Cryosupernatant as replacement fluid for plasma exchange in thrombotic thrombocytopenic purpura

The current established treatment of thrombotic thrombocytopenic purpura (TTP) is plasma exchange with fresh frozen plasma (FFP). With this treatment, there is a 49% response after seven exchanges and a 78% survival at 1 month. Although the exact cause of TTP is unknown, the presence of von Willebrand factor (VWF) multimers has been implicated in the disease. Accordingly, it has been suggested that cryosupernatant (plasma from which cryoprecipitate has been removed), which is relatively deficient in VWF multimers, might be an effective replacement fluid during plasma exchange.
Patients from six centres were treated by plasma exchange with cryosupernatant. 18 patients who had failed a first course (average 7.7 exchanges) of plasma exchange with FFP, received a further seven exchanges with cryosupernatant. Subsequently, 40 previously untreated patients were exchanged with cryosupernatant.
Of the 18 previously treated patients, 11 responded (defined as an increase in platelet count to >150 × 10⁹/l and no neurological events) after seven exchanges and 15 (83%) of the patients were alive at 1 month. The response rate in the 40 previously untreated patients was 75% at the end of seven exchanges and 95% of the patients were alive at 1 month. These values are significantly different ( P <0.05) from those reported in our earlier study and in other patients concurrently treated at the same centres with FFP when cryosupernatant was not available.
Some patients who have failed to respond to plasma exchange with FFP replacement will respond to further exchange with cryosupernatant. Cryosupernatant replacement may be more effective as first-line treatment of TTP than FFP.     

When Ventricular Safety Standby Does Not Work

Dual chamber pacemakers have inbuilt advanced safety systems such as ventricular safety standby (crosstalk detection) to prevent ventricular oversensing resulting in inappropriate pacing inhibition. We describe a case where this safety mechanism does not reliably work and the management required to rectify the situation in an educational format.     

Radiological appearance of pancreatic calculi in tropical versus alcoholic chronic pancreatitis

Tropical and alcoholic forms of chronic pancreatitis differ in their clinical, aetiological and epidemiological features. We compared the radiological appearances of pancreatic calculi seen on plain roentgenogram of the abdomen of 89 patients with tropical calcific pancreatitis (TCP) and 32 patients with alcoholic calcific pancreatitis (ACP) seen in Madras, Southern India. While TCP was characterized by the frequent occurrence of large, discrete, dense calculi, patients with ACP had typically small, speckled calculi with irregular, hazy margins. The calculi in TCP resembled those described for hereditary pancreatitis. This is the first report comparing the radiological appearances of TCP and ACP patients seen at the same centre.