Infectious diseases Flashcards
Macular/maculopapular viral rashes
Roseola infantum
Slapped cheek
Measles
Rubella
Macular/maculopapular bacterial rashes
Scarlet fever
Rheumatic fever
Typhoid fever
Lyme’s disease
Macular/maculopapular rash other causes
Kawasaki’s disease
Juvenile RA
Vesicular, bullous or pustular viral rashes
Herpes simplex
Varicella
Hand-foot-and-mouth
Vesicular, bullous or pustular bacterial rashes
Boils
Impetigo
Staphylococcal scalded skin
Vesicular, bullous or pustular rashes other causes
Erythema multiforme
TEN
SJS
Petechial/purpuric viral rashes
Enterovirus
Adenovirus
Petechial/purpuric bacterial rashes
Meningococcal
Infective endocarditis
Petechial/purpuric rashes other causes
HSP
Thrombocytopenia
Vasculitis
Cellulitis
Bacterial infection that affects the dermis and the deeper subcutaneous tissues
Clinical diagnosis
Cellulitis clinical features
Commonly occurs on shins → usually unilateral
Erythema → well-demarcated margins
Swelling
Systemic upset - fever, malaise & nausea
Cellulitis classification
Eron classification
I - no signs of systemic toxicity & no uncontrolled co-morbidities
II - person is either systemically unwell/systemically unwell but a co-morbidity that may complicate resolution of infection
III - significant systemic upset/unstable co-morbidities/limb-threatening infection due to vascular compromise
IV - sepsis syndrome/severe life-threatening infection
Cellulitis admission criteria
Eron class III/class IV cellulitis
Severe or rapidly deteriorating cellulitis
Very young (< 1 year) or frail
Immunocompromised
Significant lymphoedema
Facial cellulitis/periorbital cellulitis
Cellulitis mx
Guided by Eron classification
I - oral flucloxacillin, clarithromycin/erythromycin/doxycycline for penicillin allergic
II - admission may not be required if facilities are available in the community & can be monitored closely
III-IV - admit, IV co-amoxiclav/clindamycin/cefuroxime/ceftriaxone
Epiglottitis
Acute, life threatening condition, most commonly caused by an infection
Epiglottis = flap of cartilage behind the tongue, designed to protect the larynx during swallowing
Epiglottitis pathophysiology
H. influenzae and strep pneumoniae may locally invade the epiglottis → inflammation
Inflammation starts on the lingual surface of the epiglottis before spreading to other laryngeal structures → aryepiglottic folds, the arytenoids and supraglottic larynx
Children are at a higher risk of acute airway obstruction as epiglottis is much more floppy, broader, longer & angled more obliquely to the trachea
Epiglottitis risk factors
Children not receiving the HiB vaccine
Male gender
Immunosuppression
Epiglottitis clinical features
4 D’s - dyspnoea, dysphagia, drooling & dysphonia
Symptoms < 12 hours & typically no cough
High grade fever, sore throat, dehydration & signs of partial airway obstruction
Stridor is a late sign
Some children may adopt a tripod position → patient leans forward on outstretched arms with neck extended & tongue out
Epiglottitis ix
Shouldn’t be examined → high risk of airway obstruction
Throat swabs - bacterial and viral
Blood tests - FBC, cultures & CRP
Lateral neck x-ray
- thumb-print sign
- thickened aryepiglottic folds
- increased opacity of the larynx and vocal cards
CT/MRI only if not responding to the initial treatment
Epiglottitis mx
Secure the airway
Oxygen
Nebulised adrenaline
IV antibiotics - cefotaxime/ceftriaxone
IV steroids
IVI - resus and maintenance
Epiglottitis complications
Mediastinitis - infection spreads to retropharyngeal space
Deep neck space infection
Pneumonia
Meningitis
Sepsis/bacteraemia
Neonatal HSV aetiology
Can occur when the baby comes into contact with primary vesicles in the maternal genital tract during delivery
Risk is low with recurrent herpes infection
Neonatal HSV clinical features
Vesicular lesions on the skin
Eye involvement
Oral mucosa involvement, without internal organ involvement
Disseminated features - seizures, encephalitis, hepatitis, sepsis
Features commonly appear in first week of birth but manifestation can be as late as fourth week of life
Neonatal HSV ix
Identifying presence of virus in the newborn - PCR, virus culture, DFA testing
MRI brain - cases of suspected encephalitis
Neonatal mx
Parenteral acyclovir with intensive supportive therapy for severe cases
Elective c-section/intrapartum IV acyclovir may be advised if active primary herpes lesions are present on mother at term OR primary outbreak within 6 weeks of labour
8 weeks vaccine
- 6 in 1 vaccine (diphtheria, tetanus, pertussis, polio, haemophilus influenza type B (Hib) and hepatitis B)
- meningococcal type B
- rotavirus (oral vaccine)
12 weeks vaccine
- 6 in 1 vaccine
- pneumococcal
- rotavirus
16 weeks vaccine
- 6 in 1 vaccine
- meningococcal type B
1 year vaccine
- 2 in 1 (haemophilus influenza type B and meningococcal type C)
- pneumococcal
- MMR vaccine
- meningococcal type B
Yearly from age 2-8 vaccine
influenza vaccine (nasal vaccine)
3 years 4 months vaccine
- 4 in 1 (diphtheria, tetanus, pertussis and polio)
- MMR vaccine
12-13 years vaccine
HPV vaccine
14 years vaccine
- 3 in 1 (tetanus, diphtheria and polio)
- meningococcal groups A, C, W & Y
Malaria
Disease caused by Plasmodium protozoa which is spread by the female Anopheles mosquito
Malaria protective factors
Sickle-cell trait
G6PD deficiency
HLA-B53
Absence of Duffy antigens
Features of severe malaria
Schizonts on a blood film
Parasitaemia > 2%
Hypoglycaemia
Acidosis
Temperature > 39
Severe anaemia
Complications
Malaria complications
Cerebral malaria - seizures, coma
Acute renal failure - blackwater fever, secondary to intravascular haemolysis
ARDS
Hypoglycaemia
DIC
Uncomplicated falciparum malaria management
Artemisinin-based combination therapies as first-line
E.g. artesunate + amodiaquine
Severe falciparum malaria management
Parasite count > 2% → parenteral mx irrespective of clinical state
IV artesunate
Parasite count > 10%, exchange transfusion should be considered
Non-falciparum features
General features of malaria - fever headache, splenomegaly
Plasmodium vivax/ovale - cyclical fever every 48 hours, plasmodium malariae - cyclical fever every 72 hours
Plasmodium malariae - associated with nephrotic syndrome
Non-falciparum management
Artemisinin-based combination therapy or chloroquine
ACTs avoided in pregnant women
Patients with ovale/vivax - given primaquine following acute mx with chloroquine to destroy liver hypnozoites & prevent relapse
Measles clinical features
Prodromal phase - irritable, conjunctivitis, fever
Koplik spots - typically develop before the rash, white (’grain of salt’) on the buccal mucosa
Rash - starts behind ears then to the whole body, discrete maculopapular rash becoming blotchy & confluent
- desquamation that typically spares the palms & soles may occurs after a week
Diarrhoea (10%)
Measles ix
Measles-specific IgM and IgG serology (ELISA)
- most sensitive 3-14 days after onset of the rash
Measles RNA detection by PCR
- best for swabs taken 1-3 days after rash onset
Measles mx
Mainly supportive
Vitamin A in children < 2 years
Admission may be considered in immunosuppressed/pregnant patient
Notifiable disease → inform public health
Measles complications
Otitis media
Pneumonia
Encephalitis
Subacute sclerosing panencephalitis - 5-10 years after illness
Febrile convulsions
Keratoconjunctivitis, corneal ulceration
Diarrhoea
Increased risk of appendicitis
Myocarditis
Measles mx of contacts
Child not immunised against measles comes into contact → MMR should be offered
- given within 72 hours
Meningitis
- inflammation of the meninges
- meningococcal septicaemia = meningococcus (N. meningitidis) infection in the bloodstream
- causes ‘non-blanching rash’ → DIC & subcutaneous haemorrhages
- bacterial meningitis - neisseria meningitidis & strep pneumoniae; in neonates = GBS
Meningitis presentation
Fever
Neck stiffness
Vomiting
Headache
Photophobia
Altered consciousness
Seizures
Meningococcal septicaemia → non-blanching rash
Neonates & babies → hypotonia, poor feeding, lethargy, hypothermia & bulging fontanelle
Kernig’s test & Brudzinski’s test
Management of bacterial meningitis
- community - suspected meningitis & a non blanching rash should receive an urgent stat injection (IM/IV) of benzylpenicillin prior to transfer to hospital
- hospital → blood culture & LP for CSF should be performed prior to starting abx
- if pt is acutely unwell → abx should not be delayed
- sent blood tests for meningococcal PCR
- typical abx:
- under 3 months: cefotaxime & amoxicillin (cover listeria)
- above 3 months: ceftriaxone
- vanc can be added if there is a risk of penicillin resistant pneumococcal infection
- steroids → reduce frequency & severity of hearing loss and neurological damage
- notifiable disease
Meningitis post exposure prophylaxis
Risk highest for people that have had close prolonged contact within the 7 days prior to the onset of the illness
Single dose of ciprofloxacin
Viral meningitis
Most common causes - HSV, enterovirus & VZV
Sample of CSF should be sent for viral PCR testing
Supportive treatment, aciclovir can be used to treated suspected/confirmed HSV or VZV infection
Meningitis complications
Hearing loss
Seizures & epilepsy
Cognitive impairment and LD
Memory loss
Cerebral palsy
Mumps
- viral infection spread by respiratory droplets
- incubation period is 14-25 days
Mumps clinical features
Initial period of flu-like symptoms known as the prodrome
- fever
- muscle aches
- lethargy
- reduced appetite
- headache
- dry mouth
Parotid gland swelling after flu-like symptoms, either unilateral/bilateral
Abdominal pain
Testicular pain & swelling
Confusion, neck stiffness & headache
Mumps mx
Diagnosis confirmed with PCR testing on a saliva swab
Blood/saliva can be tested for antibodies to the mumps virus
Notifiable disease
Supportive management → rest, fluids & analgesia
Mumps complications
Pancreatitis
Orchitis
Meningitis
Sensorineural hearing loss
Preseptal cellulitis
Infection of the soft tissues anterior to the orbital septum - the eyelids, skin and subcutaneous tissue of the face
Can progress to orbital cellulitis
Preseptal cellulitis epidemiology
Most commonly occurs in children
- 80% of pts are < 10
- median age is 21 months
More common in the winter due to the increased prevalence of RTIs
Preseptal cellulits aetiology
Staph aureus
Staph epidermidis
Streptococci
Anaerobic bacteria
Preseptal cellulitis clinical features
Red, swollen, painful eye of acute onset
Fever
Oedema of the eyelids
Partial/complete ptosis of the eye due to swelling
Orbital signs - must be absent
Preseptal cellulitis ix
Bloods
Swab of any discharge present
Contrast CT may help to differentiate between preseptal and orbital cellulitis
Preseptal cellulitis mx
All cases should be referred to secondary care for assessment
Oral abx are frequently sufficient → co-amoxiclav
Children may require admission for observation
Orbital cellulitis
Result of an infection affecting the fat & muscles posterior to the orbital septum, within the orbit but not involving the globe
Usually caused by a spreading URTIs
Medical emergency requiring hospital admission & urgent senior review
Orbital cellulitis risk factors
Childhood - 7-12 years
Previous sinus infection
Lack of Hib vaccination
Recent eyelid infection/insect bite on eyelid
Ear or facial infection
Orbital cellulitis clinical features
Redness and swelling around the eye
Severe ocular pain
Visual disturbance
Proptosis
Ophthalmoplegia/pain with eye movements
Eyelid oedema & ptosis
Drowsiness +/- N&V in meningeal involvement
Orbital cellulitis ix
FBC - WBC elevated, raised inflammatory markers
Clinical examination - complete ophthalmological assessment
CT with contrast
Blood culture & microbiological swab to determine the organism
Orbital cellulitis mx
Admission to hospital with IV abx
OM
- infection in the middle ear
- often preceded by a viral URTI → bacteria enter from the back of the throat through the eustachian tube
OM bacteria
Most common - streptococcus pneumoniae
Other common causes: haemophilus influenzae, moraxella catarrhalis & staph aureus
OM presentation
Ear pain
Reduced hearing in the affected ear
General symptoms of URTI → fever, cough, coryzal symptoms, sore throat & generally unwell
Can cause balance issues & vertigo when the infection affects the vestibular system
Can be discharge if tympanic perforation
Non-specific symptoms in young children → fever, vomiting, lethargy or poor feeding
OM examination
Bulging, red, inflamed looking membrane
If perforation → may see discharge in the ear canal & hole in the tympanic membrane
OM mx
Consider referral to paediatrics for assessment or admission if symptoms are severe or there is diagnostic doubt
Most cases of otitis media will resolve without antibiotics
Simple analgesia to help with pain and fever
First line antibiotic → amoxicillin for 5 days
- alternatives are erythromycin and clarithromycin
OM complications
Otitis media with effusion
Hearing loss (usually temporary)
Perforated eardrum
Recurrent infection
Mastoiditis
Abscess
Rubella
Viral infection caused by the togavirus
Rubella timeline
Outbreaks more common around winter and spring
Incubation period is 14-21 days
Individuals are infectious from 7 days before symptoms appear to 4 days after onset of the rash
Rubella features
Prodrome - low grade fever
Rash - maculopapular, initially on face before spreading to the whole body, usually fades by 3-5 days
Lymphadenopathy - suboccipital & postauricular
Rubella complications
Arthritis
Thrombocytopaenia
Encephalitis
Myocarditis
Features of congenital rubella syndrome
Sensorineural deafness
Congenital cataracts
Congenital heart disease
Growth retardatation
Hepatosplenomegaly
Purpuric skin lesions
Suspected rubella in pregnant women diagnosis
Discussed immediately with local health protection unit
IgM antibodies are raised in women recently exposed to the virus
Very difficult to distinguish rubella from parvovirus B19 → important to check parvovirus B19 serology
Suspected rubella in pregnant women management
Discussed with local HPU
Advised to keep away from those who might have rubella
Non-immune mothers should be offered the MMR vaccination in post-natal period
- should not be administered to women known the be pregnant/attempting to become pregnant
Tonsillitis
Inflammation of the palatine tonsils as a result of either a bacterial or viral infection
Tonsillitis organisms
Viral - adenovirus, EBV
Bacteria - group A strep
Tonsillitis risk factors
Smoking
Tonsillitis clinical features
Sore throat
Fever
Pain on swallowing
Red, inflamed & enlarged tonsils
Anterior cervical lymphadenopathy
Tonsillitis Centor criteria
Can be used to estimate the probability that tonsilitis is due to bacterial infection & will benefit from abx
Score > 3, appropriate to offer abx
Fever > 38
Tonsillar exudates
Absence of cough
Tender anterior cervical lymph nodes
FeverPAIN score
Higher score = more chance of bacterial infection
Fever during previous 24 hours
Purulence
Attended within 3 days of the onset of symptoms
Inflamed tonsils
No cough or coryza
Tonsillitis mx
1st line - Penicillin V 500mg QDS for 5-10 days
Alternative in penicillin allergy: clarithromycin/erythromycin PO BD for 5 days
Delayed prescriptions can be considered
Tonsillitis complications
Peritonsillar abscess
Otitis media
Scarlet fever
Rheumatic fever
Tonsillitis post-streptococcal conditions
Post-streptococcal glomerulonephritis
Post-streptococcal reactive arthritis
Toxic shock syndrome
Severe systemic reaction to staphylococcal exotoxins, the TSST-1 superantigen toxin
Toxic shock syndrome diagnostic criteria
Temperature > 38.9
Hypotension: systolic BP < 90 mmHg
Diffuse erythematous rash
Desquamation of rash, especially of the palms and soles
Involvement of three or more organ systems: eg, GI (D&V), mucous membrane erythema, renal failure, hepatitis, thrombocytopenia, CNS involvement
Toxic shock syndrome mx
Removal of infection focus
IV fluids
IV abx
Viral exanthema
First disease - measles
Second disease - scarlet fever
Third disease - rubella
Fourth disease - duke’s disease
Fifth disease - parvovirus B19
Sixth disease - roseola infantum
Scarlet fever
Associated with group A strep infection, usually tonsilitis (not caused by a virus !)
Caused by an exotoxin produced by streptococcus pyogenes
Scarlet fever presentation
Characterised by a red-pink, blotchy, macular rash with rough ‘sandpaper’ skin that starts on the trunk & spreads outwards
Fever
Lethargy
Flushed face
Sore throat
Strawberry tongue
Cervical lymphadenopathy
Scarlet fever mx
Phenoxymethylpenicillin for 10 days - kept off school until 24 hours after starting antibiotics
Notifiable disease
Scarlet fever associations
Post-streptococcal glomerulonephritis
Acute rheumatic fever
Duke’s disease
Never used in clinical practice
Used to describe the non-specific viral rashes
Parvovirus B19 presentation
Mild fever, coryza and non-specific viral symptoms
After 2-5 days → rash appears quite rapidly as a diffuse bright red rash on both cheeks
Few days later → a reticular mildly erythematous rash affecting the trunk & limb appears that can be raised and itchy
Parvovirus B19 mx
Self limiting & rash and symptoms usually fade over 1-2 weeks
Once rash has formed can go back to school
Parvovirus B19 complications
Aplastic anaemia
Encephalitis or meningitis
Pregnancy complications including fetal death
Rarely → hepatitis, myocarditis or nephritis
Roseola infantum
Caused by human herpesvirus 6 and less frequently by human herpesvirus 7
Roseola infantum clinical features
1-2 weeks after infection with a high fever (up to 40 degrees) that comes on suddenly, lasts for 3-5 days & then disappears suddenly
Coryzal symptoms, sore throat & swollen lymph nodes
Rash → when fever settles, appears for 1-2 days, not itchy
Roseola infantum mx
Make a full recovery within a week
Do not need to be kept off nursery if they are well enough to attend
Roseola infantum complications
Febrile convulsions due to high temperature
Immunocompromised patients → myocarditis, thrombocytopenia and Guillain-Barre syndrome
No school exclusion
Conjunctivitis
Fifth disease (slapped cheek)
Roseola
Infectious mononucleosis
Head lice
Threadworms
Hand, foot and mouth
Scarlet fever school exclusion
24 hours after commencing antibiotics
Whooping cough school exclusion
2 days after commencing abx OR
21 days from onset of symptoms if no abx
Measles school exclusion
4 days from onset of rash
Rubella school exclusion
5 days from onset of rash
Chickenpox school exclusion
All lesions crusted over
Mumps school exclusion
5 days from onset of swollen glands
D&V school exclusion
Until symptoms have settled for 48 hours
Impetigo school exclusion
Until lesions are crusted and healed OR
48 hours after commencing abx treatment
Scabies school exclusion
Until treated
Influenza school exclusion
Until recovered
