infectious disease Flashcards
walking barefoot –> abdominal pain, pruritus, diarrhoea, and an itchy lesion on the plantar aspect of the foot which resolved spontaneously
Strongyloides stercolaris
treatment of choice is ivermectin or albendazole
cholera mx
doxycycline
prolonged non-bloody diarrhoea
giardiasis
metronidazole
Infection:
haematuria and increased urinary frequency
schistosomiasis, a parasitic flatworm
mx. Praziquantel
signs of Dengue fever
Retro-orbital headache, fever, facial flushing, rash, thrombocytopenia in returning traveller
can progress to viral haemorrhagic fever
1st line abx for uti in pregnancy
nitrofurantoin
swam in Lake Malawi –> itch
Schistosomiasis is treated with praziquantel
chest x-ray containing a rounded opacity. A crescent sign may be present
aspergilloma
what accounts for around 50% of cerebral lesions in patients with HIV?
cerebral toxoplasmosis
constitutional symptoms, headache, confusion, drowsiness
CT: usually single or multiple ring-enhancing lesions, mass effect may be seen
management: pyrimethamine plus sulphadiazine for at least 6 weeks
measles
conjunctivitis
kolpick white spots in mouth
maculopapu;ar rash starting behind ears
mx. supportive, mmr vaccine
Patients with severe malaria should be treated with ?
IV artesunate, and in cases where parasitaemia >10% is seen, consideration should be given to the performance of exchange transfusions.
In severe falciparum malaria, the parasite can cause sequestration of RBCs; hence the role of exchange transfusions
management of cutaneous anthrax
ciprofloxacin
Patients with an uncertain tetanus vaccination history should be given?
a booster vaccine + immunoglobulin, unless the wound is very minor and < 6 hours old
antibiotic to treat MRSA infections
vancomycin
prophylaxis for contacts of patients with meningococcal meningitis
Oral ciprofloxacin or rifampicin
most common isolated organism in animal bites
Pasteurella multocida
which vitamin is given with TB treatment because one of the TB drugs causes peripheral neuropathy?
isoniazid causes peripheral neuropathy
give vit B6 (pyridoxine) to prevent
check visual acuity before and during treatment with which TB drug?
ethambutol
which TB drug results in arthralgia and gout?
Pyrazinamide
most common cause of viral meningitis
non-polio enteroviruses e.g. coxsackie virus, echovirus
causes of viral haemorrhagic fever
dengue fever, Lassa fever, Ebola, yellow fever
how does yellow fever present?
high fever, rigors, nausea & vomiting. Bradycardia may develop. A brief remission is followed by jaundice, haematemesis, oliguria
causes of genital warts
Genital warts - 90% are caused by HPV 6 & 11
management of genital herpes in pregnancy
primary infection - elective c section to avoid transmission
recurrent herpes - suppressive aciclovir from 36weeks, low transmission risk
measles symptomms
Measles is characterised by prodromal symptoms, Koplik spots. maculopapular rash starting behind the ears and conjunctivitis
how does tetanus cause its effects?
Tetanus toxin (tetanospasmin) blocks the release of the inhibitory neurotransmitters GABA and glycine resulting in continuous motor neuron activity
non falciparum malaria types and presentation
malaria - fever, headache, splenomegaly
vivax/ovale - cyclical fever every 48 hrs
malariae - cyclical fever every 72 hrs + nephrotic syndrome
non falciparum management
- artemisinin-based combination treatment of chloroquine
- vivax + ovale can relapse following treatment so primaquine is given following acute treatment
A 17-year-old girl presents to the emergency department complaining of a widespread erythematous rash. She has recently been commenced on amoxicillin for an upper respiratory tract infection by her general practitioner. Which of the following is the most appropriate test to provide a diagnosis?
This is infectious mononucleosis
heterophil antibody test (Monospot test) Is diagnostic
Commonly develop rash after penicillin when gave infectious mononucleosis
Most common cause of neutropenia sepsis in cancer patients
Coagulase-negative, Gram-positive bacteria such as Staphylococcus epidermidis
What is used as prophylaxis for contacts of patients with meningococcal meningitis
Oral ciprofloxacin (one dose) or rifampicin (1 tab BD for two days)
I
What is red man syndrome?
nfusion-related reaction peculiar to vancomycin [3]. It typically consists of pruritus, an erythematous rash that involves the face, neck, and upper torso. Less frequently, hypotension and angioedema can occur.
What is the Jarisch-Herxheimer reaction?
acute febrile reaction that occurs within the first 24 hours of initiating treatment for spirochetal infections, such as syphilis caused by Treponema pallidum and Lyme disease. It is characterized by fever, chills, headache, myalgia, and exacerbation of skin lesions. The reaction is believed to be due to the release of endotoxin-like substances from the dying spirochetes. The symptoms usually resolve within a few hours to a day.
whipple’s disease pneumonic
Weight loss
Hyperpigmentation
Infection by Tropheryma whippelii
PAS positive granules in macrophages
Polyarthritis
Lymphadenopathy
E
Steattorhoea diarrhoea
dementia, seizures
what is macrophage activation syndrome?
uncontrolled hyper-inflammatory state associated with many systemic autoimmune diseases but in particular Juvenile Idiopathic Arthritis.
ACR/EULAR classification criteria for macrophage activation syndrome (MAS) state that in a patient with JIA who presents with a fever, a diagnosis of MAS can be made if the 1. ferritin level is > 684 ng/ml
2. any two of the following are present (platelets < 181 * 109/L, AST > 48 U/L, triglycerides > 156 mg/dl, fibrinogen < 360 mg/dl).
Refractory fever and hepatosplenomegaly
Interferon-gamma is responsible for the activation of macrophages and is heavily implicated in the pathogenesis of this condition.
patient presents with black eschar scab that is typically painless. what disease?
anthrax
treatment for anthrax
ciproflox
treatment for non gonococcal uretheritis
doxycycline or azithromycin
Congenital toxoplasmosis
signs
cerebral cmalcification
chorioretinitis
mx gonorrhoea
Intramuscular ceftriaxone +/- cipro
mx chlamydia
Oral doxycycline
how does Clostridium tetani exert its effects?
blocks the release of GABA and glycine –> muscle spasms, hypertonia –> lockjaw and respiratory paralysis
‘erythematous, punctate, and papilliform’ cervix with itching and foul smelling discharge
‘erythematous, punctate, and papilliform’ - also known as ‘strawberry’ - cervix
Trichomonas vaginalis
oral metronidazole
is the first-line antibiotic treatment for tetanus
metronidazole to destroy the bacteria
(in addition to the immunoglobulin to neutralise the toxin)
Perianal itching in children, possibly affecting other family members →
Enterobius vermicularis (threadworms)
Gram-positive cocci
= staphylococci + streptococci (including enterococci)
Gram-negative cocci
= Neisseria meningitidis + Neisseria gonorrhoeae, also Moraxella catarrhalis
Gram-positive rods (bacilli)
mnemonic = ABCD LT
Actinomyces
Bacillus anthracis (anthrax)
Clostridium
Diphtheria: Corynebacterium diphtheriae
Listeria monocytogenes
Tropheryma whipplei (Whipple’s disease)
Gram-negative rods
Escherichia coli
Haemophilus influenzae
Pseudomonas aeruginosa
Salmonella sp.
Shigella sp.
Campylobacter jejuni
HIV in pregnancy
during pregnancy - continue antivirals
<50 copies, can do vaginal delivery with zidovudine infusion started 4hrs before + neonatal oral zidovudine antiviral therapy
if maternal viral load is >50 copies/ml - neonate needs triple ART for 4-6 weeks.
no breastfeeding
Chikungunya vs dengue
severe joint pain with Chikungunya
mx. supportive
common antibiotic that increases risk of acquisition of MRSA
Ciprofloxacin (quinolones)
first-line investigation for suspected Lyme disease in patients with no history of erythema migrans
ELISA antibodies to Borrelia burgdorferi then immunoblot
how does strongyloides present?
in soil, penetrates skin
diarrhoea
papulovesicular rash over areas where the larvae crossed
larva currens: pruritic, linear, urticarial rash that moves as the larvae move through the body
pneumonitis
mx strongyloides
- ivermectin
- albendazole
PCP mx
1) co-trimoxazole
2) IV pentamidine in severe cases
3) aerosolized pentamidine is an alternative treatment for Pneumocystis jiroveci pneumonia but is less effective with a risk of pneumothorax
4)steroids if hypoxic
flu like illness → brief remission→ followed by jaundice and haematemesis
Yellow fever
syphillis presentation
primary
- painless ulcer at site of sexual contact (chancre)
- local lymphadenopathy
secondary (6-10weeks later)
- fevers
- rash
- warty lesions around genitals (condylomata lata)
Tertiary/ late
- gummas (granulomatous lesions of the skin and bones)
- ascending aortic aneurysms
- general paralysis of the insane
- tabes dorsalis
- Argyll-Robertson pupil: bilateral small pupils that fail to constrict in response to bright light but exhibit constriction during near vision tasks
management of syphillis
benzylpenicillin
2nd line - doxy
stain for cryptosporidium
stool: modified Ziehl-Neelsen stain (acid-fast stain) of the stool –> red cysts of cryptosporidium
Mx. Chicken pox exposure in pregnancy
Do antibody levels if unsureof vaccination history - wait for result if unsure vaccinated
Give varicella zoster immunoglobulin immediately or oral aciclovir 7-14days after exposure
how is lassa fever spread?
Lassa fever is contracted by contact with the excreta of infected African rats (Mastomys rodent) or by person-to-person spread
what is the leading cause of death in patients with Chagas’ disease?
Cardiac involvement - myocarditis
Leprosy mx.
This man has multibacillary leprosy (>6 lesions) so should have triple therapy with rifampicin, dapsone and clofazimine for 12 months.
For paucibacillary leprosy (5 or less lesions) you should give rifampicin and dapsone for 6 months.
When to treat asymptomatic bacteriuria?
pregnancy, children younger than 5 years or immunosuppressed patients due to the risk of complications.
most likely infective cause of hepatitis in pregnancy?
Severe hepatitis in a pregnant woman - think hepatitis E
Diptheria clinical manifestations
fever, malaise, and the presence of a grey coating on the tonsils (known as a pseudomembrane)
extensive cervical lymphadenopathy (sometimes referred to as ‘bull neck’)
the most common complication of gonorrhoea?
Infertility secondary to pelvic inflammatory disease (PID)
who is at risk of leptospirosis and what are the symptoms?
spread by contact with infected rat urine
the early phase is due to bacteraemia and lasts around a week:
- may be mild or subclinical
fever
- flu-like symptoms
- subconjunctival suffusion (redness)/haemorrhage
second immune phase may lead to more severe disease (Weil’s disease)
- acute kidney injury (seen in 50% of patients)
- hepatitis: jaundice, hepatomegaly
- aseptic meningitis
False positive VDRL/RPR:
‘SomeTimes Mistakes Happen’ (SLE, TB, malaria, HIV)
Parasitaemia cut off for severe m. Falciparum
> 2%
rhabditiform larvae
strongyloides
What changes need to be made to anti-tuberculosis regime given renal impairment?
Reduction in ethambutol dose
The most common causes of viral meningitis in adults are
enteroviruses.
antibiotic for liver abcess
amoxicillin + ciprofloxacin + metronidazole
management of HIV in newborns from HIV positive mothers
Neonatal antiretroviral therapy
zidovudine is usually administered orally to the neonate if maternal viral load is <50 copies/ml.
Otherwise triple ART should be used. Therapy should be continued for 4-6 weeks.
common side effect of tetracyclines
discolouration of teeth: therefore should not be used in children < 12 years of age
photosensitivity
angioedema
black hairy tongue
Management of diptheria
intramuscular penicillin
diphtheria antitoxin
Management of brain abscess
Management
surgery
a craniotomy is performed and the abscess cavity debrided
the abscess may reform because the head is closed following abscess drainage.
IV antibiotics: IV 3rd-generation cephalosporin + metronidazole
intracranial pressure management: e.g. dexamethasone
HIV: anti-retrovirals - P450 interaction
nevirapine (a NNRTI): induces P450
protease inhibitors: inhibits P450
Staphylococcal toxic shock syndrome is characterised by
fever, hypotension and a rash → desquamation
pneumonia commonly due to aspiration
Klebsiella
Severe falciparum malaria management
a parasite counts of more than 2% will usually need parenteral treatment irrespective of clinical state
- intravenous artesunate
- if parasite count > 10% then exchange transfusion should be considered
Genital wart treatment
multiple, non-keratinised warts: topical podophyllum
solitary, keratinised warts: cryotherapy
which type of glomerulonephritis is most characteristically associated with streptococcal infection in children?
Diffuse proliferative glomerulonephritis
painful vs painless genital ulcers
Syphilis, Lymphogranuloma venereum (LGV) and donovanosis (granuloma inguinal) all cause painless genital ulcers.
Behcets may cause painful genital ulcers but herpes simplex is more likely if recent change in sexual partner and the lack of other symptoms.
Chancroid - painful ulcer. sharply defined, ragged, undermined border + inguinal lymphadenopathy.
where are the majority of gastrinomas are found
in the first part of the duodenum
B12 deficient mx
1 mg of IM hydroxocobalamin 3 times each week for 2 weeks, then once every 3 months
66%
which TB drug causes peripheral neuropathy?
Isoniazid therapy can cause a vitamin B6 deficiency causing peripheral neuropathy
Severe joint pain and high fever after return from Africa.
Normal blood results
chikungunya
most common cause of reactive arthritis in the UK
Chlamydia trachomatis
Treatment of pelvic inflammatory disease:
oral ofloxacin + oral metronidazole or intramuscular ceftriaxone + oral doxycycline + oral metronidazole
HIV, neuro symptoms, widespread demyelination
progressive multifocal leukoencephalopathy
granuloma inguinale organism
: Klebsiella granulomatis*
HIV testing
1) HIV-1/2 Ab/Ag Immunoassay (fourth generation) – within 10 days of infection
2) HIV-1 NAAT or p24 testing
causes of Gingival hyperplasia:
phenytoin, ciclosporin, calcium channel blockers and AML
Management of suspected/confirmed Lyme disease
doxycycline if early disease
Amoxicillin is an alternative if doxycycline is contraindicated (e.g. pregnancy)
Lyme disease is caused by
the spirochaete Borrelia burgdorferi
the most common cause of osteomyelitis
Staphylococcus aureus
first-line management
for syphillis
intramuscular benzathine penicillin is the first-line management
alternatives: doxycycline
Cat scratch disease organism
- caused by Bartonella henselae
Sepsis triggers the release of which cytokine
IL-1 causing vasodilation → hypotension
Varicella pneumonia is the most common and serious complication of chickenpox infection in adults. treatment
Auscultation of the chest is often unremarkable.
IV aciclovir
Leishmeniasis
- clinical manifestations and diagnosis
spread by sand flies
three manifestations:
cutaneous - ulcer
mucousal - ulcer of mucosa
visceral aka. kala azar
- fever, sweats, rigors
- massive splenomegaly
- hepatomegaly
- bone marrow: pancytopenia
- grey skin - ‘kala-azar’ means black sickness
the gold standard for diagnosis is bone marrow or splenic aspirate
chlamydia mx
- doxy 7 days
- if pregnant: azithromycin, erythromycin or amoxicillin
if allergic to penicillin, the person might also be allergic to?
cephalosporins.
Immune reconstitution inflammatory syndrome can occur in HIV positive patients when starting anti-retrovirals; this is an immune phenomenon that results in the clinical worsening of a pre-exisiting opportunistic infection
which HIV type is more pathogenic
HIV 1 is more dangerous than 2
HPV 8 vs HHV 8
HPV 8 - cervical, head and neck ca
HHV 8 - kaposi
Blackwater fever - what is it?
is a rare complication of malaria which can be fatal. It is caused by large intravascular haemolysis resulting in haemoglobinuria, anaemia, jaundice and acute kidney injury. Urine is classically black or dark red in colour.
schistosomiasis, urine microscopy would show ?
red cell casts
Infection characterised by parkinsonian features
inflammation of basal ganglia
japanese encephalitis
supportive mx
how is lassa fever spread?
rats
Examples of viral haemorrhagic fever (VHF) include:
Flaviviridae: dengue, yellow fever
Arenaviridae: Lassa fever
Filoviridae: Ebola virus, Marburg virus
Bunyaviridae: Hantaviruses, Crimean-Congo haemorrhagic fever, Rift Valley fever
mx cryptosporidium
Management
is largely supportive for immunocompetent patients
if the patient has HIV and is not on antiretroviral therapy then this should be started and often will be enough to resolve the infection
nitazoxanide may be used for immunocompromised patients
rifaximin is also sometimes used for immunocompromised patients/patients with severe disease
mx toxoplasmosis
No treatment is usually required unless the patient has a severe infection or is immunosuppressed.
HIV/ immunosuprressed: management: pyrimethamine plus sulphadiazine for at least 6 weeks
Definitive diagnosis of Pneumocystis carinii pneumonia
is by bronchial alveolar lavage with silver staining
