Caseation

Caseation

Caseation is a form of tissue necrosis that is characterized by a cheese-like appearance. This type of necrosis is most commonly associated with tuberculosis infections, where it occurs in the center of tuberculous granulomas. The term "caseation" is derived from the Latin word "caseus," meaning cheese, due to the friable, white, and cheesy appearance of the necrotic tissue.

Pathophysiology

Caseation necrosis occurs when the immune system attempts to wall off and kill the invading pathogen, such as Mycobacterium tuberculosis, but is unable to completely eliminate it. The immune response leads to the formation of a granuloma, which is a collection of immune cells including macrophages, lymphocytes, and epithelioid cells.

Within the granuloma, the center undergoes necrosis due to the release of lytic enzymes from the immune cells. The necrotic tissue becomes amorphous and granular, resembling cheese. This is due to the coagulation of proteins and lipids in the tissue, which gives it a distinctive appearance under the microscope.

Clinical Significance

Caseation is a hallmark of tuberculous granulomas, which are found in the lungs of patients with active tuberculosis. The presence of caseating granulomas can be a diagnostic feature in biopsy specimens. However, caseation can also occur in other conditions, such as certain fungal infections and in some cases of sarcoidosis.

The presence of caseation can lead to tissue destruction and cavitation, particularly in the lungs, where it can result in the formation of cavities that can harbor bacteria and lead to further spread of the infection.

Diagnosis

Diagnosis of caseation necrosis is typically made through histological examination of tissue samples. A biopsy of the affected tissue is taken and examined under a microscope. The presence of caseating granulomas is indicative of tuberculosis or other granulomatous diseases.

Treatment

Treatment of caseation necrosis involves addressing the underlying cause. In the case of tuberculosis, this involves a combination of antibiotics such as isoniazid, rifampicin, ethambutol, and pyrazinamide. Treatment is usually prolonged, lasting several months, to ensure complete eradication of the bacteria.

Also see

• Granuloma
• Necrosis
• Tuberculosis
• Histopathology
• Infectious disease

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