Viral or bacterial gastroenteritis, commonly referred to as a “stomach bug,” is an inflammation of the stomach and intestines causing sudden vomiting and diarrhea. Although usually mild and self-limiting, the illness causes the body to lose significant fluids and electrolytes, which can lead to dehydration. Understanding when this common illness transitions from manageable discomfort to a medical emergency is important for patients and caregivers.
Standard Symptoms and When to Manage at Home
The majority of gastroenteritis cases are caused by viruses, such as norovirus or rotavirus, and resolve on their own within one to three days. Expected symptoms include watery diarrhea, nausea, stomach cramps, and a low-grade fever, generally below 100.4°F (38°C). Vomiting often settles quickly within the first 24 to 48 hours, though diarrhea can persist for several days.
Home management focuses primarily on preventing dehydration. Rest is important, and a bland diet consisting of easily digestible foods like bananas, rice, applesauce, and toast may be tolerated once vomiting stops. Sports drinks, broth, or diluted fruit juice help replace lost water and electrolytes.
Small, frequent sips of fluid are better tolerated than large volumes, especially following an episode of vomiting. The goal is to take in more fluids than are being lost through vomiting and diarrhea. Avoiding sugary or caffeinated drinks is advised, as they can sometimes worsen diarrhea.
Urgent Warning Signs for Adults
Symptoms indicating severe dehydration or other complications require immediate professional medical attention. Adults should seek emergency care if they are unable to keep any liquids down for 12 to 24 hours. This persistent inability to hydrate makes replacing lost fluids impossible.
Severe dehydration is marked by specific signs:
- Urinating infrequently or not at all for eight hours or more.
- Extreme thirst combined with a very dry mouth.
- A rapid heart rate, lightheadedness, or feeling dizzy, particularly when standing up.
- Confusion or an altered mental state.
Other urgent indicators include a persistent high fever above 103°F (39.4°C), suggesting a more serious infection. The presence of blood in the stool or vomit is a serious warning sign, as is vomit that resembles dark “coffee grounds.” Debilitating abdominal pain that is constant, localized, or causes the patient to sit motionless warrants emergency evaluation.
Critical Indicators in Infants and Young Children
The threshold for seeking medical care is lower for infants and young children, who can become dehydrated rapidly. Caregivers must watch for specific signs of fluid loss, as these patients often cannot communicate symptoms effectively. Infants under six months old should see a doctor if they are vomiting or have a fever due to their high risk of dehydration.
The most reliable indicator of dehydration is a reduction in wet diapers. A lack of urination for six to eight hours in toddlers, or only three wet diapers in a 24-hour period for infants, is a red flag. Other physical signs include:
- Absence of tears when crying.
- An overly dry mouth and tongue.
- Eyes that appear sunken into the face.
- A noticeably sunken fontanelle (soft spot) in infants.
Behavioral changes are also a serious concern; extreme listlessness, lethargy, or being unusually sleepy are signs of distress. Persistent vomiting, such as throwing up more than three times in an hour or an inability to keep fluids down for over 24 hours, demands immediate medical assessment. Vomit that is green or yellow-green, or the presence of blood in the stool or vomit, requires emergency care.