Staph, Strep and Kawasaki Disease Flashcards
What type of bacteria is streptococci?
Gram positive cocci
What type of bacteria is staphylococci?
Gram positive cocci
What antibiotic is usually used for strep infection?
Penicillin
What antibiotic is usually used for staph infection?
Flucloxacillin (synthetic penicillin resistant to B-lactamasese) due to resistance issues
What causes scarlet fever?
Group A B-haemolytic streptoccoci
Who is relatively protected from scarlet fever?
- Children < 2 due to maternal antibodies
- Children > 10 due to natural protection
What are the virulence factors involved in scarlet fever?
- M-protein
- Exotoxins
What are the possible complications of scarlet fever?
- Erysipelas, cellulitis, impetigo
- Streptococcal toxic shock syndrome
- Rheumatic fever
- Glomerulonephritis
How is scarlet fever treated?
Penicillin for 10 days
What is the incubation period for scarlet fever?
2-4 days
How does scarlet fever present?
- Malaise and fever
- Tonsillitis
- Exanthema
- Strawberry tongue
- Squamation (hands and feet)
What is the epidemiology of scarlet fever?
- Median age 4
- 89% occur in <10 years
- 5% occur in adults over 18
What is impetigo caused by?
- Strep pyogenes
- Staph aureus
How does impetigo present?
- Highly contagious
- Sores and blisters
- No systemic symptoms
- Yellow-brown crusta
What is SSSS caused by?
Exotoxins of staph aureus
What is SSSS?
Staphylococcus Scalded Skin Syndrome
Who is usually affected by SSSS?
Children <5 (particularly new-borns)
How does SSSS present?
- Fever
- Widespread redness
- Fluid-filled blister that rupture easily especially in the skin folds
What is the clinical presentation of Kawasaki disease?
Fever for at least 5 days with 4 or more:
- Bilateral conjunctival injection
- Changes of the mucous membranes
- Cervical lymphadenopathy
- Polymorphous rash
- Changes of the extremities
- Peripheral oedema
- Peripheral erythema
- Periungual desquamation
What is the pathophysiology of Kawasaki disease?
- Self-limited vasculitis of medium-sized arteries
- Aetiology unknown but infectious cause suggested
How does prevalence of KD vary amongst individuals?
- Reported in all racial and ethnic groups
- Highest prevalence in Japan and Hawaii
- Increased risk of siblings and twins
What is the aim of treatment of KD?
To prevent complciations like vasculitis of the coronary arteries
What is the treatment for KD?
- Immunoglobulins
- Aspirin
- Other immunosuppressive agents
How does Henoch-Schonlein purpura present?
Vasculitis of the skin, kidneys and more rarely GIT
What is Henoch-Schonlein purpura associated with?
Previous aspecific viral illness
What can cause eryhtmatous maculopapulous rashes?
- Measles
- Rubella
- CMV
- Enterovirus
- Human herpesvirus 6
- Human herpesvirus 7
- Parovirus B19
- EBV
What can cause vesiculobullous rashes?
- VZV
- HSV
- Enterovirus
What can cause petechial and purpuric rashes?
- Rubella (congenital)
- Enterovirus
- CMV (congenital)
What is the incubation period for VZV infections?
14 days (10-21)
How do VZV infections present?
- Mild malaise and fever
- Exanthema
- Itching
What is the progression of exanthema in VSV infections?
- Papules
- Vesicles
- Pustules
- Crustae
- Scarring
What are the possible complications of VZV infections?
- Secondary staph/strep skin infections
- Meningoencephalitis, cerebellitis, arthrtitis
How is VZV infection prevented?
Vaccination
How is VZV infection treated?
- Self-limiting
- (Val) acyclovir if new lesions after 10 days
How can VSV infection manifest?
- Primary infection (varicella, chickenpox)
- Recurrent infection (Zoster)
Who is at risk of complicated VSV infection?
- Fatal varicella (2 : 100.000)
- < 1 year of age (8 : 100.000)
- T-cell deficiencies (7-10% mortality)
What are the warning signs for VZV complicated infection?
- High fever
- new lesions >10 days
- Inflammed lesions
- General malaise
What are the 2 types of HSV infection?
- HSV1 (oral)
- HSV2 (genital)
How can HSV infections present clinically?
- Stomatitis (primary infection)
- Recurrent cold sores
What complications of HSV are there?
- (Kerato) conjunctivitis
- Encephalitis
- Systemic neonatal infections
- Immunocompromised children
What is the therapy for HSV infection?
- Self-limiting
- (Val) acyclovir
How can neonates contract HSV infection?
- Birth canal
- Direct contact with mothers infected lesions
When does HSV infection present in neonates?
DOL 4-21
How does HSV infection present in neonates?
70-80’% disseminated/CNS infections
- Sepsis
- Meningoencaphilitis
- Hepatitis (jaundice and bleeding)
20-30% skin/eye/mouth disease
What is the incidence of HSV infection in neonates?
2-3 per 100,000
What is the mortality rate of HSV infection in neonates?
- Without acyclovir >50%
- With acyclovir 20-30%
What is the seroprevalence of VZV?
- 20% at 1 year old
- > 90% at 5 years old
- 95% of adults
What is the seroprevalence of HSV-1?
- 20-30% at 5 years old
- 40-50% of adolescents
- 60-80% of adults
What is the seroprevalence of HSV-2?
- <5% of children under 10
- 10-15% of adults
What is the cause of hand-foot-mouth disease?
Enteroviruses
- Coxsackie A16
- Enterovirus 71
What is the incubation period for hand-foot-mouth disease?
3-6 days
Who is usually affected by hand-foo-mouth disease?
Children under 10
When is hand-foot-mouth disease most prevalent?
Summer and early autumn
What is the clinical presentation of hand-foot-mouth disease?
- Exanthema and enanthema
- Painful lesions
- Recovery in 5 to 10 days
What mild infections can enteroviral disease manifest as?
- Fever +/- rash
- Hand, foot, mouth syndrome
- Herpangina
- Pleurodynia
- Pharyngitis
- Conjunctivitis
- Croup
What potentially serious infections can enteroviral disease manifest as?
- Meningitis
- Encephalitis
- Acute paralysis
- Neonatal sepsis
- Myocarditis/pericarditis
- Hepatitis
- Chronic infection in immunocompromised patients
How are vesicular rashes diagnosed?
- Clinical diagnosis
- Smear of vesicle from ulcer base (Tzanck test, cannot differentiate HSV/VZV)
- PCR of fluids, CSF and bloods
- Serology for past infections
