Tuesday, 13 March 2007

Multiple Pathology-- Pleural Effusions

Today's discussion is about pleural effusions-- it is not a full history today.

A retired male presented with dyspnoea. He was dehydrated and confused and so history was poor.

It was identified that he had a pleural effusion both clinical examination and on chest Xray.

It was noticed that he also had unilateral foot oedema which raised a suspicion of a deep vein thrombosis.

However, his calves were normal temperature, not tender, no distended veins, not red....

The effusion was tapped from the right hemithorax but it became slightly bloody as the liver may have been inadvertedly hit during the procedure.

CT scan was performed which revealed a mass sitting in amongst the pleural fluid.

It was immediately assumed to be a neoplastic lesion, but there were additional ideas !

The analysis of the fluid suggested it was an exudate rather than a transudate making diseases such as heart failure / nephrosis / liver failure unlikely.

On the other hand, with the fluid being bloody and with a possible DVT, it was considered the possibility of PE as a cause for the effusion. Moreover, chronic infections such as Tuberculosis (TB) can cause effusions.

Other causes considered included:

Infection -- as above TB, para-pneumonic effusion, sub-phrenic abscess, unusual parasitic infections
Endocrine -- Hypothyroidism

Inflammatory-- Rheumatoid lung, SLE
Neoplasia: Primary Ca Lung, Secondary tumours, Lymphoma, Lymphangiitis Carcinomatosa

Haematological: Pulmonary Embolism (PE)
Metabolic: Uraemia

The patient underwent ultrasonography revealing a proximal DVT and the spiral CT revealed PE !! However, the pleural fluid was subjected to Ziel Nielsen Stain which was negative BUT the PCR was POSITIVE for TB !!

Hence, in this rather unusual case, it would appear that the cause of respiratory problem was due to multiple pathology.

Infection, for example pneumonia, can increase the risk of PE especially in the first two weeks after an infection although the risk can last for up to a year (Smeeth et al, 2006). This was demonstrated for community acquired pneumonias and not specifically for TB infection.

Moreover, this patient had been lying in bed for several days which again, increased the risk of DVT / PE.

Hence, this patient was treated for TB and PE, both relatively uncommon diagnoses in modern Japan.

Nevertheless, malignancy still needed to be ruled out in this patient, but there were no results confirming this diagnosis.

Things to bear in mind, that despite one cause being found for an underlying disease, if there is a possibility of another cause(s), then they should also be investigated and ruled out alike.

No comments: