Gastroenteritis:
Often caused by viruses (such as norovirus or rotavirus) or bacteria (such as Salmonella or E. coli), gastroenteritis leads to inflammation of the stomach and intestines, resulting in symptoms like diarrhea, vomiting, abdominal cramps, and nausea.
Appendicitis
This occurs when the appendix becomes inflamed, usually due to blockage by stool, a foreign body, or infection. It can cause severe abdominal pain, fever, nausea, vomiting, and loss of appetite.
Hepatitis:
Hepatitis can result from viral infections (such as hepatitis A, B, or C viruses) or other causes, leading to inflammation of the liver. Symptoms may include abdominal pain (especially in the upper right quadrant), jaundice (yellowing of the skin and eyes), fatigue, nausea, vomiting, and loss of appetite.
Peptic Ulcer Disease:
Peptic ulcers are open sores that develop on the lining of the stomach, small intestine, or esophagus. Helicobacter pylori infection or prolonged use of nonsteroidal anti-inflammatory drugs (NSAIDs) can contribute to their development. Symptoms may include abdominal pain (usually in the upper abdomen), bloating, nausea, vomiting, and appetite changes.
Gallstones
Hardened deposits in the gallbladder can block the flow of bile, causing intense abdominal pain (biliary colic), nausea, vomiting, and jaundice.