Infectious Diseases Flashcards by John Smith

Which antiviral is used for HIV?

Zidovudine

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Which antiviral is used for VZV (varicella zooster virus, aka chicken pox)?

Acyclovir

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Which antiviral is used for influenza?

Oseltamivir

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What are the complications of chicken pox (VZV) in immunocompromised / at risk patients?

Most severe - Pneumonitis

Other

Encephalitis / other neurological issues
Hepatitis
Myocarditis
Dermatitis

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Following primary infection, herperviruses are able to become latent and establish lifelong infection. They can periodically reactivate, often when a patient’s immunity is low.

Name some important herpes viruses

HSV 1 and 2
CMV
EBV
VZV

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What are the typical symptoms of HSV?

Oral, Occular and Genital Ulcers

Rarely encephalitis

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What are the typical symptoms of EBV?

Which cancer is it associated with? What are the symptoms of this cancer?

Fever
Swollen glands

Associated with Burkitt’s Lymphoma (*eBv = Burkitts)
Burkitt’s lymphoma presents with aBdominal symptoms
- N&V
- LoA
- GI Bleed
- Acute abdomen
- Renal failure due to tumour-lysis syndrome

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How may you provide immunity to a pregnant mother with -ve VSV IgG?

When is the risk greatest to the mother, and greatest to the fetus?

VSV immunoglobulins (antibodies) = Passive Immunity

Mother = 3rd trimester at most risk due to greatest immunocrompomisation

Fetus = first 12 weeks

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What is the typical progression of signs and symptoms caused by a measles infection?

Initially fever, malaise, conjunctivitis, cough.

Rash presents on buccal mucosa –“Koplik Spots”– blue/grey

Begins in face, moving down the body, becoming confluent (merging together)

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What are some complications of measles infection?

Bacterial Pneumonia
Encephalitis
Otitis media

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What criteria is used to diagnose infective endocarditis?

Dukes Criteria for enDocarditis

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What investigations would you order in a patient suspected of meningitis? State why for each

Blood cultures - antibiotic sensitivity

Pneumococcal urinary antigen - Dx pneumococcal meningitis

Meningococcal PCR - Dx meningococcal infection

Viral & Bacterial throat swab - assess colonisation

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What tests would you order for CSF obtained on LP in a patient suspected of meningitis? State why for each

CSF PCR - Check for viral (HSV, enterovirus, parechovirus)

CSF microscopy and gram stain - assess RBC and WCC of CSF to help distinguish between bacterial, TB and viral meningitis

CSF culture and sensitivity - assess bacterial growth and provide specific antibiotic for eradication

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What are the elements of CURB65 and what scores indicate what management plan?

C - mental state <=8
U - urea >7
R - RR >30
B - SBP <90 or DBP <=60
65 - Age

0-1 Manage at home
2 Consider hospital supervised treatment
3+ Admit and manage in hospital as severe pneumonia (admit to ICU if 4 or 5)

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What is the purpose of a Beta-D-Glucan test?

Diagnostic investigation of invasive fungal infection, best used for ruling out.

BDG is a component of the cell wall of most fungi

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What is the first line Abx for cellulitis?

What is the most common organism causing cellulitis?

Flucoxacillin; very effective against Staph Aureus

Most cellulitic infections are caused by Staph Aureus

Which antibiotics are effective against MRSA?

Vancomycin (more suitable for severe/cellulitic)

Doxycycline (more suitable for mild-moderate)

What immunisations must be checked, and antibiotics are given, for a patient who has had an animal bite?

RAT bite requires…

Rabies vaccine / immunoglobulin
co-Amoxiclav antibiotic
Tetanus Immunisation

Why may flucloxacillin not be effective in some staph aureus causing cellulitic infections?

Depends if it is MRSA or MSSA

if MRSA, Fluclox will have little to no effect, must use either Vancomycin or Doxycycline

What is the only curative treatment for necrotising fasciitis

Surgical Debridement

What antibiotic may you prescribe for someone with MSSA cellulitis who is also penicillin allergic?

Clarithromycin, a macrolide

What is the treatment for gas gangrene?

Similar to necrotising fasciitis

Surgical debridement with antibiotic cover for possible causative organism (usually Clostridium Perfingens)

What investigations would you perform in a patient with dehydration and respiratory distress (crackles on auscultation) with a recent travel history?

Bedside

Urine for pneumococcal and leigonella antigen test
Urine cultures
Throat swabs
Sputum culture / viral PCR

Bloods

ABGs + Lactate
FBC, LFT, U&E
Culture / viral PCR

Investigations

CXR
HIV test

Which members of the public must receive flu vaccine?

All healthcare professionals directly involved with patient care

Patients with chronic lung, heart, kidney, liver, neurological diseases, diabetes or immunocompromised

Patients in long-stay care homes

Pregnant

Age >65

Children 2 years, up until 3 years (moving towards up until 17 years)

What antibiotic regimen may you prescribe in severe pneumonia (CURB 65 >3)?

Co-amoxiclav 1.2g TDS + Clarythromicin IV -------------------------------- This is classed as a severe Community Acquired Pneumonia as the CURB-65 score ≥ 3. The patient needs to be admitted for IV antibiotic treatment due to the severity of disease and because the patient can’t hold oral medication. The treatment needs to take into account not only typical pathogens such as Streptococcus pneumoniae and Haemophilus influenza but also atypical pathogens such as Mycoplasma pneumoniae and Legionella pneumophila. Some H. influenza strains can produce a beta-lactamase rendering it resistant to amoxicillin. Severely ill patients might not be well enough to take oral therapy. Meropenem is too broad-spectrum and is reserved for hospital acquired infections (e.g. caused by extended spectrum beta-lactamase (ESBL) producing Enterobacteriacae).

What are the most common causes of pneumonia in the immunocompetent patient (encompassing typical, atpyical and viral types)?

Typical - Strep - H.Influenzae Atypical - Mycoplasma - Legionella Viral - Influenza

What is the Beta D Glucagon test and who should receive this?

Highly sensitive pan-fungal test for systemic invasive fungal infections. Given to patients who are immunocompromised +/- transplant

What fungal infection may someone immunocompromised who is also on broad-spectrum antibiotics be at risk of?

Candidaema (systemic)

What are the major risk factors for candidaema?

Central Venous Lines (replace and send old for cultures) Broad Spectrum ABx (gut flora translocation) Neutropaenia / Immunosuppression

What are some complications of candidaema?

Septic shock Endopthalmitis (inflammation of inner eye) Candida endocarditis * therefore investigate * *Sepsis screen * *Opthalmoscopy * *Echocardiogram

What is the management for infectious mononucleosis?

Self limiting disease in an immunocompetent patient, therefore manage symptoms as and when *Be wary of paracetamol if LFT are raised

A reactivation of which virus are immunocompromised patients at risk of? What symptoms may they experience? How may you treat this?

Latent CMV reactivation Bloody Diarrhoea Vomiting Dehydration Pyrexia Rx: Oral Ganciclovir

How may liver abscess commonly present and what is it usually secondary to? How would you investigate liver abscess? How is it usually treated?

Non-specific symptoms of RUQ pain and Pyrexia Most commonly 2ndary to biliary tract disease Ix: USS (useful in r/o), LFTs, CRP, Rx: Broad Spectrum ABx, Drainage of Abscess

Presence of which serological marker indicates 1. Active Hep B? 2. Exposure to Hep B? 3. Immunity to hep B?

1. HBsAg (Hep B Antigen) = Active 2. Anti-HBc (antibody to core antigen) = eCsposure 3. Anti-HBs (antibody to surface antigen) = immuniSation

Which Ig indicates 1. current/recent infection of Hep A? 2. immunity to Hep A?

1. IgG = Immunity (Gee & Ty rhyme) | 2. IgM = Current/Recent

What is the role of HCV RNA quantification test?

Aka 'Viral Load' Assesses whether the Hep C infection is active or not. If detectable RNA found, then active.