Ghon focus: Difference between revisions

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'''Ghon focus''' is a primary lesion usually subpleural, often in the mid to lower zones, caused by [[Mycobacterium tuberculosis]]. The focus is usually caseous and may eventually either become calcified or undergo fibrosis.
{{Short description|An initial lesion in primary pulmonary tuberculosis}}


==Definition==
== Ghon focus ==
A Ghon focus is a small area of granulomatous inflammation that occurs in the lung tissue in response to infection with ''Mycobacterium tuberculosis''. It is named after the Austrian pathologist Anton Ghon, who first described it in 1916. The Ghon focus represents the primary site of infection in the lungs and is an important component of primary tuberculosis.


==Pathogenesis==
[[File:Chest_X-ray_of_a_Ghon’s_focus.jpg|thumb|right|Chest X-ray showing a Ghon focus]]
The Ghon focus forms when ''Mycobacterium tuberculosis'' bacteria are inhaled into the lungs and are engulfed by [[alveolar macrophages]]. The bacteria multiply within the macrophages, which eventually die and release the bacteria into the surrounding tissue. This triggers an immune response, leading to the formation of a granuloma, or Ghon focus. The Ghon focus usually measures 1-1.5 cm in diameter and is located in the subpleural region of the lower or middle lobes of the lung.


==Clinical Significance==
A '''Ghon focus''' is a primary lesion in the lung that is associated with [[primary tuberculosis]]. It is named after the Austrian pathologist [[Anton Ghon]], who first described it. The Ghon focus is typically a small area of granulomatous inflammation, usually located in the subpleural region of the lung, often in the upper part of the lower lobe or the lower part of the upper lobe.
The Ghon focus is usually asymptomatic and is often discovered incidentally on chest radiographs. It is a key component of primary tuberculosis, which is the initial infection with ''Mycobacterium tuberculosis''. The presence of a Ghon focus, along with lymphadenopathy, is known as the [[Ghon complex]], which is indicative of primary tuberculosis.
 
== Pathophysiology ==
 
The formation of a Ghon focus occurs when [[Mycobacterium tuberculosis]] bacilli are inhaled and reach the alveoli of the lungs. The body's immune response leads to the formation of a granuloma, which is a collection of macrophages, lymphocytes, and other immune cells that attempt to contain the infection. The center of the granuloma may undergo [[caseous necrosis]], a form of cell death that gives the lesion a cheese-like appearance.
 
== Ghon complex ==
 
A Ghon focus, when associated with lymphatic spread to the regional [[lymph nodes]], forms a '''Ghon complex'''. This complex is a hallmark of primary tuberculosis infection. The lymph nodes involved are typically the hilar or mediastinal nodes. Over time, the Ghon complex may calcify, becoming visible on a [[chest X-ray]] as a calcified nodule.
 
== Clinical significance ==
 
In most cases, a Ghon focus is asymptomatic and may heal spontaneously, especially in individuals with a competent immune system. However, in some cases, the infection can progress to active tuberculosis, particularly if the immune system is compromised. The presence of a Ghon focus is an indication of prior exposure to [[tuberculosis]] and can be an important finding in the diagnosis of the disease.
 
== Diagnosis ==
 
A Ghon focus is often identified through imaging studies, such as a chest X-ray or [[CT scan]]. On a chest X-ray, it may appear as a small, round opacity, often with associated calcification if the lesion has healed. In some cases, a [[tuberculin skin test]] or an [[interferon-gamma release assay]] may be used to support the diagnosis of tuberculosis infection.
 
== Treatment ==
 
The presence of a Ghon focus itself does not require treatment unless there is evidence of active tuberculosis. In cases of active disease, a combination of [[antitubercular drugs]] is used to treat the infection. These drugs typically include [[isoniazid]], [[rifampicin]], [[ethambutol]], and [[pyrazinamide]].
 
== Related pages ==


==See Also==
* [[Tuberculosis]]
* [[Tuberculosis]]
* [[Mycobacterium tuberculosis]]
* [[Mycobacterium tuberculosis]]
* [[Ghon complex]]
* [[Granuloma]]
* [[Granuloma]]
* [[Caseous necrosis]]
* [[Lymph node]]


==References==
<references />
[[Category:Medical terms]]
[[Category:Pathology]]
[[Category:Tuberculosis]]
[[Category:Tuberculosis]]
{{stub}}

Latest revision as of 06:07, 16 February 2025

An initial lesion in primary pulmonary tuberculosis


Ghon focus[edit]

Chest X-ray showing a Ghon focus

A Ghon focus is a primary lesion in the lung that is associated with primary tuberculosis. It is named after the Austrian pathologist Anton Ghon, who first described it. The Ghon focus is typically a small area of granulomatous inflammation, usually located in the subpleural region of the lung, often in the upper part of the lower lobe or the lower part of the upper lobe.

Pathophysiology[edit]

The formation of a Ghon focus occurs when Mycobacterium tuberculosis bacilli are inhaled and reach the alveoli of the lungs. The body's immune response leads to the formation of a granuloma, which is a collection of macrophages, lymphocytes, and other immune cells that attempt to contain the infection. The center of the granuloma may undergo caseous necrosis, a form of cell death that gives the lesion a cheese-like appearance.

Ghon complex[edit]

A Ghon focus, when associated with lymphatic spread to the regional lymph nodes, forms a Ghon complex. This complex is a hallmark of primary tuberculosis infection. The lymph nodes involved are typically the hilar or mediastinal nodes. Over time, the Ghon complex may calcify, becoming visible on a chest X-ray as a calcified nodule.

Clinical significance[edit]

In most cases, a Ghon focus is asymptomatic and may heal spontaneously, especially in individuals with a competent immune system. However, in some cases, the infection can progress to active tuberculosis, particularly if the immune system is compromised. The presence of a Ghon focus is an indication of prior exposure to tuberculosis and can be an important finding in the diagnosis of the disease.

Diagnosis[edit]

A Ghon focus is often identified through imaging studies, such as a chest X-ray or CT scan. On a chest X-ray, it may appear as a small, round opacity, often with associated calcification if the lesion has healed. In some cases, a tuberculin skin test or an interferon-gamma release assay may be used to support the diagnosis of tuberculosis infection.

Treatment[edit]

The presence of a Ghon focus itself does not require treatment unless there is evidence of active tuberculosis. In cases of active disease, a combination of antitubercular drugs is used to treat the infection. These drugs typically include isoniazid, rifampicin, ethambutol, and pyrazinamide.

Related pages[edit]