How often we diagnose allergy to ranitidine?

H2 receptors' antagonists (H2RA) are widely used drugs and they are generally well-tolerated. Ranitidine hypersensitivity reactions (HR) are rarely reported. The article emphasizes the importance of recognizing ranitidine as a cause of anaphylaxis and the advantages and limits of allergological evaluation to establish a positive diagnose. We reviewed a series of published cases of ranitidine-induced hypersensitivity reactions, starting from a clinical case presentation. Moreover, we analyzed the ranitidine related adverse events in the Eudravigilance European database of adverse reactions. Most of the allergic reactions induced by ranitidine are type I HR with immediate onset after exposure, with variable clinical presentation. But in a few cases, there were also described delayed reactions, some after occupational exposure. The article underlines the importance of allergy evaluation to avoid future contact with the drug to reduce the risk of more severe reactions. The suspected reactions should be reported, allowing pharmacovigilance systems to analyse them and to establish further recommendations for clinicians.

Staging of portal hypertension and portosystemic shunts using dynamic nuclear medicine investigations.

AIM: To explore portal hypertension and portosystemic shunts and to stage chronic liver disease (CLD) based on the pathophysiology of portal hemodynamics. METHODS: Per-rectal portal scintigraphy (PRPS) was performed on 312 patients with CLD and liver angioscintigraphy (LAS) on 231 of them. The control group included 25 healthy subjects. We developed a new model of PRPS interpretation by introducing two new parameters, the liver transit time (LTT) and the circulation time between right heart and liver (RHLT). LTT for each lobe was used to evaluate the early portal hypertension. RHLT is useful in cirrhosis to detect liver areas missing portal inflow. We calculated the classical per-rectal portal shunt index (PRSI) at PRPS and the hepatic perfusion index (HPI) at LAS. RESULTS: The normal LTT value was 24 +/- 1 s. Abnormal LTT had PPV = 100% for CLD. 27 non-cirrhotic patients had LTT increased up to 35 s (median 27 s). RHLT (42 +/- 1 s) was not related to liver disease. Cirrhosis could be excluded in all patients with PRSI < 5% (P < 0.01). PRSI > 30% had PPV = 100% for cirrhosis. Based on PRPS and LAS we propose the classification of CLD in 5 hemodynamic stages. Stage 0 is normal (LTT = 24 s, PRSI < 5%). In stage 1, LTT is increased, while PRSI remains normal. In stage 2, LTT is decreased between 16 s and 23 s, whereas PRSI is increased between 5% and 10%. In stage 3, PRSI is increased to 10%-30%, and LTT becomes undetectable by PRPS due to the portosystemic shunts. Stage 4 includes the patients with PRSI > 30%. RHLT and HPI were used to subtype stage 4. In our study stage 0 had NPV = 100% for CLD, stage 1 had PPV = 100% for non-cirrhotic CLD, stages 2 and 3 represented the transition from chronic hepatitis to cirrhosis, stage 4 had PPV = 100% for cirrhosis. CONCLUSION: LTT allows the detection of early portal hypertension and of opening of transhepatic shunts. PRSI is useful in CLD with extrahepatic portosystemic shunts. Our hemodynamic model stages the evolution of portal hypertension and portosystemic shunts. It may be of use in the selection of patients for interferon therapy.

Nuclear medicine dynamic investigations of diffuse chronic liver diseases and portal hypertension.

Radio-isotopic techniques may be useful in diagnosis and staging of chronic diffuse liver diseases. Liver angioscintigraphy (LAS) and per-rectal portal scintigraphy (PRPS) are at well discriminating portal hypertension (PHT), very early cirrhosis hemodynamic failure and compensatory arterialisation of liver perfusion. Supplied information is related to PHT, liver morphology and mesenchimal activity in liver, spleen and bone marrow. Correlation of LAS and PRPS may diagnose installing of PHT earlier than any actual morphologic imagistic method. Our experience (after more than 300 PRPS and 500 LAS) suggests that PHT and portal-cave shunts (PCS) may be classified in five functional stages. These five patterns (types) are characteristic for portal dynamics, supporting disease staging and follow-up of evolution to cirrhosis. All five dynamics may be assessed by PRPS and LAS. Scintigraphic techniques also explore portal thromboses, perfusion differences between the lobes of cirrhotic liver, betablockers effect in PHT, earliest stages of PHT, malignant tumours occurring on cirrhosis, the different characteristics of alcoholic liver comparing to viral etiology.

Liver angioscintigraphy: clinical applications.

Liver angioscintigraphy (LAS) is a radio-isotope method for the investigation of liver perfusion and its alteration in various hepatic diseases. It measures the arterial and portal venous fractions of total liver blood flow. The percentage of liver blood flow supplied by hepatic artery is estimated mathematically by the hepatic perfusion index (HPI), normally between 25 % and 40 %. The decrease of portal blood flow in liver cirrhosis is compensated ("buffer" mechanisms) by increased arterial supply, with higher HPI value. For a patient with chronic liver disease, HPI over 50% suggests arterialization of hepatic perfusion, guiding the diagnose to liver cirrhosis. Splenic curve is completing the diagnostic information of the hepatic curve. Corroborated with per rectal scintigraphy and liver SPECT, LAS offers a good hemodynamic staging of chronic inflammatory liver diseases. Malignant tumors (primitive or metastases) increase the arterial supply of the liver and decrease the portal flow, HPI being over 50% (currently 65 % - 90 %). Benign tumors do not change portal/arterial liver blood flow ratio. SPECT or non-scintigraphic morphological investigations increase the diagnostic value of LAS for primitive liver tumors. Liver cancer occurring on cirrhosis is a limitative factor for LAS. Hepatic metastases increase the arterial perfusion (and HPI value) very quickly, before their size allows morphologic imaging diagnosis. LAS is therefore an early method to diagnose liver metastases being especially used in colorectal cancer. Other clinical applications of LAS are: follow up of liver toxicity of drugs, evaluation of portal vein permeability, post surgery follow up of the liver tumor patients.