Pneumonia

8 Pneumonia



Background


This is an extremely common presentation to the on-call doctor. It can present on admission wards as community-acquired pneumonia or complicate a ward stay in any patient – those undergoing surgery are at particular risk of postoperative infection, particularly with thoracoabdominal surgery as the cough reflex is impaired and respiration is often limited by pain.



Clinical features



Symptoms


The symptoms include shortness of breath (SOB), productive cough (green sputum), haemoptysis, fever, rigors and pleuritic chest pain.



Signs


There are signs of local consolidation (coarse crackles, bronchial breathing, increased vocal resonance).



Differential diagnosis


This condition has both a clinical and radiological differential diagnosis. The diagnosis is made with a combination of clinical and radiological findings.



Clinical differentials to consider



• Pulmonary embolus – pleuritic chest pain/SOB/haemoptysis but sudden onset, usually no fever. The CXR is usually normal (see Chapter 24), but see also below.

• Cardiac failure – SOB, sudden onset; often many specific signs and symptoms such as orthopnoea/paroxysmal nocturnal dyspnoea (PND), displaced apex, pitting oedema, added heart sounds, raised JVP. Radiology shows specific features (see Chapter 26).


Radiographic differentials



• Any cause of fluid in the alveoli – ‘airspace disease’.

• Blood in the alveoli – traumatic contusion – should be easy to differentiate from pneumonia on clinical grounds.

• Cardiac failure – see above.

• Tumour – bronchioloalveolar carcinoma. It can be radiologically indistinguishable from pneumonia. The difference is that it does not resolve with treatment.

• Infarction – in pulmonary embolism – usually wedge shaped and may not be as extensive as infection.


Radiological features


Pneumonia can have several radiographic patterns. It can be confined to one lobe (lobar pneumonia) or be patchy and involve several lobes (bronchopneumonia). It can also cause a white-out of the hemithorax (see Chapter 9).


Fig. 8.1 is an example of both a white-out and right lower lobe pneumonia.


image

Fig. 8.1A This radiograph demonstrates bilateral pneumonia, worse on the left than on the right. Note the air bronchograms on the left. The patient also has a permanent pacemaker in situ.


image

Fig. 8.1B The consolidation appears of increased density and is patchy. This is in contrast to collapses (Chapter 17) and pleural effusions (Chapter 20), which are more homogeneous. Consolidation may also contain air bronchograms (arrow). This is an exercise in understanding silhouette signs (see p. 5).


Normally, bronchi are not seen as they are effectively air dense and are superimposed on air density of the alveoli. When the alveoli fill with pus (consolidation) the air-filled bronchi are now seen, with air adjacent to water.

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Permanent pacemakers Gastric outlet obstruction Caecal volvulus Small bowel obstruction Pleural effusion Slipped upper femoral epiphysis

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Aug 20, 2016 | Posted by in ULTRASONOGRAPHY | Comments Off on Pneumonia

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