Infection - Varicella Zoster, HUS, MMR Flashcards
Presentation of chickenpox
Chickenpox is characterised by widespread, erythematous, raised, vesicular, blistering lesions. The rash usually starts on the trunk or face and spreads outwards affecting the whole body over 2 – 5 days. Eventually the lesions scab over, at which point they stop being contagious.
Other symptoms:
- Fever is often the first symptom
- Itch
- General fatigue and malaise
Describe the infectivity of chickenpox
Complications of acute chickenpox infection
- Bacterial superinfection
- Dehydration
- Conjunctival lesions
- Pneumonia
- Encephalitis (presenting as ataxia)
Long term complications of chickenpox
After the infection the virus can lie dormant in the sensory dorsal root ganglion cells and cranial nerves and reactivate later in life as shingles or Ramsay Hunt syndrome.
Complications of chickenpox in pregnancy
Chickenpox in pregnancy, before 28 weeks gestation, can cause developmental problems in the fetus in a small portion of patients. This is known as congenital varicella syndrome.
Chickenpox in the mother around the time of delivery can lead to life threatening neonatal infection and is treated with varicella zoster immunoglobulins and aciclovir.
Chickenpox is usually a mild self limiting condition that does not require treatment in otherwise healthy children.
Who may require treatment and what does this involve?
Aciclovir may be considered in immunocompromised patients, adults and adolescents over 14 years presenting within 24 hours, neonates or those at risk of complications.
Pathophysiology of haemolytic uraemia syndrome
Classic triad of haemolytic uraemic syndrome:
- Haemolytic anaemia: anaemia caused by red blood cells being destroyed
- Acute kidney injury: failure of the kidneys to excrete waste products such as urea
- Thrombocytopenia: low platelet count
What is the most common cause of haemolytic uraemic syndrome?
The most common cause is a toxin produced by the e. coli 0157 bacteria, called the shiga toxin. Shigella also produces this toxin.
When infected with E.coli O157 or Shigella what increases the risk of getting haemolytic uraemia syndrome?
The use of antibiotics and anti-motility medications such as loperamide to treat gastroenteritis caused by these pathogens increases the risk of developing HUS.
Presentation of haemolytic uraemic syndrome
E. coli 0157 causes a brief gastroenteritis, often with bloody diarrhoea. The symptoms of haemolytic uraemic syndrome typically start around 5 days after the onset of the diarrhoea.
Signs and symptoms of HUS may include:
- Reduced urine output
- Haematuria or dark brown urine
- Abdominal pain
- Lethargy and irritability
- Confusion
- Oedema
- Hypertension
Bruising
Management of haemolytic uraemic syndrome
HUS is a medical emergency and has a 10% mortality. It needs to be managed by experienced paediatricians under the guidance of a renal specialist. The condition is self limiting and supportive management is the mainstay of treatment.
Patient may require dialysis, blood transfusion or anti hypertensives.
What is Kawasaki disease?
It is a systemic, medium-sized vessel vasculitis.
Who dose Kawasaki disease typically effect?
It affects young children, typically under 5 years. There is no clear cause or trigger. It is more common in Asian children, particularly Japanese and Korean children. It is also more common in boys
A key complication of Kawasaki disease is:
Coronary artery aneurysm
