Friday, February 15, 2008

Happy Valentine's Day

On your pathology elective, you do an autopsy and find a lung with necrotizing pneumonia; when you look at the lab results for the patient, you find gram positive cocci in clusters.

Challenge 1: What antibiotic would you use for this infection? This bacteria secretes a particular type of (Valentine related) toxin - what is it?

Here's a hard one. A 30 year old female presents with abrupt onset of these lesions and fever. You get a dermatology consult which describes the lesions as "erythematous tender papules forming plaques with an irregular pseudovesicular surface, a few centimeters in diameter with central yellowish discoloration." The patient describes these lesions as painful but not itchy. They are found on the face, neck, upper extremities, and dorsum of the hand. The patient says this presentation was preceded by a flu-like illness. Lab tests show neutrophilia with 70% bands, elevated sed rate, and elevated C-reactive protein. A biopsy shows "nodular and dense perivascular neutrophilic infiltrates with neutrophil karyorrhexis and no vasculitis." You put her on antibiotics and there is no response. You then switch her to systemic glucocorticoids and she responds well.

Challenge 2: What's the diagnosis?

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1 comment:

Craig said...

Happy Valentine’s Day

The first case of necrotizing pneumonia is most likely caused by community acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). Necrotizing pneumonia may be mediated by Panton-Valentine leukocidin toxin. Although the preferred antibiotic for MRSA is vancomycin, in the case of CA-MRSA, non-beta-lactam antibiotics should be used such as trimethoprim-sulfamethoxazole, clindamycin, and minocycline.

The second case is a neutrophilic dermatosis, characterized by skin lesions with intense epidermal and/or dermal neutrophil infiltrate with no signs of vasculitis or infection. Pathogenesis is unknown. This, in particular, is Sweet’s syndrome, also called acute febrile neutrophilic dermatosis. It affects females > males and is diagnosed by abrupt onset of these cutaneous skin lesions and consistent histopathology as well as 2 of the following: antecedent fever of infection; accompanying fever, arthralgia, conjunctivitis, or malignancy; leukocytosis; good response to glucocorticoids but no response to antibiotics.

Sources: UpToDate; Federman, Brescia, Horne, Kirsner, “Cutaneous manifestations of malignancy”, Postgraduate Medicine Online.