Caesarean section in a patient with protein S deficiency

Abstract

SummaryProtein S is a nonenzymatic and vitamin K-dependent cofactor of activated protein C. Without protein S, the anticoagulant function of protein C is almost depleted and thrombotic events occur. We report a parturient with hereditary protein S deficiency in whom the risk of thromboembolism was further complicated by pregnancy and who required emergency Caesarean section for fetal distress. Key wordsComplications; protein S deficiency, thrombosis. Anaesthesia; obstetric.Protein S, discovered in 1977 [l], is a nonenzymatic and vitamin K dependent cofactor of activated protein C [2,3].Hereditary deficiency is an autosomal dominant disorder and is associated with familial thrombosis [4,5]. Protein S in plasma is in two forms: 40% is in the free form, the remainder is bound to a complement cofactor, the C4b-binding protein. The functional activity of protein S corresponds, for the most part, to the free form [6]. Clinical manifestations of protein S deficiency include leg vein thrombosis, pulmonary embolism, superficial thrombophlebitis and thromboses in uncommon sites [7,8].Patients undergoing surgery are already at high risk of developing deep venous thrombosis and pulmonary embolism [9]. Normal pregnancy is also associated with hypercoagulable changes in the haemostatic system [ 101, and is one cause of acquired deficiency of protein S [I 1, 121. There have been no reports of the anaesthetic management of a patient with protein S deficiency and none in which all the above risk factors were present. We report a patient with hereditary protein S deficiency who had an emergency Caesarean section and discuss the anaesthetic implications of the condition. Case historyA 30-year-old primipara (gestation 39 weeks, weight 75 kg) was admitted to our hospital because of premature rupture of the membranes. Four years previously her sister's pregnancy had been complicated by a left vertebral artery thrombosis which occurred one week after delivery. After investigation of the family for a possible thrombotic tendency (her parents had two sons and five daughters), all members except her mother and one brother were found to have protein S deficiency using immunological assays.Prenatal examination of protein S levels 2 months before this admission showed aggravation of the deficiency (total: 90%; free form: 33%; functional form: 31% of normal control; Table 1). During admission, laboratory data including platelet count and routine biochemistry were within the normal range. However, the amount and function of protein S was further decreased (total: 76%; free form: 30%; functional form: 16% of normal control; Table I). Subcutaneous heparin 5000 IU 8-hourly was prescribed by the haematologist to prevent thrombosis. Oxytocin was administered intravenously for induction of labour, but after 2 days, emergency Caesarean section was undertaken because of fetal distress and prolonged labour.At the pre-operative anaesthetic assessment, the prothrombin time and partial thromboplastin time 4 h previously showed 11.0 (control 11.9) s and 4...

Anaesthetic Management of the Parturient with Protein S Deficiency and Lumboperitoneal Shunt

“…Protein C inhibits the coagulation cascade by inactivating factors Va and VIIIa 4 and accelerates clot lysis, whilst protein S, the cofactor of protein C, enhances this property of anticoagulation 5 . A physiological decrease in total and free protein S is seen in pregnancy and the post partum period, predisposing to venous thrombosis.…”

Chronic Subdural Haematoma following Caesarean Section under Spinal Anaesthesia

“…Hereditary deficiency is an autosomal dominant disorder and is associated with familial thrombosis 19 . Normal pregnancy is one of the causes of an acquired deficiency of protein S and the normal decrease in functional protein S activity during the early puerperium may be partly responsible for an increased risk of postpartum thrombotic episodes 19,20 21 . Spinal anaesthesia should be planned carefully, and timed to avoid the effects of prophylactic heparin 22 .…”

“…Without protein S, the anticoagulant function of protein C is almost depleted. Hereditary deficiency is an autosomal dominant disorder and is associated with familial thrombosis 19 . Normal pregnancy is one of the causes of an acquired deficiency of protein S and the normal decrease in functional protein S activity during the early puerperium may be partly responsible for an increased risk of postpartum thrombotic episodes 19,20 21 .…”