332
edits
Changes
Jump to navigation
Jump to search
no edit summary
Cysts associated with the ovary and surrounding structures are common. Remember they may be physiological (Graafian/ovulatory follicles can be very large, e.g. mare).
=Introduction=
Cysts associated with the ovary and surrounding structures are common. They may be '''congenital''' or '''acquired'''.
=Types of Cyst=
==Congenital==
Congenital cysts are common in the '''dog, cat and horse'''. Cysts located within the ovary itself are known as '''intraovarian''' cysts, and cysts outside the ovary are known as '''paraovarian''' cysts, and this form is more common. Intraovarian cysts may be '''functional''', but paraovarian cysts are normally an '''incidental''' finding.
==Acquired==
===Follicular Cysts===
These are also known as '''''Cystic Graffian Follices'''''.
Follicular cysts are '''thin-walled, fluid-filled cysts'''. '''Multiple''' cysts are often seen and they can grow quite '''large''' (greater than 2.5cm in the cow). They develop when the follicle fails to ovulate due to '''low levels of LH'''. Luteinization does not occur. This is known as '''Cystic Ovarian Disease (COD)'''. Underlying causes include uterine infection, high milk yeild and stress. They are seen in cattle and pigs, rarely in small animals but not at all in mares.
These cysts may secrete '''[[Ovaries Endocrine Function - Anatomy & Physiology|oestrogen]]''' which can alternate cyclic activity leading to '''[[Oestrous Cycle - Anatomy & Physiology|anoestrus]] or nymphomania''' and changes in rest of '''reproductive tract''', e.g. cystic endometrium and mammary hyperplasia in the large animal. Small animals are more likely to suffer from a '''persistent oestrus''' (and the associated clinical signs), and can ultimately suffer '''[[Bone Marrow|bone marrow]] suppression''' (causing [[Anaemia|anaemia]] and [[Platelet Abnormalities|thrombocytopaenia]]) as result of [[Hyperoestrogenism - Dog|high oestrogen levels]].
'''Ultrasonographic findings''' (identification of a thin-walled fluid filled cyst) are combined with the '''history''' and '''clinical signs''' to make a diagnosis. '''Rectal examination''' can be used in large animals to make a presumptive diagnosis.
Treatment in large animals is the administration of '''[[Oestrous Cycle Pharmacological Manipulation - Anatomy & Physiology|chorionic gonadotrophin or GnRH]]'''. Prolonged [[Oestrous Cycle Pharmacological Manipulation - Anatomy & Physiology|progesterone treatment]] ('''PRID''') can also be used. First-line treatment in small animals the administration of '''[[Oestrous Cycle Pharmacological Manipulation - Anatomy & Physiology|HCG or progestagens]]''', which should induce [[Ovulation - Anatomy & Physiology|ovulation or luteinization]] and return the animal to normal cyclical activity. They can sometimes recur following treatment. Alternatively, definitive treatment is '''ovariohysterectomy'''.
===Luteinised Cysts===
The failure to ovulate due to inadequate or delayed LH release results in '''theca luteinisation'''.
Luteinised cysts are '''firm and thick-walled cyts''', consisting of a central cystic cavity surrounded by a thin layer of fibrous tissue and a thick layer of theca cells. They cysts secreted [[Ovaries Endocrine Function - Anatomy & Physiology|progesterone]]. This can cause anoestrus and cystic ovarian disease in large animals and prolonged dioestrus, anoestrus, and pyometra in small animals.
In large animals '''rectal examination''' (palpation of a firm cyst) and '''ultrasonography''' (identification of a thick-walled cyst) are combined with the '''history''' and '''clinical signs''' to make a diagnosis. In small animals, persistently '''high''' levels of '''serum progesterone''' are diagnostic.
Treatment in large animals is a dose of '''[[Oestrous Cycle Pharmacological Manipulation - Anatomy & Physiology|prostaglandins]]''' to induce '''luteolysis''' and return the cow to cyclic activity or alternatively prolonged [[Oestrous Cycle Pharmacological Manipulation - Anatomy & Physiology|progesterone treatment]] ('''PRID'''). Treatment in small animals is '''ovariohysterectomy'''.
'''NB.''' In large animals, if the type of cyst cannot be identified, treatment with the following hormones can be attempted. [[Oestrous Cycle Pharmacological Manipulation - Anatomy & Physiology||GnRH followed prostaglandin]] administration approximately two wees later, or the use of a [[Oestrous Cycle Pharmacological Manipulation - Anatomy & Physiology|PRID and prostaglandins]].
===Cystic Corpora Lutea===
Cystic corpora lutea are a '''clinically normal''' feature that develop after ovulation. An ovulation papilla can be seen on the cyst surface.
They '''do not cause infertility''' and are of no clinical significance.
===Others===
These include '''tuboovarian cysts''' in cattle, '''cystic ovarian bursa''', '''mesonephric duct remnant cysts'''.
{{Learning
|flashcards = [[Small Animal Abdominal and Metabolic Disorders Q&A 08]]}}
==References==
Information by permission of '''Professor RW Else'''
Jeckel, S (2009) '''Pathology of the Female Genital Tract - Urogenital System''' ''RVC Course Notes''
Noakes, D (2009) '''Infertility in the cow: Ovarian problems - Urogenital System''' ''RVC Course Notes''
Tennant, B (1999) '''Self-Assessment Colour Review Small Animal Abdominal & Metabolic Disorders''' ''Manson''
Tivers, M & Baines, S (2010) '''Surgical diseases of the female genital tract 1. Ovaries and uterus''' ''In Practice 2010;32:292-299''
[[Category:To Do - Reproductive]]
[[Category:To Do - Reproductive]]
[[Category:Ovaries - Pathology]]
[[Category:Ovaries - Pathology]]
[[Category: To Do - Siobhan Brade]]
[[Category:To Do - Manson review]]