Krankheiten des Thymus der Haussäugetiere – Bedeutung und Diagnostik

Zusammenfassung

Im Gegensatz zur Humanmedizin finden Thymuskrankheiten in der Veterinärmedizin wenig differentialdiagnostische Beachtung. Ziel dieser Übersicht ist es, den Kenntnisstand zu topographischer Anatomie, physiologischer Entwicklung und Involution, Funktion und Krankheiten des Thymus sowie der Diagnostik von Thymuskrankheiten bei den verschiedenen Haussäugetieren darzustellen. Dafür wurde die Literatur, die sich mit dem Themenkomplex beschäftigt, durchsucht und zusammengefasst. Die anatomische Ausdehnung und Entwicklungs-/Involutionsprozesse unterscheiden sich von Tierart zu Tierart deutlich. Allgemein gilt, dass der Thymus zu Beginn der Geschlechtsreife seine maximale Ausdehnung hat und beim adulten Tier nicht oder nur in Residuen vorhanden ist. Eine Ausnahme bilden Hund und Ziege, bei denen auch beim Adulten funktionelles Thymusgewebe gefunden werden kann. Die Darstellung durch bildgebende Verfahren erweist sich je nach Größe des Tieres und durch die Lage des Organs häufig als schwierig. Aufgrund der schlechten Darstellbarkeit und die oft unspezifische Symptomatik stellen Krankheiten des Thymus eine diagnostische Herausforderung dar. Der Thymus kann sich als Reaktion auf Stress oder Krankheiten in seiner Größe und Struktur verändern. In diesem Zusammenhang kann es zu einer gestörten Immunfunktion kommen und in der Folge zu Infektionskrankheiten. Neoplasien des Thymus sind bei Haussäugetieren vielfach beschrieben. Die meisten Berichte finden sich für den Hund und die Ziege. Symptome treten meist auf, wenn der Tumor durch seine Größe raumfordernd wird oder durch das Auftreten von paraneoplastischen Syndromen. Dazu gehört beispielsweise die Myasthenia gravis. Mehr als 50% der Hunde mit einem Thymom entwickeln ein paraneoplastisches Syndrom. Durch die Verfügbarkeit moderner Bildgebung könnte die Untersuchung des Thymus in Zukunft vereinfacht und bei Jungtieren als ein guter Indikator zur Überprüfung des Gesundheitsstatus genutzt werden.

Abstract

In contrast to human medicine, thymic disorders receive little attention as differential diagnoses in veterinary medicine. The aim of this overview is to provide information on the current state of knowledge concerning the topographical anatomy, physiological development, and involution, function, and diseases of the thymus as well as the diagnosis of thymic disorders in various domestic mammals. Therefore, literature on this topic was searched and summarized. The anatomical extent and developmental/involutionary processes differ significantly from species to species. The thymus reaches its maximum size at the beginning of sexual maturity whereas it is largely absent or persists in mere residual form in adult animals. Dogs and goats represent an exception, as functional thymus tissue may also be found in adults. Imaging is often difficult, depending on the size of the animal and the location of the organ. Due to the poor visualization and mostly unspecific clinical signs, disorders of the thymus pose a diagnostic challenge. The thymus may change in size and structure in response to stress or disease. This can lead to impaired immune function and subsequently to infectious diseases. Neoplasia of the thymus has been widely described in domestic mammals. Most reports are found for dogs and goats. Clinical signs usually appear when the tumor becomes space-occupying due to its size or they become apparent in consequence to the occurrence of paraneoplastic syndromes. These may for example include myasthenia gravis. More than 50% of dogs with a thymoma develop a paraneoplastic syndrome. With the availability of modern imaging, assessing the thymus may in future become simpler and may prove useful in evaluating the health status of young animals.

Schlüsselwörter

Thymus - Ultraschall - Bildgebung - Thymuserkrankungen

Keywords

Thymus - ultrasonography - diagnostic imaging - thymic diseases

Publication History

Received: 15 January 2025

Accepted: 14 April 2025

Article published online:
02 September 2025

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