Differential Diagnosis for a 3-Day-Old Girl with Irritability
- Single Most Likely Diagnosis
- Dehydration: The patient's refusal to feed, significant weight loss (5% from birth), and irritability are key indicators of dehydration in a newborn. The soft anterior fontanelle also supports this diagnosis, as dehydration can lead to a decrease in intracranial pressure.
- Other Likely Diagnoses
- Infection (e.g., sepsis, meningitis): Although the patient's temperature is normal, the leukocyte count is low (3,000/mm3), which could indicate a possible infection, especially in the context of irritability and refusal to feed. Newborns can present with non-specific symptoms, and infection should always be considered.
- Hypoglycemia: With a glucose level of 70 mg/dL, which is on the lower end for a newborn, hypoglycemia could be contributing to the patient's irritability and refusal to feed. However, the level is not critically low, and other symptoms such as lethargy are not mentioned.
- Do Not Miss Diagnoses
- Congenital Heart Disease: The patient's tachycardia (pulse of 180/min) could be indicative of congenital heart disease, which is a critical diagnosis not to miss. Although the cardiac examination reveals no murmurs, some forms of congenital heart disease may not present with murmurs immediately after birth.
- Metabolic Disorders: Certain metabolic disorders can present in the neonatal period with non-specific symptoms such as irritability and refusal to feed. These disorders can be life-threatening if not identified and treated promptly.
- Bacterial Meningitis: This is a critical diagnosis to consider in any newborn presenting with irritability and refusal to feed, even without specific signs of meningismus, due to its high morbidity and mortality if not treated promptly.
- Rare Diagnoses
- Neonatal Abstinence Syndrome: If the mother has a history of substance use, neonatal abstinence syndrome could be a consideration, although it typically presents with more specific symptoms such as tremors and hyperreflexia.
- Spinal Cord or Brain Injury: Although less likely, any form of injury to the spinal cord or brain during delivery could potentially cause irritability and refusal to feed, especially if there was a complicated delivery, which is not indicated in this case.