A 32-year-old woman is diagnosed with bacterial meningitis due to Streptococcus gallolyticus (S. bovis). She has two pet dogs and had lived in rural parts of Southeast Asia as a Peace Corp volunteer over a decade prior.
Generally she has been in excellent health, but two weeks before the onset of meningitis she sustained head trauma as the result of a bicycle accident.
Five days before she presented with meningitis she was started on high dose corticosteroids to treat a severe case of poison ivy acquired while gardening.
Which one of the following is the most likely underlying problem that led to her meningitis?
Colon cancer
Strongyloidiasis
CSF leak
Common variable hypogammaglobulinemia
Strongyloidiasis is common in Southeast Asia, where she had worked, and in many other parts of the world. Infection is acquired by exposing skin to larvae in fecally contaminated water. Infection may be asymptomatic, and because the roundworm may complete its life cycle within the human host, infection may persist for years to decades.
Steroids may result in dissemination of worms that leave the GI tract carrying along with them GI flora. This may result in Gram-negative rod bacteremia, and less commonly bacteremia due to other gut organisms including Streptococcus gallolyticus or Enterococcus. Meningitis due to these bowel organisms may occur either due to direct bacteremia or larval invasion of the CNS.
S. gallolyticus bacteremia and endocarditis may be associated with underlying bowel disease including colon cancer, and colonoscopy should be considered in patients with S. gallolyticus bacteremia. However, this patient’s young age and the onset with corticosteroids make strongyloidiasis more likely.
CSF leak is a high risk factor for bacterial meningitis, but most cases are due to pneumococci or viridans streptococci; S. gallolyticus would be very unlikely.
Common variable hypogammaglobulinemia is typically associated with a history of recurrent respiratory tract infections, a history absent in this case.
Accidental ingestion of dog fleas may result in human infection with the dog tapeworm, Dipylidium caninum, but meningitis is not seen.
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