Tuesday, July 30, 2013

"Never let the sun set on an empyema"

Today in morning report we discussed the case of a patient presenting with shortness of breath for one week.

PMH is significant for AL amyloidosis with renal involvement leading to a non-proliferative GN (aka nephrotic syndrome), as well as peripheral neuropathy.

Treatment includes a regimen of CyBor-D (Cyclophosphamide, Bortezomib, and Dexamethasone).

We touched on the topic of amyloidosis, understanding it is a disease of abnormal protein infiltration that can potentially affect any organ system and it can be either primary, or secondary (classically AL amyloid is seen with multiple myeloma, as well as chronic inflammatory disease). 

Thinking laterally, before any further information was given some thoughts were that this patient may have restrictive cardiomyopathy from his amyloid and now presenting in CHF. Another thought was this patient is prone to thromboembolic disease given his nephrotic syndrome and may be presenting with a PE. Lastly given his immunosuppresive therapy, this may be an infectious etiology. Specific thought was given to thinking of PCP if he had been on longer term steroids. If the presentation was more chronic with associated constitutional symptoms, one would also put TB on the DDx.

Further history revealed no other localizing signs of infection save for a non-productive cough, no cardiac or CHF history, no risk factors for thromboembolic disease and no constitutional symptoms. ROS was significant only for some mild dysphagia on occasion. 

On exam he was afebrile, normal blood pressure, mildly tachycardic with a HR of 100. RR was 22 and he was saturating 95% on room air.
On respiratory examination he was in no distress, with dullness to percussion on the right, as well as decreased breath sounds on the right side.

Imaging showed a a large, almost complete white out of the right hemithorax. 
There was tracheal deviation away from the white out consistent with fluid as opposed to complete collapse.

CT chest showed a large pleural effusion with bubbles that raised concern for an empyema

Presumed oral aspiration (remember his history of dysphagia), possibly due to amyloid involvment, leading to empyema.

Ultimately the patient had drainage of frank pus, and the microbiology grew Streptococcus anginosus and Haemophilus parainfluenzae


Uncomplicated parapneumonic effusion: 
  • slightly turbid 
  • pH > 7.3 
  • glucose > or equal to 3.4 
  • ratio of pleural fluid to serum glucose > 0.5
  • LDH < 700
  • Negative micro

Complicated parapneumonic effusion: 

  • cloudy
  • pH < 7.2 
  • glucose < 2.2 (some quote < 3.4)
  • ratio of pleural fluid to serum glucose < 0.5 
  • LDH > 1000 
  • Micro may be positive
  • pus
  • positive micro

A word on Streptococcus anginosus aka Strep milleri
- Very "abscess-ogneic" (other bacteria that are abscess-avid....hypermucoviscous klebsiella, anaerobic bacteria such as bacteroides fragilis)
- Has a caramel smell in the micro lab

Treatment in this case, if it was truly only S.anginosus could be high dose penicillin. However, given the additional micro findings as well as possibility of polymicrobial infection with oral anaerobes, it was determined that covering for anaerobes as well is reasonable. 

Check out this clinical practice article on the diagnosis and management of parapneumonic effusions and empyema.

Click here for a CMAJ article on parapneumonic effusions.

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