Infectious Disease (Bac Men, UTI, Impetigo, Otitis media) Flashcards
Bacterial Meningitis Definitions -Meningitis - Bacteraemia - Sepsis
Meningitis causes
Neonates- 1* + 2
Older infants + children 1* + 2
Adolescents 1*
Pathogenesis
6 steps
Presentation General: 6 Rash stage 1 then 2 or 3, what is the test called? 1 Neurological 4 and 2 signs Resp 2
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Management NOT SEPSIS 6! Which antibiotics? - - - What other management?
Follow up with… 5/6
Bacterial Meningitis
Definitions
- Meningitis: Infection/ inflammation of meninges
- Bacteraemia: Bacteria in the blood (need culture)
- Sepsis: Systemic inflammation leading to end organ failure
Meningitis causes
- Neonates- *Group B Strep, E.Coli, Listeria
- Older infants and children- Streptococcus pneumonia, Neisseria meningitides, Haemophilia inflluenza
- Adolescents- Neisseria Meningitides
Pathogenesis
1) Colonisation of nasopharyngeal epithelium mucosa
2) Invasion to blood and endotoxin release therefore systemic illness with DIC (disseminated intravascular coagulation), capillary leak and shock
3) Invades meninges
4) Inflammation - cerebral oedema
5) Altered cerebral blood flow and metabolism- can lead to altered neurological function
6) Cerebral vascularitis
Presentation
General: Fever, Lethergy, Dec apetite, rigors, muscle + joint pain
Rash stage: Initially maculopapular (Flat, red small confluent bumps) progresses to petechia (1-2mm red spots showing capillary leakage) or to purpura ( >2mm non-blanching small red spots showing DIC. TUMBLAR TEST (glass)
Neurological:
- Bulging ant fontanelle, headache, neck stiffness, siezures, focal siezure suggests infarction
Brudzinski’s sign- Neck flexed and knees flex too
Kernig’s Sign- Patient’s leg at 90 degrees and painful to extend at knee
Resp: Resp distress (common with septic shock) and may have pulmonary oedema
Diagnosis
- Blood culture and PCR: meningococcus and pneumococcus test done before anti-biotics so inc yield
- Lumbar puncture: Make sure to do culture and sensitivity
- Cranial CT: to rule out other ICP pathology such as haemorrhage, trauma etc
Management NOT SEPSIS!
- Antibiotics:
Cefotoxamine and add Amoxacilllin in < 3 months to cover Listeria
- Vancomycin if recently travelled, MRSA history or resistant to S.pneumoniae
- Steroid therapy (not if < 3 months) Dexamethasone given
Follow up with: Orthopaedics, Dermatology (scarring), Developmental, Hearing loss, renal failure, Immunology
ITS MOST COMMONLY Viral Meningitis aka
Most common species 5
Treatment 2
Fungal meningitis almost entirely limited to….. such as….
Aka Encephalitis/ Meningoencephalitis
Most common species: enterovirus species, herpes virus, EBV, adenovirus, flu can also be HIV or measles but rare!
Treatment: FLuid resus and stabilization , anti-virals such as oseltamavir or zanamivir
Fungal meningitis almost entirely limited to the immunosurpressed such as neonates, immuno def, transplants, chemo.
UTIs
UTIs
Epidemiology:
- more common in… before what age?
- Polyneohritis =
- Cystitis =
Important to diagnose UTI because
- 2 Key points to get!
Host Risk Factors:
- Key word and def
- Key point with 5 causes! (one is the point above)
Presentation: Infants
8
Presentation: 1-17yo
10
UTIs
Epidemiology:
- more common in girls (3-7% compared to 1-2%) beofre 6yo
- Polyneohritis = involves kidneys (assoc. with fever + systemic involvement)
- Cystitis = No fever
Important to diagnose because 50%show structural abnormality and polynephritis can dec kidney development from scarring - predispose hypertension and CKD if bilateral
Host Risk Factors:
- Renal/ Urinary tract abnormality causing vesicoureteric reflux where urine flows back up urethra.
- Incomplete bladder emptying, causes of this include: constipation, infrequent voiding, bladder enlargement, neuropathic bladder, vesicoureteric reflux
Presentation: Infants
- fever
- vomit
- lethergy
- dec feeding
- jaundice
- sepsis
- offensive urine
- febrile seizures < 6 months
Presentation: 1-17yo
- Dysuria, freq, urgency
- Abdo pain
- Loin to groin
- Fever +- rigors
- Lethergy +- annorexia
- Vom + Diarrhoea
- Haematuria
- Offensive/ cloudy urine
- Febrile seizure
- Recurrence enuresis
UTI
Investigations
4 ways to collect urine
Interpretation of Urine Dipstick: BUT RULE OF THUMB IS…
5 Points to get
Interpretation of Bacterial Culture:
Rote learn this phrase
- Contamination is inferred from…
- Now think about mode of collection
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Organisms to watch out for: 5 and 2 of them require extra information
Management=
Urine Collection technique:
1) clean catch
2) Adhesive plastic bag on perineum but contamination from skin/ faeces
3) Urethral catheter if not passing/ urgent
4) Suprapubic aspiration with fine needle directly into bladder under USS, needs severely ill child, v rare!
Interpretation of Urine Dipstick: BUT RULE OF THUMB ALL UNEXPLAINED FEVERS OVER 38 degrees URINE NEEDS TO BE TESTED, If clinically or < 3 months then start anti-biotics
- Leukocyte esterase +ve and Nitrite +ve
Regard as UTI - Leukocyte esterase -ve and Nitrite +ve
Diagnosis needs urine culture to start antibiotics (start antibiotics) - Leukocyte esterase +ve and Nitrite -ve
Only start antibiotics if clinical evidence, need culture for diagnosis (get culture) - Leukocyte esterase -ve and Nitrite -ve
UTI unlikely. send for culture (if history) or repeat - Blood protein + glucose
Think nephritis, diabetes mellitus
Interpretation of Bacterial Culture:
More than 10^5 colony-forming units (CFU) of a single organism per ml in a properly collected specimen gives 90%. Same resulting second sample 95%.
- If mixed organisms detected then think contamination
- Any single organism per ml in a catheter or suprapubic aspiration can be diagnostic.
Explanation of why UTIs occur in children:
- Structual abnormality causing vasicoureteric reflux
- Bowel flora enter urinary tract vie urehtra
- New born can be haematogenous (carry in blood)
Organisms to watch out for:
E.coli, Klebsiella, Enterococcus faecalis, Psuedomonas (may imply structural abnormality), Proteus (more boys than girls, can predispose phosphate stones by splitting urea to ammonia -> alkalising urine)
Management - Gentamicin
Impetigo
Presentation - - - -
Management
- mild = eg
- severe = can use narrow spec or broad spec eg’s for both and why the difference?
Presentation:
- Lesions on face, neck hands
- Increased risk if pre-existing skin condition eg history of atopic eczema
- Erythymous macules (flat defined area of skin) which may progress to vesicular/ pustular or even bollous
- Some may be ruptured leading to confluent honey-coloured crusted lesions
What?
Highly contagious staphylococcal or streptococcal skin infection- common in those with pre-existing skin condition eg. history of atopic eczema
Management
Mild- topical antibiotic eg mupirocin
Severe- narrow- spec antibiotic eg. fluclozacillin are better but broad- spec such as co-amoxiclav or cephalxin have simpler regimen and taste better.
Otitis Media
Background
- Infants + young children are succeptibe because…
- most common age range =
Presentation - - - -
Pathogens 6
What can it lead to if severe and why?
How may this impact develpoment?
-ALSO…
What should you always look for?
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Background
- Infants + young children are susceptible because they have shorter, horizontal and poorly functioning Eustachian tubes so viral infections from nasopharynx pass for readily
- most common age range = 6-12 months
Presentation
- Fever (ALWAYS CHECK TYMPANIC MEMBRANE)
- Bulging red tympanic membrane
- Loss of light reflex
- Membrane may have perforated
- Irritable and bang/ tug ear
Pathogens 6
- RSV
- Rhinovirus
- Pneumococcus
- Haemophilius influenza
- Moraxella catarrhalis
- Group A beta Heamolytic Streptococcus
What can it lead to if severe and why?
Meningitis and spread via CSF if the inflammation causes a basal skull fracture
How may this impact develpoment?
Learning impairment from hearing loss (age 2-7 y/o v common!)
- ALSO glue ear if recurrent ear infections with effusion also leading to hearing loss
What should you always look for?
Mastoiditis
Treatment
- Broad- Spec PO amoxocillin or co-amoxiclav
- Analgesia
- Insert grommet to relieve pressure
