Differential Diagnosis for Breast Discharge
- Single most likely diagnosis
- Hyperprolactinemia: The patient's recent increase in risperidone, an antipsychotic medication known to cause hyperprolactinemia as a side effect, is a strong clue. Hyperprolactinemia can lead to galactorrhea (spontaneous milk production) and nipple discharge, which fits the patient's symptoms.
- Other Likely diagnoses
- Infectious mastitis: Although the culture grew bacteria sensitive to Bactrim DS, the fact that the discharge is bilateral and has been ongoing for three months makes this less likely as the primary cause. However, it could be a contributing factor or a secondary infection.
- Ductal ectasia: This condition involves the widening of milk ducts and can cause nipple discharge, often bilateral. It's more common in older women but can occur in younger women as well.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Pituitary tumor (prolactinoma): Although less likely than hyperprolactinemia caused by medication, a pituitary tumor could cause elevated prolactin levels leading to nipple discharge. Missing this diagnosis could have significant consequences due to the potential for the tumor to cause other serious health issues.
- Breast cancer: While rare in a 19-year-old, breast cancer can cause nipple discharge. It's essential to rule out this possibility, especially if other risk factors or symptoms are present.
- Rare diagnoses
- Thyroid disorders: Both hypothyroidism and hyperthyroidism can cause changes in menstrual cycles and potentially lead to galactorrhea, although this is less common.
- Idiopathic galactorrhea: This diagnosis is made when galactorrhea occurs without an identifiable cause. It could be considered if all other potential causes are ruled out.