Infectious disease Flashcards
What kind of cell walls do positive and negative bacteria have?
Positive - peptidoglycan call wall (stains purple)
Negative - no thick cell wall
What is unique about atypical bacteria?
Cannot be stained or cultured in the normal way
What are ribosomes?
Where bacterial proteins are synthesised
What are some gram positive cocci?
Staphylococcus
Streptococcus
Enterococcus
What are some gram positive rods?
corney Mike’s list of basic cars
Corneybacteria
Mycobacteria
Listeria
Bacillus
Nocardia
List some gram positive anaerobes?
CLAP
Clostridium
Lactobacillus
Actinomyces
Propionibacterium
What are some common gram negative bacteria?
Neisseria meningitis
Neisseria gonorrhoea
Haemophilia influenza
E. coli
Klebsiella
Pseudomonas aeruginosa
Moraxella catarrhalis
Name 5 organisms which can cause atypical pneumonia?
legions of psittaci MCQs
Legionella pneumophila
Chlamydia psittaci
Mycoplasma pneumoniae
Chlamydydophilia pneumoniae
Q fever (coxiella burneti)
What is Methicillin - RSA?
S. Aureus which has become resistant to beta-lactams e.g. penicillins, cephalosporins and carbapenems
How can MRSA be tackled?
Chlorhexidine body washes (if found on nasal / groin swabs)
What are the abx for MRSA?
Doxycycline
Clindamycin
Vancomycin
Teicoplanin
Linezolid
What are Extended Spectrum Beta Lactamase bacteria ?
Bacteria which is resistant to beta lactam abx
Tends to be E.Coli or Klebsiella
Normally sensitive to carbapenems e.g. meropenem imipenem
What is sepsis?
Immune response to infection which causes systemic inflammation and affects functioning of organs
Which cells recognise the bacteria in sepsis?
Macrophages
Lymphocytes
Mast Cells
What is released in a septic patient?
Cytokines
Interleukins
Tumour Necrosis Factor
to alert immune system
What causes the vaso dilation in sepsis?
Nitrous oxide
What is a result of the oedema in sepsis?
Space between the blood and the tissues - reducing amount of oxygen reaching the tissues
How can septic shock be measured?
Systolic blood pressure less than 90 despite fluid resus
Hyperlactaemia (lactate > 4 mmol/L)
What are some risk factors for sepsis?
Very old / young patients (<1 or >75)
Chronic conditions COPD/ Diabetes
Chemo, immunosuppressants, steroids
Pregnancy or peripartum
Indwelling catheters
What scoring system is used to pick up signs of sepsis?
NEWS (national early warning score):
- Temp
- HR
- RR
- O2 sats
- BP
- Consciousness level
What may be found on examination of a septic patient?
Potential sources of infection e.g. cellulitis, discharge from wound, cough / dysuria
Non-blanching rash
Reduced urine output
Mottled skin
Cyanosis
Arrhythmias e.g. new onset AF
Tachyopnoea = first sign
What can a non blanching rash a sign of?
Meningococcal septicaemia
When may a septic patient appear well?
If they’re neutropenic/immunosuppressed
What are the investigations for sepsis?
FBC (neutrophils/WCC)
U&E (kidney function)
LFTs (source of infection)
CRP (inflammation)
Clotting (DIC)
Blood cultures (bacteraemia)
Blood gas (lactate, pH and glucose)
What additional investigations can be used to source the infection in sepsis?
- Urine dipstick
- CXR
- CT for abscess
- Lumbar puncture for meningitis or encephalitis
What medications may causes neutropenic sepsis?
- Chemo
- Methotrexate
- Sulfasalazine
- Infliximab
Viral bronchitis presents similarly to pneumonia, does it requier abx?
No
What are the 5 causes of atypical pneumonia?
Lesions of psittaci MCQs
Legionella pneumophila
Chlamydia psittaci
Mycoplasma pneumoniae
Chlamydydophila pneumoniae
Q fever (coxiella burnetii)
What would be used to treat pneumonia in the community?
Amoxicillin
What are some alternative medications for CAP?
Erythromycin / clarithromycin
Doxycyclin
How do lower urinary tract infections present?
- Dysuria
- Suprapubic pain
- Frequency
- Urgency
- Incontinence
How does pyelonephritis present?
- Fever (more prominent than lower UTI)
- Vomiting
- Loss of appetite
- Back pain
- Haematuria
- Renal angle tenderness
What suggests an infection on urine dipstick?
- Nitrites (breakdown produce of nitrates by bacteria)
- Leucocytes (if only these are present then unlikely a UTI)
What are some organisms causing UTIs?
E.coli / Klebsiella pneumoniae (gram-negative anaerobic rods)
Enterococcus
Pseudomonas aeruginosa
Staphylococcus saprophyticus
Candida albicans
What length of abx for:
Simple UTI in women
Complex UTI (immunosuppressed, abnormal anatomy)
UTI in men / pregnant women or catheter related UTIs?
Simple UTI in women: 3 days
Complex UTI: 5-10 days
UTI in men?: 7 days
What abx for UTI?
Trimethoprim
Nitrofurantoin
Alternatives = cefalexin, pivmecillinam, amoxicillin
What can be used to treat pyelonephritis in the community?
Cefalexin
(or co-amoxiclav, trimethoprim, ciprofloxacin)
How does cellulitis present?
- Eythema
- Warm to touch
- Tense
- Thickened
- Oedematous
- Bullae (fluid-filled blisters)
- Golden-yellow crust (indicates staphylococcus aureus infection)
What does cellulitis with a golden crust indicate?
Staphylococcus aureus infection
What are the most common causes of cellulitis
Staphylococcus aureus
Group A Streptococcus (mainly streptococcus pyogenes)
Group C strep (mainly streptococcus dysgalactiae)
MRSA
What medication is used for cellulitis?
Flucloxacillin (oral / IV)
Clarithromycin
Clindamycin
Co-amoxiclav
What ENT problems are commonly caused by viral infections?
Tonsillitis, otitis media and rhinosinusitis
What is bacterial tonisillitis commonly caused by (if not viral - which it usually is)?
Group A Streptococcus (GAS) infections, mainly streptococcus pyogenes
What are otitis media, sinusitis and tonsillitis not caused by GAS commonly caused by?
Streptococcus pneumoniae
(other causes = H. Influenzae, morazella catarrhalis, staphylococcus aureus)
What would suggest bacterial tonsilitis over viral (Centor Criteria)?
Fever > 38ºC
Tonsillar exudates
Absence of cough
Lymphadenopathy
What is the first line medication for bacterial tonsilitis?
What are some alternatives?
Penicillin V (phenoxymethylpenicillin)
Alternatives = co-amoxiclav, clarithromycin, doxycycline
How does otitis media usually present, what is it usually caused by?
Bulging tympanic membrane, difficult to distinguish viral or bacterial
What are the treatment options for otitis media?
- Amoxicillin
- Macrolide
(co-amoxiclav if not responding)
What can sinusitis be treated with in the community (usually lasts 2-3 weeks and resolves without treatment)?
Penicillin V (phenoxymethylpenicillin)
Macrolide (if penicillin allergy)
Name some possible intra-abdominal infections?
Acute diverticulitis
Cholecystitis (with secondary infection)
Ascending cholangitis
Appendicitis
Spontaneous bacterial peritonitis
Intra-abdo abscess
What are some common organisms in intra-abdominal infections?
Anaerobes (clostridium)
E. Coli
Klebsiella
Enterococcus
Streptococcus
What does co-amoxiclav protect against?
Gram positive, gram negative and anaerobic (not pseudomonas or atypical pneumonia)
What do quinolones protect against? e.g. Ciprofloxacin and levofloxacin
Gram positive, gram negative and atypical (not anaerobes so usually given with metronidazole)
What does metronidazole protect against?
Anaerobes
What does gentamicin protect against?
Gram negative (and some staph) - bactericidal
What does vancomycin protect against?
Gram positive including MRSA (used in comb with gentamicin and metronidazole)
What are cephalosporins used for?
Gram negative and gram positive (no anaerobes and risk of C. difficile infection)
What are tazocin (piperacillin/tazobactam) and meropenem used against?
Gram positive/negative/anaerobes (not atypicals OR MRSA, tazocin not ESBLs)
What are some common abx regimes?
Co-amoxiclav alone
Amoxicillin plus gentamicin plus metronidazole
Ciprofloxacin plus metronidazole (penicillin allergy)
Vancomycin plus gentamicin plus metronidazole (penicillin allergy)
What is usually first line for spontaneous bacterial peritonitis (usually occurs in liver failure)?
Tazocin
How does septic arthritis usually present?
Hot, red, swollen, painful joint
Stiffness and reduced ROM
Fever, lethagy
What bacteria typically causes septic arthritis?
Staphylococcus aureus
Neisseria gonorrhoea
Streptococcus pyogenes (GAS)
Haemophilus influenza
E. coli
Diagnossi if a patient has urinary symptoms and swollen knee?
Septic arthritis (before reactive arthritis)
What are some differentials for a painful, swollen joint?
Gout (urate crystals = negatively birefringent of polarised light)
Pseudogout (calcium pyrophosphate crystals = postivelt birefringent)
Reactive arthritis (triggered by urethritis / gastroenteritis associated with conjunctivitis)
Haemarthrosis
Septic arthritis
What should the aspirate be tested for in joint swelling?
- Gram staining
- Crystal microscopy
- Culture
- Abx sensitivities
What are the empirical abx for septic arthritis?
Flucloxacillin plus rifampicin
Vancomycin plus rifampicin for penicillin allergy, MRSA or prosthetic joint
Clindamycin is alternative
Which patients are offered an annual flu jab?
Aged 65
Young children
Pregnant women
Asthma, COPD, heart failure and diabetes (chronic conditions)
HCW and carers
How does the flu present?
- Fever
- Coryzal symptoms
- Lethargy and fatigue
- Anorexia (loss of appetite)
- Muscle and joint aches
- Dry cough
- Muscle and joint aches
- Sore throat