Infectious Disease Flashcards
What causes Lyme disease?
Spirochete bacteria: Boriella burgdorferi
Vector: Ixodes tick
Carrier: Rodents and white tailed deer
What is the treatment for Lyme disease?
Early disease: doxycycline or Amoxicillin if doxycycline is contraindicated (e.g. pregnancy)
If they have erythema migrans - commence antibiotics without the need for further tests
Late stage: IV ceftriaxone
How is Hepatitis A spread?
Transmission: faecal oral route
Common source: raw or undercooked shellfish
How is Hepatitis E spread?
Transmission: faecal-oral
Common source: Undercooked pro
Classically causes severe hepatitis in pregnant women
What is the treatment for PCP infection?
1st line: Co-trimoxazole
2nd line: If severe - IV Pentamidine +/- steroids
What are the clinical features of Pneumocystis jiroveci infection (PCP)?
- Fungal infection
- Occurs in immunocompromised people (opportunistic infection)
- SOB, dry cough, fever, few chest signs, exercise induced desaturation
- CXR may be normal or show bilateral interstitial pulmonary infiltrates
Diagnosis: bronchoalveolar lavage
What is the treatment for gonorrhoea infection?
1st line: single dose of IM 1g ceftriaxone
What is the treatment for Campylobacter infection?
If immunocompetent - supportive management
If immunocompromised or severe or symptoms for > 1 week - clarithromycin
What is the treatment for Chlamydia infection?
1st line: Doxycycline for 8 days
2nd line: Azithromycin for 3 days
Pregnant: Azithromycin, erythromycin or amoxicillin
All contacts should be treated even if asymptomatic
What is the treatment for Syphilis infection?
Penicillin G
What is the treatment for Pelvic Inflammatory Disease?
IM Ceftriaxone + PO doxycycline + PO Metronidazole
What causes bacterial vaginosis?
An overgrowth of predominately Gardnerella vaginalis
What is the treatment for bacterial vaginosis?
Metronidazole
What are the symptoms/signs of bacterial vaginosis?
- thin grey/white discharge, - fishy’ odour upon adding 10% potassium hydroxide
- high pH (> 4.5)
- microscopy: epithelial cells with a stippled appearance (clue cells).
What is the treatment for Trichomonas vaginalis?
Metronidazole
What is the cause of Scarlet fever?
Group A beta haemolytic streptococcus
What is the gold standard for diagnosing Typhoid fever?
Bone marrow culture
What is the cause of Dengue fever?
Infection with the dengue virus
Transmission: Bites from Aedes mosquitos
What are the key features of Dengue fever?
- Fever in the returned traveller
- body aches and pains - break-bone fever
- retro-orbital eye pain
- facial flushing
- Thrombocytopenia - resulting in PR bleeding, malaria, epistaxis (dengue haemorrhage fever shock syndrome)
How is dengue fever diagnosed?
Serology (IgM anti-dengue antibodies)
What micro-organisms causes Impetigo?
Staph aureus
How does cryptosporidium infection present?
Watery diarrhoea
Can cause profuse life threatening infection in immunocompromised people such as those with HIV/AIDS
What sort of microbe is cryptosporidium parvum?
Protozoa
What is the best antibiotic to use for an MRSA infection?
Severe IV Vancomycin
Oral doxycycline
What is the most common cause of acute infective endocarditis?
Staphylococcus aureus
What valve is most commonly affected in IV drug users with acute infective endocarditis?
Tricuspid valve
They inject into veins which drain into the right atrium hence tricuspid valve is affected
What is the most common cause of Subacute infective endocarditis?
Streptococcus viridans
Subacute infective endocarditis
- strep viridans
- typically acquired through tooth brushing and dentist visits as found in mouth flora
- typically affect damaged valves
- most commonly affects the mitral valve as this valve is most common damaged by rheumatic fever
Infective endocarditis affecting prosthetic valves is most commonly caused by which organism?
Streptococcus epidermidis
Gram positive cocci in pairs
Streptococcus pneumoniae
Gram positive cocci in clusters
Staphylococcus aureus
What are important side effects of doxycycline
- not used in children as can inhibit bone growth and can discolour teeth
- not to be used in pregnancy- teratogenic
- photo sensitive rash
- GI symptoms
What is the most common cause of cellulitis?
- staph aureus
- strep pyogenes
What is the most common cause of erysipelas?
Strep pyogenes