients suspected of having pneumonia which evaluated clinical signs for diagnostic accuracy. The gold standard was chest radiography.	Systematic Review	Fever	LR+ 1.7-2.1 LR – 0.6-0.7	1. Only Medline was searched. 2. Confidence intervals were not stated 3. Chest radiograph was used as the gold standard which can be insensitive or non-specific. 4. There was no attempt to meta-analyse the data.
			Chills	LR+ 1.3-1.7 LR – 0.7-0.9
			Tachypnoea	LR+ 1.5-3.4 LR – 0.8
			Tachycardia	LR+ 1.6-2.3 LR – 0.5-0.7
			Hyperthermia	LR+ 1.4-4.4 LR – 0.6-0.8
			Dullness to percussion	LR+ 2.2-4.3 LR – 0.8-0.9
			Decreased breath sounds	LR+ 2.3—2.5 LR – 0.6-0.8
			Crackles	LR+ 1.6-2.7 LR – 0.6-0.9
			Rhonchi	LR+ 1.4-1.5 LR – 0.8-0.9
Muller 2007 Switzerland	545 patients with suspected lower respiratory tract infection, admitted to the emergency department of a university hospital in Basel, Switzerland. Gold standard of CAP (community acquired pneumonia) was defined as: one or several of the following: cough, sputum production, dyspnea, core body temperature >38oC, auscultatory findings of abnormal breath sounds and rales, leukocyte count >10 or <4 x 109 cells L-1 and an infiltrate on chest radiograph.	Preplanned post-hoc analysis of data from two randomized prospective studies. Patients with clinically suspected lower respiratory tract infections and radiologically confirmed CAP were analyzed. Chest radiographs were screened by physician in charge and reviewed by senior radiologist blinded to all clinical and laboratory findings.	AUC (Areas under the receiver operating characteristic curve) of a clinical model including fever, cough, sputum production, abnormal chest auscultation and dyspnea.	0.79 (95% CI, 0.75-0.83)	1. There may be interobserver variation in clinical findings. 2. Chest radiograph used as a standard reference may be insensitive and non-specific.

Comment(s)

It has always been said that good history taking and physical examination are the basis of a competent physician. In a patient with respiratory tract infection, how well do these methods fare in order for us to correctly diagnose pneumonia? Studies have shown conflicting results. Some show a reasonable sensitivity and specificity to diagnose or to rule out pneumonia while others don’t. These results though, are affected by the debatable concern of whether chest radiography which is used as the gold standard, is sensitive or specific enough. Interobserver variation could also have affected the results. Ultimately, the results may guide management but there is no consensus in which we can definitely rule out or rule in pneumonia with clinical methods.

Editor Comment

KMJ

Clinical Bottom Line

In the Emergency Department, pneumonia cannot be dependably confirmed or excluded by history and physical examination alone. However, with a good follow up service it may be reasonable to make a diagnosis on clinical grounds alone.

References

1. O’Brien WT Sr, Rohweder DA, Lattin GE Jr, Thornton JA, Dutton JP, Ebert-Long DL, Duncan MD. Clinical indicators of radiographic findings in patients with suspected community-acquired pneumonia: who needs a chest x-ray? J Am Coll Radiol 2006; 3(9): 703-706.
2. Lieberman D, Shvartzman P, Korsonsky I, Lieberman D. Diagnosis of ambulatory community-acquired pneumonia: Comparison of clinical assessment versus chest x-ray. Scand J Prim Health Care 2003; 21: 57-60.
3. Hopstaken RM, Muris JW, Knottnerus JA, Kester AD, Rinkens PE, Dinant GJ. Contributions of symptoms, signs, erythrocyte sedimentation rate, and C-reactive protein to a diagnosis of pneumonia in acute lower respiratory tract infection. Br J Gen Pract 2003; 53(490): 358-364.
4. Okimoto N, Yamato K, Kurihara T, Honda Y, Osaki K, Asaoka N, Fujita K, Ohba H. Clinical predictors for the detection of community-acquired pneuomina in adults as a guide to ordering chest radiographs. Respirology 2006; 11(3): 322-324.
5. Graffelman AW, le Cessie S, Knuistingh Neven A, Wilemssen FE, Zonderland HM, van den Broek PJ. Can history and exam alone reliably predict pneumonia? J Fam Pract 2007; 56(6): 465-470.
6. Metlay JP, Fine MJ. Testing strategies in the initial management of patients with community-acquired pneumonia. Ann Intern Med 2003; 138(2): 109-118.
7. Muller B, Harbarth S, Stolz D, Bingisser R, Mueller C, Leuppi J, Nusbaumer C, Tamm M, Christ-Crain M. Diagnostic and prognostic accuracy of clinical and laboratory parameters in community-acquired pneumonia BMC Infect Dis 2007; 7: 10