From the Guidelines
Histological examination is a crucial diagnostic tool that should be used when other diagnostic tests have failed to identify a definitive diagnosis, as it can provide valuable information on tissue structure and function, with sensitivity and specificity thresholds of >50%. When interpreting histological results, it is essential to consider the clinical context to minimize the impact of false results 1. The process of histological examination involves preparing thin sections of tissue samples, staining them with specific dyes, and examining them under a microscope to identify cellular and extracellular components. Some of the key techniques used in histology include:
- Hematoxylin and eosin (H&E) staining for general tissue structure
- Periodic acid-Schiff (PAS) staining for carbohydrates
- Immunohistochemistry for specific proteins Understanding histology is fundamental to comprehending normal physiology and pathological processes in the body. In the context of liver disease, liver biopsy is an important diagnostic tool that can provide information on the severity of disease, guide treatment decisions, and monitor disease progression 1. The British Society of Gastroenterology, the Royal College of Radiologists, and the Royal College of Pathology have published guidelines on the use of liver biopsy in clinical practice, which emphasize the importance of providing a detailed histopathology report that includes clinical information, biopsy size and adequacy, architecture, and a systematic description of histological abnormalities 1. In terms of specific diseases, histological examination can be used to diagnose and manage conditions such as autoimmune hepatitis, where liver biopsy is considered a prerequisite for diagnosis and can provide information on the severity of disease and guide treatment decisions 1. Overall, histological examination is a powerful diagnostic tool that can provide valuable information on tissue structure and function, and should be used in conjunction with other diagnostic tests to guide clinical decision-making. The most recent and highest quality study on this topic is the 2020 guidelines on the use of liver biopsy in clinical practice from the British Society of Gastroenterology, the Royal College of Radiologists, and the Royal College of Pathology 1.
From the Research
Histology and Desmopressin
- Desmopressin is a synthetic vasopressin analogue that increases plasma concentrations of coagulation factor VIII and von Willebrand factor 2, 3, 4, 5, 6
- It is used as a hemostatic agent in patients with mild hemophilia A, von Willebrand disease, and other bleeding disorders 2, 3, 4, 5, 6
- The drug has been shown to be effective in preventing and treating bleeding episodes, and can be administered intravenously, subcutaneously, or intranasally 2, 3, 5, 6
Mechanism of Action
- Desmopressin works by stimulating the release of factor VIII and von Willebrand factor from storage sites, resulting in a 2-6 fold increase in plasma concentrations 2, 4, 6
- The increase in factor VIII and von Willebrand factor levels typically lasts for 8 hours, after which they return to baseline 6
Clinical Use
- Desmopressin is the treatment of choice for patients with mild hemophilia A and von Willebrand disease, and can be used to prevent bleeding episodes during invasive procedures 2, 3, 6
- A test dose is recommended to assess the patient's response to desmopressin, as not all patients will respond sufficiently 2, 6
- The optimal dosage of desmopressin is 0.3 microg/kg given intravenously, and an intranasal spray is available for home treatment 2, 5