Pathology at a Glance

Barry Newell, Asma Z. Faruqi, Caroline Finlayson

• Publisher: Wiley-Blackwell
• Year: 2021
• ISBN:
  9781119472469
• Edition: 2
• Topic: Medizin
• Subtopic: Medizinische Theorie, Praxis & Referenz

Following the familiar, easy-to-use at a Glance format and in full-colour, Pathology at a Glance is an accessible introduction and revision text for medical students. Reflecting changes to the curriculum content and assessment methods employed by medical schools, this new edition provides a user-friendly overview of pathology to encapsulate all that the student needs to know.

Pathology at a Glance, Second Edition:

• Addresses the key principles of pathology that are central to medicine
• Contains full-colour artwork throughout, making the subject easy to understand
• Presents schematic diagrams on the left page and concise explanations on the right
• Is divided into three sections, covering general and systematic pathology and clinical case examples
• Contains self-assessment material, including 10 structured case study questions
• Covers general pathology mechanisms and the clinical pathology of body systems
• Provides key information on the epidemiology, pathogenesis and clinical features of the major diseases
• Revision of many chapters, particularly gynaecological pathology, acute cardiac syndromes, paediatric tumours and haematopathology

This book is an invaluable resource for all medical students, of equal benefit for those starting their study of pathology or approaching finals; for junior doctors approaching their membership exams and anybody who needs a handy reference.

Systems pathology

Multisystems disease

32 Sarcoidosis and syphilis

Sarcoidosis

Definition

Sarcoidosis is a chronic, multisystem granulomatous disease of uncertain aetiology.

Epidemiology

The prevalence is 10–40 per 100 000. The presentation is usually between 20 and 40 years and the disease is slightly more common in females. The condition is found worldwide, but the highest incidence is in Scandinavia. Afro‐Caribbeans have a higher incidence.

Pathology

The disease is characterised by the presence of non‐caseating granulomas that can develop in a wide variety of organs. Fibrosis may accompany the granulomatous response.

The granulomas are typically described as ‘naked’ in that there is little associated lymphocytic infiltrate. The macrophages within the granulomas may also include concretions known as asteroid bodies and Schaumann bodies. However, none of these features, either alone or in combination, is diagnostic of sarcoidosis. Furthermore, it is possible for the granulomas to show necrosis. Therefore, histology alone cannot offer an unequivocal diagnosis. Instead, the histology must be considered in the overall clinical context.

The cause of the granulomas is unknown. Atypical mycobacteria have been postulated, but this hypothesis has not been proven.

As well as the granulomatous and fibrotic process, a vasculitic element to the disease may be encountered, particularly in the lung.

While sarcoid can affect any organ system in the body, the lungs are one of the principal sites. Pulmonary disease can take the form of hilar lymphadenopathy alone, hilar lymphadenopathy and pulmonary fibrosis, or pulmonary fibrosis alone, or rarely a necrotising granulomatous vasculitis. Lymph nodes outside the mediastinum are also frequently involved in sarcoidosis.

• The skin is affected in 25%.
• Ocular involvement is found in 25% and is usually in the form of uveitis.
• Arthralgia or arthritis occurs in up to 50%.
• Other organs are affected less frequently, although parotid involvement, when combined with uveitis, is characteristic.

Clinical correlations

Simply knowing that sarcoidosis is a multisystem granulomatous disease makes remembering many of the potential clinical features easier, although the typical distribution still has to be learnt.

Hypercalcaemia can develop in one in ten patients with sarcoidosis and is due to the presence of the vitamin D 1α‐hydroxylase enzyme within the macrophages of the sarcoid granulomas. The activity of this enzyme leads to excess activated vitamin D, which raises blood calcium.

Prognosis

Many patients do very well in the long term, either recovering spontaneously, or after treatment with glucocorticoids.

Syphilis

Definition

Syphilis is a sexually transmitted infection that is caused by the spirochaete Treponema pallidum.

Epidemiology

Until recently, the incidence of syphilis in the UK was under 1000 cases per year for the entire population, but the disease may be making a small resurgence. The disease is found worldwide, although it has been suggested that dissemination of the organism to all parts of the globe was a consequence of migration and exploration.

Pathology

Treponema pallidum is a spirochaete that does not stain with normal methods, instead requiring specialised techniques such as Young's stain. Infection is via the mucosal membranes, usually by sexual transmission. The immune response to syphilis is granulomatous and this brings with it fibrosis. Vasculitis also occurs at certain stages and in certain organs.

Infection with Treponema pallidum is chronic and can persist for decades. Four stages are described:

1. Primary syphilis is the initial infection and presents around 2 weeks after infection. The characteristic lesion is a painless ulcer on the affected organ, usually the penis, vulva or vagina, that is associated with painless lymphadenopathy.
2. Secondary syphilis occurs approximately 6–8 weeks after the primary infection and has a myriad of features that include a skin rash (which can affect the palms and soles), mouth ulcers and other oral mucosal lesions, lymphadenopathy, fever, iritis, hepatitis and glomerulonephritis.
3. Tertiary syphilis develops at least 3 years after the primary infection and is characterised by the gumma, which consists of a collection of granulomas that surround a central region of necrosis. Many organs can be affected, although bowing of the tibia is characteristic.
4. Quaternary syphilis encompasses cardiovascular syphilis and neurosyphilis. Cardiovascular syphilis arises after 10–40 years and is a mesoaortitis of the thoracic aorta. This affects the vasa vasorum of the aorta, leading to damage to the tunica media and elastic laminae. Although fibrosis takes place, the aortic wall is structurally compromised and aneurysm develops.

Neurosyphilis is complex and features various stages that span the more general divisions of syphilis. Meningeal neurosyphilis is seen in the first 2 years and presents with a headache, cranial nerve palsies, seizures or confusion.

Meningovascular syphilis presents around 6–7 years. The pathological process is inflammation of the pia and arachnoid mater in association with vasculitis. The vasculitis can cause a cerebrovascular accident. The spinal cord may be affected as well as the brain.

Generalised paralysis of the insane and tabes dorsalis occur around 15–20 years after the initial infection and fall into the quaternary stage. The former shows meningeal fibrosis and cerebr...

Table of contents

• Cover
• Table of Contents
• Pathology at a Glance
• Copyright
• Dedication
• Preface
• Abbreviations
• General pathology
• Systems pathology
• Case studies and questions
• Answers
• Glossary
• Reference ranges
• Index
• End User License Agreement