A 6 month old male patient presents to your clinic with his mother. The mother’s chief complaint is that the baby has had a fever and diarrhea for several days and is not nursing as much as usual. The infant is quiet and warm, lung sounds are clear, heart sounds normal. No medical history, born healthy at 39 weeks 5 days via uncomplicated vaginal delivery, he is exclusively breast fed and is up-to-date on his vaccinations.


The case of a 6-month-old male patient with fever, diarrhea, and decreased breastfeeding raises concerns about potential underlying causes. This assignment aims to analyze the probable causes of these symptoms and their respective diagnostic approaches.

Potential Causes of Fever and Diarrhea in a 6-month-old Infant

The combined presence of fever and diarrhea in an infant can stem from various infectious and non-infectious etiologies. In this case, it is essential to consider the most common causes first, such as viral and bacterial infections.

1. Viral Infections: Viral gastroenteritis is a prevalent cause of diarrhea in infants. Rotavirus, specifically, is a leading cause of severe diarrhea and dehydration in young children. The clinical presentation often includes fever, vomiting, and watery diarrhea.

2. Bacterial Infections: Bacterial gastroenteritis can result from ingestion of contaminated food or water. Common bacterial pathogens include Escherichia coli, Salmonella, and Shigella. Symptoms typically include fever, bloody or mucoid diarrhea, and abdominal pain.

3. Urinary Tract Infection (UTI): Fever and diarrhea can also be indicative of a urinary tract infection in infants. However, UTI-associated diarrhea is often associated with additional symptoms such as foul-smelling urine, irritability, and poor feeding.

4. Teething: The eruption of primary teeth is a natural developmental process that can cause low-grade fever and loose stools. Although teething can potentially be associated with mild gastrointestinal disturbances, it is generally considered a benign condition.

5. Medication Side Effects: Certain medications, such as antibiotics, can cause gastrointestinal disturbances and diarrhea. A thorough medication history is crucial to identify potential side effects.

Diagnostic Approach

To accurately diagnose the cause of fever and diarrhea in the 6-month-old patient, the following diagnostic tests and evaluations are recommended:

1. Physical Examination: A comprehensive physical examination should be performed, with particular attention to the gastrointestinal and genitourinary systems. Abdominal palpation may reveal tenderness or other signs of inflammation.

2. Stool Analysis: A stool sample should be collected and analyzed for the presence of bacteria, parasites, or other pathogens. This can be achieved through microscopy, culture, and molecular testing methods (such as polymerase chain reaction).

3. Urine Analysis: A urine sample should be obtained to rule out the possibility of a urinary tract infection. Urine dipstick testing, microscopic examination, and urine culture can aid in the diagnosis.

4. Blood Tests: A complete blood count (CBC) may be useful in identifying any signs of infection, such as an elevated white blood cell count. Additionally, assessing liver and kidney function, as well as electrolyte levels, can provide valuable insights.

5. Viral Testing: Since viral infections are common causes of diarrhea in infants, specific viral tests (such as the detection of rotavirus or other enteric viruses) may be appropriate. These tests can be conducted using molecular techniques like enzyme immunoassays or polymerase chain reaction.

6. Evaluation for Other Causes: If initial tests do not yield conclusive results, additional diagnostic evaluations may be necessary. These can include imaging studies (such as an abdominal ultrasound) or further specialist consultations.


The case of a 6-month-old male patient with fever, diarrhea, and decreased breastfeeding requires a systematic diagnostic approach to identify the underlying cause accurately. Considering the potential infectious causes, conducting relevant laboratory tests, including stool analysis and viral testing, can help in determining the exact etiology. Additionally, evaluating for other causes, such as urinary tract infections or medication side effects, is essential to ensure comprehensive care for the patient.