Infection and Immunology Flashcards
(43 cards)
what is the most common cause of candidiasis?
candida albicans
Risk factors for candidiasis infection?
Broad-spectrum antibiotics
immunocompromise - HIV, steroids (oral or inhaled)
DM
cushing’s
GI tract surgery
central line
What are the features of oral candidiasis?
common in neonates
a curd-like white patches on the mouth which can be REMOVED EASILY showing a red base
what are the features of oesophageal candidiasis?
dysphagia +/- pain on swallowing
white patches on OGD
it is an AIDS DEFINING ILLNESS
what does candidiasis of the skin look like?
sore + itchy
red, moist skin with ragged peeling edge
might have papules and pustules
Name an anti-fungal which might be used to treat candidiasis?
fluconazole
what is cellulitis?
it is an acute non-purulent spreading infection of the sub-cutaneous tissue
what are the most common causative organisms of cellulitis?
Streptococcus pyogenes staphylococcus aureus (beware of MRSA)
what is the cause of orbital cellulitis?
haemophilia influenzae
what are the RF for cellulitis?
skin break
poor hygiene
poor vascularisation of tissue
what is the cause of HSV encephalitis?
HSV 1 usually
What are the symptoms of HSV 1?
primary = usually asymptomatic. gingivostomatitis, pharyngitis, herpetic whitlow (finger lesion)
lymphadenopathy (tender)
secondary = perioral tingle -> vesicles -> ulcer + crust -> healed 8-10 days alter
may cause herpetic encephalitis
what are the symptoms of HSV 2?
painful blister/rash in genital, peri-genital or anal area
MACULOPAPULAR RASH
dysuria
fever
malaise
inguinal lymphadenopathy
how is HIV transmitted?
through exchange of bodily fluids
sexual intercourse, mother-to-child, needle sharing/stick injuries, blood transfusions, organ transplantations
what is the pathophysiology of HIV?
HIV enters CD4+ lymphocytes via GP120 receptors -> reverse transcriptase enables HIV genetic material to be added to host genome
cells produce more HIV -> dissemination -> cell death and eventual T cell depletion.
what are the three phases of HIV?
- seroconversion
- early/asymptomatic
- AIDS
what are the features of stage 1 of HIV?
self-limiting stage
fever, night sweats, general lymphadenopathy, sore throat
other: oral ulcers, rash, myalgia, headache, encephalitis, diarrhoea
what are the features of stage 2 of HIV?
early/asymptomatic
usually appear well, may have persistent lymphadenopathy, progressive minor symptoms (rash, weight loss, oral thrush)
what are the features of stage 3 of HIV?
AIDS
secondary diseases due to immunodeficiency
what are some of the secondary effects arising from the immunodeficiency caused by HIV?
bacterial infections, viral infections (CMV, HSV, VZV, HPV, EBV)
fungal infection - pneuomocystic jirovecii pneumonia, cryptococcus, candidiasis, aspergillosis
protozoal - toxoplasmosis
tumour - kaposi sarcoma, SCC, both lymphomas
what kind of a virus is EBV?
a gamma-herpes virus (dsDNA)
how is EBV transmitted?
it is found in pharyngeal secretions of an infected individual
close contact leads to spread (e.g. kissing, sharing eating utensils)
what is the pathophysiology of EBV?
infection of epithelial cells in oropharynx -> infects B cells -> they disseminate the disease -> humoral and cellular immune response across the body -> primary infection ends but virus is latent in B cells
reactivation of latent virus in B cells after stress of immunosuppression
atypical lymphocytes can be detected on blood film
what happens if patients with EBV are given ampicillin or amoxicillin?
develop a widespread maculopapular rash
