Respiratory Medicine Made Simple : Pneumonia : Clinical Examination, Investigations and Management

 Pneumococcal pneumonia presents classically as lobar or segmental consolidation.

Multiple , non-contiguous and sometimes bilateral segments may be affected with multilobar involvement being a poor prognostic factor.

The absence of an air bronchogram within an area of consolidation suggests exudate or pus filling the conducting airways aside from Streptococcus pneumonia , organisms commonly responsible for this appearance include Staphylococcus and Gram negative organisms.

Early cavitation in an area of consolidation is typical ofstaphylococcal infection but consider Gram negative organism such as Klebsiella and donot forget Tuberculosis.

Also consider Aspiration pneumonia or proximal bronchial obstruction eg due to carcinoma or a foreign body.

A variety of Radiographic patterns are described in Mycoplasma pneumonia & in Lgionnaire”s disease.

The presence of pleural fluid is suggestive of bacterial aetiology and a diagnostic tap should be performed if this is anything more than trivial in size.

In pneumococcal pneumonia the radiograph maybe normal at presentation even in the presence of a classical history and signs of consolidation on examination only to become abnormal over the next few hours.

Routine blood tests :

Full blood count

Anemia will compound impared tissue oxygen delivery and white cell count is likely to be elevated.

However a patient with overwhelming sepsis may have a normal white cell count.

Electrolytes and Renal function

Uremia is a bad prognostic sign in pneumonia

Hyponatremia is another non-specific marker of severity of infection and is also a particular feature of Legionaires disease.

Liver function Tests :

Derangement of liver enzymes maybe seen in any severe sepsis but transient hepatitis is seen as a part of multisystem involvement in atypical infections such as Legionairres disease.

Also inflammatory markers such as CRP is a more sensitive marker of severity of pneumonia than an increased temperature or a white cell count.

Microbiological Tests :

Sputum microscopy and culture

If sputum is obtainable,it is important to send early in infection

And do a sputum for AFB test / Acid fast bacilli

Blood cultures

Urinary assays of specific antigens : pneumococcal antigen and Legionella antigen

Serological testing : Send acute and convalescent titres for atypical serology

Pleural fluid if there is significant effusion.

Management

General management and resuscitation if needed.

CURB -65 score

Assessment using CURB-65 is vital as a prognostic indicator

Confusion

Mini mental scale Examination < 8

Or new disorientation in person , place and time

Urea > 7 mmol/l

Respiratory rate > 30 / minute

BP systolic < 90 mm Hg or

Diastolic < 60 mmHg

Age > 65 yrs

Score 1 point for each feature present.

A score of 3 – 5 suggests severe pneumonia,

Antibiotics :

Antibiotics should be given without delay with the choice guarded by the BTS guidelines

And / or local knowledge of of the pathogens commonly implicated.

Always consult local prescribing policies in addition to obtaining microbiological advice as necessary.

CURB-65 score 1 or 2 in the moderately sick patient ,oral amoxicillin and a macrolide should be given.

In those patients allergic to penicillin, a fluoroquinolone should be given ie levofloxacin

CURB 65 score 3 or more

In the more severely ill patient , co-amoxiclav or a third generation cephalosporin should be given intravenously in conjunction with a macrolide.

In patients who are penicillin allergic, an intravenous fluoroquinolone in addition to a macrolide shoukd be considered.

If Legionaires disease is considered, then intravenous Erythromycin 1 Gram every 6 hours should be considered.

If there is any suggestion of preceding influenza , consider adding a specific antistaphylococcal antibiotic eg Fluclocloxacillin.

If Gram negative infection or aspiration is suspected , then a 3rd Generation Cephalosporin is the antibiotic of choice.