Infectious Diseases Flashcards
What is the role of Folic Acid
Synthesis and regulation of DNA within bacteria
What does gram negative bacteria mean
They do not have a cell wall
How to treat MRSA
Teciplanin or vancomycin
Name three beta lactams (antibiotics that inhibit cell wall synthesis)
Penicillin
Carbapenems (meropenem)
Cephalosporins
Name two antibiotics that inhibit wall synthesis but are not beta lactams
Vancomycin
Teicoplanin
What antibiotic inhibits folic acid metabolism
Trimethoprim
Why is tazocin typically added after co-moxiclav
To cover pseudomonas (co amoxiclav does not cover atypical bacteria)
Describe the stepwise approach of escalating antibiotic treatment in a hospital patient
- Amoxicillin
- Co-Amoxiclav
- Tazocin
- Meropenem to cover ESBLs
- Teicoplanin to cover MRSA
- Clarithromycin
What is the pathological consequence that leads to raised blood lactate in the body
Cause hypoperfusion of the tissues = anaeraobic respiration
First line management of septic shock
IV Fluids
if IV fluids does not improve BP, switch to inotropes (noradrenaline)
At what level of lactate should sepsis be suspected
> 2 mmol/L
What medications can cause neutropenic sepsis
Clozapine Hydrocychloroquine (RA) Methotrexate (RA) Sulfsalazine (RA) Carbimazole Quinine Infliximab Rituximab
Chemotherapy
Treatment of neutropenic sepsis
IMMEDIATE IV Pipperacillin with Tazobactam
First line management of UTIs in pregnancy
Nitrofurantoin 7 days
Then Cefalexin
What antibiotic should be avoided in the first trimester for UTIs
Trimethoprinm
What antibiotic should be avoided in the third trimester for UTIs
Nitrofurantoin
First line management of Pyelonephritis
Cefalexin for 7-10 days
What classification is used to grade Cellulitis
Eron
What antibiotic is given for cellulitis
Flucloxacillin
First line management of sinusitis
Phenoxymethylpenicillin for a 5 day course
Second line: Co-Amoxiclav
Management of intra-abdominal infections
Co-Amoxiclav
or
Amoxicillin + Gentamycin + Metronidazole
First line management of spontaneous bacterial peritonitis
Tazocin
What disease is spontaneous bacterial peritonitis seen in
Liver Failure
Diagnosis of influenza
Viral nasal swabs -> PCR
Management of influenza
Oral Oseltamivir 75mg twice daily for 5 days
within 48 hours to reduce risk of complication
What post-exposure prophylaxis is given for influenza
Oral Oseltamivir
What species is the most comon cause of traveller’s diarrhoea
Campylobacter jejuni
How does campylobacter jejuni spread
Raw poultry
Unpasteurised milk
Incubatino period of campylobacter jejuni
2-5 days
Antiibtiotcs for campylobacter jejuni infection
Azithromycin
Treatment of shigella
Azithromycin
What species causes diarrhoea from leftover fried rice left at room temperature
Bacillus Cereus
Management of bacillus cereus infection
leave for 24 hours
Treatment of giardiasis
Metronidazole
What is meningococcal septicaemia
Where the meningococcus bacterial infection spreads in the blood
This causes the classic non-blanching rash from DIC
What is meningococcal meningitis
Bacteria infetcing the meninges and CSF around the brain and spinal cord
What is the most common cause of bacterial meningitis in neonates
Group B strep
What is the criteria for lumbar puncture in children
<1 month with fever
1-3 months with fever and are unwell
<1 year with unexplained fever + other features of serious illness
What is the kernig’s test
Lie on back, flex one hip at 90 degrees and slowly straighten (causes pain)
What is the Brudzinski’s test
Lying the patient flat on their back and gently using your hands to lift their head and neck off the bed (cause involuntary flexing of their hips and knees)
Management of meningitis in the community
IM Benzylpenecillin
Management of meningitis <3 months
Cefotaxime + Amoxicillin
Management of meningitis >3 months
Ceftriaxone
At what age can dexamethasone be given to children with meningitis
> 3 months
Post-exposure prophylaxis for meningitis
Ciprofloxacin
Most common cause of viral meningitis
HSV
Management of Viral Meningitis
Aciclovir
Glucose levels in Bacterial vs Viral meningitis
Low vs High
Appearance of CSF fludi in bacterial vs virus
Cloudy vs clear
Protein levels in bacterial vs viral meningitis
High vs Normal
Appearance of disseminated miliary TB on a chest X-rAy
Millet seeds uniformly distributed across the lung fileds
In what lobes in reactivated TB found in
Upper Zones of the lungs
Management of latent TB (those at risk of re-activation)
Isoniazide + Rifampicin for 3 months
Then
Isoniazid for 6 months
Management of Acute Pulmonary TB
RIPE
R + I for 6 months
P + E for 2 months
Side-effect of isoniazid
Peripheral neuropathy
How to prevent peripheral neuropathy from isoniazid
Prescribe B6
Side-effect of Pyrazinamide
Hyperuricaemia
Side-effect of Ethambutol
Colour Blindness
What is the problem with antibocyd testing in HIV
Can be negative for up to 3 months
Three ways we can test for HIV
Antibody testing
p24 antigen testing
PCR tetsing for HIV RNA to get viral load
How to monitor HIV progression
CD4 count
What is the normal CD4 count
500 +
When is a virla load referred to as undetectable
<100
Treatment of HIv
2 NRTIs (Tenofovir and emricitabine) + third agent
Management of Pneumocytis jirovecii pneumonia
Co-Tramoxazole
How does birth change in women with a viral load
Require C-Sections
WHat is post-exposure prophylaxis given for HIV
Truvada + Reltegravir for 28 days
What is the most dangerous species of malaria
Plasmodium Flaciparum
Which species of malaria lie dormant in the liver (as hypnozoites) for years
P. vivax
P. Ovale
IN which organ to malarial species mature in
Liver
Where do merozoites move to after maturing in the liver
RBCs where they reproduce and destroy the cells = haemolytic anaemia
Describe the pattern of fevers in malaria
High fever spikes every 48 hours as that’ show long it takes for meroxoites to reproduce inside RBCs
Incubation period of malaria
1-4 weeks
Diagnosis of Malaria
Blood film (EDTA bottle) - 3 samples over 3 days
Management of uncomplicated malaria (orally treatable)
Artemether with lumefantrine
Proguanil + Atovaquone
Quinine
IV Management of severe malaria
Artesunate
or
Quinine Dihydrochloride
What prophylaxis can be given for malaria
Proguanil + Atovaquone
second line:
Mefloquine (but can cause bad dreams)
What antibody in Heb B implies past or current infection
HBcAb
What antibody indicates vaccination or precious infection in Hep B
HBsAb
What does a CT scan show for toxoplasmosis gondii infections
Multiple ring enhancing lesions
What does a CT scan show for Primary CNS lymphoma
Single lesion
What does a CT show for HIV caused encephalitis
Oedematous brain
Most common fungal infection of the CNS
Cryptococcus
What stain is used to check for cryptococcus infections
India ink staining
Symptoms of progressive multifocal leukoencephalopathy
Widespread demyelination
Behavioural changes, speech, motor and visual impairment
What does an MRI show for PML
Widespread demyelination
What does stool microscopy show for amoebiasis
Trophozoites
Treatment for amoebiasis
Oral metronidazole
What causes yellow fever
Aedes mosquitos (zoonotic infections)
Symptoms of yellow fever
Sudden onset fever, rigors, nausea and vomiting
Then remission
Then jaundice and oliguria
What is seen under microscopy for yellow fever
Concilman bodies
Management of encephalitis
Ceftriaxone and acyclovir
Clinical features of trypanosomiasis
Painless subcutaneous nodule at site of infection + fever
then get sleepiness and headaches later on
Management of trypanosomiasis
IV pentamidine
Late IV melarsoprol (CNS involvement)
What type of microbe is toxoplasmosis
Protozoan
If someone’s received a full 5 dose of the tetanus vaccine in the past 10 years, should they receive another at A&E?
No. Over 10 = yes
Clinical features of schistosomiasis
Swimmer’ itch
Fever, cough and diarrhoea
Why does schistosomiasis cause bladder cancer
Deposit eggs in the bladder causing inflammation
Investigation for schistosomiasis
Asymptomatic: Serum schistosome antibodies
Symptomatic: Urine or stool microscopy
Complications of rubella
Thrombocytopaenia
Arthritis of small hands
Encephalitis
Myocarditis
Management of p oval and vivax infections
Chloroquine and THEN primaquine to destroy liver hypnozoites - prevents relapse
Management of leptospirosis
Benzylpenicillin
What species causes leprosy
Mycobacterium leprae
Clinical features of leprosy
Patches of hypo pigmented skin affecting the buttocks, face and extensors
Sensory loss
What typiclaly causes acute pyelonephritis
E.coli
What type of bacteria is entamoeba histolytica
Protozoan
Symptoms of amoebiasis
Profuse and bloody diarrhoea
Long incubation period
Investigation for suspected amoebiasis
stool microscopy - hot stool + trophozoites
Management of amoebiasis
Metronidazole
Management of liiver amoebic abscess
Metronidazole (usually a singular mass in the liver)
Features of anthrax
Painless black eschar (pus)
Oedema
GI Bleeding
Management of Anthrax
Ciprofloxacin
How is anthrax spread
Infected carcasses
Management of PID
Oral Ofloxacin + Metronidazole
Ceftriaxone + doxycycline + Metronidazole
Management of c.diff
Oral vancomycin
second line: Fidaxomicin
Antibiotic given for salmonella and shigella
Ciprofloxacin
What antibiotic typically results in c.diff infections
Clindamycin
Name two conditions that can predispose someone to aspergilliosus
TB
Lung cancer
CF
Management of botulism
Botulism antitoxin and supportive care
How do people get boutlism toxins
From food that has not been preserved well
Incubation of campylobacter infections
6 days
What species causes cat scratch disease
Bartonella Henslae
Criteria for IV antibiotics in cellulitis
Class III or IV cellulitis on the eron scale
Rapidly deteriorating
<1 years old
Immunocompromisd
Facial cellulitis
Management of cellulitis in pregnancy
Erythromycin
Management of Class III + Cellulitis
IV co amoxiclav
What species causes a chancroid
Haemophilus ducreyi
Mangement of cholera
Oral Rehdyration therapy first
Doxycycline
How is the cholera vaccine given
Orally
What species causes pseudomembranous colitis
C.diff
What type of species is cryptosporidium
Protozoal
Symptoms of cryptosporridium infection
Wstery diarrhoea
Abdominal cramps
Stool sample results in cryptosporidium infections
Red cysts on ziehl-neelsen stain
Management of cryptosporridium infection
Supoprtive
Rifaximin if severe symptoms
Microscopy in CMV infections
Owl’s eye
Three symptoms of CMV infection
- Slow growth
- Blueberry muffin rash
- Microcephaly
Management of CMV retinitis
IV Ganciclovir
(has pizza retina)
What mosquito typically carry dengue
Aedes Aegypti mosquito
Symptoms of dengue fever
Fever
Bone pain
Haemorrhages
Warning signs: Hepatosplenomegaly + ascites
Complication of dengue
DIC
Shock
Diagnostic test of dengue
NAAT
Serology
Management of dengue
Supportive
What bacteria causes diptheria
Gram positive: Cornyebacterium diptheriae
Presentation of diptehria
Greying of the posterior pharyngeal wall
Cervical lymphadenopathy (causes bulky neck)
Heart block
Invetsiation of diptheria
Throat swab
Management of diptheria
IM penecillin + antitoxin
What virus is the only one that is single stranded
Parvovirus
What species causes ebola
Filoviridae
How is ebola spread
Througgh direct contact (secretions etc)
Incubation period of ebola
2-21 days
What species causes typhod
Salmonella
Features of typhoid
Bradycardia
Constipation (even though salmonella usually causes diarrhoea)
Rose spots on trunk
What species causes osteomyelitis in SCA
Salmonella
Name two types of lymphomas associated with EBV
Burkitt’s lymphoma
HOdgkin’s lymphoma
What diarrhoeeal infection has appendicitis type symptoms
Campylobacter infections
What is the most common cause of infective diarrhoea in HIV +ve patients
Cryptosporidium infections
What species causes Kaposi’s sarcoma
Human Herpes Virus 8
Management of Kaposi’s sarcoma
Radiotherapy + Resection
Management of HIV
Two NRTIs + PI or NNRTI
What virus is associated with Primary CNS lymphoma
EBV
A patient presents with headache, fever and malaise - india ink stain is positive. What species has caused this invasion of the CNS
Cryptococcus
Management of oesophageal candidiasis
FLuconazole + Itraconazole
What species causes hairy leukoplakia
EBV
Under what CD4 count should all HIV patients recieve PCP prophylaxis
<200
COmplication of PCP
Pneumothorax
What examination finding is consistent with PCP
Excercise-induced desaturation
What is diagnostic of PCP
Bronchoalveolar lavage - silver stain shows cysts
Management of PCP
Co-trimoxazole
or
IV pentamidine
When should steroids be given in PCP
pO2 < 9.3kPa
What factor in HIV diagnosis correlates to poor long term prognosis
Symptom severity
When should a repeat test be offered in asymptomatic patients for HIV
4 weeks after exposure
Tehn 12 weeks after
When do HIV antibodies get detected in the blood
4-6 weeks after infection
What HPV strains are linked to cervical cancer
16 and 18
What is the triad seen in infectious mononucleosis
Sore throat
Pyrexia
Lymphadenopathy
Splenomegaly
When should the monospot test be conducted
2nd week of illness
How is the influenza vaccine given to children
INtranasally (live vaccine)
Contradinications to the influenza vaccine
People taking aspirin for kawasaki
Egg allergy
Pregnancy
Asthma
<2 years
Diganosis of legionella pneumophilia
Urinary antigen
Management of legionella
Erythromycin
How is leishmaniasis spread
Sandflies bites
Signs of a leishmaniasis bite
Underlying red ulcer
How is leishmaniasis diagnosed
Punch biopsy
Where is leishmaniasis spread
South america
What is a positive mantoux test
Erythema > 10mm = previous exposure including BCG
Signs of false negative mantoux test
Sarcoidosis
Lymphoma
Fevers
How does IV antibiotics change for managing meningitis 3 months - 50 years and > 50 years
3 months - 50 years: IV Cefotaxime
50 + : IV cefotaxime + Amoxiccillin
Side-effects of metronidazole
Increases anticoagulant effects of warfarin
Causes bad experiences with alcohol intake
Management of MRSA
Vancomycin
Triad for congenital toxoplasmosis
Cerebral calcification
Hydrocephalus
Chorioretinitis
Management of latent TB
3 months of isoniazid (with pyridoxine) + rifampicin
6 months of isoniazid (with pyridoxine)
Management of TB
First 2 motnhs: RIPE
Next 4 months: RI
Side effect of pyrazinamide
GOUT
What is yellow fever
It is a viral haeemorhagic fever from aedes mosquitos
What strain of HIV is common in the world
HIV-1
Name trhee cells that carry CD4+ cells
T-helper cells
Macrophages
Dendritic cells
Describe how HIV molecules get into cells
Bind to CD4 cells by GP120 receptors on their cell surface
Then GP120 binds to CXCR4 co receptor
Has to bind to both to get in
WHat enzyme causes the RNA HIV virus to be turned into DNA
Reverse transcriptase enzymes
Basically: whenever you get an infection in the body, these immune cells try and replicate but the viral DNA gets replicated instead - producing more HIV cells by accident!
What causes the acute stage of HIV
The dentritic cells just chill in the epithelium - then migrate to the lymph nodes to elsewhere in the body. High concentrtaion of immune cells means HIV has a field day and infects all the other cells
Symptoms of teh acute phase of HIV
Flu like symptoms:
By 12 weeks, the HIV virus reaches almost zero.
Then we enter the chronic phase
What happens in the chronic phase
Some HIV strains carry an X4 receptor that SPECFICIALLY targets T-cells. It hides in the lymphoid tissues and attacks the T4 cells causing them to deceline.
HIV count goes up
Symptoms of HIV at 200-500 T cells
Swollen lymph nodes
Hairy leukoplakia (EBV)
Oral candidiasis
Name four AIDS defining illnesses
Kaposi’s lymphoma
Pneumocystis pneumonia
Candidiasis of oesophagus
Primary CNS lymphoma
Progressive multifocal leucoencepholopathy
Toxoplasma gondii infection
Name two conditions that are protective against amalria
SCA
Thalassamia
G6PD deficiency
Where do the sporozoites in malaria develop
IN the liver - form merozoites
Name two species that go dormant in the liver
p.vivax
p.ovale
called hypnozoites at this point
How does malaria cause haemolysis
The merozoites invade the blood stream and bind to RBCs
(p.vivax typically only infects reticulocytes)
Then reproduce inside the RBCs to form trophozoites
They eat up haemoglobin from inside the cells: Schizont (they are differentiated)
Burst the RBCs and go into the blood
What species causes the worts malarial infections
p.falciparum
Complication of p.falciparum infections
Blocks up blood vessels
Blocks blood supply to spleen
Blocks blood supply to the brain (seizures)
BLocks blood supply to the liver.
Causes RBCs to clump together
Diagnosis of malaria
Blood smear