Disseminated Intravascular Coagulation (DIC): The patient's elevated D-dimer (4000), prolonged PT (180), and low platelet count (45 k) are all consistent with DIC, a condition often seen in patients with advanced cancer, including cervical cancer. The consumption of clotting factors and platelets in DIC can lead to both bleeding and thrombotic complications.

Thrombotic Thrombocytopenic Purpura (TTP): Although less common, TTP could present with thrombocytopenia and elevated D-dimer. However, TTP typically includes a pentad of symptoms (thrombocytopenia, microangiopathic hemolytic anemia, renal failure, neurological symptoms, and fever), and not all may be present in this patient.
Heparin-Induced Thrombocytopenia (HIT): If the patient has been exposed to heparin, HIT is a possibility, characterized by thrombocytopenia and often an increase in thrombotic events. The elevated D-dimer could be consistent with HIT, especially if the patient has been receiving heparin.

Sepsis: Sepsis can cause DIC and should be considered, especially if there are signs of infection. Sepsis can lead to organ dysfunction and failure if not promptly treated.
Venous Thromboembolism (VTE): An elevated D-dimer can also indicate VTE (deep vein thrombosis or pulmonary embolism), which is a significant risk in cancer patients due to hypercoagulability.

Hemolytic Uremic Syndrome (HUS): Similar to TTP, HUS involves microangiopathic hemolytic anemia and thrombocytopenia but is more commonly associated with renal failure and less frequently with neurological symptoms.
Paroxysmal Nocturnal Hemoglobinuria (PNH): A rare, acquired, life-threatening disease of the blood characterized by the destruction of red blood cells, bone marrow failure, and the potential for thrombotic events. It could present with some similar laboratory findings but is much less common.