Febrile Neutropenia

Quick post today from morning report where discussed a patient with a hematologic malignancy post chemotherapy presenting with fever and an absolute neutrophil count (ANC) of 0.3.

Remember that Febrile Neutropenia is a syndrome, not on its own a diagnosis, and we still need to do our job to find the cause/source.

Definition of Febrile Neutropenia is:
- Fever 38.3 x 1 or > 38 on multiple occasions (ie > 1 hour apart)
- Neutropenia (< 0.5 or < 1.0 with expected nadir less than 0.5)

Degree of neutropenia correlates with likelihood of developing fever, such that an ANC of 0.25-0.5 within approximately 7 days, there is ~30% chance of fever, and if ANC less than 0.25, 
chances can go up to ~90%.

Infection is always the concern, and a source will be found in approximately 30% of cases.

History and Physical (as always) is key! and remembering that these patients have no immune response reminds us that they might not have the ability to mount a dramatic inflammatory picture and so their signs/symptoms might be subtle.

Things to consider specifically:
- mucositis (oral, GI tract)
- dentition
- line: often these patients will have indwelling lines for chemotherapy. 
- abdominal findings
- subtle findings might warrant further investigation with imaging.

Full physical exam....
- inspect lines for: erythema, tenderness, purulent discharge (expressible?), induration, fluctuance
- DRE is contraindicated in patients with febrile neutropenia.

At risk organisms in general
- Gram negatives including Pseudomonas
- Gram positives especially if concerned with line infection
- C. Diffiicile, resistant organisms - depending on case.

Empiric therapy is aimed towards the above, and so often will consist of broad spectrum antibiotics including Pseudomonas coverage. Often times "double coverage" for Pseudomonas will be started, this is more for the concern that one of the agents might have resistance against it, so thus (hopefully) ensuring that one of the agents will work. 

Who gets Vanco? (not absolute, and certainly will vary depending on local micro patterns)
- concern for line infection
- known MRSA positive
- mucositis on prior fluoroquinolone proophylaxis (selects out for Viridans Group Strep with high MIC for penicillin).

When to stop?
- Consider stopping or stepping down once ANC normal, and afebrile x 48 hours
- Treat any identified source as you normally would

What if fever persists?
- if after day 4 fever continues consider antifungal coverage, especially if receiving prophylaxis

A word on typhlitis/neutropenic enterocolitis:

Mucous membrane damage can occur with chemotherapy (some more than others) which can lead to bacterial invasion of GI wall.
Major criteria for NEC would be
- Fever
- ANC < 0.5
- Bowel wall thickening > 4mm

These patients will have abdo pain, cramping, diarrhea.
Important to think about C.Diff in these patients in addition to above, and to get surgery consultation early if warranted. 

Full IDSA guidelines here. Remember that local micro patterns will alter protocols.