Infectious Disease Flashcards
Define fever
- 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
List the differential for a fever in a returning traveller
Unique for Returning Traveller - Malaria - Dengue fever - Typhoid - Chikungunya - Mononucleosis - Rickettsial infection - Ameobiasis Other Common - Pneumonia - TB - C diff - Hepatitis - STI
Discuss the epidemiology, presentation, investigations and management for malaria
- 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 clindamycinDiscuss the epidemiology, presentation, investigations and management for thyphoid fever
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
Discuss the contraindications to a lumbar puncture
- papilledema
- focal neurological deficit
- abnormal LOC
- new onset seizure
- immunocompromised
- recent head trauma
- known cancer
- known sinusitis
Discuss the findings of bacterial, viral and TB/fungal meningitis
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
Discuss the presentation and management of meningitis
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 >20List the risk factors and pathogenesis of infective endocarditis
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
- FungiDiscuss the presentation and investigation for infective endocarditis
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
List the Duke criteria for diagnosis of infective endocarditis
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 possibleDiscuss the management of infective endocarditis
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 procedureList the diagnosis of HIV
- 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
List the opportunistic infections associated with specific CD4 count
>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
Discuss primary prevention in HIV
- CD4 100-200 then Septra PO to prevent PCP
- CD4 <100 Septra PO to prevent PCP and toxoplasmosis and Azithromycin to prevent MAC
List the indications and types of anti-retroviral medication
- 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
List the common HIV formulation
- usually 2 NRTI with 1 NNRTI or 2 NRTI with 1 protease
Atriplia - Tenoforvir (NRTI) + Emtricitabine (NRTI) + Efavirenz (NNRTI)
Discuss the different infectious disease precautions
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
Discuss factors leading to increasing antibiotic resistance
- over use of unnecessary prescription
- improper antimicrobial use
- lack of proper infection control
- lack of resistance tracking
Discuss the risk factors for tuberculosis
- 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
Discuss the presentation, investigation and management of tuberculosis
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
Discuss the diagnosis of TB
- 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
Discuss the risk factors and pathophysiology of clostridium difficile
- 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
Discuss the presentation, investigation and treatment for c difficile
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 weeksDiscuss the diagnosis of acute otitis media
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
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
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
Discuss secondary therapy for acute otitis media
No improvement after two days
- Amox-clav 45-60mg/kg/day divided TID for 10 days
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
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
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
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
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
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
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
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
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
List the microorganism and antibiotic option for otitis externa
Organism - Pseudomonas aeruginosa - Coliforms - Staph aureus Treatment - Ciprodex 2 drops BID
List the microorganism and antibiotic option for pyelonephritis
Organism - E coli - K pneumonia - P mirabilis Treatment - Ciprofloxacin 500mg BID for 7 days
List the microorganism and antibiotic option for urethritis
Organism - N gonorrhea - C trachomatis Treatment - Ceftriaxone 250 mg IM once and - Azithromycin 1g PO once
List the microorganism and antibiotic option for bacterial vaginosis
Organism - G vaginalis - M hominis anaerobes Treatment - Metronidazole 500mg BID PO for 7 days
List the microorganism and antiviral option for mucocutaneous herpes
Organism
- Herpes Simples 1 or 2
Treatment
- Valacyclovir 2g BID once
List the microorganism and antiviral option for genital herpes
Organism
- Herpes simplex 1 or 2
Treatment
- Acyclovir 400mg TID for 5-7 days
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
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)
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
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
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
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
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
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
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
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
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
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
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
Discuss the causes of acute blood diarrhea
CHESS
- Campylobacter
- Hemorrhagic E Coli
- Entamaeba histolytica
- Salmonella
- Shigella
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
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
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
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
