Tuesday, October 8, 2013

Invasive pneumococcal disease

In today’s morning report, we discussed a 72 year old female presenting with fever, cough, and headache.

PMH was significant for recurrent ovarian cancer with prior debulking, radiation therapy, and multiple courses of chemotherapy, and a Port-A-Cath in place, most recent chemo 6 weeks ago for disease recurrence. She also has a history of (truly) recurrent UTI, in part due to mass compression requiring a ureteric stent.

History reveals a 5 day history of subjective fevers, productive cough, and tension headache.

Exam was normal, no evidence of CNS infection, normal respiratory exam with no oxygen requirements, no signs of IE, and a normal abdo exam, with no flank tenderness.

DDx is infection, including
-        -sinusitis
-        -pneumonia
-        -CNS infection
-        -Urinary infection (given her personal hx and RF)
     -Line infection given her Port-A-Cath

Some take home points;

Fever from a GU source points to pyelo.
Fever is a very sensitive sign for pyelo, over 90% sensitive
Flank pain is INSENSITIVE.

Sinusitis can be differentiated into acute vs chronic

-        -within 4 weeks
-        -within first 7 days, 98% viral
-        -Risk of bacterial goes up after day 7
           o   S. pneumo, H. inf, moraxella

Aside: The American Academy of Family Medicine recommends (as part of the choosing wisely campaign) against empiric antibiotic therapy in patients presenting with mild to moderate sinusitis lasting less than 7-days from the start of their illness

-       - 6 or more weeks
-        -structural abnormality

Complications of acute bacterial sinusitis are rare, but are important to consider and can be thought of as intracranial (subdural empyema, epidural abscess, brain abscess, venous sinus thrombosis, meningitis) or extracranial (orbital cellulitis, orbital abscess and subperisoteal abscess). 

Back to the case…admitted for further workup, blood cultures grew 2/2 S. pneumo. 
*Given the presence of positive cultures from a sterile site, she is considered to have invasive pneumococcal disease

S. pneumo sensitive to Penicillin for both CNS or non-CNS infections, essentially meaning MIC is low.
Rates of penicillin resistance are rising, 3rd generation cephalosporins would then be the next choice.

Strep pneumo
-        -Gram positive cocci in pairs/chains, alpha hemolytic, ENCAPSULATED
-        -Other encapsulated organisms:
      o   H.inf (Type B)
      o   Neisseria
      o   GBS
      o   Klebsiella
            o   Capnocytophagia

Clinical manifestations of S.pneumo
-        -colonized in URTI: can lead to OM, sinusitis, pneumonia,

-        -this can lead to bacteremia, CNS infection, IE, MSK (Vertebral OM)
     See here for more on invasive pneumococcal disease

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