Infectious Diseases Flashcards
Investigations in suspected MRSA?
screening cultures
CXR
Management of MRSA?
vancomycin/daptomycin/linezolid
Features of C. Diff?
fever, nausea, abdo pain, watery diarrhoea
Investigations in suspected C. Diff?
stool PCR for toxins A + B
Management of C. diff?
vancomycin or fidaxomicin +/- metronidazole (if ileus present)
When should klebsiella pneumonia be considered?
Aspiration pneumonia
Alocholics
Abscess in the lungs
Common causes of pneumonia?
s. pneumoniae, h. influenzae, s. aureus, GAS
Signs of pneumonia?
Consolidation (crackles, dull to percuss, bronchial breath sounds)
Ix pneumonia?
- Bloods
- serum gram stain (C + S), blood C+S
- pleural fluid (C+S) IF effusion over >5cm or resp. -distress
- CXR
- bronchoscopy/washings if very ill/refractory to Tx
Criteria for hospitalisation w/ suspected pneumonia?
CURB 65 or PSI (pneumonia severity Index)
CURB-65 Score
Confusion Urea 7mmol/L or BUN >20mg/dL RR >30 sBP <90 or dBP <60 age 65+ (0-1 point treat outpt, 2-3 consider hospital, 4-5 consider ICU)
Management of CAP?
outpt: amoxicillin OR doxycycline OR macrolide (cliarithromycin)
inpatient: Beta lactam (ceftriaxone) +/- macrolide
Management of HAP?
piperacilllin - tazobactam
Prevention of pneumonia?
pneumococcal polysaccharide vaccine: all adults 65+ or younger pts at high risk for invasive pneumococcal disease
pneumococcal conjugate vaccine for 5-17 yr at high risk and has not received the conjugate vaccine
Types of influenzae strains?
strain A (humans, birds, mammals) strain B (humans only)
Features of influenzae?
Systemic (fever, chill, myalgia)
Resp (cough, dyspnoea, pharyngitis)
typically resolve 7-10 days
Ix in influenzae?
primarily clinical
nasopharyngeal swabs for RT- PCR
Tx of influenzae?
Supportive
Neuraminidase Inhibitors (oseltamivir/ zanamivir) - IF severe/high risk for complications
Common causes of cellulitis?
B-hemolytic streptococci
Ix cellulitis?
CBC + differential
blood C+S
skin swab (if open w/ pus)
Tx cellulitis?
cephalexin
consider IV cefazolin
Features of nec fasc?
pain out of proportion
edema + crepitus + fever
necrosis
Ix in nec fasc?
clinical Dx
blood + tissue C+S
serum CK
X- ray
Tx nec fasc?
surgical debridement
IV fluids
IV antibiotics
Features of oral candidiasis?
white patches + can be wiped off w/ erythematous base
red patches localised to palate + dorsum of tongue
Tx oral candidiasis?
topical antifungals
Features of gonococcal arthritis?
arthralgia
bacteremia Fx
pustular skin lesions and migratory arthralgias (if disseminated)
Features of septic arthritis?
acute onset, non wt bear, swelling/warmth often in large weight bearing joints + wrists
Ix in septic arthritis?
gonococcal: blood C+S, endocervical/urethra/rectal swabs
non-gonococcal: Blood C+S
arthrocenteisis (synovial fluid analysis)
CBC w/ diff
gram strain
Management of septic arthritis?
empiric IV: cefazolin +/- vancomycin
gonococcal: ceftriaxone
Management of diabetic food infections?
mild/mod: cefazolin/cephalexin
severe: ceftriaxone+metronidazole
optimise glycemic control, pressure offloading, wound care
Causes of infective endocarditis?
native valve - streptococcus
IVDU - s. aureus
Fx of infective endocarditis?
systemic
cardiac: CHF - MR, AR
embolic/vascular: splinter haemorrhages, janeway lesions, splenomegaly
immune: osler nodes, glomerulonephritis, arthritis
Dx of infective endocarditis?
Dukes Criteria
2 major OR 1 major + 3 minor OR 5 minor
MAJOR: all positive blood cultures, evidence of endocardial involvement
MINOR: predisposing condition fever vascular/ immune signs positive blood culture
Ix of infective endocarditis?
BC x3 (different sites over 1hr apart)
bloods: anemia, ESR increased, RF+
urinalysis + C/S
ECHO: vegetation, regurgitation, abscess
Rx for infective endocarditis?
native valve: vancomycin + gentamicin / ceftriaxone
prosthetic valve: vancomycin + gent + rifampin
surgical
When do pts need prophylactic ABx in prev infective endocarditis?
if high risk +
dental/respiratory procedure (amoxicillin or clindamycin)
skin/soft tissue procedure (cephalexin or clindamycin)
Common organisms in meningitis (age 0-4 wks)
GBS
e. coli
L. monocytogenes
Common organisms in meningitis (age 1-3mo)
GBS
Common organisms in meningitis (age >3m)
s. pnuemoniae
N. meningitiditis
L. monocytogenes (if over 50 + cormorbid)
Ix in meningitis?
CBC, eletrolytes, blood C+S
CSF
imagining/neuro studies if focal neurological signs
Gram stain for S. pneumoniae?
Gram + diplococci
Gram stain for N. meningitidis?
Gram - diplococci
Gram stain for L. monocytogenes?
Gram + rods
CSF findings for bacterial vs viral causes?
Bacterial: high protein, low glucose, neutrophils
Viral: high protein, normal glucose, lymphocytes
Management of meningitis (age 0-4 wks)
ampicillin + cefotaxime
Management of meningitis (4 wks - <3m)
ceftriaxone + ampicillin + vancomycin
Management of meningitis (>3m)
ceftriaxone + vancomycin
+ ampicillin (IF RF for L. monocytogenes)
When is IV dex used in meningitis?
within 20 min prior or w/ 1st dose ABx
continue if proven pneumococcal meningitis
Post exposure prophylaxis in meningitis?
h. influenzae - rifampin (if not adequately immunized or immunocompromised)
n. meningitidis - rifampicin, ciprofloxacin
Rx of encephalitis?
supportive care IV acyclovir (until HSV encephalitis ruled out)
Features of tetanus?
trismus / lockjaw
contraction of skeletal muscle w/ periods of painful muscle spasms
paralysis
HTN/tachycardia/pyrexia
Rx of tetatus?
wound debridement
IV metronidazole OR IV pen G
tetanus immuneglobulin
Prevention of tetanus?
toxoid vaccine
Management of rabies if not previously immunized?
wound care
passive immunization: immunoglobulin
active: inactivated human diploid cell rabies virus vaccine - 4 shots post exposure
Management of rabies if previously immunized?
wound care
two doses of inactivated human diploid cell rabies virus vaccine
qSOFA score
RR 22+
systolic BP <=100
GCS <15
septic shock definition
persistent hypotension requiring vasopresins + serum lactate >2 mmol/L
Management of sepsis?
resp support CVS support IV antibiotics Source control Hydrocortisone IV if unresponsive to fluid resus/vasopressors (norepinephrine)
Fx of leprosy?
chronic granulomatous disease
- tuberculoid type: less lesions, well defined
- lepromatous type: multiple lesions, facies
Ix in leprosy?
skin biopsy for AFB staining
PCR (Mycobacterium leprae)
Cause of lyme disease in N. america?
Borrelia burgdorferi transmitted by ticks
Fx of lyme disease?
BAKE Bell's palsy arthralgia kardiac block erythema migrans: non itchy bulls-eye lesion (stage 1: rash and malaise) (stage 2/3: systemic involvement)
Tx of lyme disease?
doxycycline
Causes of toxic shock syndrome?
staphylococcus or streptococcus
Rx of toxic shock syndrome MSSA and MRSA?
MSSA: clindamycin + cloxacillin
MRSA: clindamycin + vancomycin
Rx of toxic shock syndrome streptococcal?
penicillin + clindamycin
Bug that causes cat scratch disease?
Bartonella henselae (GN bacilli)
Fx of cat scratch disease?
malaise, fever
disseminated: organomegaly, lymphadenopathy, retinitis,IE, encephalopathy, uveitis
Tx of cat scratch disease?
Azithromycin
Cause of rocky mountain spotted fever?
Rickettsia rickettsii
Fx of rocky mountain spotted fever?
flu like prodrome
macular rash d2-4 starting on wrists/ankles then spread centrally
Rx of rocky mountain spotted fever?
doxycycline
Cause of syphilis?
treponema pallidum
Fx of syphilis?
1: chancre
2: maculopapular rash, condylomata lata
3 (tertiary): nodular granulomas, aortic aneurysm/AR
4: neurosyphilis - argyll robertson pupil
What is argyll robertson pupil?
accomodates but does not react to light
Rx for syphilis?
Benzathine penicillin G
Types of TB?
Pulmonary type
Miliary type
Extra-pulmonary
Fx of pulmonary TB?
productive cough non- resolving pneumonia haemoptysis night sweats wt loss, CP
Fx of miliary TB?
widely disseminated spread to other organs
Ix for latent TB?
tuberculin skin test - >10mm induration is + test
Ix for active TB?
- CXR: apical infiltrates, lung volume loss, cavitation, Ghon complexes
- sputum samples: acid fast bacilli smear
+/- BAL (if other pathology also suspected)
Rx of active TB?
RIPE Rifampin Isoniazid (+ pyridoxine) Pyrazinamide Ethambutol
Primary prevention of TB?
BCG vaccine
HIV acute infection features?
non specific illness
heme: lymphopenia, thrombocytopenia
Initial screening test for HIV?
ELISA for anti-HIV antibodies (3mo period before detectable)
Conformation test for HIV?
Western blot
Why does the CD4 count and viral load matter in HIV?
CD4 - progress and stage of disease
Viral load - rate of progression
What vaccines are recommended for HIV+ pts?
flu yearly
pnuemococcal every 5 yrs
HBV + HAV if not immune
HPV
Overall Rx for HIV + pts?
reduce viral load
2NRTIs + 1INSTI or protease inhibitor
Ix in Pneumocystis jirovecii pneumonia?
CXR: bilat. interstitial infiltrates
ABG: reduced pO2, increased alveloar arterial gradient
serum LDH: elevated
PCR
Rx of PJP Pneumonia?
trimethoprim - sulfamethoxazole
What fungi can be inhaled from pigeon droppings?
Cryptococcus neoformans
Features of cryptococcus spp?
opportunistic fungi - think HIV Raised ICP (abducens palsy)
Ix of cryptococcus spp?
LP and indian ink stain
antigen test
Rx of aspergillus spp?
voriconazole or amphotericin B
surgical resection if aspergillioma
Causes of malaria?
plasmodium species
Features of malaria?
flu like prodrome
high spiking fevers + shaking chills
hepatosplenomegaly + thrombocytopenia without leucocytosis
Most lethal type of malaria?
Plasmodium falciparum
- CNS involvement
- ARDS
- AKI
Ix in malaria?
CBC: thrombocytopenia, anemia, elevated LDH
microscopy: blood smear x 3
rapid antigen / PCR
Management of malaria?
chloroquine
Exposure to what causes toxoplasma gondii?
cat feces
ingestion of undercooked meat
Features of toxoplasma gondii?
immunocompetent - mononucleosis like syndrome
immunocompromised - encephalitis
Ring enhancing lesions on CT
Ix in toxoplasma gondii?
serology
CSF wright-giemsa stain
antigen or PCR
Rx in toxoplasma gondii?
Trimethoprim -sulfamethoxazole if immunocompromised
Features of ascaris lumbricoides?
Roundworm
intestinal blockage, pul infiltrates
Features of trichuris trichira?
whipworm (roundworm)
diarrhoea
abdo pain
Features of strongyloids stercoralis?
threadworm (roundworm)
pruritic dermatitis
abdominal pain, diarrhea, pruritis ani
Rx of roundworms?
mebendazole
albendazole
ivermectin
What flatworm is found in undercooked pork?
Taenia solium
What flatworm is found in undercooked beef?
taenia saginata
What flatworm is found in raw fish?
diphyllobothrium latum
common in great lakes
Features of diphyllobothrium latum?
b12 deficiency
Rx of flatworms?
Praziquantel
What flatworm can be found in fresh water?
Schistosoma species
Features of schistosoma spp infection?
Swimmers itch Acute schistosomiasis (Katayama) - hypersensitivity reaction
Features of chronic schistosomiasis infection?
Neurological manifestation
Pulmonary manifestation
Most common causes in returning traveller?
malaria (parasite)
viral - mononucleosis like syndrome, hepatitis
salmonella