Infectious Diseases Flashcards

1
Q

Brucellosis (organism, endemic areas, exposure)

A

Organism: Brucella bacteria
Areas: NSW and QLD
Exposure: Wild pigs (i.e. pig hunters) through cuts and wounds

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2
Q

Hepatitis A (incubation, prognosis, complications, clinical features)

A

Incubation period: 15-45 days

Prognosis: Recovery in 3-6 weeks

Complications: Fulminant hepatitis (rare)

Clinical features:
Pre-icteric (prodromal) phase
- Anorexia, nausea +/- vomiting
- Malaise
- Headache
- Distaste for cigarette in smokes
- Mild fever
\+/- diarrhoea
\+/- upper abdominal discomfort

Icteric phase

  • Dark urine
  • Pale stools
  • Hepatomegaly
  • Splenomegaly
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3
Q

Hepatitis C - key points

A

● Curable
● Direct-acting antiviral drug are highly effective and well tolerated
● Goals of treatment: prevent liver cirrhosis, prevent transmission
● Treatment can be prescribed by specialists, GPs, nurse practitioners
○ GPs can prescribe independently without specialist guidance one they are experienced in
managing hepatitis C

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4
Q

Hepatitis C - who to test

A
IVDU
Prison 
Sexual partner with hep C
HIV or hepatitis B infection 
Child of mother with Hep C
Evidence of liver disease
Needle stick injury 
Tattoos or body piercing
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5
Q

Hepatitis C - how to test

A
  1. Perform hepatitis C virus antibody
  2. If positive, test for HCV RNA +/- genotyping
    ● In practice 1 + 2 would be performed together
    ● Not necessary given antivirals target genotype 1-6 but useful for individuals at high risk of
    re-infection
    ● MBS funded
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6
Q

Hepatitis C - pretreatment assessment

A
  1. Confirm current hepatitis C infection (HCV RNA)
  2. Assess whether treatment-naive or previously treated and not cured
  3. Assess for presence of cirrhosis
    Risk factors
    - Longer duration of infection
    - Alcohol consumption
    - Obesity
    - Type 2 diabetes
    - Co-infection with hepatitis B or HIV
    Examination
    - Spider naevi, palmar erythema, gynaecomastia, splenomegaly
    Investigations
    - Pathology: Thrombocytopaenia, low albumin, prolonged PT/INR, aspartate aminotransferase-to-platelet ratio index > 1.0
    - Imaging: FibroScan
    Significance
    - Determines treatment regimen and duration
    - Needing ongoing surveillance for hepatocellular carcinoma, oesophageal varices and
    osteoporosis
  4. Consider whether patient has hepatitis B or HIV co-infection
  5. Review medications for potential drug interactions with direct-acting antiviral drugs
    ● Drug interactions between hepatitis C and HIV can be challenging and specialist input is
    recommended
  6. Consider pregnancy
  7. Consider whether patient has decompensated liver disease
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7
Q

Hepatitis C - medications and monitoring post-treatment

A

Medications
Consists one of 3 tablets and taken daily for 8 to 12 weeks.
● Patients with cirrhosis are treated for 12 weeks.

Monitoring after hepatitis C treatment
All: HCV RNA test at least 12 weeks after completion of treatment to confirm cure.
Long-term: For those with persisting liver pathology and at risk of reinfection.
Re-infection: Perform annual hepatitis C virus RNA in people with risk factors for hepatitis C reinfection.

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8
Q

Hookworm (key point, clinical features, diagnosis, treatment, prevention)

A

Key point
● Common in humid tropic regions
● Acquired by walking barefoot on earth contaminated by faeces - larvae penetrates the skin, travels through
the lungs and settle in the small intestine
Clinical features: local irritation/eruption at point of entry, followed by 1-2 weeks of respiratory symptoms, iron/protein
deficiency anaemia.
Diagnosis: faecal microscopy.
Treatment: Albendazole 400mg STAT
Prevention: Wearing shoes and socks in endemic regions.

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9
Q

Influenza A - oseltamivir doses

A
Needs to be dosed according to eGFR
CrCl >60 75mg PO BD
CrCl >30-60 30mg PO BD
CrCl >10-30 30mg PO daily
ESRD Not recommended
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10
Q

Leptospirosis (exposure, treatment)

A

Exposure: Through urine of affected animals
Treatment: Doxycycline 100mg PO BD for 7 days

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11
Q

Listeriosis (organism, exposure, significant, treatment)

A

Organism: Listeria monocytogenes
Exposure: contaminated food, unwashed vegetables, unpasteurised foods
Significant: Stillborn in pregnancy
Treatment: amoxicillin 1g PO/IV 8 hourly for 10-14 days

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12
Q

Measles (epidemiology, characteristic, pathology, complications, treatment, DHHS)

A

Epidemiology: endemic, immunity lifelong.

Characteristics: Koplik spots (tiny white spots like grains of salt, opposite the molars).

Pathology: Measles IgM rising 3-5 days after the onset of the rash.

Clinical features:

  • Prodromal, 3-4 days, The three Cs’: cough, coryza and conjunctivitis
  • Exanthema, 4-5 days, Blotchy, bright red maculopapular eruption. May become confluent and blanches under pressure.
  • Convalescent, 7-10 days, Recover period.

Complications: otitis media, pneumonia, diarrhoea, miscarriage/premature delivery, encephalitis.

Treatment: No cure. Rest, avoid bright lights and stay in bed until fever subsides.
Prevention: MMR vaccine. Consider normal immunoglobulin ASAP from exposure if under 12 months or MMR is contraindicated.

Department of health advice:
1. Isolate suspected cases
2. Notify DHHS
3. Measles serology +/- PCR (PCR requires approval)
4. Offer MMR vaccine to eligible individuals (born after 1966, <14 years of age) - generally given 12 months
and 18 months

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13
Q

5F presenting with fever and lethargy. Returned from a trip from Brazil 2/7. Current outbreak of measles. COVID-19 negative.

  1. What are the six important findings in history and physical examination that would make you more suspicious of measles?
  2. What are the 4 immediate actions you need to take to reduce the risk of transmission of possible infection to others?
A

What are the six important findings in history and physical examination that would make you more suspicious of
measles?
● Lack of complete/2 doses of immunisation against measles
● Contact with suspicious case
● Coryzal symptoms at the beginning
● Dry cough
● Red eyes/conjunctivitis
● Classic descending exanthema of measles
● Koplik spots in the mouth

What are the 4 immediate actions you need to take to reduce the risk of transmission of possible infection to others?

  1. Isolate Maya
  2. Contact communicable disease prevention section of Department of Health
  3. Take blood for measles serology
  4. Record the details of the people who have been exposed to the case within the practice
  5. Discuss nasal swab for measles PCR with Department of Health
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14
Q

Pertussis (testing, prevention, treatment, vaccination, school exclusion)

A

Testing:
● 2-4 weeks: sputum PCR
● >3-4 weeks: serology (should not be performed <2 weeks)

Infectiousness: Nil after 3 weeks and antibiotic therapy after this point is not indicated.

Prevention:
1. Identify contacts (individuals who have been within 1 m for more than 1 hour)
2. Prescribe pertussis prophylaxis if:
● Infant < 6 months
● Women in the last month of pregnancy
● Individuals who may transmit pertussis to infants younger than 6 months
3. Start antibiotic prophylaxis ASAP (more benefit than harm if commenced within 14 days of first contact) -
aimed at preventing spread to those <6 months
4. Seek advice from local public health authority if uncertain

Treatment: Azithromycin 500mg STAT followed by 250mg for 4 days (total 5 days)

Vaccination: Close contacts that are not up to date with pertussis should be given booster ASAP

School exclusion: Unimmunised < 7 years must be excluded from school or childcare for 14 days from last exposure to infection or until they have taken 5 days of effective antibiotics

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15
Q

Pinworm infection (treatment, recommendation)

A

AKA: Threadworm infection.
Treatment: Albendazole 400mg (child <10kg 200mg) PO as single dose.
Recommendation: Consider repeating dose after 2 weeks and treatment household contacts/carers at the same time
due to risk of reinfection.

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16
Q

Pneumococcal disease (RF, vaccination)

A
Risk factors:
● Previous episode
● Functional or anatomical asplenia
● Immunocompromising conditions
● Proven or presumptive CSF leak
● Chronic respiratory disease
● Chronic kidney disease
● Cardiac disease
● Down’s syndrome
● Chronic liver disease
● Diabetes
● Smoking, harmful use of alcohol

Vaccination:
● At risk children (ATSI)
● > 70 years should be given Prevenar 13 (needs to be 12 months apart from Prevenar 23)

17
Q

Psittacosis (organism, diagnosis, exposure, treatment)

A

Organism: Chlamydia psittaci
Diagnosis: PCR (throat swab/sputum), serology is unreliable
Exposure: Bird faeces
Treatment: Doxycycline 100mg PO BD for 7-10 days

18
Q

Q Fever

A

Organism: Coxiella burnetii
Exposure: Abattoir associated, farmer
Investigation: PCR
Course: Generally resolves within 2-6 weeks
Treatment: Doxycycline 100mg PO BD for 14 days

19
Q

Ross River virus (area, transmission, incubation, symptoms)

A

Area: Tropical regions e.g. NT
Transmission: Mosquitoes
Incubation: 3 days to 3 weeks
Symptoms: Joint and muscle pain with fever

20
Q

Scarlet fever (cause, presentation, features of rash, investigations, indications for treatment)

A

Cause: Group A S.pyogenes
Presentation: Malaise, sore throat, fever and vomiting.
Features of rash: Lasts for 5 days
● Occurs 12-24 hours post-fever
● Starts on neck then becomes generalised
● Boiled lobster or sunburnt appearance
● Blanches on pressure, fine like sandpaper
● Prominent on neck, axilla, cubital fossa, groin and skinfolds
● Absent/sparse on face, palms and soles
Investigations: throat swab prior to antibiotics if possible.
Indications for treatment of streptococcal pharyngitis and tonsillitis:
● Patients aged 2 to 25 years in populations with high incidence of acute rheumatic fever
● Patients with existing rheumatic heart disease
● Patients with scarlet fever
● Severe symptoms of pharyngitis
Treatment: phenoxymethylpenicillin 500mg (child 15mg/kg) PO, 12 hourly for 10 days.

21
Q

TORCH infections

A
Significance: Can lead to impaired growth, developmental issues and mortality.
TORCH:
- toxoplasma
- other agents (syphilis)
- rubella
- cytomegalovirus 
- herpes simplex virus 
Other includes: hepatitis B, enteroviruses, varicella-zoster virus, Zika, parvovirus B19.
22
Q

Tuberculosis (diagnosis, investigations, precautions, notification)

A

Diagnosis: Sputum AFB smear or NAA testing (PCR)
Investigations: CXR, quantiferon test
Precautions: Until 14 days of active treatment has been received
● Isolate patient away from others at the practice
● Ask patient to wear surgical mask or cover nose/mouth when coughing or sneezing
● Staff to put on N95 mask
● Notify health department
● Inform ID team at nearest hospital
● Advise patient that measures need to be put in place to prevent spread of possible TB
Notification: In writing within 5 days of diagnosis or clinical suspicion

23
Q

Varicella zoster - infectious period

A

2 days before the appearance of the rash, for the duration of the rash until the lesions have crusted over.

24
Q

Varicella zoster - exposure during pregnancy

A

Note: Significant exposure = living in the same household or face-to-face contact for at least 5 minutes or in the same room for at least 1 hour.

If immune or has history of vaccination - no action required

If no history or uncertain:
1. check serology
2. if serology not available in <96 hrs
x < 96 hours = varicella zoster immunoglobulin
x > 96 hours = consider post-exposure prophylaxis (aciclovir)

** Refer to page 299 of GP Study Notes