Diagnostic criteria

 

The "gold standard" for diagnosis of CAP is chest radiography. If pneumonia is suspected based on history of present illness, subjective symptoms, and physical exam, the clinician should obtain a standard chest x ray with PA and lateral views. Patients that may benefit from a chest xray include the following:

(Watkins & Lemonovich, 2011)

On plain films, typical bacteria may be suspected when lobar consolidation, cavitation, or pleural effusion is present. Diffuse infiltration (bilateral "white outs") are more often associated with an atypical pathogen.

Left: Lobar consolidation in the right lower lobe

Right: Bilateral infiltrates (aka: "white outs")

 

A normal chest xray; no pneumonia present

 

In the outpatient setting, sputum cultures are not indicated. If the clinician suspects a pathogen that would alter the patient's treatment regimen from the guidelines, laboratory testing can be performed. Clinical findings that may indicate specific laboratory evaluation can be found in table 3 of the article by Watkins & Lemonovich (2011). Empiric therapy   after diagnosis via chest radiography is generally the standard.

Severity index- Inpatient vs. outpatient

Pneumonia is an illness with considerable morbidity and mortality. After diagnosis is confirmed, it is important to assess whether or not outpatient treatment is safe. Patients with acute illness may need hospitalization. Both the Pneumonia Severity Index and the CURB-65 scales can be used to assist the clinician in determining whether inpatient or outpatient treatment is appropriate.

Pneumonia Severity Index (PSI)

The PSI classifies the patients risk from class I through V. Class I patients can be treated at home with oral antibiotics. Classes II and III should be treated with either brief hospitalization (~24 hrs) or treated at home with IV antibiotics. Classes IV and V should be hospitalized. The PSI algorithm is listed below:

Step 1: Stratify to Risk Class I vs. Risk Classes II-V

Presence of:

Over 50 years of age

Yes/No

Altered mental status

Yes/No

Pulse ≥125/minute

Yes/No

Respiratory rate >30/minute

Yes/No

Systolic blood pressure <90 mm Hg

Yes/No

Temperature <35°C or ≥40°C

Yes/No

History of:

Neoplastic disease

Yes/No

Congestive heart failure

Yes/No

Cerebrovascular disease

Yes/No

Renal disease

Yes/No

Liver disease

Yes/No

If any "Yes", then proceed to Step 2

If all "No" then assign to  Risk Class I

Step 2: Stratify to Risk Class II vs III vs IV vs V

Demographics

Points Assigned

If Male

+Age (yr)

If Female

+Age (yr) - 10

Nursing home resident

+10

Comorbidity

Neoplastic disease

+30

Liver disease

+20

Congestive heart failure

+10

Cerebrovascular disease

+10

Renal disease

+10

Physical Exam Findings

Altered mental status

+20

Pulse ≥125/minute

+10

Respiratory rate >30/minute

+20

Systolic blood pressure <90 mm Hg

+20

Temperature <35°C or ≥40°C

+15

Lab and Radiographic Findings

Arterial pH <7.35

+30

Blood urea nitrogen ≥30 mg/dl (9 mmol/liter)

+20

Sodium <130 mmol/liter

+20

Glucose ≥250 mg/dl (14 mmol/liter)

+10

Hematocrit <30%

+10

Partial pressure of arterial O2 <60mmHg

+10

Pleural effusion

+10

∑ <70 =  Risk Class II

∑ 71-90 =  Risk Class III

∑ 91-130 =  Risk Class IV

∑ >130 =  Risk Class V

(http://en.wikipedia.org/wiki/Pneumonia_severity_index)

CURB-65

The CURB-65 scale is simpler to determine pneumonia severity; however, it is less sensitive than the PSI. Clinicians should assign 1 point for each criteria met by the patient.

If the individual scores 0-1 points, outpatient treatment is appropriate. 2 points indicates hospitalization and inpatient treatment. Greater than or equal to 3 points warrants inpatient treatment in the ICU.


Click to close