Infectious Diarrhoeal Diseases Flashcards
What is the burden of diarrhoeal diseases?
In 2017, 1.6 million people died from diarrhoeal diseases globally
1/3 were child mortalities
For the past 30 years, it has caused significant burden on children
In 1990- it killed 1.7 million
Our world in data: Burden is predominantly on children (immune system growing and developing-maturation)
then the aging population (immune system deterioration)
What is the challenge for U5M?
Every year
Approx. 7 million children die before 5th birthday
3 million within 1st month of life
2 million between 1-12 months
What do most children die from?
Lower respiratory tract infections
Neonatal preterm complications
Diarrhoeal diseases
(Major fall in infectious diseases)
In U5s:
14% of deaths occur as a result of pneumonia
10% as a result from diarrhoea
Describe the regional burden of severe diarrhoea abd pneumonia episodes among children aged 0-4 years in 2010
Diarrhoea: 36 million episodes
Pneumonia: 14.1 million episodes
Africa and SE Asia are the biggest proportion of episodes
Why are diarrhoeal diseases important in the world, and describe the epidemiology.
One of the leading causes of mortality globally under 5
Globally (in general): 1.7 mill deaths annually
Leading cause of malnutrition under 5
Among the top 10 DALYs Under 5
Great impact on child development (growth and cognitive)
Yearly: kills 525 000 under 5’s in SE Asia and Africa
8.5% and 7.7% of deaths respectively
It is Preventable & Treatable:
- Safe drinking water/adequate sanitation/hygiene
Oral Rehydration Solution (ORS)
Vaccines (for some infections)
Why is life threatening diarrhoea important to consider?
most people who die from diarrhoea die of severe dehydration and fluid loss
Children who are malnourished or have impaired immunity and people living with HIV are most at risk
Causes metabolic consequenes (osmotic impalance, electrolyte imbalance)
ORGAN failure
death
malnourished patients are predisposed to infection
`What are some public health shortcomings in relation to diarrhoea?
- •Diarrhoeal disease mostly results from contaminated food and water sources.
- Worldwide, 780 million individuals lack access to improved drinking-water and 2.5 billion lack improved sanitation.
- Diarrhoea due to infection is widespread throughout LMICs (countries with a low SDI index)
- In LMICs, children under three years old experience on average three episodes of diarrhoea every year.
- Each episode deprives the child of the nutrition necessary for growth. As a result, diarrhoea is a major cause of malnutrition, and malnourished children are more likely to fall ill from diarrhoea.
Describe the relationship between diarrhoea and the long term risks of sequelae
- A single episode of diarrhoes is typically self-limiting with ORS and zinc for treatment
- In low income settings, multiple diarrhoea episodes per year can increase the odds of stunting such that the proportion of stunting attributable to 5 episodes of diarrhoea in the first 2 years of life is 25%
- Additionally rare sequelae include: GUILLIAN BARRE SYNDROME, REACTIVE ARTHRITIS, HAEMOLYTIC UREMIC SYNDROME
Define diarrhoea
watery or liquid stools,
usually with an increase in stool weight above 200 g per day
and an increase in daily stool frequency for > 2 days
and often a sense of urgency
(but very difficult to know exactly what is “normal”)
Define dysentry
Inflammatory disorder of G.I. tract – usually large intestine
- often associated with blood and pus
- pain, fever, abdominal cramps
Acute inflammation of the intestine associated with infectious DIARRHEA of various etiologies, generally acquired by eating contaminated food containing TOXINS, BIOLOGICAL derived from BACTERIA or other microorganisms. Dysentery is characterized initially by watery FECES then by bloody mucoid stools.
Shigella, Campylobacter, Salmonella, Schistosoma mansoni, and Entamoeba histolytica are among bacteria and parasites causing dysentery. Shigella is responsible for most cases of this disease in tropical regions. Mortality during the epidemics of Shigella dysenteriae type I has been estimated at 6.2%. On the other hand, Salmonella is the main contributing factor for this disease in developed countries
How can dysentry be lifethreatening?
- You’ve damaged the lining of the colon
- Displacement of the coloniser bacteria may cause sepsis and death
What are the common complications of infections with different organisms that cause diarrhoea
Aeromonas caviae - Intussusception, hemolytic-uremic syndrome (HUS), gram-negative sepsis
Campylobacter species - Bacteremia, meningitis, urinary tract infection, pancreatitis, cholecystitis, Reiter syndrome (RS)
C difficile - Chronic diarrhea
C perfringens - Enteritis necroticans
Plesiomonas species - Septicemia
Enterohemorrhagic E coli O157:H7 - HUS
Enterohemorrhagic E coli - Hemorrhagic colitis
Salmonella species - Seizures, RS, HUS, perforation, enteric fever
Vibrio species - Rapid dehydration
Giardia species - Chronic fat malabsorption
Rotavirus - Isotonic dehydration, carbohydrate intolerance
Y enterocolitica - Appendicitis, intussusception, perforation, toxic megacolon, peritonitis, cholangitis, bacteremia, RS
Cryptosporidium species - Chronic diarrhea
Entamoeba species - Liver abscess, colonic perforation
What are the complications of dysentry?
- Intestinal Complications:
Colon perforation- Very rare and primarily occurs in infants and malnourished patients. It is associated with S. flexneri and S. dysenteriae 1. [36]
Intestinal obstruction-usually seen in severe disease and S. dysenteriae 1.[37]
Toxic megacolon-Usually occurs in S. dysenteriae 1 infection.[24]
Proctitis or rectal prolapse-Invasion of shigella organisms into colonic mucosa can lead to rectal prolapse and proctitis in infants and young children.[5]
- •Electrolyte imbalances
- Convulsions
- Hemolytic uremic syndrome (HUS)
–Toxin produced by shigella causes damage to the endothelial layers of the body particularly the kidneys
•Toxic megacolon
–Fluid is not being absorbed
–Could give birth to your colon
- Protein losing enteropathy
- Arthritis
- Perforation
what are some important considerations to be made while diagnosing and managing diarrhea
- Identification of the etiological agent is very important
- Stool characteristics vary between different causes, such as consistency, color, volume, and frequency
Presence or absence of associated intestinal symptoms, such as nausea/vomiting, fever, and abdominal pain
Exposure to child daycare where commonly encountered pathogens are rotavirus, astrovirus, calicivirus; Shigella, Campylobacter, Giardia, and Cryptosporidium species
History of the ingestion of infected food, such as raw or contaminated foods
History of water exposure from swimming pools, camping, or marine environment
Travel history is crucial as common pathogens affect certain regions; enterotoxigenic Escherichia coli is the predominant pathogen [4]
Animal exposure has been historically linked with diarrhea, such as young dogs/cats: Campylobacter; turtles: Salmonella [5]
Predisposing factors such as hospitalization, antibiotic use, immunosuppression
What are non-infectious causes of diarrhoeal disease?
- Inflammatory bowel disease
- Metabolic disease
- Hyperthyroidism
- Diabetes mellitus
- Pancreatic insufficiency
- Coeliac disease
- Food allergy
- Lactose intolerance
- Antibiotics
- Irritable bowel syndrome
- Laxative abuse
- Malignancy
What the common causes of child deaths due to diarrhoeal disease?
Mostly viral
Mainly Rotavirus, then adenovirus
The second biggest section is bacteria, with the biggets cause of bacterial related diarrhoeal deaths being attributed to Shigella
Parasytic infections makeup a very small section of deaths, but cryptosporidium is the main killer in parasitic infections
What the common causes of over 70s deaths due to diarrhoeal disease?
Mostly bacterial. Mainly attributeed to shigella
What are the clinical consequences for diarrhoea?
-can lead to severe dehydration
excessive fluid and electrolyte loss
hypovolaemia; hypokalaemia;
organ failure
- long-term morbidity and
reduced growth
What are the causes of diarrhoeal disease (BACTERIA)?
- •Vibrio cholerae - outbreaks
•Shigella sp (5 – 15%)
•Escherichia coli (10 – 20%)
- Salmonella
- Campylobacter jejuni (10 – 15%)
- Yersinia enterocolitica
- Staphylococcus
- Vibrio parahemolyticus
- Clostridium difficile
Causes of diarrhoeal disease: VIRUS
- Rotavirus (20 – 50%)
- Adenoviruses
- Caliciviruses
- Astroviruses
- Norwalk agents and Norwalk-like viruses
(e.g. norovirus)
•Cytomegalovirus
Many others
Causes of diarrhoeal disease: PARASITE
- Entamoeba histolytica
- Giardia lamblia (~10%)
•Cryptosporidium (5 – 15%)
•Microsporidium
Isospora
What is the transmission of some of the major infectious agents that contibute to diarrhoeal disease?
- Most of the diarrhoeal agents are transmitted by the fecal-oral route
- Some viruses (such as rotavirus) can be transmitted through air
- Nosocomial transmission is possible
- Shigella (the bacteria causing dysentery) is mainly transmitted person-to-person (not fomites)
Food and water contaminated directly or indirectly with faeces or vomitus of infected persons are the principal mode of transmission. Ingestion of raw or inadequately cooked seafood or eating shellfish from coastal and estuarine waters can cause outbreaks of diarrhoea. Person-to-person transmission occurs by hand-to-mouth transfer of the agent from faeces of an infected individual. Respiratory spread is possible for rotavirus.
When is the most common season for different forms of diarrhoea?
What are the characteristics of G.lamblia?
G. lamblia is pear shaped and has one or two transverse, claw-shaped median bodies
They attach to the gut mucosa
lONG FLAGELLAE
Decreases absorption (malabsorption)
Fatty stool
Hatch eggs (cycts) which are very durable and highly transmmitable
Can survive in water for weeks and has effects on stunting
diarrhoea prevention
goals for 2025 (diarrhoea)
