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
