Differential Diagnosis for Nausea, Vomiting, and Low-Grade Fever in a Teenager

Single Most Likely Diagnosis

• Viral Gastroenteritis: This is the most common cause of nausea, vomiting, and low-grade fever in teenagers, often due to norovirus or rotavirus infections. The symptoms are usually self-limiting and resolve within a few days.

Other Likely Diagnoses

• Food Poisoning: Bacterial or viral infections from contaminated food can cause similar symptoms. Common culprits include Salmonella, E. coli, and Staphylococcus aureus.
• Influenza: Although more commonly associated with high fever, influenza can present with nausea, vomiting, and low-grade fever, especially in the early stages.
• Appendicitis: Early appendicitis can manifest with nausea, vomiting, and low-grade fever before the onset of more severe abdominal pain.
• Urinary Tract Infection (UTI): UTIs, particularly pyelonephritis, can cause systemic symptoms including nausea, vomiting, and fever.

Do Not Miss Diagnoses

• Meningitis: Although less common, meningitis is a life-threatening condition that can initially present with non-specific symptoms such as nausea, vomiting, and low-grade fever, progressing to severe headache and neck stiffness.
• Septicemia: Bacterial sepsis can cause a wide range of symptoms including nausea, vomiting, and fever. Early recognition and treatment are crucial.
• Pancreatitis: Acute pancreatitis can present with nausea, vomiting, and abdominal pain, and while less common in teenagers, it requires prompt medical attention.
• Pregnancy-related Conditions: In female teenagers, conditions related to pregnancy, such as ectopic pregnancy or hyperemesis gravidarum, must be considered, especially if there's a possibility of pregnancy.

Rare Diagnoses

• Adrenal Insufficiency: Rarely, adrenal insufficiency (Addison's disease) can present with nausea, vomiting, and low-grade fever among other symptoms.
• Thyroid Storm: A life-threatening complication of untreated or undertreated hyperthyroidism, which can cause nausea, vomiting, fever, and other systemic symptoms.
• Cyclic Vomiting Syndrome: A rare condition characterized by recurrent episodes of severe vomiting, often with no apparent cause, and can be associated with low-grade fever.
• Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can present with chronic or recurrent nausea, vomiting, and low-grade fever, among other gastrointestinal symptoms.