Infectious Disease Flashcards
(60 cards)
1
Q
Define fever
A
- body temperature >37.8 oral or >38.2 rectal
- acute if less than 4 days
Fever of Unknown Origin - fever >38.3 lasting >3 weeks with unknown diagnosis after 1 week of workup investigations
2
Q
List the differential for a fever in a returning traveller
A
Unique for Returning Traveller - Malaria - Dengue fever - Typhoid - Chikungunya - Mononucleosis - Rickettsial infection - Ameobiasis Other Common - Pneumonia - TB - C diff - Hepatitis - STI
3
Q
Discuss the epidemiology, presentation, investigations and management for malaria
A
- falciparum malaris
Epidemiology
- Southern America
- Sub-Saharan Africa
- South Asia
Presentation
- present within 1 month
- flu-like prodrome of fever, chills, myalgia, cough, diarrhea
- jaundice
- hepatosplenomegaly
Investigations
- Blood thick and thin same with pathogen visualized within erythrocyte
- Hemolytic anemia
- thrombocytopenia
Management
- Artemisinin combination therapy
- artesunate with doxycyline or clindamycin
4
Q
Discuss the epidemiology, presentation, investigations and management for thyphoid fever
A
Epidemiology - Worldwide but endemic to Africa, Asia and Central and South America Pathophysiology - bacteria salmonella typhi that infect GI, liver, gallbladder - fecal-oral transmission Presentation - incubation for 1-3 weeks Management - clean food and water - oral rehydration - Ceftriaxone IV
5
Q
Discuss the contraindications to a lumbar puncture
A
- papilledema
- focal neurological deficit
- abnormal LOC
- new onset seizure
- immunocompromised
- recent head trauma
- known cancer
- known sinusitis
6
Q
Discuss the findings of bacterial, viral and TB/fungal meningitis
A
Opening Pressure - high in bacterial - normal in viral (10-20cm H20) - variable in TB Protein - high in bacterial - normal in viral (<0.45g/L) - high in fungal Glucose - low (<40%) in bacterial - normal (>60%) in viral - low in TB WBC - >1000 with neutrophils in bacterial - <100 with lymphocytes in viral - variable in TB RBC - normal (0-5) in bacterial - high in HSV encephalitis Gram Stain - positive in bacterial - negative in viral and TB
7
Q
Discuss the presentation and management of meningitis
A
Etiology
- strep pneumonia
- neisseria meningitidis
- hemophilus influenza
Presentation
- triad of headache, fever, stiff neck
- photophobia
- seizure
- petechial rash in meningitis
- cranial nerve abnormality if involve brainstem
- nuchal rigidity
- positive Kernig (thigh and knee at 90 and pain with resisted knee extension)
- positive Brudzinski (flexion of neck elicits flexion at hips)
Investigation
- Lumbar puncture demonstrating
- High WBC with neutrophils
- low glucose, high protein, high lactate
- Gram stain and culture
Management
- <50 IV ceftriaxone with vancomycin
- >50 and immunocompromised IV ceftriaxone, vancomycin, ampicillin
- Dexamethasone
- Intracranial pressure control
- Elevate head of bed
- control BP
- Glycerol/Mannitol if ICP >20
8
Q
List the risk factors and pathogenesis of infective endocarditis
A
Risk Factors
- pre-existing heart disease (prosthetic valve, valvular disease, congenital heart defect)
- IV drug use
Pathogenesis
- endocardium injury from turbulent flow due to valvular structural abnormality form thrombus -> bacteria from bacteremia infect thrombus and adhere to endocardium -> proliferate and form vegetation
Microbiology
- Staphylococcus aurea or epidermidis
- Streptococcus viridins or bovis
- Enterococcus
- Gram Negative
- HACEK: Hemophilus, Aggregatibactor, Cardiobacterium, Eikennela corrodens, Kingella
- Fungi
9
Q
Discuss the presentation and investigation for infective endocarditis
A
Presentation - fever, chills - dyspnea and chest pain - SOB - joint pain - Roth spots in eyes - new murmur - petechiae - Janeway lesion (non-tender, small erythematous macular lesion) - Osler nodes (tender, red, raised lesions on hands or feet) - splinter hemorrhages Investigation - CBC, electrolytes, creatinine/BUN - ECG - urine analysis - blood culture - Echocardiogram
10
Q
List the Duke criteria for diagnosis of infective endocarditis
A
Major Criteria
- Positive blood cultures
- typical microorganism from 2 seperate cultures
- OR persistently positive culture (>12h apart or all 3
- OR single positive for Coxiella burnetii or antiphase I IgG titer >1:800
- Evidence of endocardial involvement
- positive echocardiogram
- New valvular regurgitation
Minor Criteria
- Predisposing condition
- Fever
- Vascular phenomenom
- major arterial emboli
- septic pulmonary infarct
- conjunctival hemorrhage
- Janeway lesion
- Immunologic phenomenom
- glomerulonephritis
- Rheumatoid factor
- Osler nodes
- Roth's spots
- Positive blood culture but not meeting major criteria
Diagnosis
- 2 major OR 1 major + 3 minor OR 5 minor then diagnosis
- 1 major + 1 minor OR 3 minor then possible
11
Q
Discuss the management of infective endocarditis
A
Antibiotic
- Vancomycin 1g IV Q12H
- Gentamicin 1mg/kg IV Q8H
- Ceftriaxone 2g IV Q24H
Surgical Indications
- refractory CHF
- valve ring abscess
- fungal infective endocarditis
- valve perforation
- unstable prothesis
- >2 major emboli
- antimicrobial failure
- mycotic aneurysm
- Staph on prosthetic valve
Prophylaxis
- Amoxicillin 2g PO or Clindamycin 600mg PO before
- dental
- respiratory
- skin
- MSK
- GU procedure
12
Q
List the diagnosis of HIV
A
- enzyme linked immunosorbent assay (ELISA) to detect serum antibody to HIV
- if positive ELISA, western blot detect antibodies to 2 different HIV protein bands
- PCR to detect HIV DNA and HIV RNA to monitor viral load
13
Q
List the opportunistic infections associated with specific CD4 count
A
>500 - normal immune function <500 - recurrent HSV - VZV reactivation leading to shingles - oral hairy leukoplakia due to EBV - Oral or vaginal candidiasis - Sinusitis - Recurrent pneumonia - Lymphima - Pulmonary and extra-pulmonary tuberculosis <200 (AIDS) - Pneumocystis jiroveci pneumonia - Kaposi's sarcoma - Cryptococcosis meningitis or lung - Histoplasmosis lung - Cerebral toxoplasmosis <100 - progressive multifocal leukoencephalopathy (PML) by PJ - Cerebral toxoplasmosis <50 - CMV - Mycobacterium avium complex (MAC) - CNS lymphoma - Bacillary angiomatosis - Dementia - Wasting
14
Q
Discuss primary prevention in HIV
A
- CD4 100-200 then Septra PO to prevent PCP
- CD4 <100 Septra PO to prevent PCP and toxoplasmosis and Azithromycin to prevent MAC
15
Q
List the indications and types of anti-retroviral medication
A
- suppress viral load <40 and restore CD4 count
Indications - CD4 <350
- HIV patient that is pregnant
- HIV patient with opportunistic infection
- HIV patient being treated for hepatitis
- HIV patient with nephropathy or thrombocytopenia due to HIV
Classes (6) - Nucleoside Reverse transcriptase inhibitors
- inhibit HIV reverse transcriptase by binding to active site - Non-nucleoside reverse transcriptase inhibitor
- bind outside of active site - Protease inhibitor
- inhibit HIV protease activity to prevent viral maturation and release - Integrase inhibitor
- inhibit HIV integrase block integration of provirus to cellular genome - Fusion inhibitor
- prevent HIV-cell membrane fusion - CCR5 inhibitor
- bind CCR5 co-receptor prevent HIV binding
16
Q
List the common HIV formulation
A
- usually 2 NRTI with 1 NNRTI or 2 NRTI with 1 protease
Atriplia - Tenoforvir (NRTI) + Emtricitabine (NRTI) + Efavirenz (NNRTI)
17
Q
Discuss the different infectious disease precautions
A
Contact Precaution
- Indications: acute diarrhea/vomiting, abscess, undiagnosed rash without fever
- gloves required with possible gown
Droplet Precaution
- indications: meningitis, sepsis with petechial rash, acute respiratory infection
- mask with visor, gloves, with possible gown
Airborne Precautions
- indications: suspected measles, TB, VZV
- negative pressure room with N95, gloves and possible gown
18
Q
Discuss factors leading to increasing antibiotic resistance
A
- over use of unnecessary prescription
- improper antimicrobial use
- lack of proper infection control
- lack of resistance tracking
19
Q
Discuss the risk factors for tuberculosis
A
- Aboriginal
- Foreign born individuals from Asia, Sub-Saharan Africa
- Urban, poor homeless population
- High risk occupation
- Travel to TB endemic area
- contact with high risk population
20
Q
Discuss the presentation, investigation and management of tuberculosis
A
Presentation
- latent is asymptomatic
- active TB: fever, chills, anorexia, night sweats, weight loss
- pulmonary: productive cough, hemoptysis
- extra-pulmonary: pleurisy, pericarditis, osteomyelitis, adrenal or renal infection
Investigation
- Pulmonary TB: nodular/alverolar infiltrate with cavitation in upper lobe
- Miliary TB: scattered discrete nodules
- Latent TB: pulmonary nodule, hilar adenopathy
- Resolved: calcified hilar node, pleural thickening
Management
- 4 for 2
- Isozianid + Rifampin + Pyrazinamide + Ethambutol
- 2 for 4 months
- Isozianid + Rifampin
- extra-pulmonary require 12 months of treatment
21
Q
Discuss the diagnosis of TB
A
- Mantoux skin test for latent
- >5mm induration for immunosuppresed, active
- >10mm - 3 consecutive sputum culture staining for acid fast bacilli, culture and AMTD
- biopsy of infected site
22
Q
Discuss the risk factors and pathophysiology of clostridium difficile
A
- gram positive anaerobic bacillus
- secrete enterotoxin A, B
- spread by fecal-oral
Risk Factors - antimicrobial therapy in last 3 months
- hospitalization
- immunodeficiency
- IBD
- chronic renal failure and chemotherapy
Pathophysiology - Hos acquires and experience dysbiosis -> spore survive gastric acid and germinate in small bowel -> anaerobic environment allow to colonize -> secrete toxins leading to waterry diarrhea
23
Q
Discuss the presentation, investigation and treatment for c difficile
A
Presentation
- watery diarrhea
Investigation
- stool test for C diff
- direct examination of colon show pseudomembrane and histology
Management
- Isolation
- Address underlying cause
- Stabilize patient
- Antibiotic
- Flagyl 500mg PO/IV Q6-8H for 2 weeks
- Vancomycin 125-500 PO Q6H for 2 weeks
24
Q
Discuss the diagnosis of acute otitis media
A
Acute onset of symptoms and both of the following
Signs of middle ear effusion (any of the following)
- bulging TM
- limited TM mobility
- air fluid levels behind TM
- otorrhea
Signs of middle ear inflammation (any of the following)
- TM redness
- otalgia
25
Discuss the indications for treatment and indications for 48h observation
```
Indications for Antibiotic
- age <6 months old
- Fever >38.5
- Perforated TM with purulent drainage
- Significant comorbidities
- Current or previous complicated otitis media
Indications for 48h Observation
- Age >2 years old
- Reliable parents
- If child worsens or fails to improve in 48hrs begin antibiotics
```
26
Discuss the antibiotic treatment for acute otitis media
```
Amoxicillin 75-90mg/kg/day divided BID
- for 5 days if >2 years old
- for 10 days if <2 or >2 with complicated acute otitis media
Allergy to Amoxicillin
- Clarithromycin
- Azithromycin
- Septra
```
27
Discuss secondary therapy for acute otitis media
No improvement after two days
| - Amox-clav 45-60mg/kg/day divided TID for 10 days
28
Discuss the history, presentation and treatment for allergic conjunctivitis
```
History
- atopy or allergies
Presentation
- itching
- rhinitis
- bilateral watery eyes
- papillae
Treatment
- cool compression
- oral/topical antihistamine
- artificial tears
```
29
Discuss the history, presentation and treatment for bacterial conjunctivitis
```
History
- Conjunctivitis
Presentation
- burning
- tearing
- foreign body sensation
- mild photophobia
- blurry vision
- purulent discharge
- papillae
- progress to periorbital cellulitis
Treatment
- topical antibiotic x1 week
```
30
Discuss the history, presentation and treatment for gonococcal/chlamydia conjunctivitis
```
History
- sexual contact
- possible vertical transmission in neonates
Presentation
- chronic unilateral conjunctivitis not responsive to drops
- tearing
- foreign body sensation
- urinary tract symptoms
- new sexual partner
Treatment
- Ceftriazone 1g IM once
- azithromycin 1g PO with topical antibiotic
- Ophthalmology referral
```
31
Discuss the history, presentation and treatment for viral/adenovirus conjuctivits
```
History
- sick contact
Presentation
- Recent upper respiratory infection
- Itching
- burning
- foreign body sensation
- Mild photophobia
- Affect one eye and spread to the other
- Clear mucoid discharge
- Follicles
- Tender pre-auricular lymphadenopathy
Treatment
- Self limiting in 2-3 weeks
- Contagious for weeks after symptom onset
- Cold/warm compresses
- Artificial tears
- Proper hand hygiene
```
32
Discuss the history, presentation and treatment for hordeolum (stye)
```
History
- acute inflammation of eyelid gland
- Staph Aureus
Treatment
- Warm compresses
- Gentle massage
- Topical antibiotic (erythromycin ointment)
- resolves 2-5 days
```
33
Discuss the history, presentation and treatment for chalazion
```
History
- chronic granulomatous inflammation of meibomian gland
- produced by internal hordeolum
Presentation
- no acute inflammatory signs
Treatment
- warm compress
- no improvement after 1 month consider incision and curretage
- chronic biopsy for malignancy
```
34
Discuss the history, presentation and treatment for blepharitis
```
History
- inflammation of lid margins
- ulcerative dry scals: Staph aureus
- seborrheic: no ulcer, greasy scales
Presentation
- itching
- tearing
- foreign body sensation
- thickened
- red lid margins
- crusting
- toothpaste sign
Management
- warm compressed and lid scrubs
- topical or systemic antibiotics
- ophthalmologist may prescribe corticosteroid
```
35
List the microorganism and antibiotic option for community acquired pneumonia in adults (outpatient no comorbidities)
```
Organism
- Strep pneumonia
- Mycoplasma pneumonia
- C pneumonia
Antibiotics
- Clarithromycin 500mg BID or 1000mg OD for 7-14 days
Amoxicillin 1g TID for 7-14 days
Azithromycin 500mg on first day then 250mg for 4 days
```
36
List the microorganism and antibiotic option for community acquired pneumonia in children (outpatient no comorbidities)
Microorganism
- 1-3 months: RSV, viruses
- 3 months - 5 years: Strep pneumo, Staph aureus, GAS, H influenza
- 5-18 years: Mycoplasma Pneumonia, C pneumonia, Strep pneumonia, Influenza A or B
Treatment
- 1-3 months: no antibiotic
- 3mon-5yr: Amoxicillin 80mg/kg/day divided TID for 7-10 days
- 5-18yrs: Clarithromycin 15mg/kg/day divided BID for 7-10 days
37
List the microorganism and antibiotic option for otitis externa
```
Organism
- Pseudomonas aeruginosa
- Coliforms
- Staph aureus
Treatment
- Ciprodex 2 drops BID
```
38
List the microorganism and antibiotic option for pyelonephritis
```
Organism
- E coli
- K pneumonia
- P mirabilis
Treatment
- Ciprofloxacin 500mg BID for 7 days
```
39
List the microorganism and antibiotic option for urethritis
```
Organism
- N gonorrhea
- C trachomatis
Treatment
- Ceftriaxone 250 mg IM once and
- Azithromycin 1g PO once
```
40
List the microorganism and antibiotic option for bacterial vaginosis
```
Organism
- G vaginalis
- M hominis anaerobes
Treatment
- Metronidazole 500mg BID PO for 7 days
```
41
List the microorganism and antiviral option for mucocutaneous herpes
Organism
- Herpes Simples 1 or 2
Treatment
- Valacyclovir 2g BID once
42
List the microorganism and antiviral option for genital herpes
Organism
- Herpes simplex 1 or 2
Treatment
- Acyclovir 400mg TID for 5-7 days
43
List the microorganism and antiviral option for shingles
```
Organism
- Varicella zoster
Treatment (initiate within 72hrs)
- Valacyclovir 1g TID for 7 days
- Famciclovir 500mg TID for 7 days
```
44
List the microorganism and antiviral option for infleuza
Organism
- Influenza A or B
Treatment
- Oseltamivir (tamiflu) 75mg daily for 10 days (begin 48hrs after exposure)
45
Discuss the presentation and management of allergic rhinitis
- increased IgE levels to certain antigens resulting in excessive degranulation of mast cells to release of inflammatory mediators and cytokines leading to inflammatory reaction
Management
- reduce exposure to allergens
- oral antihistamines
- cetirizine (reactine)
- loratadine (Claritin)
- intranasal corticosteroids for severe or persistant (>1mon) symptoms
46
Discuss the presentation and management of bronchitis
```
Organism
- 80% viral: rhinovirus, adenovirus, influenza
- 20% bacterial: Mycoplasma pneumonia, C pneumonia, S pneumonia
Bacterial Presentation
- high fever
- excessive purulent sputum
- COPD
Investigations
- CXR if cough >3week, abnormal vital signs and chest findings
Management
- infection control
- 3-4L/d of fluids
- Salbutamol
```
47
Discuss the presentation and management of acute rhinitis
```
Organism
- rhinovirus
- incubation 1-5 days
Presentation
- nasal congestion
- clear to mucopurulent secretions
- sore throat
- cough
- mild fever
- erythematous oropharyngeal mucosa
Management
- peak 1-3 days and subside in 1 week
- secondary bacterial 3-10 days after onset
- Nasal irrigation
- acetaminophen
- dextromethorphan
- decongestants
```
48
Discuss the presentation and management of sinusitis
Etiology
- rhinovirus
- strep pneumonia
- H influenza
- M catarrhalis
Presentation
- symptoms for >7 days or <7 days but acute worsen then bacterial likely
- require nasal obstruction or nasal purulence/discolored postnasal discharge and one other PODS symptoms
- Facial Pain
- Nasal obstruction
- Nasal purulence/discolored postnasal discharge
- Hyposmia/anosmia
- symptoms for 3-4 days with high fever
Management
- mild to moderate then intranasal corticosteroids and reassess in 72h
- severe then intranasal corticosteroids and antibiotics
- first line: amoxicillin
- second line: amox-clav, fluoroquinolones
49
Discuss the presentation and management of pharyngitis
```
Etiology
- adenovirus (90% viral)
- rhinovirus
- group A beta-hemolytic strep
Presentation - Viral
- pharyngitis
- conjunctivitis
- rhinorrhea
- hoarseness, cough
- fever, malaise
Presentation - Bacterial
- pharyngitis
- fever
- headache
- abdominal pain
- absence of cough
- tonsillar/pharyngeal erythema/exudate
- swollen anterior lymph nodes
Investigations
- rapid strep test
Management - Bacterial
- antibiotics to decrease risk of transmission, rheumatic fever and suppurative complications
- risk of glomerulonephritis unchanged
```
50
Discuss the Modified centor score for risk of Group A Beta-hemolytic strep infection
- Cough present
- History of fever >38
- Tonsillar exudate
- Swollen, tender anterior nodes
- Age 3-14
- Age 15-44 (0 points)
- Age >45 (-1 points)
Scoring
- score 0-1 then no culture or treatment
- score 2-3 then culture and treat if positive
- score >=4 then culture and treat immediately
51
Discuss the presentation and management of ebstein barr virus (infectious mononucleosis)
```
Presentation
- pharyngitis
- tonsillar exudate
- fever
- lymphadenopathy
- rash
Investigation
- peripheral blood smear
- antibody test
Management
- symptomatic
- avoid physical activity and contact sports for 1 month until splenomegaly resolves
```
52
Discuss the presentation and management of coxsackie virus (hand, foot, mouth disease)
Presentation
- fever
- pharyngitis
- abdominal pain
- vomiting
- small vesiscles that rupture and ulcerate on tonsils, soft palate and pharynx
- ulcer that are pale grey with surrounding erythema on hands and feet
53
Discuss the antiobiotic treatment for hospital acquired pneumonia
```
No likelihood of MRSA
- Pip-tazo
- Levofloxicin
- Meropenem
Increased likelihood of MRSA
- Pip-tazo
- Plus vancomycin
With high risk of mortality or recent recipient of IV abx in last 90 days
- Two of: pip-tazo, meropenem, levofloxacin, gentamicin
- plus vancomycin
Plus Pseudomonas coverage
- B-lactam: Pip-tazo
- carbapenem: meropenem
- Plus: fluroquinolone or aminoglycoside
- Plus vancomycin
```
54
Discuss the pathophysiology, presentation and management of cellulitis
```
Pathophysiology
- infetion of dermis or subcutaneous tissue by B-hemolytic strep or S aureus
Presentation
- pain, edema, erythema with indistinct borders
- ascending lymphangitis
Investigation
- CBC
- Blood culture if febrile
- Skin swab only if pus
Management
- Cephalexin
```
55
Discuss the pathophysiology, presentation and management of necrotizing fasciitis
```
- infection of deep fascia
Pathophysiology
- type 1: polymycrobial infection with aerobes and anerobes
- type 2: monomicrobial with GAS
Presentation
- pain out of proportion
- edema and crepitus
- spreads rapidly
- shock
Investigation
- clinical diagnosis to bring to operative debridement
- blood and tissue culture
Management
- IV fluids
- surgical debridement
- Unknown organism: mero or pip-tazo + clindamycin + vancomycin
```
56
Discuss the causes of acute blood diarrhea
CHESS
- Campylobacter
- Hemorrhagic E Coli
- Entamaeba histolytica
- Salmonella
- Shigella
57
Discuss the pathophysiology, presentation and management of encephalitis
```
- inflammation of brain parenchyma
Pathophysiology
- virus most common: HSV, VZV, EBV, West nile
- bacterial: spirochetes (Lyme, syphillis)
- virus reach brain parenchyma via nerves
Presentation
- constitutional: fever, chillds
- Headache, nuchal rigidity
- seziures, altered mental status
- focal neurological signs: hemiparesis, ataxia, aphasia
- behavioural disturbance
Investigation
- opening pressure
- PCR
- MRI
Management
- supportive care
- IV acyclovir until HSV ruled out
```
58
Discuss the pathophysiology, presentation and management of generalized tetanus
Pathophysiology
- clostridium tetani produce tetanus toxin which travel retrograde where irreversibly bind presynaptic neurons to prevent release of inhibitory neurostransmitters (GABA)
- Result in disinhibition of spinal motor reflexes resulting in tetany and autonomic hyperactivity
Presentation
- Painful spasms of masseters
- Sustanained contraction of skeletal muscle
- paralysis
Management
- wound debridement
- IV flagyl, IV pen G
- tetanus Ig
59
Discuss the pathophysiology, presentation and management of leprosy
Pathophysiology
- Mycobacterium leprae transmitted via nasal secretions
- granulomatous disease
Presentation
- lesions on cooler body tissue
- Paucibacillary: <=5 hypoesthetic lesions
- multibacillary: >=6 lesions with symmetrical distributions
- leonine facies
Investigation
- Skin biopsy down to fat
Management
- paucibacillary: dapsone daily + rifampin monthly x6month
- multibacillary: dapsone + rifampin monthly + clofazimine monthy x 12 months and low dose clofazimine daily x 12 months
60
Discuss the pathophysiology, presentation and management of Lyme Disease
Pathophysiology
- borrelia bourgdorferi transmitted by Ixodes tick
- require >36h tick attachment
Presentation
- Stage 1: malaise, fatigue, headahce with erythema migrans
- Stage 2: CNS: aseptic meningitis, CNVII palsy, Cardiac: heart block
- Stage 3: monoarticular or olgioarticular arthritis, encephalopathy
Investigation
- Public health approved
Prevention
- Doxycycline within 72h of an engorged tick in hyperendemic area
Management
- stage 1: doxycycline/amox
- stage 2/3: ceftriaxone
