Infective Endocarditis

Presentation

  • Fairly nonspecific
  • New murmurs and classic peripheral stigmata are uncommon signs

Duke Criteria

  • 2 major OR 1 major + 3 minor OR 5 minor
  • Major criteria
    • Culture evidence of IE organisms
      • 2X blood cultures positive for typical organisms
      • Cultures persistently positive 12 hours apart
      • Cultures should be drawn 1 hour apart and at least 3 should be peformed
    • Echocardiographic evidence
      • Intracardiac mass
      • Myocardial abscess
      • Partial dehiscence of prosthetic valve
      • New-onset valvular regurgitation
  • Minor criteria
    • Predisposing heart condition or drug use
    • Fever >38C
    • Vascular phenomenon (septic embolic, mycotic aneurysm, Janeway lesions)
    • Immunological phenomenon (GN, Osler nodes, Roth spots, RF positive)
    • Blood cultures consistent for dx but not meeting major criteria requirements
    • Echo results consistent for dx but not meeting major criteria requirements

Management

  • Standard empirical regimen
    • Benzylpenicillin 1.8g IV q4hours
    • Flucloxacillin 2g IV q4hours
    • Gentamicin 6mg/kg IV for 1 dose, then either 1 or 2 further doses based on renal function
  • Subsititute vancomycin 1.5g IV bd for benzylpenicillin and flucloxacillin if
    • Cardiac device in situ (prosthetic valve, ICD etc.)
    • Hospital-acquired
    • Clinical suspicion of MRSA
  • Cease gentamicin once susceptibilities known; howeevr,  mantain low dose for streptococcal or enterococaal endocarditis
  • Uncomplicated viridans streptococci, treat for 2 weeks
    • Benzypenicillin 1.8g IV q4hours
    • Gentamicin 1mg/kg IV q8hours

Social issues

  • Requires PICC line; not ideal for a druggie with a craving for a hit of his favourite stuff
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Hepatitis C Salient Points

Presentation

  • History depends on stage
    • Replication – asymptomatic but lab finding come up
    • Prodromal – anorexia, N+V, pruitus, malaise and fatigue
    • Icteric – dark urine, pale stools, jaundice, RUQ pain
    • Convalescent – resolution
  • Tender hepatomegaly with firm, sharp and smooth edge

Natural history and course

  • 70% of acute hep C patients will go on to be chronically infected
  • 20% risk of developing cirrhosis over 30 years; the risk is much less (1-2%) for the young infected
  • 1% per year risk of HCC in cirrhotic patients

Diagnosis

  • LFTs may show hepatocellular picture
    • Beware the LFT with decreased synthetic function but normal transaminases – implies severe disease
  • Coags to estimate synthetic function
  • Hepatitis C
    •  First test for anti-HCV
    • If anti-HCV positive or clinically suspicious despite negative anti-HCV, HCV RNA testing should be done
    • HCV genotyping should be performed prior to interferon treatment to direct regimen
    • Liver biopsy for fibrosis stage = gold standard = directs treatment
Interpretation of HCV Assays
Anti-HCV HCV RNA Interpretation
Positive Positive Acute or chronic HCV depending on the clinical context
Positive Negative Resolution of HCV; Acute HCV during period of low-level viremia.
Negative Positive Early acute HCV infection; chronic HCV in setting of immunosuppressed state; false positive HCV RNA test
Negative Negative Absence of HCV infection

 

Management

  • Hepatitis C
    • Treatment directed by biopsy – bridging fibrosis or compensated cirrhosis
    • peginterferon-alpha + ribavirin
    • HCV RNA test at Week 0 and Week 12 of therapy
    • Genotypes 1 and 4 require a 48 week course
      • If the HCV RNA at Week 12 shoulds complete early virologic response (EVR), continue treatment
      • If RNA at Week 12 shows partial EVR, repeat RNA at Week 24 and decide to stop (if RNA postive) or continue (if RNA negative) treatment
      • If no EVR at Week 12, stop treamtnet
    • Genotypes 2 and 3 require a 24 week course
      • HCV RNA at Week 24 determines treatment failure or success
      • If treatment sucessful, repeat RNA at Week 48 to establish sustained response
    • All patients with cirrhosis regardless of genotype and treatment response should be monitored half-yearly for HCC
    • Retreatment is  only indicated if the first failure was with a non-pegylated interferon +/- ribavirin
    • Ledipasvir and sofosbuvir pretty much kick ass but are still new and exepsnive

 

ID OSCE Prep – Headache and Fever in the Adult (with meningitis)

  • History
    • Patterns of fever, SOCRATES of headache
    • Review of symptoms
      • Systemic – Night sweats, chills, rigors, muscle aches, rashes and skin lesions, N+V
      • Neurological – neck stiffness, photophobia,  altered mental state
      • GIT – Abdominal pain, constipation, diarrhoea
      • Respiratory – Cough, sputum, haemoptysis, pleuritic pain
      • Genitourinary – frequency, dysuria, discharge, dyspareunia, lesions (HSV encephalitis), recent sexual changes
      • ENT – otitis or sinusitis (S. pneumoniae)
    • Travel (Russia-N. Australia Orientia tsutsugamushi assoc. with eschar)
    • Exposure: bathing in warm fresh water (Naegleria fowleri, leptospirosis), animal bites, ticks, cleaning out sheds with rats (murine typhus)
    • Occupation (abattoir worker, Q fever)
    • Risk factors: IVDU, pregnancy, EtOH abuse, age>50 (L. monocytogenes)
    • PMHx – immunosuppression, HIV
  • Exam
    • Mental state
    • Resisted neck flexion, photophobia
    • Head jolt accentuation test (lateral head rotation worsens headache = very sensitive)
    • Brudzinski (forced flexion of the neck elicits a reflex flexion of the hips) Kernig’s (an inability to straighten the leg when the hip is flexed to 90 degrees); both not sensitive
    • Pailloedema, focal neurology (raised ICP)
  • Ddx
    • Bacterial meningitis
    • Viral meningitis
    • HSV encephalitis
    • Subarachnoid haemorrhage
    • Fungal meningitis
  • Investigations
    • FBP, U&Es, Renal fx (for vanc dosing)
    • Serum PCT – helps diff. bacterial aetiology
    • Blood cultures before Abx – 3X from three different sites; do not delay Abx
    • LP before ABx IF no clinical signs of increased ICP; otherwise after CT head
      • Opening pressure >200 = bacterial or cryptococcal meningitis
        • V. high opening pressures >300 + unremarkable findings, think Cryptococcus
      • WBC – >500/ul;  >80% PMN = bacterial, lymphocytes everything else
      • Glucose = normal in HSV and aseptic
      • Gram stain, PCR, India ink
    • CT head – rules out ICP before LP; rules out SAH
    • VDRL, HSV serology
  • Management
    • Empirical – within 30 minutes of assessment
      • Dexamethasone 10mg IV with the first Abx dose then q6h for 4 days
      • Ceftriaxone 4g IV od
      • Add  benzypenicillin 2.4g IV q4h if IC, adult>50, hx EtOH, pregnant, or debilitated
      • Add vancomycin 1.5g IV q12h if otitis or sinusitis or recent Mx with beta-lactam or G+ diplococci on LP stain
      • Add acyclovir 10mg/kg IV q8h if suspicious of HSV (evidence is weak)
      • Add amphotericin B 1mg/kg IV od PLUS flucytosine 25mg/kg IV q6h if suspicious of cryptococcal meningitis
    • Directed
      • N. meningitides – Benzypenicillin 1.8g IV q4h for 5 days
      • S. penumoniae – Benzypenicillin 2.4g IV q4h for 14 days; add vanc as above if MIC to benpen is >0.125 mg/L
      • Hib – Ceftriaxone as above for 7 days, benpen as for strep if susceptible
      • Doxy 100mg bd is a generally reasonable guess for most of the weird and wacky stuff
    • Prophylaxis
      • Children Rifampicin PO BD for 2 days
      • Adults Ciprofloxacin PO one dose
      • Pregnant women Ceftriaxone IM singe dose
  • Supplementary
    • Indications of increased ICP
      • Immunocompromised state
      • History of CNS disease (eg, mass lesion, stroke, or focal infection)
      • Seizure within 1 week of presentation
      • Papilledema
      • Abnormal level of consciousness
      • Focal neurologic deficit
    • Some good stuff worth a listen here http://emcrit.org/podcasts/meningitis/

ID OSCE Prep – The Patient With An STI

Obviously a massive topic so apologies if it seems a tad disorganised.

  • Sexual
    • Presenting complaint
      • Presence of systemic symptoms
      • Ask about ulcers and lymphadenopathy
      • Precipitating factors – new partners, new practices, ran out of condoms etc.
      • Dysuria in women – internal (NG, CT) vs. external (HSV, candidiasis, trich)
      • Vaginal discharge – normal amount and no odour (NG/CT), profuse and purulent (trich), malodorous and slightly increased (BV)
      • Abdominal pain, bleeding (PID)
      • Ask about the triad of urethritis, arthritis and uveitis (Reiter’s)
    • Sexual History
      • Sexual orientation. Are your sex partners men, women or both?
      • Have you been sexually active over the last 12 months?
      • Have you travelled recently?
      • 5 Ps
        • Partners
          • Length of relationship
          • Number of partners
          • Partner risk factors – drug use, partner risky sexual behaviour
          • Practices
            • Penetrative vs. oral
            • Anal
          • Protection
          • PMHx
            • Ever dx with an STI
            • Ever tested for HIV and other STIs
            • Has your partner ever been dx or managed for an ST
          • Pregnancy prevention
            • Are you using contraception?
            • If using the pill, are you taking the pills every day at roughly the same time?
            • Are you trying to for a child?
  • Examination
    • Ulcers
      • Syphilis – Painless, non-tender, indurated with firm, non-tender inguinal adenopathy
      •  H. ducreyi – Painful, purulent, inguinal adenopathy with fluctuance or erythema
  • Investigations
    • B-HCG
    • Urethritis
      • Urethral swab – Gram’s stain for dx of GU vs. NGU
      • First void urine for NG/CT NAAT
    • Epididymitis
      • Doppler – absence of flow indicates torsion vs. epididymitis
    • Vaginal discharge analysis
      • pH Candida <4.5 < BV < Trichomonas
      • Amine odour with 10% KOH – BV, possibly trich
      • Wet mount – mycelia, motile trichomonads, clue cells (BV)
    • Genital ulcer
      • Syphilis serology (VDRL, EIA)
      • HIV test
      • Herpes serology
      • If progressive beyond the normal hx of herpes (3/52) or syphilis (6/52) biopsy for donovanosis, carcinoma and nonveneral dermatoses
  • Management
    • Urethritis – Ceftriaxone 500mg IV single dose PLUS azithromycin 1g PO single dose
    • Epididymitis – Ceftriaxone 500mg IV for 3 days PLYS azithromycin 1g PO once weekly for two weeks
    • BV – Metronidazole 400mg PO bd for 7 days, reduce to 300mg if pregnant
    • Trichomoniasis – Metronidazole 2g PO single dose
    • Vulvovaginal candidiasis – Clotrimazole 10% vaginal cream 1 applicatorful single dose at night)

ID OSCE Prep – Infection (in the Return Traveller)

  • Further questioning
    • What is the GCS? Is she (relatively) well?
    • Systemic review of symptoms
      • Systemic – Night sweats, chills, rigors, muscle aches, rashes and skin lesions, N+V
      • Neurological – neck stiffness, photophobia, headache,  altered mental state
      • GIT – Abdominal pain, constipation, diarrhoea, jaundice (urine and stool), blood
      • Respiratory – Cough, sputum, haemoptysis, pleuritic pain
      • Cardiovascular – Dental work, previous hx of rheumatic fever
      • Genitourinary – frequency, dysuria, discharge, dyspareunia, lesions
    • Have you been travelling? Where did you go? How long was the plane flight?
    • Did you have sex? Were you using protection? Condoms or the pill?
    • Did you bath in lakes or rivers?
    • Were you on malarial prophylaxis?
    • Were you vaccinated?
  • Ddx Fever
    • Malaria – ask for patterns of fever, urine colour
    • Dengue – SEA, myalgia
    • Typhoid – typhoid vaccine only 70% protection, enteric symptoms are only variably present
    • Brucellosis
    • Typhus; scrub or murine endemic – pretty much presents as everything; include in ddx of pneumonia
    • Q fever
    • Pulmonary embolism
    • HAV, HBV
    • TB
    • Schistosomiasis
    • Trypanosomiasis – probably be dead by now
  • Ddx diarrhoea
    • Typhoid
    • Shigella
    • Entamoeba histolytica
    • Campylobacter jejuni
    • Giardia lamblia
    • E. coli –enteroaggregative, enteropathogenic
  • Labs
    • FBP
      • Thrombocytopenia – malaria, dengue, scrub fever, Q fever
      • Eosinophilia – helminths, schistosomiasis
    • LFTs
      • AST and ALT elevated, AST:ALT ratio high (around 1.2) – malaria
    • ID-ey stuff
      • Procalcitonin – may help distinguish bacterial from viral and other non-infective causes
      • Thick and thin films repeat X3 – negative films does not rule out malaria
      • Serology – keep one set of serology bloods for the matching with convalescent bloods
      • Septic screen – blood cultures, urine M/C/S
      • Stool M/C/S
  • Mx
    • Malaria – because it’s always malaria
      • 1. artemether+lumefantrine tablets 20+120 mg
        adult and child more than 34 kg: 4 tablets (child 5 to 14 kg: 1 tablet; 15 to 24 kg: 2 tablets; 25 to 34 kg: 3 tablets) orally with fatty food or full-fat milk, at 0, 8, 24, 36, 48 and 60 hours, making a total adult dose of 24 tablets in 6 doses
      • 2. atovaquone+proguanil tablets 250+100 mg (adult formulation)
        adult and child more than 40 kg: 4 tablets (child 11 to 20 kg: 1 tablet; 21 to 30 kg: 2 tablets; 31 to 40 kg: 3 tablets) orally with fatty food or full-fat milk, daily for 3 days
      • 3. quinine sulfate 600 mg (adult less than 50 kg: 450 mg) (child: 10 mg/kg up to 600 mg) orally, 8-hourly for 7 days PLUS EITHER doxycycline 100 mg (child more than 8 years: 2.5 mg/kg up to 100 mg) orally, 12-hourly for 7 days, which need not commence on day 1 OR (for pregnant females or children) clindamycin 300 mg (child: 5 mg/kg up to 300 mg) orally, 8-hourly for 7 days.

      • If severe; artesunate (adult and child) 2.4 mg/kg IV, on admission and repeat at 12 hours and 24 hours, then once daily until oral therapy is possible. When patient is able to tolerate oral therapy, give a full course (6 doses) of artemether+lumefantrine
    • Typhoid – azithromycin 1 g (child: 20 mg/kg up to 1 g) orally, or IV until oral azithromycin can be tolerated, daily for 7 days
    • Brucellosis – doxycycline 100 mg (child more than 8 years: 2.5 mg/kg up to 100 mg) orally, 12-hourly for 6 weeks PLUS gentamicin 4 to 6 mg/kg IV, for 1 dose, then monitor plasma concentrations and adjust dosage accordingly). Give gentamicin for the initial 7 days.