Acute diarrhea in a child means looser or more liquid stools than usual, or more frequent stools. It typically means at least 3 stools in 24 hours, for less than 7 days, with or without fever or vomiting.
Does the count mean the same in a baby?
The count is the working test, but a young infant’s normal stool pattern varies considerably. So in the first months of life, the change in consistency is the more informative signal.
Is this the same as gastroenteritis?
An infant’s loose stools raise the next question: which illness usually travels with them? Acute gastroenteritis is the syndrome that usually travels with acute diarrhea: acute diarrhea with or without vomiting, fever or abdominal pain. It is generally of infectious origin. In practice the labels acute diarrhea and acute gastroenteritis are used interchangeably.
How long does it last, and when is it no longer acute?
The illness is short, so the next question is where the acute problem ends. Acute diarrhea typically lasts less than 7 days and does not extend beyond 14 days. Beyond the 14-day boundary the problem is different, and so is the differential. The malabsorption categories considered are celiac disease, cow’s-milk protein allergy, inflammatory bowel disease and congenital transport defects. None of them is settled by rehydrating the child. Persistent diarrhea is a separate workup and is deliberately out of scope here.
Is the illness usually serious?
The time frame is short, but how serious is it? Most children in Europe with acute gastroenteritis have a mild, self-limited illness. Mild cases are managed at home with oral rehydration, which means drinking a solution of salts and glucose that replaces what the stools remove. The minority who deteriorate do so because losses continue faster than they are replaced.
What decides the plan, if not the germ?
If losses are what matter, the germ is not the first question. The stool carries water and salts out of the body, and the harm of the illness usually follows that loss. That is why what changes management is rarely which organism is responsible. What changes management is how much fluid the child has already lost, how fast more fluid is being lost, and whether replacement should be oral, nasogastric or intravenous. Each of the following notes answers one part of that question.
What does each note teach?
The notes follow the order in which a child is seen. Assessment comes first, then the tests that follow from it. Treatment follows the order a child would receive it: admission and resuscitation, the fluid phases, then feeding and drugs. The last two notes turn to what can still go wrong and to prevention.
- Pathophysiology of Acute Diarrhea and Dehydration: how the intestine normally handles water, the osmotic and secretory mechanisms that interrupt it, and why children lose fluid faster than adults.
- Etiology and Risk Factors of Acute Diarrhea in Children: which organisms cause most childhood diarrhea in Europe, their clinical patterns, and which children run a higher risk of severe dehydration.
- Clinical Assessment of Acute Diarrhea and Dehydration: grading the severity of dehydration at the bedside, the signs that carry the most weight, and recognising hypernatremia before the laboratory result returns.
- Investigations in Acute Diarrhea and Dehydration: when a stool specimen is worth sending, why inflammatory markers cannot separate bacterial from viral illness, and when electrolytes or glucose change the plan.
- Admission and Shock Management in Acute Diarrhea: when a child should be admitted, when oral rehydration fails, and how shock is recognised and resuscitated.
- Rehydration Management in Acute Diarrhea: the order of the fluid phases, the arithmetic behind each volume, which solution belongs in which phase, and how fast sodium may be corrected.
- Refeeding and Drug Therapy in Acute Diarrhea: when and what to feed, why breastfeeding continues throughout, and where probiotics, racecadotril and antibiotics do and do not belong.
- Complications and Outcome of Acute Diarrhea and Dehydration: the usual course of the illness, the complications that change management, and which problems settle on their own.
- Prevention of Acute Diarrhea and Dehydration: rotavirus vaccination, household and day-care hygiene, breastfeeding, and home measures that keep a mild illness from becoming a severe one.
Where should a new reader start?
After the list, the reader needs a route in. If the topic is new, start with the pathophysiology note, which asks why a child with diarrhea loses fluid and what in the illness causes it.