JH IM Board Review - Infectious Disease I Flashcards
(95 cards)
1
Q
Which infections result in more abx prescriptions than any other group of medical disorders in the outpatient setting?
A
Infections of the resp. tract.
2
Q
In many cases, resp. infections …?
A
DO NOT REQUIRE ABX. (result in abx resistance of S.pneumo).
3
Q
Bacterial sinusitis - Basic info - Acute bacterial sinusitis (ABS) is often preceded by …?
A
- A viral URTI.
- Environmental allergen flare.
- Flare.
- Trauma.
- Recent dental manipulation.
4
Q
ABS - Only …-…% of all clinical sinusitis are bacterial in origin.
A
0.2-10%.
==> Likely 2% of ALL cases.
5
Q
ABS - Symptoms often mimicked by …?
A
Common cold or allergies.
6
Q
ABS - Diagnosis is often made on …?
A
Clinical grounds, because history and physical findings are NOT specific.
7
Q
ABS - Why some view this as rhinosinusitis?
A
Nasal passages are commonly involved.
8
Q
Chronic sinusitis is well or poorly understood?
A
POORLY UNDESTOOD.
9
Q
Chronic sinusitis is diagnosed after at least …?
A
12 WEEKS of sinus symptoms/signs.
10
Q
Chronic sinusitis - Results from …?
A
Chronic obstruction of sinus passages.
==> Role of bacterial pathogens is debated.
11
Q
Microbiology of ABS shows that resp. pathogens predominate (in order of decreasing freq):
A
- S.pneumo.
- H.flu.
- Moraxella catarrhalis.
12
Q
Antibacterial resistance among these organisms is increasingly common:
A
- > 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.
13
Q
Other pathogens in ABS:
A
- Anaerobes.
- Other streptococci.
- S.aureus.
==> Small percentages of isolates in ABS.
14
Q
In chronic sinusitis, which pathogens predominate:
A
- S.aureus.
- S.epi.
- Anaerobes.
15
Q
Chronic sinusitis - ABX?
A
Whether or not abx Tx helps this condition is UNCLEAR, but it is often used.
16
Q
Bacterial sinusitis - Clinical presentation - ABS MC follows …?
A
Viral URTI.
17
Q
Bacterial sinusitis - Clinical presentation - Change in color or character of nasal discharge is …?
A
NOT specifically indicative of bacterial infection.
18
Q
ABS (as opposed to viral or allergic sinusitis) is unlikely if symptoms are …?
A
Less than 10 days in duration.
19
Q
Hx of PEx suggestive of ABS include:
A
- 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.
20
Q
Bacterial sinusitis - Diagnosis - Gold standard:
A
Culture from sinus puncture ==> NOT commonly done.
21
Q
Bacterial sinusitis - Dx - Best made on what grounds?
A
CLINICAL GROUNDS, usually only after symptoms have lasted for more than 10 days.
==>Although se/sp of Hx/PEx are poor.
22
Q
Bacterial sinusitis - Dx - Imaging:
A
NOT recommended for UNCOMPLICATED cases of ABS because findings are NO more se/sp than clinical evaluation.
23
Q
Bacterial sinusitis - Tx:
A
Many patients with signs/symptoms of sinusitis (even those with true ABS) will have RESOLUTION of their symptoms without antimicrobial Tx.
24
Q
Bacterial sinusitis - Tx - What to give?
A
- Use of decongestants, analgesics, antipyretics ==> Possibly helpful but NOT well studied.
- Patients with moderate or severe symptoms should receive abx.
25
Bacterial sinusitis - Abx goal:
Avoid ACUTE complications (eg brain abscess, meningitis, or osteomyelitis - ALL RARE).
==> And CHRONIC complications (eg chronic sinusitis).
26
Bacterial sinusitis - Abx choice dictated by ...?
1. Local sensitivities.
2. Cost.
3. Drug allergy history.
27
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.
28
Bacterial sinusitis - Tx - Attempts to treat chronic sinusitis with abx may result in ...?
LITTLE IMPROVEMENT.
==> Tx should focus on relieving obstruction.
29
Chronic sinusitis - Tx:
1. Decr. mucosal swelling + exudates.
| 2. Crusting by using nasal saline irrigation, topical nasal C/S, antihistamines, decongestants, LT antagonists.
30
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.
31
If a patient with chronic sinusitis has an acute flare, treatment with ...?
ABX against S.pneumo, H.flu should be given.
32
Recurrent ABS may indicate ...?
Obstruction OR IMMUNODEFICIENCY (eg HIV, hypogammaglobulinemia).
33
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).
34
Otitis media involves ...?
Obstruction of the Eustachian tube, resulting in a pressure imbalance of the inner ear and subsequent bacterial infection.
35
Otitis media is often initiated by ...?
URTI or allergies.
36
Otitis media is uncommon in ...?
ADULTS.
==> <0.25% incidence.
37
Otitis media - Common isolates?
1. S.pneumo.
2. H.flu.
==> Unclear freq of viral and allergic inflammation.
38
Otitis media - Clinical presentation:
1. Commonly follows URTI or history of allergies.
2. Otalgia and fever are most frequent symptoms.
3. Severe cases may be complicated by meningitis, mastoiditis, or brain abscess (ALL RARE).
39
Otitis media - Dx:
1. PEx in children imprecise, BUT accuracy increases with INSUFFLATION demonstrating decr. mobility of tympanic membrane.
2. Exam findings in adults have NOT been studied, but typical presentation is bulging, red tympanic membrane.
3. Perforation of tympanic membrane may occur and lead to drainage or crusting within ear canal.
40
Otitis media - Tx:
Antimicrobial Tx NOT WELL DEFINED.
==> Amoxil/clavul, cefuroxime axetil, azithromycin possible options.
41
Pharyngitis - Basic info:
1. Outpatient visits for pharyngitis account for 1-2% of ALL office visits.
2. Viral etiology is the MCC in adults (up to 80%).
3. S.pyogenes is the MC BACTERIAL CAUSE in adults (5-10%).
42
Pharyngitis - Viral etiology:
1. Rhinovirus (20%).
| 2. Coronavirus (5-10%), adenovirus (5%), HSV (2-4%) less common.
43
Pharyngitis - UNCOMMON viral etiologies:
1. Parainfluenza (2%).
2. Influenza (1%).
3. EBV (<1%).
4. CMV (<1%).
5. Acute HIV-1 (<1%).
6. Coxsackievirus (<1%).
44
Pharyngitis - S.pyogenes is the MC BACTERIAL CAUSE. Other:
1. Other strep are less common, usually group G or C.
2. Rare bacterial causes include N.gonorrhoeae (<1%), C.diphtheriae (<1%), Arcanobacterium haemolyticum (often associated with rash, <1%), Chlamydophila pneumoniae (1%), or M.pneumoniae (<1%).
45
Pharyngitis - Clinical presentation:
1. Sore throat, malaise, with possible fever or cervical lymphadenopathy.
2. Severe sore throat with inability to swallow secretions or associated dyspnea should be evaluated in an ED ==> May indicate EPIGLOTTITIS.
3. Dehydration (in severe cases) may require IV hydration.
46
Pharyngitis - Clinical presentation - Red, beefy tonsils with exudates may ...?
Have EITHER BACTERIAL or VIRAL CAUSES.
==> The presence of EXUDATE IS NOT SPECIFIC FOR BACTERIAL CAUSE.
47
Primary infection with EBV is easily confused with ...?
GABHS.
==> May present with fever, sore throat, splenomegaly, LAN (either ANTERIOR + POSTERIOR CERVICAL or GENERALIZED).
48
Infectious mono - Lab:
1. Predominance of lymphocytes or atypical lymphocytes.
| 2. 90% of adult cases, AST, ALT, OR LDH are elevated 2-3x nl.
49
Infectious mono - Prescription of amoxicillin for patients mistakenly believed to have GABHS or who have 2o concurrent GABHS predictably yields ...?
DIFFUSE, PRURITIC, MACULOPAPULAR rash in 95-100% of patients.
==> THIS RASH DOES NOT MEAN PATIENT IS AMOXIL ALLERGIC.
50
Pharyngitis - Diagnosis:
Signs/symptoms of GABHS and viral etiologies overlap, physician are generally unable to include or exclude the diagnosis of strep pharyngitis.
==> Se/sp of clinical presentation 50-75% for GABHS.
51
Pharyngitis - Diagnosis - Gold standard:
Throat culture (90%).
==> False(+) may result from carrier state.
52
Pharyngitis - Diagnosis - Rapid strep tests:
1. Throat swab detects carbohydrate antigen.
2. Sensitivity 80% to 90% in adults, but highly specific.
==> If POSITIVE test, treat as GABHS; NO further culture required.
==> Because of higher prevalence in children and adolescents, negative tests should be confirmed by standard culture. It is UNCLEAR whether this is necessary in adults.
53
Acute pharyngitis - Favors GAHBS - Symptoms:
1. Sudden onset.
2. Fever.
3. Abdominal pain.
4. Nausea/vomiting.
54
Acute pharyngitis - Favors viral - Symptoms:
1. Cough.
2. Hoarseness.
3. Coryza.
4. Diarrhea.
55
Acute pharyngitis - Favors GABHS - Signs:
1. Fever.
2. Toxicity.
3. Anterior cervical LAN.
4. Scarlatiniform rash.
5. Lack of cough.
56
Acute pharyngitis - Favors viral - Signs:
1. Ulcers.
| 2. Conjunctivitis.
57
Heterophile antibodies are used to diagnose IM:
1. Occur in 90% of cases and are detected by blood testing with commercial kits (Eg Monospot, Meridian Bioscience, Cincinnati, OH).
2. Are NOT directed against EBV; Agglutinate either horse or sheep RBCs.
3. Detection of anti-EBV capsid IgM antibodies typically done if heterophilic antibodies are negative but EBV still suspected (approx. 10% of cases).
4. Anti-EBV IgG may be present at presentation in new infection or with preexisting infection and has less clinical utility in diagnosis of acute infection.
58
Acute pharyngitis - Tx - GAHBS:
RF is now RARE in adults and the main use of abx is to shorten the duration of illness (16-24h).
==> Should be given within 72h of symptom onset.
59
All GABHS strains remain ...?
PCN sensitive.
60
Acute GAHBS pharyngitis - Tx:
PCN V is standard for adults.
==> 250mg 4x daily OR 500mg twice daily orally OR long-acting intramuscular PCN given as one dose (1.2 million units benzathine +/- procaine PCN G).
61
Acute GABHS pharyngitis - Tx for PCN-allergic patients:
1. Clindamycin.
2. Azithromycin.
3. Clarithromycin.
62
Acute bronchitis - Basic info - MCC:
Acute cough in the outpatient setting.
63
Acute bronchitis - Clinical challenge to distinguish ...?
Bronchitis from pneumonia.
64
Acute bronchitis - 90% of cases are from ...?
NON BACTERIAL CAUSES IN HEALTHY NON SMOKERS.
65
Acute bronchitis - Purulent sputum may or may not ...?
INDICATE A BACTERIALLY INDUCED PROCESS.
66
Acute bronchitis - Viral causes predominate:
1. Coronaviruses.
2. Paramyxoviruses.
3. Rhinoviruses.
4. Influenza A and B (in season).
67
Acute bronchitis - Pertussis:
UNCOMMON cause of bronchitis.
==> but is more likely if cough is severe or persists longer than 3 weeks.
68
Acute bronchitis - Clinical presentation:
Acute resp. infection with cough (with or without phlegm) for less than 3 weeks.
==> Wheezing may be present, including in those WITHOUT asthma.
69
Acute bronchitis - Dx:
1. Based on Hx and PEx; sputum cultures are NOT recommended.
| 2. Pneumonia is UNCOMMON if vital signs and chest exam is normal.
70
Acute bronchitis - Tx:
1. Symptomatic support. Abx NOT recommended regardless of cough duration ==> Prescription represents abx abuse.
2. 50% will experience resolution of cough at 14 days.
3. 90% will experience resolution at 21 days.
71
Acute bronchitis - Albuterol inhalation:
May decrease cough.
==> Most beneficial in those with documented reductions in peak airflow.
72
Acute bronchitis - Antitussives?
Often prescribed, but FEW DATA to clarify role.
73
Acute bronchitis - Consider antiviral therapy for influenza if ...?
Early in course of illness (less than 48h) for ambulatory patients who are not significantly ill.
74
Acute bronchitis - Pertussis should be suspected if cough ...?
Persists beyond 3 weeks.
75
Acute bronchitis - Tx initiation after 7-10 days of cough onset does ...?
NOT lead to reduction in cough duration.
==> Can persist for 6-10 weeks regardless of therapy.
76
Acute bronchitis - Historically, which abx were provided to limit the potential for transmission?
Azithro or tetracycline.
==> Recently, routine use of macrolides in adults in outbreak situations has been discouraged because of lack of data to suggest staunching spread.
77
Acute bronchitis - Because of risk of infant infection, ...?
Routine Tx is now only suggested in pregnant women within 6 weeks of cough onset.
78
Acute bronchitis - Patient education essential:
Patients not receiving abx are happier if told they have a chest cold rather than bronchitis.
79
Chronic bronchitis with acute exacerbation - Basic info:
1. Part of the clinical spectrum of COPD.
2. Smoking major factor - less than 10% due to other reasons.
3. 5% of all deaths in USA.
4. Viral/bacterial infections may cause acute exacerbations of chronic bronchitis.
80
Chronic bronchitis with acute exacerbation - Bacterial causes:
1. H.flu ==> MCC (approx. 22%), particularly in smokers.
2. M.catarrhalis (9-15%).
3. S.pneumo (10-12%).
4. Pseudomonas aeruginosa or other gram(-) (up to 15%).
==> Seen in those with recent previous abx use or hospitalizations + in those with acute flares.
81
Acute bronchitis with acute exacerbation - Clinical presentation:
Patients with COPD flare may have a combination of worsening dyspnea and increased sputum purulence and/or volume.
82
Which criteria may be used to stratify severity of COPD flares?
Winnipeg criteria.
83
Winnipeg criteria for stratifying severity of acute exacerbation of chronic bronchitis:
SYMPTOMS: Incr. dyspnea/ Incr. purulence of sputum/ Incr. volume of sputum.
Type I ==> Severe, all 3 symptoms.
Type II ==> Moderate, 2/3.
Type III ==> Mild, at least 1/3 along with:
1. URTI within last 5 days.
2. Fever without other apparent cause.
3. Incr. wheezing.
4. Incr. non productive cough.
5. Incr. respirations or pulse >20% over baseline.
84
Type 1 and type 2 flares require ...?
Hospitalization ==> Associated with incr. mortality (3-4%).
==> Mortality increases to 11-24% in hospital if admission to ICU is required.
85
COPD flares - CXR:
Abnormalities are common.
86
COPD flares - Consider DVT leading to PE if ...?
No other clear etiology is found.
87
COPD flares - Dx:
On clinical grounds.
88
COPD flares - Dx - Which tests are beneficial to rule out pneumonia?
1. CXR.
2. Pulse ox.
3. ABG.
==> May be difficult to Ddx from pneumonia if CXR has baseline abnormalities.
89
COPD flares - Unlike in acute asthma exacerbations ...?
Acute spirometry considered UNHELPFUL.
90
COPD flares - Sputum culture?
NOT routinely recommended, but may be helpful in:
1. Severe cases.
2. Pts with concurrent pneumonia.
3. Cases with recent abx use/hospitalization.
91
COPD flare - Tx:
1. Bronchodilators and C/S recommended.
2. Abx recommended for moderately to severely ill patients (defined as patients with increased sputum purulence and either incr. sputum volume or dyspnea OR patients requiring ventilatory support).
3. Abx also recommended for patients with moderate to severe COPD exacerbation requiring hospitalization.
92
COPD flare - Choice of abx depends on ...?
Patients' risk factors for pseudomonas and risk of complicated COPD.
93
Data are limited regarding optimal abx for COPD exacerbations, but include ...?
1. Macrolides and doxycycline for uncomplicated COPD exacerbations (patients >65 with FEV1 >50%, no cardiac disease, and greater than 3 exacerbation per year).
2. Fluoroquinolones and amoxicillin/clavulanate for complicated COPD exacerbations.
94
COPD flares - Tx - Benefit from mucolytics and chest physio?
Without clear benefit.
95
COPD flares - O2?
Helpful with hypoxemia ==> May heighten risk of resp. failure if patient has chronic hypoxemia.
