ID Flashcards

Question

Meningitis Chemoprophylaxis Criteria

Answer 1

1. Household contacts / overnight stay in last 7 days inc hostel, dormitory or military 2. Sexual and intimate contacts (sharing saliva) 3. Family daycare attendees 4. Travel contacts immeidately adjacent to index case for >8hrs 5. HCW providing airway Mx if mask not worn 6. Special Hib < 24 months old or 4 yrs + not immunised Regimes: 1. Ciproflxacin 500mg single dose (30mg/kg up to 125mg < 5yrs) 2. Rifampicin 600mg PO q12h for 2/7 (10mg/kg kids) 3. Ceftriaxone 250mg IM - preferred in pregnant women 3. Hib a. Rifampicin 600mg PO QID 4 days b. Ceftriaxone 1g IM QID 2 days c. Hib vaccination course when well

Answer 2

Bacterial < 3mo * GBS * E coli * Listeria * S aureus * Pseudomonas <6yrs old * Hib * N meningitidis * S pneumonia Adults * N meningitidis * S penumoniae * Klebisella * S aureus * Listeria (> 50yrs) * Ecoli (immuno comp) Viral Echo, ENtero, Coxsackie, HSV, CMV, VZV, EBV Other Mycobacterium tuberculosis Crypotcoccus neoformans (Immunocompromised) Aseptic

Answer 3

SAH Br + Xanthochromia from 4th tube RBC > 1000 suggest not from traumatic tap

Answer 4

Risk of herniation 5% in acute bacterial meningitis Any concerns for Raised ICP: Altered LOC / confusion Severe headache Vomiting ++ Brainstem signs - Papilloedma, ophthalmoplegia, posturing, irreg respirations Seizure Other: Known SOL Imunocompromise - HIV

Answer 5

HHV 3 Transmission - direct contact w/ vesicular fluid, droplet Incubation - 10-21d Communcability - 48 hrs before rash, until all lesions crusted High risj groups 1. Immunocompromised i. Hameatological malignancy ii. Chemotherapy iii. HIV 2. Neonates < 1mo 3. Pregnancy females Course Rash evolves over 4-5/7 Macules → papules → vesicles → pustular type lesions → crusting lesions Crusting scabs can then last 1-2/52 Complications 1. Viral Pneumonia 2. Infection in Pregnancy 3. Infection of newborn 4. Secondary skin infection 5. Reye's Syndrome 6. Encephalitis / Meningitis 7. Rare Neuro - GBS, transverse myelitis, acute cerebellar ataxia 8. Hepatitis 9. Shingles **Infection in Pregnancy** Infection within 2/52 of delivery = greatest risk of developing neonatal varicella (fever + vesicular rash +/- pneumonia/meningoencephalitis/hepatitis. Mortality = 25% and is higher in premature babies Rx with acyclovir to reduce her risk 2 complications NB treatment does not reduce risk of transmission to baby If delivery occurs within 5 days of the patient developing a rash, the neonate should receive varicella-zoster immune globulin as PEP. Congenital varicella syndrome Infection between 8-20/40 Transmission risk is low (2%) IUGR, Skin and ocular abN, hypoplastic extremities, DD

Answer 6

EYE - peri-orbital oedema, Subconunctival haemorrhage Pulmonary - Haemoptysis, PTx, Pneumomediastinum, SC emphysema, Diaphragm rupture SKIN - petechiae ENT - epistaxis GI - umbilical and inguinal hernia, rectal prolapse

Answer 7

Org: RNA virus **Highly contagious** Transmission: airborne resp droplet Incubation: 10d, rash appears 14d Reservoir: Humans Communicability: 3-5d before rash until 4 days post rash Clinical Fevers 3 C's - cough, coryza, conjunctivitis **Koplick spots** (grains salt on red background) Rash begin head and neck before becoming generalised GIT Sx Lymphadenopathy / Splenomegaly DDx Rubella Parvovirus Ix Routine bloods - leucopaenia and thrombocytopaenia **IgM** - anti-measles IgM increases to 100% betw/ 4-14d after onset rash PCR Rx Infection control for droplet - N95, PPE, negative pressure **Vitamin A** (deficiency predisposes to severe and complicated course **Complications** AOM Pneumonia Meningitis Subacute Sclerosing Panencephalitis Prevention Vaccination Exclusion for 4 days post rash PEP - Chemoprophylaxis Household / overnight / sharing accommodation / students of school Waiting room contacts Travel contacts up to 2 rows infront/behind All HCW with contact

Answer 8

Org: RNA virus **Potential to cause congenital abN pregnancy** Transmission: resp droplet or direct contact Incubation: 2-3/52 Reservoir: Humans Communicability: 7d before rash until 4 days post rash/ Susceptibility: infants born to vaccinated mothers confer protection for 6-9/12, life long immunity after infection Clinical 25-30% Subclinical Clinical illness usually mild Constitutional symptoms Mild URTI Sx LN - post chain **Rash 50-80%** - maculopapular Ix Rubella Specific IgM PCR Complications Pregnancy related 1. Miscarriage 2. Stillbirth 3. **Congenital Rubella Syndrome** a. < 25% pregnancies that acquire rubella 1st trimester b. Risk falls > 16/40 gestation, Rare > 20/40 c. Sx: Cerebral Palsy, Deafness, Blindness / Cataracts / CHD Uncommon: arthralgia, encephalitis

Answer 9

Toxic shock syndrome = infection with S aureus or Gp A Streptococcus which release harmful exotoxins, which can function as superantigens. Mortality up to 80% if not treated. Pathophysiology: Bacteria produce superantigens, which trigger T lymphocytes, which bypass normal immune checkpoints and lead to cytokine release and multiorgan injury. Epidemiology: **Streptococcal TSS** is more common and affects** local, invasive infection** **all ages**. This usually starts as a ** local, invasive infection** like cellulitis, pharyngitis, pneumonia, or necrotizing fasciitis. Up to 20% of these patients with an invasive infection can experience TSS. **Staphylococcal TSS** (due to MSSA or MRSA) is less common and usually affects those **< 40 years**. Usually occurs due to colonization and not invasive infection. May occur due to **menstrual related causes (50%) ** but is also associated with postsurgical, postpartum, burns, focal infections, soft tissue injuries. Presentation: Combination of two factors: 1) toxin production (rash, multiorgan dysfunction, flu-like symptoms) and 2) significant focus of infection. Classic presentation: Diffuse red rash, hypotension, fever, organ dysfunction. Patients may also consitutional symptoms May have mucosal involvement, and desquamation is late 1-3 weeks after initial Sx. Rapid decompensation: shock, acute kidney injury, neurologic symptoms due to cerebral edema, cardiopulmonary complications. Ix One of the first findings is **renal injury**, which may precede hypotension. Inc CK, electrolyte abnormalities, and liver function test abnormalities common. LATE = Thrombocytopenia, anemia, and DIC BC +ve in 60% of streptococcal cases but < 5% of staphylococcal cases. Consider in anyone with** red flag** symptoms: * Diffuse rash in a patient with systemic illness * Known /suspected Strep/Staph infection + sepsis/hemodynamic instability * Localized infection that appears minor cf patient hemodynamics. * Patient with viral, GI, or flu like illness who is hemodynamically unstable with no clear etiology. * Pregnant + septic shock = 20 x inc risk of TSS Mx 1. Hypotension * Resuscitate with IVF + early vasopressors * Endothelial injury -> risk of edema with extensive IV fluid resuscitation * Stress dose steroids (hydrocortisone) if hemodynamics refractory 2. Broad spectrum antibiotics - Taz / clinda / meropenem * Clindamycin inhibits toxin production 3. Source control (remove foreign body, drain abscess, debridement for necrotizing fasciitis). Other treatments: IVIG can neutralize the toxin. Observational studies suggest mortality benefit. RCTs show no statistically significant benefit, but improved SOFA score.

Answer 10

Hand, foot and mouth disease is a common, infectious skin disorder most frequently affecting infants and young children. It can affect older children and adults occasionally. It is usually caused by coxackievirus A16 but some cases are caused by enterovirus 71. Transmission: very contagious faeco-oral contamination Incubation period is 3–5 days Reservoir: Humans Communicability: blister, nasal and throat secretions, virus persists in stool for weeks Presentation Small blisters appear on palms and soles Painful ulcers appear in the oral mucosa. Bottocks / nappy area DDx EM, pustular psoriasis and EBV

Answer 11

Caused by Mycobacterium tuberculosis **Risk factors**: HIV, immigration from an endemic area, immunosuppression, malnutrition **Primary TB** Usually asymptomatic and progresses to latent TB with no intervention CXR: often normal, hilar adenopathy, Ghon focus **Latent TB** Asymptomatic Screening: tuberculin skin test (TST) or interferon-gamma release assay (IGRA) Tx: rifampin for 4 months, INH-rifampin daily for 3 months, or INH-rifapentine weekly for 3 months. Alternative is INH for 9 months or 6 months. **Reactivation TB** Sx: fever, night sweats, weight loss, productive cough, hemoptysis CXR: upper lobe infiltrates, apical cavitary lesions Dx: sputum smears for acid-fast bacilli (AFB) x3, sputum or tissue culture for AFB (gold standard) Tx: rifampin, INH, pyrazinamide, ethambutol (RIPE) for 6 months Monitor LFTs, add vitamin B6 (prevent peripheral neuropathy due to INH) Comment: Positive TST determined by mm of induration and risk factors 15 mm: people with no known risk factors 10 mm: immigration from high-prevalence countries < 5 years ago, injection drug use, residents/employees of high risk settings (homeless shelter, correctional facilities, hospitals, nursing homes), children < 4 years old or exposed to adults in high risk categories 5 mm: HIV infection, recent TB contact, CXR consistent with prior TB, organ transplant, TNF-α inhibitors or chronic steroids

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