Infectious disease Flashcards
What is the most common cause of gastroenteritis?
Viral: rotavirus, norovirus, adenovirus
What is the spread of E.coli?
Infected faeces, unwashed salad, water
What is the incubation time of campylobacter jejuni?
2-5 days
What is the spread of campylobacter jejuni?
Raw poultry, untreated water, unpasteurised milk
What are the symptoms of campylobacter jejuni gastroenteritis?
- Cramps
- bloody diarrhoea
- fever
What is the incubation time of shigella?
1-2 days
What is the spread of shigella?
Contaminated water and food
What are the symptoms of shigella?
- abdominal cramps
- bloody diarrhoea
- fever
What is the incubation time of salmonella?
12 hours to 3 days
What is the spread of salmonella?
- raw egg/poultry
- contaminated food
What are the symptoms of salmonella?
- watery diarrhoea ± blood/mucus
- abdominal pain
- vomiting
What is haemolytic uraemic syndrome?
- Shiga toxin produced by EHEC and sometimes shigella and strep pneumoniae
- Triad of: microangiopathic anameia, thrombocytopenia and AKI
What should be avoided in haemolytic uraemic syndrome?
- Antibiotics
- anti-motility agents
- NSAIDs
What bacteria can cause bloody diarrhoea?
- Campylocbater jejuni
- shigella
- EHEC
What bacteria can cause watery diarrhoea?
- Salmonella
- ETEC, EPEC
- Bacillus cereus
What is the incubation time for bacillus cereus?
5 hours
What is the most common cause of the common cold?
Rhinovirus
What are complications of the common cold?
- otitis media
- sinusitis
What is the presentation of pharyngitis?
- sore throat
- fever
- pharyngeal inflammation
In a patient presenting with pharyngitis and mouth vesicles, what is the most likely cause?
Enterovirus
What is the peak age of croup infection?
2 years old
What are the symptoms of croup?
- fever
- rhinorrhoea
- harsh seal like cough
- tachypnoea
- subglottic obstruction
What is the cause of croup?
Parainfluenza viruses 1-4
What are the symptoms of influenza?
- fever
- fatigue
- anorexia
- muscle aches
- headache
- dry cough
- sore throat
What is the diagnosis of influenza?
Viral nasal/throat swab -> PCR
Who should get the vaccine for influenza?
- > 65
- Young children
- pregnant women
- chronic health conditions
- healthcare workers
What is the treatment for influenza?
Oral oseltamivir 75mg twice daily for 5 days if at risk of complications but must be within 49 hours
What are the complications of influenza?
- otitis media
- sinusitis
- bronchitis
- viral pneumonia
- worsening of health conditions
What type of bacteria is klebsiella?
Gram positive ros
What is the marker of a klebsiella respiratory infection?
Red currant jelly sputum
Which patient groups is klebsiella more common in?
Diabetics and alcoholics
What is the most common cause of pneumonia?
Streptococcus pneumonia
What is the most common cause of pneumonia following an influenza infection?
Staphylococcus aureus
What is mycoplasma pneumoniae associated with?
Erythema multiforme and cold autoimmune haemolytic anaemia
What should you treat mycoplasma pneumoniae with
Macrolide
What is MRSA resistant to?
- beta lactams
- cephalosporins
What is the treatment of MRSA bacteraemia
IV vancomycin
What is the treatment of MRSA pneumonia?
IV vancomycin
What is the treatment of MRSA UTI?
Trimethoprim
What type of bacteria is clostridium difficile?
Gram positive rod
What is the presentation of c. diff infection?
- diarrhoea
- abdominal pain
- raised white cell count
What is the diagnosis of c diff
- c.diff toxin in the stool
- c.diff antigen only shows exposure to the bacteria
What is the management of first presentation of c diff infection?
oral vancomycin for 10 days
What is the management of recurrent c diff?
oral Fidaxomicin for 10 days
What is the management of life threatening c diff?
Oral vancomycin and IV metronidazole
Which antibiotics are associated with C diff?
- Cephalosporins
- clindamycin
- ciprofloxacin (fluoroquinolones)
What are the complications of c diff?
- ileus
- toxic megacolon
- perforation and peritonitis
What are the causes of viral meningitis?
- Enteroviruses
- HSV
- mumps
- Varicella zoster virus
- WEst nile
- HIV
CSF in viral meningitis
- clear
- White blood cell 50-100
- Protein >50
What is the treatment of viral meningitis?
- supportive care
- analgesia
- anti-emetic
- IV fluids
What are the causes of bacterial meningitis?
- Streptococcus pneumoniae
- Neisseria meningitidis
- Haemophilus influenzae
CSF in bacterial meningitis
- Cloudy and turbid
- WBC >100
- Low glucose
- Increased protein
- increased opening pressure (>25cm H2O)
Empirical antibiotics in bacterial meningitis
Ceftriaxone IV
What are the causes of fungal meningitis?
Cryptococcus species
CSF in fungal meningitis
- clear/cloudy
- increased opening pressure
- white cell count 10-100
- low glucose
- increased protein
What is the most common cause of bacterial meningitis in 0-3 month olds?
Group B strep
What is the most common cause of bacterial meningitis in 3mth to 6 year olds?
N.meningitidis, strep pneumoniae, haemophilus influenzae
What is the most common cause of bacterial meningitis in 6 to 60 year olds
N. meningitidis, streptococcus pneumoniae
What is the most common cause of bacterial meningitis in immunosuppressed
Listeria monocytogenes
What is the prophylaxis for meningitis and when does it need to be offered?
Oral ciprafloxacin or rifampicin, if they have had close contact with the patient within 7 days of symptom onset
What is the presentation of herpes simplex virus?
- prodrome (may experience tingling)
- genital ulcer
- oral ulcer
- dysuria
Investigation for herpes simplex virus
Viral PCR swab
What is the treatment for HSV?
1st episode: aciclovir 200mg 5 a day for 7-10 days
How can you decrease the transmission of HSV?
aciclovir 400mg PO twice a day for 12 months
What is the presentation of TB?
- cough
- fever
- anorexia
- weight loss
- malaise
- night sweats
What are the risk factors of TB?
- immunosuppression
- HIV
- Asia/latin america/africa
What is the investigation for TB?
- sputum acid-fast bacilli smear and culture
- CXR: fibronodular opacities in the upper lobes
- Full blood count: increased WCC and decreased Hb
What is the treatment of TB?
For four months:
- Isoniazid
- Rifampicin
- Pyrazinamide
- Ethambutol
For a further 2 months:
- Isoniazid
- rifampicin
What is the treatment of latent TB?
Isoniazid monotherapy
What is HIV?
A retrovirus that destorys CD4 cells
What are the risk factors for HIV?
- IVDU
- Men who have sex with men
What is the presentation of HIV?
- Fever and night sweats
- Weight loss
- Oral ulcers
- angular chelitis
- oral thrush
- recent admission due to infection
- generalised lymphadenopathy
What is the investigation for HIV?
- ELISA serum HIV enzyme-linked immmunisorbent assay
- serum p24 antigen
- test asymptomatic patients at 4 weeks after possible exposure
What CD4 count is considered end stage HIV/AIDS
<200
What is the antiretroviral therapy for HIV?
- 2x NTRIs and protease inhibitor or non nucleoside reverse transcriptase
- Start as soon as diagnosed
What is the management of HIV?
- Co-trimoxazole if CD4<200 to protect agaisnt pneumocystis jiroveci pneumonia
- yearly cervical smears
- vaccination: influenza, pneumococcal, Hep A+B, tetanus, diptheria and polio
What is post exposure prophylaxis for HIV?
- <72 hours
- Truvada (emtricitabine/tenofovir) and raltegravir for 28 days
What is meant by undetectable in HIV?
Viral load/no. of HIV RNA per ml blood (50-100)
What are the AIDS defining illnesses?
- kaposi’s sarcoma
- Pneumocystis jirovecii pneumonia
- cytomegalovirus
- candidiasis
- lymphoma
- tuberculosis
SIRS
- sweats
- chills/rigors
- tachypnoea
- tachycardia
- hypotentsion
Sepsis
Evidence of infection plus organ dysfunction: ≥2 of: hypotension, confusion, or tachypnoea (≥22)
What is neutropenic sepsis?
Neutrophil count of <0.5 or 1 if recent chemo and fever or hypothermia or SIRS or sepsis/septic shock
What is septic shock?
Sepsis induced hypotension requiring inotropic support or hypotension which is not responsive to adequate fluid resuscitation
What are the risk factors for staphylococcus bacteraemia?
- intravascular and other invasive devices
- skin and soft tissue infection
- surgical site infection
- IVDU
Treatment of staph aureus bacteraemia
IV flucloxacillin 2 grams 6 hourly
Presentation of chlamydia
- asymptomatic
- cloudy/yellow discharge, post coital or intermenstrual bleeding in women
- mucoid discharge in men
- dysuria in men and women
Investigation for chlamydia
- NAAT: vulvovaginal in women, urine for men
- testing should be carried out two weeks after exposure
What is the management of chlamydia?
- doxycycline 7 days
Presentation of gonorrhoea
- mucopurulent cervicitis
- urethral discharge in men
Investigation for gonorrhoea
- NAAT
- culture
Management gonorrhoea
- ceftriaxone IM 1g
Presentation of syphilis
Primary:
- chancre: painless ulcer
- local, non tender lymphadenopathy
Secondary:
- systemic symptoms
- rash on trunk, palms and soles
- buccal ‘snail track’ ulcers
- condylomata lata (painless warty lesions on genitals
Territory:
- Gummas
- Neurosyphilis
- aortitis, aortic valve disease, aortic aneurysm
Treatment of syphilis
Benzathine penicillin IM
Presentation of trichomonas vaginalis
- offensive yellow/green and frothy discharge
- vulvovaginitis
- strawberry cervix
- pH>4.5
- usually asymptomatic in men but may cause urethritis
Treatment trichomonas vaginalis
Oral metronidazole for 5-7 days
What species of plasmodium cause malaria?
- falciparum
- ovale
- vivax
- malariae
What causes severe malaria
falciparum
What are the features of severe malaria?
- schizonts on a blood film
- parasitaemia >2%
- hypoglycaemia
- acidosis
- temperature >39
- severe anaemia
What are the features of non-falciparum malaria
- fever
- headache
- splenomegaly
- vivax/ovale: cyclical fever every 48 hours, malariae: 72 hours
- malariae is associated with nephrotic syndrome
investigation for malaria
- blood film: thick/thin
- antigen testing
- FBC
What causes infectious mononucleosis?
Epstein barr virus
What is the presentation of infectious mononucleosis?
- sore throat
- pyrexia
- lymphadenopathy
- malaise, anorexia, headache
- palatal petechiae
What are the investigations for infectious mononucleosis?
- FBC: lymphocytosis (at least 10% atypical0
- monospot test (heterophil antibody test)
What is the presentation of dengue fever?
- Fever
- headache
- myalgia, bone pain, arthralgia
- pleuritic chest pain
- facial flushing
- maculopapular rash
Severe dengue
- Haemorrhagic fever
- thrombocytopenia and spontaneous bleeding
Investigation for dengue
- FBC: leukopenia, thrombocytopenia, raised aminotransferases
- Serology/NAAT
What are the causes of enteric fever?
- S.typhi
- S.paratyphi
Presentation of enteric fever
- HEadache, fever, arthralgia
- Relative bradycardia
- Abdominal pain and distension
- Constipation
- Rose spots
What are the investigations for enteric fever?
- blood and stool culture
What is schistosomiasis?
Parasitic flatworm infection
What is the presentation of schistosomiasis ?
- Swimmer’s itch
- Acute schistosomiasis syndrome: fever, urticaria, arthralgia, cough, diarrhoea
Treatment of schistosomiasis
Praziquantel
What is the most common cause of community acquired pneumonia?
Streptococcus pneumoniae
What is the treatment of choice for non falciparum malaria?
Chloroquine
What is the spread of hepatitis A?
Faecal-oral
What is the spread of hepatitis C?
Parenteral, sex, vertical transmission
What is the spread of Hep B?
Parenteral, sex, vertical transmission
What is e coli
Gram negative rod
Rice
Bacillus cereus
What is the spread of Hepatitis E?
Faecal-oral
What is haemophilus influenzae?
Gram negative rod
Rusty sputum
Strep pneumoniae
What causes syphilis?
Treponema pallidum
Which vaccines are live attenuated?
- MMR
- BCG
- influenza (intranasal)
- polio
- typhoid
- yellow fever
- Oral rotavirus
India ink positive
Cryptococcus
clue cell
Bacterial vaginosis
What is the most common cause of diarrhoea in those with HIV?
Cryptosporidium
What is the management of hospital acquired pneumonia?
Within 5 days of admission: co-amoxiclav or cefuroxime
More than 5 days after admission: piperacillin with tazobactam OR a broad-spectrum cephalosporin (e.g. ceftazidime) OR a quinolone (e.g. ciprofloxacin)
What is the length of post exposure prophylaxis?
28 days
