Infectious Disease Flashcards
What is otitis media?
Rapid onset of S+S of ear infection
Inflammation in the middle ear
Associated with an effusion
From NICE CKS
Causes of acute otitis media?
what are the common pathogens?
Bacterial:
* Haemophilus influenzae
* Moraxella catarrhalis
* Streptococcus pyogenes
* Streptococcus pneumoniae - less of this now since pnuemococcal vaccine
Viral:
* RSV - respiratory syncytial virus
* rhinovirus
* adenovirus
* influenza virus
* parainfluenza virus
What are RF for acute otitis media?
(for children in particular)
- Young age.
- Male sex.
- Frequent contact with other children such as daycare or nursery attendance or having siblings (increases exposure to viral illnesses).
- Formula feeding — breastfeeding has a protective effect.
- Craniofacial abnormalities (such as cleft palate).
- Use of a dummy.
- Prolonged bottle feeding in the supine position.
- Family history of otitis media.
- Lack of pneumococcal vaccination.
- Gastro-oesophageal reflux.
- Prematurity.
- Recurrent upper respiratory tract infection.
- Immunodeficiency
from NICE CKS
What are RF for acute otitis media?
(for children in particular)
- Young age.
- Male sex.
- Frequent contact with other children such as daycare or nursery attendance or having siblings (increases exposure to viral illnesses).
- Formula feeding — breastfeeding has a protective effect.
- Craniofacial abnormalities (such as cleft palate).
- Use of a dummy.
- Prolonged bottle feeding in the supine position.
- Family history of otitis media.
- Lack of pneumococcal vaccination.
- Gastro-oesophageal reflux.
- Prematurity.
- Recurrent upper respiratory tract infection.
- Immunodeficiency
from NICE CKS
What are complications of acute otitis media?
- Persistent otitis media with effusion.
- Recurrence of infection.
- Hearing loss (usually conductive and temporary).
- Tympanic membrane perforation.
- Labyrinthitis.
- Rarely, mastoiditis, meningitis, intracranial abscess, sinus thrombosis, and facial nerve paralysis.
How does acute otitis media present?
Presentation Hx and examination findings
Older children:
* earache
* reduced hearing in affected ear
* balance issues and vertigo if affected vestibular system
Younger children
* holding, tugging or rubbing ear
* fever
* crying
* poor feeding
* restlessness
* behavioural changes
* cough
* rhinorrhoea
* reduced hearing in affected ear
On examination:
* distinctly red, yellow or cloudy TM
* bulging of the TM, has loss of landmarks and air-fluid level behind the TM
* Perforation of the TM and/or discharge in external canal
* reduced hearing in affected ear.
nice cks
Why is Dx of otitis media difficult in children younger than 6m?
from nice cks
- may have coexisting systemic illness - e.g. bronchiolitis
- symptoms are more non-specific when younger
- TM is not as visible in child as ear canal is small and tends to collapse
DDx for acute otitis media?
If PC is middle ear inflam or efffusion:
* OM with effusion aka glue ear
* chronic suppurative OM
* Myringitis
If PC is just earache
* Otitis externa
How is acute otitis media managed?
When need to admit?
treatment options in community?
Admit if:
* younger than 3m
* 3-6m with temp of 39+
* severe systemic infection (remember we have a low threshold for sepsis in children)
* present with complications of AOM.
In community:
* Analgesia - NSAIDs, paracetamol. Can be provided as an ear drop analgesia
* If think abx are needed = 5-7 day course amoxicillin. / clarithromycin or erythromycin. Co-amoxiclav can also be used if no response to these.
How is recurrent AOM managed?
Urgent referal (2weeks) to ENT specialist
- especiallly if they have Hx of cleft palate or Down’s syndrome
- have nosebleeds too
- have lymphadenopathy
If they don’t have these features:
* avoid exposure to passive smoking, dummies, flat supine feeding
* ensure they have had pnuemococcal vaccine
* ensure GORD is managed (as can present together)
What is tonsillitis?
Inflamation of the tonsils.
Can occur in isolation or as part of a generalised pharyngitis
What are common organisms causing tonsillitis?
Viral causes:
* Rhinovirus
* Coronavirus
* Parainfluenza virus
* Influenza type A and B
* Adenovirus
* HSV1
* EBV
Bacterial causes:
* Group A Streptococcal infection - Streptococcus pyogenes.
* Group C and G Beta-haemolytic streptococci. = Streptococcus pneumoniae
* Haemophilus influenzae
* Moraxella catarrhalis
* Staphylococcus aureus
- What is Waldeyer’s Tonsillar Ring?
- Why is it relevant in tonsillitis?
- A ring of lymphoid tissue made up of the adenoids, tubal tonsils, palatine tonsils and lingual tonsil.
- These get infected and enlarged in tonsilitis - the palatine tonsils are most commonly infected
How does acute tonsillitis present?
Hx and Ex
- Sore throat
- Fever (above 38C)
- Pain on swallowing
O/E:
* red, inflamed and enlarged tonsils
* can have exudate on = white pus on tonsil
* anterior cervical lymphadenopathy (in anterior triangle of neck)
What 2 criteria can be used to estimate probability that tonsillitis is due to a bacterial cause, and requires abx?
Describe each.
- Centor criteria - score of 3 or more = bacterial tonsilitis
* Fever over 38C
* Tonsillar exudate
* Absence of cough
* Tender anterior cervical lymph nodes (lymphadenopathy) - FeverPAIN Score - score of 4 or 5 = bacterial tonsillitis
* Fever above 38C
* Purulence (exudate)
* Attended rapidly (within 3 days)
* Inflamed tonsils (severe)
* No cough or coryza
You should consider admission for tonsillitis if the patient is…
- immunocompromised
- systematically unwell
- dehydrated
- has stridor
- has respiratory distress
- has evidece of peritonsillar abscess or cellulitis
How would you manage viral based acute tonsillitis?
- educate patients and parents
- Safety net - return if pain not settled after 3 days, or fever rises above 38.3C
- Simple analgesia
How would you manage bacterial acute tonsillitis?
Penicillin V = phenoxymethylpenicillin
10 day course
If allergic - Clarithromycin
What are complications of tonisillitis?
- Quinsy aka peritonsillar absces
- Otitis media
- Scarlet fever
- Rheumatic fever
- Post-strep glomerulonephritis
- Post-strep reactive arthritis
What is periorbital cellulitis (also called preseptal cellulitis)?
An infection of the soft tissues anterior to the orbital septum - this includes the eyelids, skin and subcutaneous tissue of the face, but not the contents of the orbit.
- What is pathophysiology of periorbital (preseptal) cellulitis?
- What organsisms commonly cause this infection?
- Infection spreads to structures around orbit from other sites = usually breaks in skin or local infections e.g. sinusiits, resp tract infections
- Staphylococcus aureus, staphylococcus epidermidis, Streptococci and anaerobic bacteria
What is the epidemiology of periorbital / preseptal cellulitis?
Children - usually under 10.
Median age = 21 months / around 2 years
More common in winter due to increased prevalence of respiratory tract infections
How does periorbital /preseptal cellulitis present?
- red, swollen, painful
- acute onset
- fever
O/E:
* erythema and odema of eyelid which can spread to surrounding skin
* partial or complete ptosis of eye due to swelling
Differentials of periorbital cellulitis?
Orbital cellulitis
Allergic reaction
What inv would you do for periorbital cellulitis?
- Bloods - raised inflammatory markers
- Swab of any discharge present
- Contrast CT of the orbit may help to differentiate between preseptal and orbital cellulitis. It should be performed in all patients suspected to have orbital cellulitis
How is periorbital cellulitis managed?
- All cases should be referred to secondary care for assessment
- Systemic antibiotics are frequently sufficient - usually co-amoxiclav (Iv or oral)
Children may require admission for observation as it can develop into orbital cellulitis
What is orbital cellulitis?
the result of an infection affecting the fat and muscles posterior to the orbital septum, within the orbit but not involving the globe
Presentation of orbital cellulitis?
- Redness and swelling around the eye
- Severe ocular pain
- Visual disturbance
- Proptosis
- Ophthalmoplegia/pain with eye movements
- Eyelid oedema and ptosis
- Drowsiness +/- Nausea/vomiting in meningeal involvement (Rare
What features would differentiate periorbital cellulitis from orbital cellulitis?
Orbital cellulitis has:
* reduced visual acuity,
* reduced eye movements
* proptosis (forward movement of eyeball),
* ophthalmoplegia/pain with eye movements
* abnormal pupil reactions
These are NOT consistent with preseptal cellulitis
What are RF for orbital cellulitis?
- Childhood - Mean age of hospitalisation 7-12 years
- Previous sinus infection
- Lack of Haemophilus influenzae type b (Hib) vaccination
- Recent eyelid infection/ insect bite on eyelid (periorbital cellulitis)
- Ear or facial infection
What investigations would you do for suspected orbital cellulitis?
- Full blood count – WBC elevated, raised inflammatory markers.
- Clinical examination involving complete ophthalmological assessment – Decreased vision, afferent pupillary defect, proptosis, dysmotility, oedema, erythema.
- CT with contrast – Inflammation of the orbital tissues deep to the septum, sinusitis.
- Blood culture and microbiological swab to determine the organism. Most common bacterial causes – Streptococcus, Staphylococcus aureus, Haemophilus influenzae B.
How is orbital cellulitis managed?
This is a MEDICAL EMERGENCY
Admission for IV abx
What is Rubella caused by?
Viral infection caused by togavirus
- How can child contract rubella?
- How long is incubation period for rubella?
- When are people infectious?
- Contracted during pregnancy in first 20weeks –> congenital rubella syndrome
- 14-21 days
- infectious from 7 days before symptoms appear to 4 days after onset of rash
Before - - - - how many - - - - weeks of gestation does rubella pose the highest risk to baby?
before 10 weeks of gestation
- damage to fetus is as high as 90% !
How can you prevent congenital rubella infection from mother?
Before getting pregnant:
* Women planning to become pregnant should ensure they have had the MMR vaccine.
* When in doubt, they can be tested for rubella immunity.
* If they do not have antibodies to rubella, they can be vaccinated with two doses of the MMR, three months apart.
When pregnant:
* Pregnant women should not receive the MMR vaccination, as this is a live vaccine.
* Non-immune women should be offered the vaccine after giving birth.
What are features of congenital rubella syndrome?
- Congenital sensiorineural deafness
- Congenital cataracts
- Congential heart disease - usually have PDA and pulmonary stenosis
- Learning diability
- Growth retardation
- Hepatosplenomegaly
- Purpuric skin lesions
- Salt and pepper chorioretinitis
- Microphthalmia
- Cerebral palsy
Dr Tom says know top 4 bullet points,.
When suspecting congenital rubella syndrome, what other condition should you investigate for, and why?
B19 Parovirus
Why? It’s hard to distinguish between parovirus and rubella so need to check both in serology.
In a women recently exposed to the rubella togovirus, what type of anitbodies will be raised?
IgM antibodies.
What commonly causes toxic shock syndrome?
Staphylococcal exotoxins = TSST-1 superantigen toxin
What is diagnostic criteria for toxic shock syndrome?
- fever: temperature > 38.9ºC
- hypotension: systolic blood pressure < 90 mmHg
- diffuse erythematous rash
- desquamation of rash, especially of the palms and soles
- involvement of three or more organ systems: e.g. gastrointestinal (diarrhoea and vomiting), mucous membrane erythema, renal failure, hepatitis, thrombocytopenia, CNS involvement (e.g. confusion)
How is toxic shock syndrome managed?
Remove infection focus - e.g. a retained tampon
IV fluids
IV antibiotics
Is viral gastroenteritis is contagious?
Highly contangious
What are the common causes of viral gastroenteritis?
- Norovirus
- Rotavirus
- Adenovirus - more subacute
What are differential diagnosis for child presenting with diarrhoea?
Infection (gastroenteritis)
Inflammatory bowel disease
Lactose intolerance
Coeliac disease
Cystic fibrosis
Toddler’s diarrhoea
Irritable bowel syndrome
Medications (e.g. antibiotics)
What is gastroenteritis?
How does it present?
Gastroenteritis is inflammation all the way from the stomach to the intestines and presents with nausea, vomiting and diarrhoea, fever and abdominal cramps, blood in stool.
What is main concern when a child presents with gastroenteritis?
Dehydration
What does primary TB show on CXR?
Patchy consolidation, pleural effusions and hilar lympadenopathy
What does reactivated TB show on CXR
TB revision
Patchy or nodular consolidation
Cavitation usually in upper zones
What does disseminated miliary TB show on CXR?
See picture of ‘millet seeds’ uniformly distributed throughout lung fields.
What feature are pathognomonic for measles (i.e. after seeing this feature, you can diagnose measles)?
Koplik spots
Presentation of scarlet fever?
- fever: typically lasts 24 to 48 hours
- malaise, headache, nausea/vomiting
- sore throat
- ‘strawberry’ tongue
- rash –> a red-pink, blotchy, macular rash with rough “sandpaper” skin that starts on the trunk and spreads outwards. Rash described as fine punctate erythema (‘pinhead’). Spares palms and soles.
- Patients can have red, flushed cheeks.
- cervical lymphadenopathy
Presentation of roseola infantum?
- presents 1 – 2 weeks after infection with a high fever (up to 40ºC)
- fever comes on suddenly, lasts for 3 – 5 days and then disappears suddenly.
- there may be coryzal symptoms, sore throat and swollen lymph nodes during the illness.
- When the fever settles, the rash appears for 1 – 2 days. The rash consists of a mild erythematous macular rash across the arms, legs, trunk and face and is not itchy.
- Nagayama spots on the uvula and soft palate
- febrile convulsions due to high temperature
