JH IM Board Review - Infectious Disease I Flashcards
Which infections result in more abx prescriptions than any other group of medical disorders in the outpatient setting?
Infections of the resp. tract.
In many cases, resp. infections …?
DO NOT REQUIRE ABX. (result in abx resistance of S.pneumo).
Bacterial sinusitis - Basic info - Acute bacterial sinusitis (ABS) is often preceded by …?
- A viral URTI.
- Environmental allergen flare.
- Flare.
- Trauma.
- Recent dental manipulation.
ABS - Only …-…% of all clinical sinusitis are bacterial in origin.
0.2-10%.
==> Likely 2% of ALL cases.
ABS - Symptoms often mimicked by …?
Common cold or allergies.
ABS - Diagnosis is often made on …?
Clinical grounds, because history and physical findings are NOT specific.
ABS - Why some view this as rhinosinusitis?
Nasal passages are commonly involved.
Chronic sinusitis is well or poorly understood?
POORLY UNDESTOOD.
Chronic sinusitis is diagnosed after at least …?
12 WEEKS of sinus symptoms/signs.
Chronic sinusitis - Results from …?
Chronic obstruction of sinus passages.
==> Role of bacterial pathogens is debated.
Microbiology of ABS shows that resp. pathogens predominate (in order of decreasing freq):
- S.pneumo.
- H.flu.
- Moraxella catarrhalis.
Antibacterial resistance among these organisms is increasingly common:
- > 40% of H.flu + 100% of M.cat are beta-lactamase producers.
- High S.pneumo resistance to PCN (MIC >8mg/dL) for nonmeningeal isolates is UNCOMMON, accounting for approx. 4% of isolates in USA.
==> The clinical importance of resistant bacteria is DEBATED.
Other pathogens in ABS:
- Anaerobes.
- Other streptococci.
- S.aureus.
==> Small percentages of isolates in ABS.
In chronic sinusitis, which pathogens predominate:
- S.aureus.
- S.epi.
- Anaerobes.
Chronic sinusitis - ABX?
Whether or not abx Tx helps this condition is UNCLEAR, but it is often used.
Bacterial sinusitis - Clinical presentation - ABS MC follows …?
Viral URTI.
Bacterial sinusitis - Clinical presentation - Change in color or character of nasal discharge is …?
NOT specifically indicative of bacterial infection.
ABS (as opposed to viral or allergic sinusitis) is unlikely if symptoms are …?
Less than 10 days in duration.
Hx of PEx suggestive of ABS include:
- Persistent or worsening symptoms lasting at least 10 days.
- Significant unilateral sinus pain or tenderness, fever higher than 39C, purulent nasal discharge, maxillary, tooth, or facial pain (particularly unilateral) lasting at least 3-4 days in the beginning of the illness OR …
- Worsening signs/symptoms of nasal discharge, headache, and fever after URTI ==> Usually in this scenario the URTI symptoms lasted 5-6 days and were initially improving.
Bacterial sinusitis - Diagnosis - Gold standard:
Culture from sinus puncture ==> NOT commonly done.
Bacterial sinusitis - Dx - Best made on what grounds?
CLINICAL GROUNDS, usually only after symptoms have lasted for more than 10 days.
==>Although se/sp of Hx/PEx are poor.
Bacterial sinusitis - Dx - Imaging:
NOT recommended for UNCOMPLICATED cases of ABS because findings are NO more se/sp than clinical evaluation.
Bacterial sinusitis - Tx:
Many patients with signs/symptoms of sinusitis (even those with true ABS) will have RESOLUTION of their symptoms without antimicrobial Tx.
Bacterial sinusitis - Tx - What to give?
- Use of decongestants, analgesics, antipyretics ==> Possibly helpful but NOT well studied.
- Patients with moderate or severe symptoms should receive abx.
Bacterial sinusitis - Abx goal:
Avoid ACUTE complications (eg brain abscess, meningitis, or osteomyelitis - ALL RARE).
==> And CHRONIC complications (eg chronic sinusitis).
Bacterial sinusitis - Abx choice dictated by …?
- Local sensitivities.
- Cost.
- Drug allergy history.
Bacterial sinusitis - Preferred drug:
Amoxil/clavul for 5-7 days.
==> Amoxil without clavul is NO LONGER 1st LINE because of high rates of resistance in sinus pathogens.
Bacterial sinusitis - Tx - Attempts to treat chronic sinusitis with abx may result in …?
LITTLE IMPROVEMENT.
==> Tx should focus on relieving obstruction.
Chronic sinusitis - Tx:
- Decr. mucosal swelling + exudates.
2. Crusting by using nasal saline irrigation, topical nasal C/S, antihistamines, decongestants, LT antagonists.
What can be helpful in the evaluation of chronic sinusitis?
Sinus CT to evaluate obstruction (eg polyps) in patients with suspected chronic sinusitis who are NOT responding to Tx.
==> ENT consultation is recommended.
If a patient with chronic sinusitis has an acute flare, treatment with …?
ABX against S.pneumo, H.flu should be given.
Recurrent ABS may indicate …?
Obstruction OR IMMUNODEFICIENCY (eg HIV, hypogammaglobulinemia).
Otitis media - Basic info:
Acute otitis media is an infection of the middle ear.
==> It needs to be distinguished from otitis media with effusion (non infectious).
Otitis media involves …?
Obstruction of the Eustachian tube, resulting in a pressure imbalance of the inner ear and subsequent bacterial infection.
Otitis media is often initiated by …?
URTI or allergies.
Otitis media is uncommon in …?
ADULTS.
==> <0.25% incidence.
Otitis media - Common isolates?
- S.pneumo.
- H.flu.
==> Unclear freq of viral and allergic inflammation.
Otitis media - Clinical presentation:
- Commonly follows URTI or history of allergies.
- Otalgia and fever are most frequent symptoms.
- Severe cases may be complicated by meningitis, mastoiditis, or brain abscess (ALL RARE).