Penicillin Allergy

Not to be understated in terms of potential severity, it is true that the number of penicillin 'allergic' patients far outnumbers the number of patients with an actual allergy to penicillin.

The validity of allergies to penicillin recorded in the chart is questionable. The JAMA classic article on history of pencillin allergy is here.

This study (and others) shows meropenem is *likely* safe in patients with IgE mediated penicillin allergy.

The following review article discusses the use of other agents and a strategy for evaluating patients with penicillin allergy. This review discusses antibiotic allergies in general.

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The ACLS guidelines for the management of anaphalaxis are here.

Delusional Parasitosis

Interesting case today -- and sad. Delusional parasitosis can be very difficult to treat and can be debilitating for patients. There is a role for consult liason psychiatry and newer generation antipsychotics (see review here).

An interesting case report of IATROGENIC delusional parasitosis (i.e. patient believed she had infestation because her doctors told her she did) is here.

Surgery for Infective Endocarditis

Recent publication in circulation addresses the issue very well.

For the cutting edge -- vegetectomy (removal of vegetation) without valve replacement may be an option worthy of study.

See previous posts on IE for more info on IE.

PCP with steroids

Frequently invoked, rarely proven the development of PCP with steroid therapy is rare but important to consider.

TMP/SMX prophylaxis for PCP in patients on high dose steroids (see the table contained within) from this meta-analysis. In general, though there is no consensus, PCP prophylaxis should be considered in patients on greater than 30mg of prednisone for greater than three months or those who are on moderate-high dose steroids with another immunosuppressive agent (i.e. patients with Wegner's)

However, the story may be different in lymphoma treatment, particularly with rituximab and high dose CHOP therapy but overall is also low in hematologic (exclude ALL) and solid organ malignancy.

Vancomycin Nephrotoxicity

A review of vancomycin nephrotoxicity is available here.

The IDSA guidelines for therapeutic drug monitoring of vancomycin here.

The first vancomycin trough achieved seems to have predictive value for who will develop nephrotoxicity.

The role of dialysis in acute vancomycin mediated renal injury is discussed here (little evidence from which to draw conclusions, but seems reasonable).

Recurrent HSV Encephalitis

Interesting case. Second episode of Herpes Simplex encephalitis in an adult approximately 3 years after the first. Here is a case report and literature review on recurrent disease.

The main deteminant of outcome in HSV encephalitis is time to acyclovir. This article discusses factors associated with the delay of administration.

This article discusses the outcomes of HSV in population based study.

I discuss viral encephalitis in a previous blog.

Neutropenic Entercolysis

With thanks for the suggestion.

Today we saw a patient with lymphoma, status post bone marrow transplant, who developed fever, neutropenia, abdominal pain, diarrhea and colitis on CT scan with a presumed diagnosis of neutropenic enterocolitis.

This condition, loosely defined (but best defined as fever, abdominal pain and colonic thickening -- see here) is seen in about 5% of patients. The mortality approaches 50% in some studies.

Ultrasound may be useful in screening for this condition early on.

Usual pathogens are bacterial (gram negative bowel flora including pseudomonas, and gram positive bowel flora). Bacteremia is seen in 35-80% of cases. A reasonable coverage choice would be an anti-pseudomonal beta-lactam (i.e. piperacillin-tazobactam or meropenem) with anerobic activity, or something like ceftazadime with metronidazole.

Fungal infection is rare (~5%) and usually candidal, but caries a high mortality (~80% in some studies). Emperic antifungal coverage should be considered if still febrile and neutropenic at 5 days or in the severely ill.

Critically ill patients should be considered for colectomy as should patients with complications (megacolon, perforation).