Week 2: Infectious diseases (2) (Disease model, bacteria, 10-point approach) Flashcards
infection model
types of pathogen
-
Prokaryotes
- Virus
- Bacteria
-
Eukaryotes
- fungus (yeast and mould)
- parasite (protozoa and helminths
person factors?
- Age
- Gender
- Physiological state
- Pathological state/ co-morbidities
- Social factors
time factors
- Calendar time e.g. length of symptoms
- Relative time e.g. incubation
environment factors
- Current
- Recent (e.g. travel, hospital)
mechanisms of ifnection
- inhalation
- contiguous (direct) spread
- haemtogenous
- inoculation
- vector
- vertical transmission
- sexual transmission
examples of contigious spread
abscess, bone, meningitis
examples of haematogenous spread
septicaemia/septic emboli
examples of inocultion
IVDU e.g. viral hepatitis
inhalation
colds, influenza, TB
vector
malaria, lyme disease
vertical tranmission
HIV, rubella, syphilis
sexual transmission
HIV, gonorrhoea, syphillis
infection management
- history
- examination
- investigation
- management
- specific (antibiotics, surgery)
- support (symptom relief, physiological restoration)
- infection prevention
gram positive
purple
gram negative
pink
outline gram staining
fans can intimidate dad sadly
name gram positive coccus
staphylococcus aureus
staphylococcus epidermis
alpha haemolytic streps (strep pneumoniae)
beta haemolotidy strep (s. pyogenes
enterococcus
gram positive bacillus
listeria monocytogenes
corynebacterium diptheriae
C.difficile
gram negative coccus
neisseria meningitiis
neisseria gonorrhoea
gram negative bacillus (predominant infective bacteria)
- Enterobacteriaceae
- E.coli
- Klebsiella spp
- Proteus spp
- Salmonella spp.
- Pseudomonas aeruginosa
- Haemophilus influenzae
common skin and soft tissue infections in secondary care
- Cellulitis
- Necrotising fasciitis
- Diabetic foot
common MSK infections in secondary care
- Septic arthritis (native/prosthetic joint)
- Spondylodiscitis
- Osteomyelitis
common cardio-respiratory infections in secondary care
- URTI
- Otitis media
- Pharyngitis
- LRTI
- CAP
- Exacerbations of COPD
- Atypical pneumonia
- TB
- Endocarditis
common GI infections in secondary care
- Infectious diarrhoea/gastroenteritis inc C.diff
- Visceral perforation/peritonitis
- Hepato-biliary infections
- Viral hepatitis- ABCE
- Gastritis/peptic ulceration- H pylori
common genitourinary infections in secondary care
- Cystitis, pyelonephritis
- Pelvic inflammatory disease
common CNS infections in secondary care
- Meningitis
- Encephalitis
- Brain abscess
Immunodeficiency
- HIV/AIDS
- Drugs
- Post chemotherapy/transplantation
- Corticosteroids/ DMARDs/ biologics
- Congenital immunodeficiency
common post-surgical/iatrogenic in secondary care
- Post op wound infectious
- Vascular line infections
- Prosthetic material (urinary catheter, PPM)
Drug resistant organisms
- MRSA
- Extended-spectrum beta-lactamase (ESBL) producer
- Carbapenem resistant organisms (CRO)
- Isolation/ PPE
Antimicrobial stewardship
- Safe prescribing
- No antibiotics unless necessary
- As narrow-spectrum as possible
- Minimal duration on IV
- Hospital guidelines
sepsis
Life threatening organ dysfunction caused by dysregulated host response to infection
- Blood culture
- U&E
- Fluids
- Antibiotics
- Lactate
- Output
pneumonia screening tool
CURB-65
confusion
urea
resp rate
BP
>65
10-Point approach to the Patient with Infection
- What is the evidence for infection?
- How severe is it?
- Any patient factors to consider?
- Which body system / organ is infected?
- Which micro-organism(s) may be involved?
- Which antimicrobial therapy is best?
- What route of administration is best?
- Is any other treatment needed?
- Is there risk of transmission to others?
- What planning is required for follow-up and discharge?
- What is the evidence for infection?
- Symptoms / focal signs / examination findings / EWS / investigation results
- Any non-infective differentials?
- How severe is it?
- Mild/moderate/severe
- Severity score / evidence for Red-flag sepsis
- Any patient factors to consider?
Co-morbidities / drugs / age / gender / nutrition / social / immunocompromise / travel
- Which body system / organ is infected?
- Localised symptoms/signs?
- Multi-organ involvement / sepsis?
- Which micro-organism(s) may be involved?
use focal symptoms/signs and the tables above
- Which antimicrobial therapy is best?
dependent on likely micro-organism (above)
- What route of administration is best?
IV/ PO / other
- Is any other treatment needed?
e.g. Sepsis 6 / supportive / analgesia / surgery / change in usual meds / IV insulin
- Is there risk of transmission to others?
measures required to prevent this eg isolation / personal protective equipment (PPE) / inform laboratory of biohazard / inform public health
- What planning is required for follow-up and discharge?
e.g. switch to oral or stop antibiotics / MDT involvement / re- instate usual drugs / appropriate follow-up
You are an F1 working on AMU. A 30 year old male medical student presents having returned 2 weeks ago from his medical elective in Senegal, where he had been staying for 3 weeks. He has been feeling feverish and unwell for the last 3 days, with flu-like symptoms and a headache. He saw an out-of-hospital GP a day before who suggested it may be viral, but did some blood tests. Today, he feels worse, and has noticed a change in his skin colour.
Which infection is present
‘ Banana shaped gametocytes’ consistent with P Falciparum
patient with malaria: You are called by Microbiology with blood culture results taken previously by the GP. An organism has been cultured, with further identification and sensitivities to follow. This is the microscopy/gram stain result-
- Gram negative bacilli- E.coli, Salmonella typhi
- Malaria predisposes you to developing gram negative infections
antimicrobial therapy for malaria
- IV artesunate with IV meropenem (as he is pen allergic)
You are an F1 covering the GPAU. A 51 year old man has presented after complaining of a fever, headache and abdominal pain for the last 5 days. He returned from India 18 days ago .He initially had diarrhoea but is now feeling more constipated. He also has a dry cough.
He has a history of atrial fibrilliation. His medications are: bisoprolol, warfarin. He has no known allergies.
On examination, he looks comfortable at rest. His chest is clear and there are no audible murmurs. His abdomen is soft but mildly tender in the suprapubic area. There are no obvious enlarged organs.
What does it show? Which organism(s) could it be?
Gram negative (as its pink-ish) rods. It could be many different organisms but with the travel history Salmonella Typhi/paratyphi needs to be considered.
what does this show
- Mycobcterium tuberculosis (Zheel- nelson stain)
Following a positive TB result, what would your next steps be? Who needs to be involved?
- Isolate
- Start treatment (RIPE)
- Contact tracing
RIPE treatment for TB
-
Rifampicin
- causes urine/tears to turn orange (reverses when rifampicin stops)
- Drug induced hepatitis +
-
Isoniazid
- Peripheral neuropathy (reduced by giving pyridoxine) Colour blindness
- Drug induced hepatitis ++
-
Pyrazinamide
- Drug induced hepatitis +++
-
Ethambutol
- optic neuropathy/ reduced visual acuity
Patient with cellulitis causing sepsi
Describe what is seen. Which organism(s) could it be? What would be an appropriate antimicrobial choice?
- Gram positive cocci- streptococcus pyogenes
- IV Benzylpenicillin/ Flucloxacillin
