Infectious Diseases Flashcards
How long do you take post-exposure prophylaxis for HIV?
Oral antiretroviral therapy for 4 weeks
What does post-exposure prophylaxis for HIV include?
A combination of triple oral antiretrovirals within 1-2 hours, but may be started up to 72 hours following exposure.
How much does post-exposure prophylaxis for HIV reduce transmission risk by?
80%
What is used to treat schistosomiasis?
Praziquantel
How does amoebic dysentery present?
- Profuse, bloody diarrhoea
- There may be a long incubation period
- Stool microscopy may show trophozoites if examined within 15 minutes or kept warm (known as a ‘hot stool’)
What is the management of amoebiasis?
Oral metronidazole
A ‘luminal agent’ (to eliminate intraluminal cysts) is recommended usually as well e.g. diloxanide furoate
What is the incubation period of:
Campylobacter
Salmonella
Shigella
Campylobacter: 48-72 hours
Salmonella: 12-48 hours
Shigella: 48-72 hours
What is leprosy and how does it present?
Granulomatous disease primarily affecting the peripheral nerves and skin. It is caused by Mycobacterium leprae.
Features:
* patches of hypopigmented skin typically affecting the buttocks, face, and extensor surfaces of limbs
* sensory loss
What is tested for in a HIV blood test?
HIV antibody
and
HIV p24 antigen
*These are tested 4 weeks post-insult and after 3 months as well
What is cryptosporidiosis?
Commonest protozoal cause of diarrhoea in the UK: Cryptosporidium hominis and Cryptosporidium parvum
More common in immunocompromised patients (e.g. HIV) and young children.
Features
* watery diarrhoea
* abdominal cramps
* fever
* in immunocompromised patients, the entire gastrointestinal tract may be affected resulting in complications such as sclerosing cholangitis and pancreatitis
Ziehl-Neelsen stain (acid-fast stain) of the stool may reveal the characteristic protozoal red cysts of Cryptosporidium
What is the presentation of disseminated gonococcal infection?
- tenosynovitis
- migratory polyarthritis
- dermatitis (lesions can be maculopapular or vesicular)
What is chancroid?
This is caused by Haemophilus ducreyi and is characterised by a single deep ulcer, which is painful, as opposed to multiple painful ulcers seen here. The progression of the lesions can be appreciated if the patient presents early, as it starts as a painful papule which pustulates and then ulcerates.
What is lymphogranuloma venereum?
This infection is characterised by tender lymphadenopathy, usually unilateral, pyrexia and lower back pain (indicative of deep iliac node lymphadenopathy). Ulcers are uncommon or if present undetectable. Anorectal involvement and skin conditions like erythema nodosum are usually associated with it.
A 25 year old man has had penile pain for two days. His most recent sexual intercourse was one week ago. There are multiple tender ulcers on his preputial skin. His penile and scrotal skin does not have any other abnormality.
Which is the most likely diagnosis?
A. Genital warts
B. Gonorrhoea
C. Herpes simplex
D. Lymphogranuloma venereum
E. Syphilis
C. Herpes simplex
Genital herpes is caused by the herpes simplex virus (HSV). The classic presentation includes painful ulcers or sores on the genital or anal areas. The lesions can be associated with systemic symptoms such as fever and malaise. The lesions often recur, and the initial outbreak is usually more severe.
What are features of dengue fever?
- fever
- headache (often retro-orbital)
- myalgia, bone pain and arthralgia (‘break-bone fever’)
- pleuritic pain
- facial flushing (dengue)
- maculopapular rash
- haemorrhagic manifestations e.g. positive tourniquet test, petechiae, purpura/ecchymosis, epistaxis
‘warning signs’ include:
* abdominal pain
* hepatomegaly
* persistent vomiting
* clinical fluid accumulation (ascites, pleural effusion)
