ID Flashcards
slapped cheek rash
parvovirus
can cause fetal hydrops
asymptomatic
pancytopaenia in immunosuppressed patients
aplastic crises e.g. in sickle-cell disease (parvovirus B19 suppresses erythropoiesis for about a week so aplastic anaemia is rare unless there is a chronic haemolytic anaemia)
trypanosomiasis
african sleeping sickness
Trypanosoma chancre - painless subcutaneous nodule at site of infection
intermittent fever
enlargement of posterior cervical lymph nodes
later: central nervous system involvement e.g. somnolence, headaches, mood changes, meningoencephalitis
Management
early disease: IV pentamidine or suramin
later disease or central nervous system involvement: IV melarsoprol
lyme disease treatment
doxycycline 14-21 days
malaria Rx
Uncomplicated falciparum malaria
strains resistant to chloroquine are prevalent in certain areas of Asia and Africa
the 2010 WHO guidelines recommend artemisinin-based combination therapies (ACTs) as first-line therapy
examples include artemether plus lumefantrine, artesunate plus amodiaquine, artesunate plus mefloquine, artesunate plus sulfadoxine-pyrimethamine, dihydroartemisinin plus piperaquine
Severe falciparum malaria
a parasite counts of more than 2% will usually need parenteral treatment irrespective of clinical state
intravenous artesunate is now recommended by WHO in preference to intravenous quinine
if parasite count > 10% then exchange transfusion should be considered
shock may indicate coexistent bacterial septicaemia - malaria rarely causes haemodynamic collapse
viral meningitis low glucose
mumps
chlamydia Rx
pregnant vs non pregnant
doxycycline (7 day course) or azithromycin (single dose). The 2009 SIGN guidelines suggest azithromycin should be used first-line due to potentially poor compliance with a 7 day course of doxycycline
if pregnant then azithromycin, erythromycin or amoxicillin may be used.
breastfeeding in HIV
no
endocarditis with -ve blood cultures
coxiella burnetti
Q fever is caused by Coxiella burnetii, a rickettsia. The source of infection is typically an abattoir, cattle/sheep or it may be inhaled from infected dust
typically prodrome: fever, malaise
causes pyrexia of unknown origin, atypical pneumonia, endocarditis (culture-negative)
Rx - doxycycline
Lyme disease Ix
NICE recommend that Lyme disease can be diagnosed clinically if erythema migrans is present
enzyme-linked immunosorbent assay (ELISA) antibodies to Borrelia burgdorferi are the first-line test
if this test is positive or equivocal then an immunoblot test for Lyme disease should be done
Mycobacterium avium
Prophylaxis
clarithromycin or azithromycin when CD4 is less than 100 cells/mm³
Management
rifampicin + ethambutol + clarithromycin
mycobacterium features and diagnosis
Features fever, sweats abdominal: pain, diarrhoea lung: dyspnoea, cough anaemia lymphadenopathy hepatomegaly/deranged LFTs
Diagnosis
blood cultures
bone marrow aspirate
Amphotericin B
Used for systemic fungal infections
Binds with ergosterol forming a transmembrane channel that leads to monovalent ion (K+, Na+, H+ and Cl) leakage
Nephrotoxicity, flu-like symptoms, hypokalaemia, hypomagnaseamia
primary and secondary syphyllis features
spirochaete Treponema pallidum
Primary features
chancre - painless ulcer at the site of sexual contact
local non-tender lymphadenopathy
often not seen in women (the lesion may be on the cervix)
Secondary features - occurs 6-10 weeks after primary infection
systemic symptoms: fevers, lymphadenopathy
rash on trunk, palms and soles
buccal ‘snail track’ ulcers (30%)
condylomata lata (painless, warty lesions on the genitalia )
Therefore, only a small list of Gram-positive rods (bacilli) need to be memorised to categorise all bacteria - mnemonic = ABCD L
Actinomyces Bacillus anthracis (anthrax) Clostridium Diphtheria: Corynebacterium diphtheriae Listeria monocytogenes
diarrhoea after reheating rice
bacillus cereus
chlamydia causes which skin condition
Lymphogranuloma venereum (LGV) is caused by Chlamydia trachomatis.
Typically infection comprises of three stages
stage 1: small painless pustule which later forms an ulcer
stage 2: painful inguinal lymphadenopathy
stage 3: proctocolitis
LGV is treated using doxycycline.
cellulitis Rx
Flucloxacillin 1st line
Clarithromycin, erythromycin (in pregnancy) or doxycyline is recommended in patients allergic to penicillin.
NICE recommend that patients severe cellulitis should be offered co-amoxiclav, cefuroxime, clindamycin or ceftriaxone.
Pneumocystis jiroveci Rx
co-trimoxazole
IV pentamidine in severe cases
Lyme disease with disseminated or central nervous system involvement
IV ceftriaxone
painful genital ulcers
herpes
consider behcets
cerebral toxoplasmosis
ring enhancing lesions on CT
Treatment is usually reserved for those with severe infections or patients who are immunosuppressed
pyrimethamine plus sulphadiazine for at least 6 weeks
contact to meningitis
oral ciprofloxacin (or rifampicin) meningococcal vaccination should be offered to close contacts when serotype results are available, including booster doses to those who had the vaccine in infancy
pneumococcal meningitis, no prophylaxis is generally needed
Primaquine
non-falciparum malaria to destroy liver hypnozoites and prevent relapse
non falciparum malaria Rx
Treatment
in areas which are known to be chloroquine-sensitive then WHO recommend either an artemisinin-based combination therapy (ACT) or chloroquine
in areas which are known to be chloroquine-resistant an ACT should be used
ACTs should be avoided in pregnant women
patients with ovale or vivax malaria should be given primaquine following acute treatment with chloroquine to destroy liver hypnozoites and prevent relapse
latent tuberculosis Rx
3 months of isoniazid (with pyridoxine) and rifampicin OR 6 months of isoniazid (with pyridoxine)
PCP bronchoalveolar lavage
silver stain shows cysts
