Differential Diagnosis for a 42-year-old Woman with Abnormal Bleeding

Single Most Likely Diagnosis

• Dysfunctional Uterine Bleeding (DUB): This condition is characterized by abnormal uterine bleeding that is not associated with any other recognizable pathology. Given the patient's age, the absence of pregnancy (negative HCG), and the pattern of bleeding, DUB is a plausible explanation. The heavy bleeding and the need for frequent pad changes also support this diagnosis.

Other Likely Diagnoses

• Uterine Fibroids: These are common in women of this age group and can cause heavy, prolonged menstrual bleeding, and pelvic discomfort.
• Endometrial Hyperplasia: This condition, often associated with anovulatory cycles, can lead to irregular and heavy bleeding.
• Thyroid Dysfunction: Both hypothyroidism and hyperthyroidism can cause menstrual irregularities, including heavy bleeding.

Do Not Miss Diagnoses

• Malignancy (Endometrial or Cervical Cancer): Although less likely, it is crucial to rule out cancer, especially given the patient's age and the presence of abnormal bleeding. Endometrial cancer can present with postmenopausal or irregular bleeding in premenopausal women.
• Pregnancy-Related Complications (Despite Negative HCG): Although the HCG is negative, it's essential to consider the possibility of a very early pregnancy or a rare condition like a molar pregnancy, especially if the patient reports any symptoms suggestive of pregnancy.
• Bleeding Disorders: Conditions like von Willebrand disease can cause heavy menstrual bleeding.

Rare Diagnoses

• Adenomyosis: A condition where tissue similar to the lining inside the uterus grows into the muscular walls of the uterus, leading to heavy bleeding and pelvic pain.
• Uterine Arteriovenous Malformation (AVM): A rare condition that can cause heavy, life-threatening bleeding.
• Systemic Diseases (e.g., Bleeding Disorders, Coagulopathy): Certain systemic conditions can manifest with heavy menstrual bleeding as one of the symptoms.

Each of these diagnoses should be considered and investigated based on the patient's full clinical presentation, medical history, and the results of diagnostic tests.