7- Infectious diseases (2/3) Flashcards
meningitis background
inflammation of the meninges
causes of meningitis
bacteria
viral
fungal (rare)
bacterial meningitis
- Neisseria meningitidis (meningococcal)
–>Classical non-blanching rash (DIC and subcutaneous haemorrhages) - Streptococcus pneumonia (pneumococcus)
- Group B strep (GBS) in neonates
viral meningitis
- Herpes simplex virus (HSV)
- Enterovirus
- Varicella zoster virus (VZV)
typical presentation of meningitis
- Fever
- Neck stiffness
- Vomiting
- Headache
- Photophobia
- Altered consciousness
- Seizures
Meningococal ->Non-blanching rash (tumbler test)
neonatal presentation of meninigitis
Non specific signs and symptoms e.g. hypotonia, poor feeding, lethargy, hypothermia and bulging fontanelle
investigations for meninigitis
Lumbar puncture ( not if child is haemodynamically unstable) – if you think child has meningococcal - skip
- Under 1 month presenting with fever
- 1 to 3 months with fever and are unwell
- Under 1 year with unexplained fever and other features of serious illness
Special tests
- Kernig’s test- creates a stretch in the meninges
- Brudzinski’s
Lumbar puncture
- Taken from L3-L4 intervertebral space
- Samples sent for bacterial culture, viral PCR, cell count, protein and glucose
- Blood glucose sample should be sent at the same time so that it can be compared to CSF sample
management of bacterial meningitis
If discovered in the community
- Urgent stat injection (IM or IV) of benzylpenicillin prior to transfer to hospital
Hospital
Investigations
- Blood culture and lumbar puncture
- Send bloods for meningococcal PCE if suspected -> quicker result than blood culture
Antibiotics
- <3 months: cefotaxime plus amoxicillin (to cover listeria)
- >3 months: ceftriaxone
- Pneumococcal infection : ceftriaxone + vancomycin
Steroids
- Steroids (dexamethasone) -> reduces frequency and severity of hearing loss and neurological damage
meningococcal meninigitis
Post exposure prophylaxis
- Contact tracing- risk is highest for people that have had close prolonged contact within the 7 days prior to onset of the illness
- If no symptoms have developed 7 days after exposure they are unlikely to develop the illness
- PEP -> single doses of ciprofloxacin ideally within 24 hours
management of viral meningitis
Viral
- Sample of lumbar puncture should be sent for viral PCR
- Aciclovir can be used to treat suspected or confirmed HSV or ZVZ infection
Meningococcal infections summary
- Meningitis (found in CSF)
- Septicaemia (found in blood)
- Meningococcal sepsis (found in CSF and blood)
Candidiasis
- Infection caused by a yeast called Candida
- Normally not harmful and found on the skin, vaginal area and digestive system
- If it overgrows can cause a rash, itching and other symptoms
Pathophysiology candidiasis
Candida can thrive in certain conditions and overgrow
o Damaged skin
o When its too warm and humid
o Weak immune system
o Steroids
o Antibiotics (weaken immune system)
Risk factors for candidiasis
- Hot humid weather
- Too much time between diaper change
- Poor hygiene
- Antibiotics
- Corticosteroids
- Immunosuppression
presentation of candidiasis
Skin fold or navel
- Rash
- Clear fluid oozing
- Pimples
- Itching or burning
Vagina
- White or yellow discharge
- Itching
- Redness in external area of the vagina
- Burning
Penis
- Redness on the penis
- Scaling on the penis
- Painful rash on the penis
Mouth
- White patches on the tongue, top of the mouth and inside cheeks
- Itching
- Bad taste
- Pain
management of candidiasis
Management
- Mouth thrush – Nystatin mouth gel
- Vaginal- fluconazole tablet or suppository
- Skin rash- oral or topical fluconazole
conjunctivitis background
Inflammation of the conjunctiva
- Conjunctiva is a thin layer of tissue which covers the inside of the eyelids and sclera of the eye
- Types
o Bacterial
o Viral
o Allergic
Presentation of conjunctivitis
- Unilateral or bilateral
- Red eyes
- Bloodshot
- Itchy or gritty sensation
- Discharge from the eye
presentation of bacterial conjunctivitis
Bacterial
- Purulent discharged
- Inflamed conjunctiva
- Worse in morning when eyes may be stuck together
- Usually starts in one eye and spreads to the other
- Highly contagious
presentation of viral conjunctivitis
- Common
- Presents with clear discharge
- Often associated with other symptoms of viral infection
o Dry cough
o Sore throat
o Blocked nose
o Preauricular lymph nodes may be tender - Also contagious
What conjunctivitis doesn’t present as
- No pain
- No photophobia
- No reduced visual acuity
–> May be blurry when covered in discharge
management of conjunctivitis
Advice on good hygiene to avoid spread
- Avoid towel sharing or rubbing eyes
- Regular hand washing
- Avoid contact lenses
- Clean eye with cooled boiled water and cotton wool to clear discharge
Bacterial:
- Often gets better without treatment
- Abx eye drops to consider: Chloramphenicol and fuscidic eye drops
Children <1 month: urgent ophthalmology reviews
- Can be associated with gonococcal infection and can cause loss of sight
Differential Diagnosis of Acute Red Eye
A common exam topic and clinical challenge is to differentiate between the causes of an acute red eye. The more serious differentials tend to cause pain and reduced visual acuity.
Painless Red Eye
- Conjunctivitis
- Episcleritis
- Subconjunctival Haemorrhage
Painful Red Eye
- Glaucoma
- Anterior uveitis
- Scleritis
- Corneal abrasions or ulceration
- Keratitis
- Foreign body
- Traumatic or chemical injury
Allergic Conjunctivitis
Allergic conjunctivitis is caused by contact with allergens. It causes swelling of the conjunctival sac and eye lid with a significant watery discharge and itch.
Antihistamines (oral or topical) can be used to reduce symptoms.
Topical mast-cell stabilisers can be used in patients with chronic seasonal symptoms. They work by preventing mast cells releasing histamine. These require use for several weeks before showing any benefit.
periorbital cellulitis background
- Infection of the periorbital soft tissue characterised by
o Erythema
o Oedema - Life and vision threatening if not treated
- Most commonly 0-15 yo
o X2 as common in males
o Peak occurrence in late winter/early spring (due to URTI and paranasal sinusitis peaks)
pathogens which causes periorbital cellulitis
o Hameophilus influenzas type B was most common prior to HiB vaccine
o Streptococcus pneumonia (most common)
o Haemophilus influenzae
o Staphylococcus aureus
pathophysiology of periorbital cellulitis
Types depend on the orbital septum (thin, fibrous, multilaminate structure that attaches peripherally to the periosteum of the orbital margin to form the arcus marginalis).
Septum is the only barrier between infection spreading from eyelid to the orbit
- Pre-septal
o Anterior to septum
- Post-septal
o Posterior to septum
Mode of infection periorbital cellulitis
Contingous spread from surrounding periorbital structures such as paranasal sinuses (ethmoidal most common)
why periorbital cellulitis more common in children
More common in children/neonates
- Due to thinner and dehiscent bone surface of lamina papyracea and increased diploic venous supply
- Reduced immune system
presentation of pre-septal cellulitis
usually history of acute sinusitis or URTI
Eyelid oedema
- Erythema of upper eyelid
Absence of orbital signs
- Normal vision
- Absence of proptosis
- Full ocular motility without pain on movement
presentation of orbital cellulitis
Worsening oedema
Orbital signs
- Proptosis
- Ophthalmoplegia
- Decreased visual acquity
- Loss of red colour vision – first sign of optic neuropathy
- Chemosis
- Painful diplopia
classification of periorbital cellulitis
Complications of periorbital cellulitis
- Encephalomeningitis
- Cavernous sinus thrombosis
- Sepsis
- Intracranial abscess
investigations for periorbital cellulitis
Thorough history
- Inc recent URTI
Clinical examination
- Vital signs
- Dentition
- Anterior rhinoscopy
- Ophthalmic examination
- Neurological examination
Investigation
- Local culture of purulent discharge from nasal passage
- Bloods (degree of sepsis)
o FBC
o U and Es
o CRP
o ABG
o Lactate
- Imaging
o CT -> allows for confirmation of extent of infection into the orbit
management of mild pre-septal cellulitis
o Outpatient with empirical broad spectrum oral antibiotics
management of orbital cellulitis
- Inpatient
- IV abx covering most gram positive and negative bacteria
- Nasal decongestants
- Steroid nasal drops
- Nasal douching
- Supportive
o IV fluid hydration
o Analgesia
o Optic nerve monitoring
If optic nerve or retinal function compromised
Large abscesses surgically drained
Intracranial complications of periorbital cellulitis
Urgent drainage of abscess (can be endoscopic or via an external approach)
Tonsillitis background
- Inflammation of the tonsils
- Most commonly caused by viral infections
- If bacterial usually:
o Group A streptococcus (strep pyogenes)
o Streptococcus pneumonia
o Haemophilus influenzae
o Morazella catarrhalis
o Staphylococcus aureus - Most common in those aged 5 to 10, another peak between 15 and 20
Pathophysiology of tonsillitis
- Palatine tonsils classically infected in tonsilitis
- Part of Waldeyers Tonsillar Ring
presentation of tonsilitis
- Fever
- Sore throat
- Painful swallowing
- In young children (less specific symptoms)
o Fever
o Poor oral intake
o Headache
o Vomiting
o Abdominal pain - On examination
o Red, inflamed and enlarged tonsils with or without exudate
investigations for tonsilitis
- Always examine in the ear – visualising tympanic membrane and palpate for any cervical lymphadenopathy
- FeverPain score
- Centor criteria
Centor criteria
A score of >3 gives 40-60% probability of bacterial tonsilitis and it is appropriate to offer antibiotics. A point is given if each of the following are present;
* Fever over 38ºC
* Tonsillar exudates
* Absence of cough
* Tender anterior cervical lymph nodes (lymphadenopathy)
FeverPAIN score
The FeverPAIN score is an alternative to the Centor criteria. A score of 2 – 3 gives a 34 – 40% probability and 4 – 5 gives a 62 – 65% probability of bacterial tonsillitis:
* Fever during previous 24 hours
* P – Purulence (pus on tonsils)
* A – Attended within 3 days of the onset of symptoms
* I – Inflamed tonsils (severely inflamed)
* N – No cough or coryza
management of viral tonsilitis
- No role of antibiotics- EDUCATE AND SAFETY NET
- Simple analgesia
- Advise patient to return if pain has not settled after 3 days or fever >38.3
management of bacterial tonsilitis
Penicillin V (phenoxymethylpenicillin) or clarithromycin for penicillin allergy
- FeverPAIN >4, centor >3
- Immunocompromised
when to consider admission with tonsilitis
- Consider admission if patient is: immunocompromised, systemically unwell, dehydrated, stridor, resp distress or evidence of peritonsillar abscess or cellulitis
Complications of tonsilitis
- Chronic tonsilitis
- Peritonsillaru abscess- quinsy
- Otitis media
- Scarlet fever
- Rheumatic fever
Otitis media
Background
- Infection in the middle ear
o Space between the tympanic membrane and inner ear - Common place of infection – usually bacterial
Bacterial causes of otitis media
- Streptococcus pneumoniae (most common)
- Haemophilus influenza
- Moraxella catarrhalis
- Staphylococcus aureus
pathophysiology of otitis media
- Bacteria enters from the back of throat via eustachian tube into the middle ear
- Often preceded by a viral upper respiratory tract infection
Presentation otitis media
- Ear pain
- Reduced hearing
- Symptoms of upper airway infection
o Fever
o Cough
o Coryzal symptoms
o Sore throat
o Generally unwell - Can cause balance issues and vertigo
- Child may tug ear
- On exam
o Look at both ears and throat
o Visualise tympanic membrane
o Bulging, red inflamed looking membrane
o Discharge
Management of otitis media
- Child <3 months with temp above 38 -> admit
- Most cases resolve without antibiotics within 3 days
o Complications like mastoiditis are rare - Simple analgesia
- When to prescribe Abx - amoxicillin
o Signifi co-morbidities
o Systemically unwell
o Immunocompromised
o Children <2yrs with bilateral otitis media and children with otorrhoea - Consider delayed prescription to use after 3 days if symptoms have not improved
Complications of otitis media
- Otitis medial with effusion
- Hearing loss (usually temporary)
- Perforated eardrum
- Recurrent infection
- Mastoiditis (rare)
- Abscess (rare)
