GIT infection (viruses)

Question 1

What is the pathophysiology of viral gastroenteritis

Answer 1

1. Virus enters enterocytes at the tips of small intestinal villi.
2. Causes structural changes to small bowel mucosa leading to: sloughing leads to smoothing of intestinal epithelium, villus shortening & mononuclear cell infiltration of lamina propria → inflammation & maldigestion
3. Ion channels blocked → water reabsorption fails
4. Malabsorption and fluid loss result
5. Lactose intolerance: lactase secretion decrease due to enterocyte death (several weeks)
6. 3-8 weeks later, villi have recovered

Question 2

What is the main way to diagnosis viral gastroenteritis

Answer 2

Clinical diagnosis

Question 3

What is the 2 general treatments for viral gastroenteritis

Answer 3

1. Rehydration & nutrition: IV/electrolyte replacement to prevent deterioration, dehydration & malnutrition
2. Prevention of spread & infection: hand washing & vaccines

Question 4

What is 6 strategies to prevent viral gastroenteritis

Answer 4

1. Vaccine
2. Hand washing
3. Good hygiene
4. Clean water
5. Breastfeeding - passive immunity of rota-/adenovirus
6. Ethanol, detergents or chlorine

Question 5

What is the four main pathogens for viral gastroenteritis

Answer 5

Calicivirus
Rotavirus
Adenovirus
Astrovirus
Poo

Question 6

Which of the viral gastroenteritis viruses has the highest mortality

Answer 6

Rotavirus

Question 7

Describe the following for Calicivirus:
Virology
Clinical features (severity, mortality, duration & shedding, symptoms)
Diagnoses

Answer 7

Virology:
Uneveloped
ss RNA
Noro-/sapoviruses
Clinical features:
Highly severe & not high mortality
1-2 days duration & prolonged shedding
V, N, D, abdominal cramps & fever
Diagnosis:
Mainly clinical can be ELISA/PCR

Question 8

What populations are at high risk for severe disease

Answer 8

Immunocompromised
Elderly
Children

Question 9

Describe the following for Rotavirus:
Virology
Clinical features (severity, mortality, duration & shedding, symptoms)
Prevention
Diagnoses

Answer 9

Virology:
Uneveloped
ds RNA
Serogroup A, B & C
Clinical features:
Highly severe & mortality
5-7 days duration & 10 day shedding
Abdominal pain, fever, LOA, V & dehydration
Associated w/ intussusception, Reye’s syndrome, encephalitis & IBD
Prevention:
Vaccine: Rotarix
Diagnosis:
Rapid test
Agglutination
ELISA/PCR

Question 10

Describe the following for Adenovirus:
Virology
Clinical features (severity, mortality, duration & shedding, symptoms)
Prevention
Diagnoses

Answer 10

Virology:
Uneveloped
ds DNA
Group F- 40/41 enteroadeno
Resistant virus (acid, bile & proteolytic enzymes)
Clinical features:
Slightly severe & mortality
1-3 weeks duration & weeks of shedding
Fever, V, D & RTI
Prevention:
Good hygiene w/ soap or >70% alcohol sanitiser
Diagnosis:
Rapid test & PCR

Question 11

Describe the following for Astrovirus:
Virology
Clinical features (severity, mortality, duration & shedding, symptoms)
Diagnoses

Answer 11

Virology:
Unenveloped
ss RNA
Genotype 1
Clinical features:
Slightly severe & mortality
1 week duration & short shedding
Mild D & co-infections common (asymptomatic, mild watery D & systemic infection)
Diagnosis:
Mainly clinical can be ELISA/PCR