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Recognition and Description of Lesions (view source)
Revision as of 12:50, 15 February 2011
, 12:50, 15 February 2011Text replace - "[[Disorders of Cell Growth - Pathology" to "[[Cell Growth Disorders"
==Introduction==
* In order to make a veterinary diagnosis, it is essential to be able to recognise an abnormality.
* In order to make a veterinary diagnosis, it is essential to be able to recognise an abnormality.
** From the abnormality, we should be able to formulate an differential diagnosis before arriving at a diagnosis.
** From the abnormality, we should be able to formulate an differential diagnosis before arriving at a diagnosis.
** [[Necrosis - Pathology|Necrosis]]
** [[Necrosis - Pathology|Necrosis]]
*** Once the active phase of [[Necrosis - Pathology|necrosis]] has resolved, an irregular, disrupted shape can be created by the traction of scar tissue on adjacent tissue.
*** Once the active phase of [[Necrosis - Pathology|necrosis]] has resolved, an irregular, disrupted shape can be created by the traction of scar tissue on adjacent tissue.
** [[Disorders of Cell Growth - Pathology#Atrophy|Atrophy]]
** [[Cell Growth Disorders#Atrophy|Atrophy]]
** In the lung, collapse (lack of air).
** In the lung, collapse (lack of air).
[[Image:consolidation and haemorrhage lung.jpg|thumb|right|150px|Consolidation and haemorrhage in the lung (Courtesy of BioMed Archive)]]
[[Image:consolidation and haemorrhage lung.jpg|thumb|right|150px|Consolidation and haemorrhage in the lung (Courtesy of BioMed Archive)]]
* This colouration is commonly seen with an increase in the amount of blood- may indicate
* This colouration is commonly seen with an increase in the amount of blood- may indicate
** [[Haemorrhage - Pathology|Haemorrhage]]
** [[Haemorrhage|Haemorrhage]]
*** Significant [[Haemorrhage - Pathology|haemorrhage]] is usually very dark, since the haemoglobin is depleted of oxygen.
*** Significant [[Haemorrhage|haemorrhage]] is usually very dark, since the haemoglobin is depleted of oxygen.
** Congestion.
** Congestion.
* This colour change is most obvious in light coloured tissues due to the contrast in colour.
* This colour change is most obvious in light coloured tissues due to the contrast in colour.
** More difficult to see in e.g. spleen.
** More difficult to see in e.g. spleen.
* If seen in a nodular lesion, the lesion may be
* If seen in a nodular lesion, the lesion may be
** A [[Haemorrhage - Pathology#Haematoma|haematoma]].
** A [[Haemorrhage#Haematoma|haematoma]].
** A vascular lesion.
** A vascular lesion.
** An abscess with [[Haemorrhage - Pathology|haemorrhage]].
** An abscess with [[Haemorrhage|haemorrhage]].
====Black or Brown/ Black====
====Black or Brown/ Black====
* This pigmentation may be due to
* This pigmentation may be due to
** [[Pigmentation and Calcification - Pathology#Melanin|Melanin]]
** [[Pigmentation - Pathology#Melanin|Melanin]]
** [[Pigmentation and Calcification - Pathology#Carbon (Anthracosis)|Exogenous carbon]]
** [[Pigmentation - Pathology#Carbon (Anthracosis)|Exogenous carbon]]
** Putrefactive bacteria
** Putrefactive bacteria
** [[Pigmentation and Calcification - Pathology#Haemosiderin|Haemosiderin]].
** [[Pigmentation - Pathology#Haemosiderin|Haemosiderin]].
* Examples
* Examples
** If the lesion is a mass, consider a melanoma.
** If the lesion is a mass, consider a melanoma.
*** Hydrogen sulphide from gastro-intestinal bacteria can give black discolouration
*** Hydrogen sulphide from gastro-intestinal bacteria can give black discolouration
**** Known as pseudomelanosis
**** Known as pseudomelanosis
** [[Pigmentation and Calcification - Pathology#Haemosiderin|Haemosiderosis]] (brown to golden brown).
** [[Pigmentation - Pathology#Haemosiderin|Haemosiderosis]] (brown to golden brown).
*** Implies old/ chronic congestion or [[Haemorrhage - Pathology|haemorrhage]].
*** Implies old/ chronic congestion or [[Haemorrhage|haemorrhage]].
====Green====
====Green====
* Yellow pigmentation can be given by:
* Yellow pigmentation can be given by:
** Fat
** Fat
** Bile pigment (bilirubin)
** Bile pigment ([[Bilirubin|bilirubin]])
** Fibrin
** Fibrin
** [[Oedema - Pathology#Composition of oedema fluid|Cellular exudates]]
** [[Oedema#Composition of oedema fluid|Cellular exudates]]
** [[Neoplasia - Pathology|Neoplasms]]
** [[Neoplasia - Pathology|Neoplasms]]
* Fluid may be:
* Fluid may be:
** [[Oedema - Pathology|'''Oedema''']]
** [[Oedema|'''Oedema''']]
*** Clear
*** Clear
** '''Serofibrinous'''
** '''Serofibrinous'''
** '''Blood'''
** '''Blood'''
*** Dark red.
*** Dark red.
*** Recent [[Haemorrhage - Pathology|haemorrhage]] into the body cavities is thick, and often contains clots.
*** Recent [[Haemorrhage|haemorrhage]] into the body cavities is thick, and often contains clots.
*** Serosanguinous fluid (blood tinged oedema) is often seen at necropsy.
*** Serosanguinous fluid (blood tinged oedema) is often seen at necropsy.
**** Is much thinner than [[Haemorrhage - Pathology|haemorrhage]], and does not contain clots.
**** Is much thinner than [[Haemorrhage|haemorrhage]], and does not contain clots.
* Fluid can also accumulate post-mortem.
* Fluid can also accumulate post-mortem.
** Could be:
** Could be:
*** A focus of inflammation
*** A focus of inflammation
**** [[Acute Inflammation - Pathology#Purulent|Abscess]], [[Chronic Inflammation - Pathology#Granulomatous Inflammation|granuloma]]
**** [[Purulent Inflammation|Abscess]], [[Granulomatous Inflammation|granuloma]]
*** A [[Neoplasia - Pathology|neoplasm]]
*** A [[Neoplasia - Pathology|neoplasm]]
*** A [[Haemorrhage - Pathology#Haematoma|haematoma]]
*** A [[Haemorrhage#Haematoma|haematoma]]
*** A cyst.
*** A cyst.
** Considering the categories for description of the lesion should allow a ‘most-likely’ identity to be reached, or at least a short list of possibilities to be made.
** Considering the categories for description of the lesion should allow a ‘most-likely’ identity to be reached, or at least a short list of possibilities to be made.
*** Definitive diagnosis may sometimes require histology.
*** Definitive diagnosis may sometimes require histology.
[[Category:General Pathology]]