Differential Diagnosis for a 14-year-old with Heavy Periods, Easy Bruising, and Prolonged Bleeding from Cuts

Single Most Likely Diagnosis

• Von Willebrand Disease (VWD): This condition is the most common inherited bleeding disorder and is characterized by easy bruising, heavy menstrual periods (menorrhagia), and prolonged bleeding after injury. The normal platelet count, PTT, PT, and fibrinogen levels do not rule out VWD, as the disorder primarily affects the von Willebrand factor, which is not directly measured by these tests.

Other Likely Diagnoses

• Platelet Function Disorders: Although the platelet count is normal, disorders affecting platelet function (such as Bernard-Soulier syndrome or platelet storage pool defects) can lead to easy bruising and prolonged bleeding. These conditions often require specific tests to diagnose.
• Hormonal Imbalance: Hormonal changes, particularly those affecting the balance between estrogen and progesterone, can lead to heavy periods. However, this would not typically explain easy bruising or prolonged bleeding from cuts unless there's an associated coagulopathy.

Do Not Miss Diagnoses

• Bleeding Disorders Due to Medications: Certain medications (e.g., aspirin, NSAIDs) can affect platelet function or the coagulation cascade, leading to bleeding symptoms. It's crucial to inquire about any medication use.
• Liver Disease: Although less common in adolescents, liver disease can lead to coagulopathy due to decreased production of clotting factors. Normal PT, PTT, and fibrinogen levels make this less likely but do not rule it out entirely, especially if there's significant liver dysfunction.
• Vitamin K Deficiency: This can lead to a coagulopathy characterized by easy bruising and bleeding, despite normal platelet counts. However, PT and PTT would typically be elevated.

Rare Diagnoses

• Factor XIII Deficiency: A rare bleeding disorder that can cause prolonged bleeding after trauma or surgery, despite normal PT, PTT, and platelet counts.
• Glanzmann's Thrombasthenia: A rare inherited platelet disorder characterized by the inability of platelets to aggregate, leading to bleeding symptoms.
• Ehlers-Danlos Syndrome: A group of disorders that affect connective tissues supporting the skin, bones, blood vessels, and many other organs and tissues. Some types can lead to easy bruising and bleeding due to fragile blood vessels.

Each of these diagnoses requires careful consideration of the patient's clinical presentation, laboratory results, and sometimes specific diagnostic tests to confirm the diagnosis.