Infectious diseases 2 Flashcards
Define meningitis
Inflammation of leptomeningeal (pia mater and arachnoid) coverings of the brain
Which meningeal layers are inflamed in meningitis
Pia and arachnoid
Define encephalitis
Inflammation of brain parenchyma
Bacterial causative agents in meningitis (3)
Streptococcus pneumoniae,
Neisseria meningitidis
Haemophilus influenzae type B
Most common cause of aseptic meningitis
Enterovirus
Main cause of encephalitis
Herpes virus
Main symptoms of meningitis (4)
Photophobia
Neck stiffness
Headache
Fever
Symptoms of encephalitis (7)
Altered state of consciousness, seizures, personality change, cranial nerve palsies, speech problems, motor and sensory deficit
Ix for meningitis
lumbar puncture to obtain CSF
Ix for encephalitis (3)
Blood cultures, neuroimaging (MRI), CSF analysis
What organisms commonly infect neonates (3)
Group B streptococcus
E coli
Listeria monocytogenes
Which gram -ve diplococci often infects children and teenagers
Neisseria meningitides
Which bacteria often infects unvaccinated children and teenagers
Haemophilus influenzae
Which gram +ve cocci often infects adults and the elderly
Strep pneumonia
Which bacteria often infects the elderly, alcoholics and cheese/unpasteurised milk
Listeria monocytogenes
Which organism infects neonates with an extended delivery
Group B strep
Which organism infects neonates that have had an infection in a previous pregnancy
Group B strep
Which organism causes a late neonatal infection
E coli
What buzzword guides you to Group B strep infection in a neonate (2)
Extended labour, infection in previous pregnancy
What buzzword guides you to E coli infection in a neonate
Late neonatal infection
What buzzword guides you to neisseria meningitides infection in children and teenagers
grame -ve diplococci
What buzzword guides you to haemophilia influenzae infection in children and teenagers
Unvaccinated
What buzzword guides you to strep pneumoniae infection in adults and elderly
grame +ve cocci
What buzzword guides you to Listeria monocytogenes infection in adults and elderly (4)
Elderly, unpasteurised milk, cheese, alcoholics
What is Brudsinkins sign
Flexing the neck causes the patient s hips and knees to flex (meningitis)
What is Kernigs sign
Inability to straighten the leg when the hip is flexed to 90 degrees
Signs of meningitis infection (5)
Fever Tachycardia Hypotension Skin rash – petechiae meningococcal septicaemia Altered mental state.
Ix for meningitis (3)
Blood: Two sets of blood cultures
Imaging: CT scan to exclude intracranial pressure.
Lumbar puncture: Send CSF for MC&S and Gram staining
When do you avoid LP (3)
Neurological signs suggesting raised ICP
Superficial infection over LP site
Coagulopathy
CSF normally: Appearance WCC Protein Glucose Gram stain
Clear Very low Normal Normal Normal
CSF in bacterial meningitis: Appearance WCC and which cell Protein Glucose Gram stain
Turbid Very high - neutrophils Very very very high Very very very low Positive
CSF in viral meningitis: Appearance WCC and which cell Protein Glucose Gram stain
Clear/cloudy High - lymphocytes Increased Normal Normal
CSF in fungal/TB meningitis: Appearance WCC and which cell Protein Glucose Gram stain
Clear/cloudy
High lymphocytes
Increased protein
Decreased glucose
Mx of meningococcal septicaemia
Admit
Give single dose IV benzylpenicillin
Mx of bacterial meningitis
IV Ceftriaxone (3rd generation cephalosporin)
Consider corticosteroids – Dexamethasone for bacterial meningitis BUT not if meningococcal septicaemia is suspected
(cover Listeria with ampicillin)
If consciousness affected, consider IV acyclovir to cover encephalitis
Prophylaxis to close contacts: Rifampicin or ciprofloxacin
Viral causes of encephalitis (6)
(HSV-1, HSV-2, VZV, CMV, EBV, Human herpes virus)
Bacterial causes of encephalitis (4)
Neisseria meningitides
TB
Syphilis
Listeria
What type of encephalitis does neisseria meningitides cause
Meningo-encephalitis
Fungal causes of encephalitis (2)
Cryptococcus
Candida
Parasitic causes of encephalitis (2)
Toxoplasma Gondii, malaria
Which three organisms (and subtypes) are the main causes of infective endocarditis
Group A Streptococci (viridian’s or Boris)
Staphylococci aureus or epidermis
Enterococci faecalis
What are the RF of IE
Abnormal valves Prosthetic valves IV drug use Turbulent flow Recent dental work
What are 4 causes of abnormal valves
congenital, post-rheumatic, calcification/ degeneration
What organism does a case of infective endocarditis with abnormal valves suggest
Strep viridian’s or strep bovis
What organism does a case of infective endocarditis with prosthetic heart valves suggest
Staph a or epidermis
What organism does a case of infective endocarditis with IV drug use suggest
Staph A or staph epidermis
Symptoms of infective endocarditis (5)
Fever with sweats/chills/rigors
Malaise, arthralgia, myalgia, confusion
Signs of infective endocarditis
Pyrexia, tachycardia, signs of anaemia. Clubbing New murmur Splenomegaly. Vasculitic lesions
Order of which valves are most likely to get infective endocarditis
Frequency: Mitral > aortic > tricuspid > pulmonary.
What does right sided infective endocarditis suggest
Drug use
Mnemonic to help remember signs of infective endocarditis
Fever Roth spots Osler nodes Murmur Janeway lesions Anaemia Nail-bed splinter haemorrhage Emboli
Buzzwords for infective endocarditis (6)
Prosthetic valve Dental procedure New onset murmur Vegetation on echo Right heart Indwelling catheter
Ix for endocarditis
Bloods 3 blood cultures, 1 h apart, within 24 hs Urgent echo Dukes classification Broad spectrum
What do you look for in the bloods of infective endocarditis (5)
Bloods: FBC (high neutrophils, normocytic anaemia), ESR and CRP, U&Es, rheumatoid factor positive
Complications of infective endocarditis (6)
Congestive heart failure Valve incompetence Aneurysm formation Systemic embolization Renal failure Glomerulonephritis.
Mx of infective endocarditis
Dependent upon organism.
On clinical suspicion benzylpenicillin or vancomycin if allergic until confirmed.
Then switch to targeted antibiotics
Penicillin-sensitive Streptococcus viridans = Benzylpenicillin + gentamicin
S. aureus = Flucloxacillin
Prosthetic Valves
Staphylococci = Flucloxacillin/Vancomycin + rifampicin + gentamicin
Common causes of dysentry (6 mnemonic)
CCHESS
Campylobacter / Clostridium difficile Haemorrhagic E. coli Entamoeba histolytica Shigella Salmonella
Common causes of diarrhoea (6)
Campylobacter / Clostridium difficile Staph aureus Vibrio cholera E. coli Bacillus cereus Salmonella
History clues to suggest gastroenteritis due to C diff (4)
> 70 yo, past C. diff, use of antibiotics, antiperistaltic drugs
History clues to suggest gastroenteritis due to staph A (3)
food, 1-6 hours after eating, short lived
History clues to suggest gastroenteritis due to vibrio cholera (3)
rice water diarrhoea, poor sanitation, shock
History clues to suggest gastroenteritis due to e coli
leafy vegetables
History clues to suggest gastroenteritis due to bacillus cereus (2)
reheated rice, can cause cerebral abscess
History clues to suggest gastroenteritis due to salmonella (3)
eggs, poultry may present with constipation, multiplies in Payer’s patches of the intestine
Which diarrhoea causing organism can cause a cerebral abscess
Bacillus cereus
History clues to suggest dysentry due to campylobacter (31
Uncooked poultry
History clues to suggest dysentry due to HEC (1)
Leafy vegetables
What follows bloody diarrhoea in HEC
Haemolytic uraemia syndrome
History clues to suggest dysentry due to entamoeba histolytica (2)
poor sanitation, tropical places
History clues to suggest dysentry due to entamoeba histolytica (2)
person-to-person contact, poor sanitation
History clues to suggest dysentry due to salmonella (2)
eggs
Examinations for gastroenteritis (3)
Mucous membranes, skin turgor, cap refill dehydration?
HR, BP shock?
Temperature
Ix for gastroenteritis
Bloods: FBC, ESR/CRP, U&Es - deranged (low K in severe D&V) Stool MC&S Bacterial pathogens Ova cysts (eggs) Parasites
Mx of gastroenteritis
No systemic signs - bed rest, fluids and electrolyte replacement with oral rehydration and no stool culture
Systemic signs:
Admit
Oral fluids/IV if severe vomiting
Direct faecal smear then culture
What counts as systemic signs in gastroenteritis
> 39C or dehydration
Visible blood or >2wks
baby girl born 1 day ago born after a prolonged vaginal delivery, becomes drowsy. On examination, T: 38.9, HR: 170bpm, RR: 30. Which is the most likely causative agent?
Group B streptococcus
Non-blanching rash in meningitis indicates what viral/bacterial/fungal meningitis?
Bacterial
A 72-year-old patient with a new onset murmur, fever and clubbing presents with blood in his stools, diarrhoea and weight loss over the past 5 months. Which is the most likely causative agent?
Strep bovis as it is suggestive of infective endocarditis with colorectal cancer
A 15-year-old boy with DiGeorge syndrome had a dental tooth extraction 2 weeks ago, visits his GP who on auscultation finds a new murmur on the left sternal edge. Basic observations: BP 110/80, HR: 95, Temperature: 38.5, SaO2 98% on air. What is the most likely causative agent?
Strep viridans due to congenital heart defect
A 24 year old medical student comes back from their holiday and presents to A&E with profuse diarrhoea of rice water appearance. There is no blood. What is the most likely causative agent?
Vibrio cholera
A 40 year old woman presents to A&E with bloody, foul smelling diarrhoea. She went to a barbeque yesterday where she suspects she ate undercooked chicken. She has a fever and severe abdominal pain. What is the most likely causative agent?
Campylobacter
Salmonella is more associated with raw eggs
A 67 year old male has been in hospital for the past two weeks for severe pneumonia. He develops bloody diarrhoea, colitis and reduced urine output. He has raised CRP, WCC and low albumin. What is the most likely causative organism?
C. Difficile
Due to likelihood of having broad spectrum antibiotics with the pneumonia
3 key features of hepatitis
Fever
Jaundice
Raised ALT, raised AST
3 key causes of hepatitis
Viral (ABCDE)
Alcohol
Autoimmune
Hep A transmission route
Faeco-oral
vowels = bowels
Hep B transmission route
Sexual
Contaminated needles
(also infected tears and saliva)
Hep C transmission route
Blood to blood
Hep D transmission route
Resides inside B
Hep E transmission route
Faeco-oral
Which hepatic virus’ are chronic and which %
B 10% is chronic
C 80% is chronic
Mx for HCV
Antiretrovirals are now curative
e.g. NS5A inhibitors,
NS3/4 protease inhibitors
Symptoms of acute HBV (4)
Antiretrovirals are now curative
e.g. NS5A inhibitors,
NS3/4 protease inhibitors
Hep A symptoms (5)
Usually asymptomatic 90% but can get: Nausea Vomiting (+ Diarrhoea) Fever Jaundice Abdominal pain (particularly RUQ)
Hep E RF: (4)
Enteric
Epidemics (water)
Expectant mothers
E- immunocompromised
Hep B transmission (3)
Baby making Unprotected sex, MSM,
Blood (transfusion, IVDU)
Birthing (perinatal)
Which hepatic viruses causes liver cancer/cirrhosis
B and C
Most common cause of UTI
E coli
Mx of UTI
Trimethoprim
Ix for UTI (4)
Assess RF
Dipstick urinalysis: positive nitrites +/- leukocytes
Urine MC&S
(Abdo USS – exclude urinary tract obstruction or renal stones)
Ix for viral hepatitis (8)
Blood:
FBC
LFTs (bilirubin, albumin, AlkPhos, GGT).
U&E
Clotting: Prolonged PT is a sensitive marker of significant liver damage.
Ultrasound scan: For other causes of liver impairment (e.g. malignancies).
Viral serology
Viral PCR
Liver biopsy: To assess degree of inflammation and liver damage (useful in diagnosing cirrhosis as patients)
Which is chronic which is acute IgG or IgM
IgG – Gone
IgM – Now
Symptoms of malaria (5)
Headache Weakness Myalgia/ Arthralgia Anorexia Fever - Characteristic paroxysms of severe cold / rigors followed by severing sweating
Signs of malaria (3)
Pyrexia
Anaemia
Splenomegaly
Ix for malaria
Giemsa-stained thick and thin blood smears
Thick – detects parasites present
Thin – identifies species
Other: FBC (Hb, platelets), Clotting profile, U+E, LFTs, blood glucose, Urinalysis, ABG
A 37-year-old bride-to-be returned from Jamaica 3 days ago, where she partied and explored the local cuisine with her best friends. She presents to her GP complaining of being jaundiced with right upper quadrant pain and fever. What is the most likely cause of her symptoms?
Hep A due to faeco-oral transmission
How long does Hep E last 4
2-8
How long does hep A last for
6 weeks
Differences between hep A and E
A: loss of appetite, diarrhoea, fever, malaise, not chronic
E: chronic, risk of fulminant liver failure
A 37-year-old bride-to-be returned from Jamaica 3 days ago, where she partied and explored the local cuisine with her best friends. She presents to her GP complaining of being jaundiced with right upper quadrant pain and fever. What is the most likely cause of her symptoms?
Hep A
A 64-year-old male with thalassaemia is investigated under the two-week wait for jaundice, hepatomegaly and weight loss. His blood tests show a raised αFP. Which chronic infection is he most likely to have?
Hep C
Recurrent blood transfusions due to thalassaemia which is a major risk factor for HCV
27-year-old promiscuous man returns from a trip to Thailand with a right upper quadrant pain, fever and raised ALP and AST. Which is the most likely causative agent?
HBV due to sexual transmission
A 35-year-old woman presenting to her GP with increased urinary frequency and lower back pain. On examination her BP is 130/90, HR: 83bpm, RR: 17bpm and T: 38.3. Which is the most likely finding on her urine dip stick and MC&S?
Positive nitrites and gram-negative bacilli
E. coli is what type of bacteria
Gram -ve bacillus
A 45-year old man presented to his GP with cyclical fevers. He returned from Ethiopia 10 days ago. What is the most likely causative agent?
Plasmodium falciparum
