This patient is presenting with asymptomatic hypocalcemia and deep venous thrombosis (DVT), suggesting a diagnosis of nephrotic syndrome.
Nephrotic syndrome occurs when large amounts of protein are lost in the urine. This can lead to hyperlipidemia (due to loss of lipoproteins), hypercoagulable state (due to loss of antithrombin III and protein C/S), and hypoalbuminemia. Most serum calcium is bound to albumin, so when albumin is lost in the urine, it can lead to profound hypocalcemia. However, the ionized or free portion of calcium remains the same; therefore, these patients do not exhibit symptoms of hypocalcemia.
Answer 1: Factor V Leiden is the most common cause of a hypercoagulable state. This is a possible explanation for this patient's DVT, however, it does not explain her profound hypocalcemia.
Answer 2: Antithrombin III deficiency is a common cause of a hypercoagulable state. This is a possible explanation for this patient's DVT, however, it does not explain her profound hypocalcemia.
Answer 3: Prothrombin gene mutation could explain this patient's hypercoagulable state; however, it does not explain the laboratory abnormalities.
Answer 4: Liver dysfunction is possible given this patient's history of alcohol use and IV drug abuse, placing her at risk for chronic hepatitis C infection. This patient has no other stigmata of liver failure such as jaundice or ascites, making nephrotic syndrome more likely.
Nephrotic syndrome can present with a hypercoagulable state due to loss of antithrombin III and protein C/S, electrolyte abnormalities, and profound hypocalcemia from loss of albumin in the urine.