Infection and Immunity Flashcards
What are the investigations for meningitis?
• CRP • WCC • Blood culture • PCR • Lumbar puncture ○ CI: Raised ICP, meningococcal septicaemia
What is the management of meningitis?
• <3 months
○ IV Cefotaxime and amoxicillin
• >3 months
○ IV ceftriaxone
Dexamethasone may be given if on the CSF you see: • Purulent CSF • Signs of raised ICP • Raised WBC • Bacteria on gram stain
If meningococcal septicaemia: • IM/IV Benzylpenicillin ○ Used if presents in GP setting before sending to A&E • Steroids should NOT be used • LP contraindicated, due to likely DIC
Follow-up:
• Audiological assessment for hearing impairment (common complication)
Prophylaxis for family:
• Ciprofloxacin/Rifampicin
What are the clinical features of encephalitis?
- Altered consciousness
- Fever
- Seizures
Common infectious causes:
• Enteroviruses
• Respiratory viruses
• HSV (Very dangerous)
What is the management of encephalitis?
Investigation:
• PCR to detect HSV in CSF
• HSV encephalitis may show destructive changes on EEG or CT/MRI
Treatment:
• Treat with high dose aciclovir till HSV ruled out
• If HSV confirmed, continue treating with aciclovir for 3 weeks
What are the clinical features of toxic shock syndrome?
Characterised by:
• High fever (>39)
• Hypotension
• Maculopapular rash
Caused by toxin producing staph aureus, this toxin acts as a superantigen, resulting in organ dysfunction
What is the management of toxic shock syndrome?
- ITU if in shock
- Cephalosporins
- Clindamycin
- IVIG
- IV Linezolid (Can’t use with antidepressants)
- Surgical debridement
What are the clinical features of necrotising fasciitis?
- Severe pain
- Rapidly enlarging area of necrotic tissue (Very tender to touch)
- Systemic illness
What is the management of necrotising fasciitis?
- Medical emergency
- Surgical debridement of necrotic area
- IV broad spectrum antibiotics
- IV fluids
What are the clinical features of impetigo?
- Begins as erythematous macules
- Becomes vesicular/bullous
- When vesicle ruptures, forms honey crusted lesions
- Most commonly on hands, face, neck affecting those with pre-existing skin conditions
What is the management of impetigo?
• Reassurance:
○ Typically heals by itself
○ Good hygiene encouraged
○ Stay away from school until lesions dry and scabbed over
○ Follow-up if no improvement after 7-days
• Medical treatment
○ Local infection = Topical fusidic acid (7 days)
○ Extensive infection = Oral flucloxacillin (7 days)
What are the features of (peri)orbital cellulitis?
• Periorbital cellulitis ○ Fever ○ Unilateral erythema, tenderness and oedema of the eyelid • Orbital cellulitis ○ Same as above ○ Proptosis ○ Painful/limited ocular movement ○ Reduced visual acuity
What is the management of (peri)orbital cellulitis?
• Periorbital cellulitis ○ IV antibiotics (ceftriaxone) immediately, to prevent posterior spread • Orbital cellulitis ○ IV antibiotics ○ CT/MRI to see spread of infection
What are the clinical features of scalded skin syndrome?
- Caused by exfoliative staphylococcal toxins
- Fever
- Malaise
- Purulent, crusting lesions on face
- Widespread erythema and tenderness of skin
- Nikolsky sign - Epidermis will separate on gentle pressure
What is the management of scalded skin syndrome?
- IV antibiotics (Flucloxacillin)
* Analgesia
What are the clinical features of gingivostomatitis?
- Most common form of primary HSV in children
- 3 months - 10 years most common age
- Painful vesicular lesions on lips, gums, anterior surface of tongue, hard palate
- Usually progresses to painful ulceration and bleeding
- High fevers
- Pain on eating food, drinking (Risk of dehydration)
What is the management of gingivostomatitis?
- Symptomatic
* If severe, IV aciclovir and IV fluids
What is the management of VZV infection in an immunocompromised patient?
IV aciclovir
Prevention is key:
• VZV immunoglobulins
What are the features of EBV infection?
• Causes infectious mononucleosis ○ Fever ○ Lymphadenopathy (Typically cervical) ○ Tonsillitis/Pharyngitis ○ Splenomegaly
Investigation:
• Clinical
• Positive monospot test (Heterophile antibodies)
What is the management of EBV infection:
Investigation:
• Clinical
• Positive monospot test (Heterophile antibodies)
Treatment: • Paracetamol/Ibuprofen • Lasts for 1-3 months • Can go to work/school • Avoid contact sports (splenic rupture) • No amoxicillin/ampicillin
What are the clinical features of roseola infantum?
Alternate name: Exanthema subitum, Sixth disease
• Caused by HHV-6/HHV-7 infection
• Affects children younger than 2
- High fever & malaise
- Generalised macular rash as fever wanes
What is the management of roseola infantum?
- Paracetamol/Ibuprofen for symptom relief
- Resolves over a few days/weeks
- Risk of febrile convulsions
What are the features of erythema infectiosum?
Alternative name: Slapped-cheek syndrome, fifth disease
• Caused by human parvovirus B19 infection
- Initially presents with fever, headache, myalgia
- After one week, a rash develops on the cheeks
- This progresses to a maculopapular rash that spreads to the rest of the body
What is the management of erythema infectiosum?
Paracetamol/Ibuprofen
Fluids
What are the features of hand, foot and mouth disease?
Painful vesicular lesions on hands, feet and mouth
Mild systemic symptoms
Lasts a few days
What is the management of hand, foot and mouth disease?
Nothing lol
What are the clinical features of measles?
Begins with:
• Fever
• Coryza
• Conjunctivitis
Then:
• Koplik spots = White spots on buccal mucosa (Pathognomonic)
Then rash:
• Begins behind the ears
• Spreads to rest of body
• Initially maculopapular, before becoming blotchy
Investigations
• IgM antibodies can be detected within a few days of rash onset
What is the management of measles?
Investigations:
• IgM antibodies detected within a few days of rash onset
Treatment:
• Notify authorities
• Self limiting
• Symptom relief (paracetamol/ibuprofen)
• Stay away from school for 4 days from the onset of rash
Complications:
• Otitis media is most common
• Pneumonia most common cause of death
• Encephalitis starts 1-2 weeks after onset of illness
What are the clinical features of rubella?
Maculopapular rash is typically the first sign of infection
• Begins on the face
• Spreads to the rest of the body
• Fades after 5 days
Lymphadenopathy
• Particularly postauricular and occipital
May have low grade fever
What is the management of rubella?
Investigations:
• IgM antibodies serology from oral fluid sample
Treatment:
• Notify authorities
• Self limiting
• Symptom relief (paracetamol/ibuprofen)
• Stay away from school for 4 days from the onset of rash
What are the clinical features of mumps?
Begins with • Fever • Malaise • Parotitis ○ Initially unilateral ○ Proceeds to bilateral ○ Children complain of earaches and pain when eating/drinking
What is the management of mumps?
Investigations:
• Oral swab serology
Treatment:
• Notify authorities
• Self limiting
• Symptom relief (paracetamol/ibuprofen)
• Adequate fluids
• Stay away from school for 5 days from the onset of parotitis
Complication:
• Orchitis
What are the clinical features of kawasaki disease?
How does it differ from scarlet fever?
Conjunctivitis Rash - Maculopapular rash that desquamates Adenopathy - Typically cervical Strawberry tongue Hands - Swelling of hands/feet and Burn - High fever lasting >5 days
In scarlet fever, the rash is sheet like with fine, tiny papillae
Kawasaki typically presents in <5s
Scarlet fever typically presents in 5-15 year olds
What is the management of kawasaki disease?
Investigation - Clinical
IVIG
High dose aspirin
Complication:
Coronary artery aneurysm - Hence you do an echocardiogram (Not a angiogram due to radiation)
What is the management of scarlet fever?
Investigation:
• Throat swab (Start Abx immediately however)
Treatment:
• Oral penicillin V for 10 days
• Patients who have a penicillin allergy should be given azithromycin
• Children can return to school 24 hours after commencing antibiotics
• Scarlet fever is a notifiable disease
Complications:
Otitis media
Rheumatic fever
Acute glomerulonephritis
What are the clinical features of tuberculosis?
In children they are NON-SPECIFIC Prolonged fever Malaise Anorexia Weight loss Focal signs of infection (e.g. lymph node swelling)
Diagnosed via gastric washings followed by Ziehl-Neelsen stains
What is the management of tuberculosis?
Rifampicin + Isoniazid = 6 months
Pyrazinamide + Ethambutol = 2 months
Pyridoxine in adolescents to prevent peripheral neuropathy
Prevention:
• BCG vaccine from birth to high risk groups
• If a child <2 years is in contact with someone with TB, they should receive prophylactic isoniazid. If after 6 weeks they are negative for TB, stop meds and give vaccine
How is HIV infection detected in children?
Child >18 months = HIV antibodies
Child <18 months = HIV RNA PCR
This is because children to HIV positive mothers will have transplacental HIV antibodies from mother. Hence, it is not a reliable indicator of infection in the child. After 18 months these antibodies will be gone if the child is negative for HIV
What are the clinical features of Lyme disease?
Erythematous macule at the sight of the bite, that looks like a target shaped rash (erythema migrans) Headache Fever Myalgia Lymphadenopathy
Late features:
Neurological - meningoencephalitis
Cardiac - myocarditis, heart block
Joint - Episodes of arthritis
What is the management of lyme disease?
Investigation:
• Clinical (Presence of erythema migrans)
• If no erythema migrans, ELISA, then immunoblot test
Management:
1st line = Doxycycline
2nd line = Amoxicillin
3rd line = Azithromycin
What are the clinical features of Henoch-Schonlein Purpura?
At presentation, affected children often have a fever.
The rash is the most obvious feature, but HSP affects four systems:
• Skin: Palpable purpuric rash on buttocks and extensors of lower limbs - “gravity-depending areas”.
• Gastro-intestinal system: Non-specific abdominal pain which can be acute and severe.
• Joints: Arthralgia, particularly of the knees and ankles. Long-term damage of the joints does not occur
○ ±Oedema
• Kidneys: Renal involvement is common but is rarely the first symptom.
○ Glomerulonephritis: Over 80% have microscopic or macroscopic haematuria or mild proteinuria.
What are the clinical features of threadworm infestation?
Children present with intense perianal itching, which is typically worse at night when the worms come out of the anus. Nocturnal itching may lead to disturbed sleep and irritability.
Some people may be asymptomatic, and only notice worms on stool or on the perianal skin.
Girls may also experience itching around the vulva.
How is threadworm infestation diagnosed?
Based on clinical features. If uncertain can perform adhesive tape test: Transparent tape is applied to the perianal area first thing in the morning and then examined under a microscope to detect threadworm eggs. Stool examination is not recommended.
What is the management of threadworm infestation?
Generally recommended that all household members are treated at the same time, with an anthelmintic (mebendazole).
Improve hygiene
