Bleeding and Coagulation Disorders | Mnemonics And Proven Ways To Memorize for the PANCE, PANRE

Bleeding and Coagulation Disorders Overview

This note includes information on various bleeding and coagulation disorders, with a focus on Hemophilia A, Hemophilia B, von Willebrand disease, Factor V Leiden, and Protein C and S deficiency. Understanding the pathophysiology of these conditions is crucial, as it simplifies the details needed for exams and clinical practice.

Hemophilia A

• Prevalence: Hemophilia A is the most common type of hemophilia, affecting approximately 1 in 5,000 male births. However, it is not the most common bleeding disorder overall, as other conditions like von Willebrand disease are more prevalent in the general population.

• Inheritance: This disorder follows an X-linked recessive pattern, primarily affecting males due to having a single X chromosome. Females can be carriers if they have one affected X chromosome, but they typically do not present with symptoms. Cases where females exhibit symptoms are rare and usually occur only when both X chromosomes are affected (a condition known as manifesting carriers).

• Memory Aid: To help remember the association with males, think of "hemophilia" and envision "Phil" (like Dr. Phil), as the majority of cases present in boys and men.

Pathophysiology

• Deficiency: Hemophilia A is characterized by a deficiency in Factor VIII, which is essential for proper blood coagulation.

• Coagulation Cascade Role: Factor VIII functions within the intrinsic pathway of the coagulation cascade, contributing significantly to normal clot formation and hemostasis.

Clinical Manifestations

• Common Bleeding Sites: Patients frequently experience bleeding in various areas, including:

  • Gastrointestinal tract (GI bleeding)

  • Urinary tract (hematuria)

  • Mucosal membranes (easy bruising and bleeding gums)

  • Intracranial regions (risk of severe complications)

• Unique Presentation: The most characteristic symptom of Hemophilia A is hemarthrosis, which refers to bleeding into the joints. This occurs in approximately 80% of cases and can lead to chronic joint issues if not managed appropriately.

  • Clinical Vignette: A typical patient scenario might involve a young boy who presents with a swollen knee after a minor injury, such as bumping his leg on the playground, indicative of hemarthrosis.

Diagnosis

• Lab Findings:

  • Prothrombin Time (PT): Normal levels are observed in most cases.

  • Partial Thromboplastin Time (PTT): Prolonged levels are indicative of Hemophilia A, reflecting the deficiency of intrinsic pathway factors, especially Factor VIII.

  • Additional Testing: A Factor VIII assay may confirm the diagnosis by revealing decreased or absent levels of Factor VIII. It's important to note that mild cases of Hemophilia A might present with normal PTT, making assay testing essential for accurate diagnosis.

Treatment

• Management Options:

  • Factor VIII Infusions: These are critical for patients, serving both as prophylaxis to prevent bleeding episodes and as a treatment for acute bleeding incidents.

  • Desmopressin (DDAVP): This is the first-line treatment for mild cases of Hemophilia A. It acts by stimulating the release of von Willebrand factor from endothelial cells, which helps stabilize Factor VIII and reduces its degradation in circulation.

  • Important Note: DDAVP is not effective in treating Hemophilia B, as it does not interact with Factor IX, the deficient factor in that condition.

Key Takeaways for Hemophilia A

• Hemophilia A is associated with a deficiency of Factor VIII, primarily diagnosed in male patients.

• Laboratory findings typically show elevated PTT with normal PT.

• Treatment includes Factor VIII replacement therapy and possibly DDAVP for mild cases.

Hemophilia B

• Comparison to Hemophilia A: Hemophilia B shares many similarities with Hemophilia A but differs mainly in the affected clotting factor (Factor IX vs. Factor VIII) and its prevalence, which is less common than Hemophilia A. Patients with Hemophilia B also present with similar bleeding symptoms, but the treatment modalities, along with certain clinical manifestations, may vary considerably.