Infectious Diseases Flashcards
(64 cards)
1
Q
Define sepsis
A
Life-threatening organ dysfunction causes by a dysregulated host response to infection
2
Q
Define septic shock
A
Subset of sepsis with profound circulatory and metabolic abnormalities
- associated with greater mortality
3
Q
Sepsis red flags
A
RR > 25
New need for > 40% O2 to keep saturations over 91%
- 87% in COPD
Systolic BP < 91 mmHg or fall of 40 from normal
HR > 130 bpm
No urine output for 16hrs or < 10ml/hr
New onset delirium
Responds only to voice or pain/unresponsive
Non-blanching rash / mottled / ashen / cyanotic
Neutropenia or chemotherapy in last 6 weeks
4
Q
Time frame for sepsis 6
A
1 hour
5
Q
Features of sepsis 6
A
Oxygen - sats > 94% Take blood cultures Give IV antibiotics - meropenem IV 1g stat Fluid challenge - 500mls Hartmann's or 0.9% saline over 15 mins Measure lactate - blood gas Measure urine output - hourly fluid balance chart
6
Q
Common organisms of skin/soft tissue infection and antibiotics used
A
Staphylococci, staph. aureus - Flucloxacillin
Coagulase negative staph - often fluclox/penicillin resistant
Streptococci - Benzylpenicillin/Fluclox
MRSA - Glycopeptide ( Vancomycin, Teicoplanin)
Penicillin allergy
- Doxycycline (tetracycline)
- Meropenem (carbapenem)
- Ceftriaxone (cephalosporin)
7
Q
Common organisms of musculo-skeltal infection and antibiotics used
A
Diabetic foot - mixed infections - Pseudomonas sp, Enterobacteriacae - Broad spec penicillin - Tazocin - Carbapenem TB - quadruple therapy
8
Q
Common organisms of respiratory infection and antibiotics used
A
Streptococci ( S. pneumoniae) - Amoxicillin (penicillin) - Erythromycin, Clarithromycin (macrolide) H. influenzae - Co-amoxiclav (amoxicllin + clavulinic acid) Atypical (Legionella, Mycoplasma) - Doxycycline - Levofloxacin (fluroquinolone) Rhinovirus/adenovirus/enterovirus - no specific treatment Influenza - Osletamivir
9
Q
Common organisms of diarrhoea/enterocolitis infection and antibiotics used
A
Virus (rotavirus, adenovirus)
- no specific treatment
Enterobacteriacae (Campylobacter, Shigella, E.Coli
- usually nil
- if severe:
- Ciprofloxacin
- Clarithromycin, Azithromycin
Salmonella spp. (S.typhi/parathyphi)
- Ceftriaxone/Azithromycin
C.difficle
- PO Metronidazole/Vancomycin
10
Q
Common organisms of visceral infection/ peritonitis and antibiotics used
A
Enterobacteriacae - Co-amoxicillin or Ciprofloxacin or Gentamicin - Metronidazole (anaerobic cover) If severe/penicillin allergy - Carbapenem
11
Q
Common organisms of GU tract infection and antibiotics used
A
Enterobacteriacae - E.coli, Klebsiella sp, Proteus sp - mild infection = PO Trimethoprim / Nitrofurantoin / Co-amoxicillin - mod-severe infection = IV Co-amoxiclav / PO Ciproflaxacin Pseudomonas aerogenosa - Ciprofloxacillin - Gentamicin - Tazocin ESBL/resistant organisms - Carbapenem Gonorrhoea (Neiseria gonorrhoea) - IM/IV Ceftriaxone Chlamydia trachomatis - Azithromycin
12
Q
Common organisms of CNS infection and antibiotics used
A
S. pneumoniae - IV Ceftriaxone N. meningitidis / H. influenzae - IV Ceftriaxone Listeria - age >55 / immunocompromised = high dose IV amoxicillin Penecillin allergy - Meropenem Herpes simplex virus (encephalitis) - IV Aciclovir
13
Q
Common organisms of endocarditis and antibiotics used
A
S. viridans group - Benzylpenicillin +/- Gentamicin Enterococci (E.facealis) - Amoxicilin +/- Gentamicin Staph. aures (IV drug users) - Flucoxacillin +/- Gentamicin +/- Rifampicin Culture negative endocarditis - Ceftriaxone MRSA / penicillin allergy / penecillin resistant - Vancomycin
14
Q
Common organisms of line infection and antibiotics used
A
Staphylococci, staph. aureus - Flucloxacillin Coagulase negative staph - often fluclox/penicillin resistant Streptococci - Benzylpenicillin/Fluclox MRSA - Vancomycin Penicillin allergy - Doxycycline (tetracycline) - Meropenem (carbapenem) - Ceftriaxone (cephalosporin)
15
Q
Common organisms of hospital inquired infection and antibiotics used
A
Enterobacteriacae (E.coli, Klebsiella spp) - Co-amoxiclav Pseudomonas spp - Ciprofloxacin - Gentamicin C.difficile - Metronidazole - Vancomycin Multi-drug resistant - Tazocin - Carbapenem
16
Q
Presentation of travel-related illness
A
Febrile GI symptoms - diarrhoea - vomiting Jaundice Reticuloendothelial change - lymphadenopathy - hepatosplenomegaly Respiratory symptoms - cough - SOB Rash
17
Q
Featuers of travel history
A
Geographic region within last 12 months Dates and duration of stay - incubation period Onset and nature of signs/symptoms Types of accomodation - rural vs urban Recrational activities and expsoures - insects - malaria, rickettsia - animals - biets, ticks - freshwater lakes and streams - schistosomiasis - well/canal - leptospirosis Food and water drunk - faecal-oral transfer Sexual history - HIV, Hep B/C PMH and immunosuppression
18
Q
Infections develop within 0-10 days of travel
A
Dengue Rickettsia Viral - infectious mononucleosis GI - bacteria - amoeba
19
Q
Infections that develop within 10-21 days of foreign travel
A
Malaria
Typhoid
Primary HIV
20
Q
Infections that develop > 21 days of foreign travel
A
Malaria Chronic bacterial infections - brucella - coxiella - endocarditis - bone and joint infections TB Parasitic infections - helminths - protozoa
21
Q
What does a pulse rate slow for the degree of fever suggest?
A
Typhoid fever
22
Q
Skin changes in infection post foreign travel
A
Maculopapular rash - dengue fever - leptospirosis - rickettsia - infectious mononucleosis (EBV, CMV) - childhood viruses (rubella, parvovirus B19) - primary HIV infection Rose spots on chest/abdomen - typhoid fever Black nectrotic ulcer with erythematous margins - tick exposure Petechiae, ecchymoses or haemorrhagic lesions - dengue fever - meningococcaemia - viral haemorrhagic fever
23
Q
What does conjunctival suffusion suggest?
A
Leptospirosis
24
Q
What does splenomegaly post foreign travel suggest?
A
Mononucleosis Maleria Visceral leishmaniasis Typhoid fever Brucellosis
25
What does altered mental state in fever suggest?
```
Meningo-encephalitis
Post travel
- cerebral malaria
- Japanese encephalitis
- West Nile Viral encephalitis
Common infective causes
- N. meningitis
- Strep. pneumonia
- Herpes simplex virus
```
26
Investigations in post foreign travel infections
Complete blood count
LFTs
U+Es and electrolytes
Malaria smears +/- antigen dipstick - 3 times over 24-48hrs
Blood cultures - x2
Urinalysis +/- urine culture
Stool culture +/- stool for ova, cysts and parasites (OCP)
CXR
HIV, Hep B/C, Syphillis (treponema) serology
Acute serology tube to be saved in lab
27
Cause of malaria
```
Blood protozoa transmitted by night-biting Anopheles mosquitoes
Plasmodium species
- P. falciparum - most serious
- P. vivax
- P. ovale - mostly SE Asia
```
28
Presentation of malaria
Abrupt onset of rigors followed by high fevers, malaise, severe headache and myalgia, vague abdominal pain, N+V
Diarrhoea
Jaundice and hepatosplenogmegaly
Bloods
- anaemia, thrombocytopenia, leukopenia, abonormal LFTs
29
Complications of untreated P. falciparum
```
Hypoglycaemia
Renal failure
Pulmonary oedema
Neurologic deterioration
Death
```
30
Presentation of typhoid fever
```
Sustained fever
Anorexia
Vague abdominal discomfort
Constipation or diarrhoea
Dry cough
```
31
Findings on examination for typhoid fever
Pulse-temperature dissociation
Hepatosplenomegaly
Rose spots
32
Labatory findings for typhoid fever
Non-specific
- leuocpenia
- lymphopenia
- raised CRP
33
Diagnosis and treatment of typhoid fever
Isolation of organism in cultures of blood, stool, urine, bone marrow or duodenal aspiraties
IV Ceftriaxone 2g OD
- once sensitivities known PO Ciprofloxacin 500mg BD or PO Azithromycin 500mg OD
34
PUO
Pyrexia of unknown origin
35
Definition of PUO
Temperature > 38 on multiple occasions
Illness > 3 weeks duration
No diagnosis despite > 1 week worth of inpatient investigation
36
Common causes of PUO
```
Infective
- TB
- abscess
- infective endocarditis
- brucellosis
Autoimmune/connective tissue
- adult onset Stills disease
- temporal arteritis
Neoplastic
- leukamias
- lymphomas
- renal cell carcinoma
Other
- drugs
- emboli
- hyperthyroidism
- adrenal insufficiency
```
37
Management of PUO
Establish diagnosis
Do no start empirical antibiotics/steriods/anti-fungals without speaking to senior
Rhematology/haematology review
Stable patients managed in outpatients following period of observation in hospital
38
Epidemiology of Tuberculosis
Caused by mycobacterium tuberculosis
| Endemic in many parts of Asia, Africa, South America and Eastern Europe
39
Pathogenesis of TB
```
Transmitted by aerosol inhalation
- causes pulmonary infection
- haematogenosus spread to body
Initial infection can be asymptomatic
- can be latent for many years
Lifetime reactivation risk is 10-15%
- usually due to immunosuppression, advancing age or HIV infection
```
40
Classification of TB
Active
- classified by affected site - pulmonary, pericardial. abdominal, miliary
Latent
- asymptomatic
- identified by screening - CSR and interferon gamma
41
What does QuantiFERON test involve
Assess amount of interferon gamma relased by T cells when they are exposed to proteins found of mycobacteria - pre-exposed cells release more interferon
Does not differentiate between active and latent TB
Patients with immunosuppression may not release interferon gamma causing false negatives
42
What does T-spot test involve
Lymphocytes isolated and tested directly
| Postive test does not mean patient has active TB
43
What does TB screening involve
Used in asymptomatic patients with risk factors for latent TB
- immigrants from high prevalence countries
- healthcare workers
- HIV positive patients
- patients starting immunosuppression
44
Treatment of latent TB
3 months rifampicin and isoniazid or 6 months rifampicin alone
- balance reduced risk of reactiviation and risk of hepatotoxicity
45
Common symptoms of TB
Non-resolving cough
Unexplained persistent fever (low or high grade)
Drenching night sweats
Weight loss
46
Common signs of TB
```
Clubbing
Cachexia
Lymphadenopathy
Hepto/splenomegaly
Erythema nodosum
Crepitations or bronchial breathing
Pericardial rub
```
47
Imaging for TB
```
CXR
- mediastinal lymphadenopathy
- cavitating pneumonia
- pleural effusion
CT
- lymphadenopathy
- lesions in viscera
MRI
- leptomeningeal enhancement in TB meningitis
```
48
Investigations for TB
Culturing bacteria
- 6 weeks so ATT usually started after samples taken
Pulmonary TB
- sputum samples or induced sputum
- seen on microscopy = smear positive - high bacterial load and high infectivity so start ATT immediately
Meningeal TB
- lumbar puncture for TB culture and TB PCR
Lymph node TB
- core biopsy of lymph node
Pericardial TB
- pericardiocentesis - but often not practical
GI TB
- colonscopy and bowel biopsy / USS guided omentum biopsy
49
Histological appearance of TB
Caseating/necrotising granulomatous inflammation
50
Paradoxical reaction in TB
Increase in inflammation as bacteria die -> woresening symptoms
- usually occurs at start of treatment
If TB is affecting sites where additional swelling cannot be tolerated
51
Features of TB meningitis
1% of TB patients
All patients with millary TB should have lumbar puncture to exclude TB meningitis
- shows high protein, low glucose and lymphocytosis
MRI shows leptomeningeal enhancement
12 month treatment with steriods
52
Symptoms of TB meningitis
```
Varied
Personality change
Headache
Meningitic
Coma
```
53
Features of pericardial TB
Result in pericardial effusion and tamponade
Signs include pericardial rub or kussmauls sign
6 months treatment - steroids at start
54
Features of Miliary TB
Characteristic appearance on CXR/CT
Widespread and found in multiple sites
Neuroimaging and lumbar puncture to exclude CNS involvement
ATT started as soon as determined whether CNS involvement
55
Multi Drug Resistant TB
```
Consider in
- patients who have had incomplete treatment for TB previously
- patients from abroad
Treatment based on sensitivities
Infection control paramount
- negative pressure room
```
56
Standard ATT treatment for TB
```
2 months
- Rifampicin
- Isoniazid
- Ethambutol
- Pyrazinamide
- plus pyridoxine (vitamin b)
4 months
- Rifampicin
- Isoniazid
- plus pyridoxine (vitamin b)
```
57
Side effects of TB treatment
```
Rifampicin
- urine/tears turn orange
- drug induced hepatitis +
Isoniazid
- peripheral neuropathy - reduced by pyridoxine
- colour blindness
- drug induced hepatitis ++
Ethambutol
- optic neuropathy/reduced visual acuity
Pyrazinamide
- drug induced hepatitis +++
```
58
Monitoring for TB treatment
Measure baseline LFTs and visual acuity
Monitior LFTs
- if deranged stop treatment and gradually reintroduce drugs once normalised
- liver friendly regime - amikacin, levofloxacin and ethambutol for 24 months
59
Screening for bacterial STIs performed in
All patients who are already know to have a sexually transmitted/transmissible infection
All patients who request testing
Any patient identified as high risk of STI from history
60
Tests for asymptomatic patients STI
First pass urine (men)
Vulvo-vaginal swab
Pharyngeal swab
Rectal swab
61
Additional tests for symptomatic STI patients
Urethral / vaginal / anal discharge - charcoal swab for Gonococcal culture
- Posterior fornix for Trichomonas vaginalis and Candida culture
Oral/genital ulceration - for HSV 1 and 2 PCR
Conjunctivitis
62
Baseline investigations for all new HIV diagnoses
Confirmatory HIV test
CD4 count
HIV viral load
HIV resistance profile
HLA B*5701 status
Serology for syphilis, hepatitis A, B, C
Toxoplasma IgG, measles IgG, varicella IgG, rubella IgG
FBC, U&Es, LFTs, bone profile, lipid profile
Schistosoma serology - if spent >1 month in sub-Saharan Africa
Cervial cytology - annually
63
HIV patients with low CD4 counts
Susceptible to infection
CD4 < 200
- Co-trimoxazole 480mg PO OD - primary prophylaxis against PCP
CD4 < 50
- Azithromycin 1250mg PO once weekly - MAI
- opthalmology with dilated fundoscopy - evidence of intra-ocular infections such as CMV retinitis
64
Vaccinations for those with HIV
Hepatitis B
Pneumococcus
Annual influenza
