Diarrhoea in children Flashcards
Comment on the Diarrheal disease burden
It is a mild to life threatening diseases.
It accounts for 8% of deaths in under 5’s.
It is the leading cause of malnutrition in U5’s.
Diarrheal disease mortality is greater in HIV+ children than in those without.
There are occasional epidemics.
Most diarrheal deaths preventable by simple low cost interventions.
It is part of the top ten causes of childhood mortality in KATH.
What is diarrhea? What happens in diarrhea?
Diarrhea is the passage of 3 or more loose watery stools within 24 hours. It is caused by increased stool fluidity and frequency due to increased gut motility, increased gut secretions and decreased gut absorption.
Take into consideration the patient’s usual habit in the history.
Give the various mechanisms of diarrhea
There are four mechanisms of diarrhea - invasive, secretory, osmotic and other
What are the types of diarrhea?
Acute watery diarrhea - <14 days in duration
Persistent diarrhea - >14 days duration
Severe persistent diarrhea - Persistent diarrhea with signs of dehydration
Dysentry - Bloody diarrhea
Chronic diarrhea
What are the features and etiological agents of acute watery diarrhea - most common?
It lasts for <14 days, with not more than 3 days break. Occurs with or without vomiting, no visible blood in stool.
Shigella, Campylobactor Jejuni, E. Coli (ETEC, EPEC), Rotavirus, Norovirus, Cryptosporodium, Vibrio Cholerae 01
What are the features and etiological agents of dysentery?
There is visible blood in stool, rapid weight loss, anorexia, intestinal mucosal damage.
Caused by Entamoeba histolytica in young adults, shigella, salmonella, EIEC, Campylobacter jejuni
What are the features of persistent diarrhea and its etiological agents?
It starts out as acute watery diarrhea or dysentery but lasts for more than 14 days. There is marked weight loss.
It is caused by Entero-adherence E.coli, Giardia Lamblia, Cryptosporidium, Shigella
What is severe persistent diarrhea?
It is persistent diarrhea with signs of dehydration.
What should you note about Chronic diarrhea?
It is recurrent diarrhea, not due to an infectious cause (eg. Metabolic disorders)
What are the three major pathways to infectious diarrhea?
A sick person without proper sanitation facilities defecates near a water source > this contaminated water is used by farmers to irrigate their crops > the contaminated corps are used to prepare food which is then eaten.
Animals defecate in or near a water source > this water is used for drinking and cooking > the food is ingested, water drank by families
Caregivers change the diapers of a sick baby and contaminate their hands > They touch people, objects and surfaces with their contaminated hands > prepare food with their contaminated hands.
What is the viral mechanism for diarrhea?
The virus replicates in the epithelial cell, then there’s villous destruction and shortening, with loss of disaccharidase enzymes. There’s then replacement by immature cells and finally water and electrolyte secretion. Diarrhea persists till the cells mature.
What are the various bacterial mechanisms for diarrhea?
Mucosal adhesion, leading to decreased absorption. There’s also mucosa invasion, and toxin secretion.
What are the protozoal mechanisms for diarrhea?
Mucosal adhesion - Giardia Lamblia, Cryptosporodium in the ileum. And mucosal invasion - Entamoeba histolytica in the ileum or colon.
What is the mechanism for invasive diarrhea and what are some examples of pathogens that cause invasive diarrhea?
The pathogen invades the distal ileum, colon > Inflammation, intestinal mucosal cell destruction > decreased function( increased fluid and nutrient absorption, inflammatory exudate, +/- pain) > diarrhea (dead tissue, mucus, blood, partially digested food).
Entamoeba histolytica, EIEC, EHEC, Yersinia enterocolitica, Vibrio parahaemolitica, Shigella, Salmonella, Campylobactor Jejuni
What is the mechanisms for secretory diarrhea and what are examples of pathogens that cause secretory diarrhea (acute watery diarrhea?
Pathogen multiplies in the ileum > Toxin production > Toxin attaches to mucosal cell > Toxin causes conversion of ATP to cAMP > cAMP leads to a reduction in the absorption of Na+, increase in the secretion of Cl-. This leads to increased secretion of water, K+ and HCO3 form the tissues into the gut lumen, leading to diarrhea.
Those that secrete enterotoxins: Shigella, Vibrio Cholera, Campylobacter Jejuni, Salmonella, ETEC.
Those that don’t secrete enterotoxins: Rotavirus
What is the mechanism for osmotic diarrhea and which agents cause osmotic diarrhea?
There’s presence of osmotically active substances in the gut. These substances cause the movement of fluid from tissues into the gut, leading to diarrhea.
It is caused by purgatives like Epsom salt, improperly prepared ORS/Salt-Sugar solutions, Lactose in lactose intolerant patients, Glucose in Glucose malabsorption patients.
Give an overview of the effects of diarrhea
There are two main effects - Dehydration and Nutrient deficit. Dehydration leads to fluid and electrolyte loss, Tissue hypo-perfusuion and multiple organ failure. Nutrient deficit leads to malnutrition, then infection. These can both result in death.
What are the effects of dehydration?
Hypovolemia, which leads to cardiovascular collapse and finally multiple organ failure.
Hypoxia which leads to multiple organ failure.
Tissue damage by the release of chemical mediators which amplify the damage done by the hypo-perfusional state.
TNF, Coagulation cascade, Interleukins, Complement, Leukotrienes, Leucocytes, endorphins, platelet activating factors, Lipopolysaccharides.
Abnormal physiology - Plugged capillaries, Abnormal starling’s mechanism, damaged barrier function, abnormal smooth muscle contraction (ileus), blood viscosity changes, AV shunting, altered interstitium, coagulation cascade.
What are the effects of dehydration?
Hypovolemia, which leads to cardiovascular collapse and finally multiple organ failure.
Hypoxia which leads to multiple organ failure.
Tissue damage by the release of chemical mediators which amplify the damage done by the hypo-perfusional state.
TNF, Coagulation cascade, Interleukins, Complement, Leukotrienes, Leucocytes, endorphins, platelet activating factors, Lipopolysaccharides.
Abnormal physiology - Plugged capillaries, Abnormal starling’s mechanism, damaged barrier function, abnormal smooth muscle contraction (ileus), blood viscosity changes, AV shunting, altered interstitium, coagulation cascade.
What are the other effects of diarrhea?
Acidosis (Base deficit)
Deep, rabid breathing - leading to complementary respiratory alkalosis.
Increased vomiting, Arterial pH < 7.10, Serum bicarbonate < 10.0mmol/L
Not a problem if renal function (perfusion is normal), otherwise acidosis progresses rapidly.
Potassium deficit
Due to large fecal losses (greatest in infants and undernourished children) of K+. Patient presents with general muscle weakness, cardiac arrhythmias and paralytic ileus (especially with the intake of antimotility drugs to treat acute diarrhea like codeine phosphate, co-phenotrope, Loperamide, Kaolin + morphine mixture.
Not a problem if HCO3 and K+ are lost simultaneously. However if the base deficit is corrected first (with Bicarbonate) without correcting K+ hypokalemia could worsen, unless K+ depletion corrected simultaneously.
