Infection of the cysts in this region can compress trachea, causing respiratory problems, or it can compress the oesophagus, causing dysphagia, and irritating the sternocleidomastoid muscle, causing torticollis. Third and fourth branchial cleft cysts are rare, usually consisting of 2% of all branchial arch abnormalities, located below the second branchial arch. They usually have sinus tracts that start from the anterior neck at the thyroid gland until pyriform sinus posteriorly. If infected, it can cause acute infectious thyroiditis in children and if enlarge rapidly, can cause tracheal compression in children. Treatment
Conservative (i.e. no treatment), or surgical excision. With surgical excision, recurrence is common, usually due to incomplete excision. Often, the tracts of the cyst will pass near important structures, such as the internal jugular vein, carotid artery, or facial nerve, making complete excision impractical due to the high risk of complications. See also
Cutaneous columnar cyst
Cystic hygroma
Gingival cyst
Mucocele
Ranula
Thyroglossal duct cyst

References
External links
Pictures and Imaging of Branchial Cleft Cysts
Ethambutol (EMB, E) is a medication primarily used to treat tuberculosis. It is usually given in combination with other tuberculosis medications, such as isoniazid, rifampicin and pyrazinamide. It may also be used to treat Mycobacterium avium complex, and Mycobacterium kansasii. It is taken by mouth.Common side effects include problems with vision, joint pain, nausea, headaches, and feeling tired. Other side effects include liver problems and allergic reactions. It is not recommended in people with optic neuritis, significant kidney problems, or under the age of five. Use during pregnancy or breastfeeding has not been found to cause harm. In the United States the FDA has raised concerns about eye issues in the baby if used during pregnancy. Ethambutol is believed to work by interfering with the bacterias metabolism.Ethambutol was discovered in 1961. It is on the World Health Organizations List of Essential Medicines and is available as a generic medication. Chirality and biological activity
(S,S)-(+)-Ethambutol is powerful and selective antitubercular drug. It is a typical example of an old drug that was introduced for clinical use in its unichiral form. Ethambutol contains two constitutionally symmetrical chiral centers in its structure and exists in three stereoisomeric forms. An enantiomeric pair (S,S)- and (R,R)-ethmabutol, along with the achiral stereoisomer called meso-form. The (S,S)-(+)-enantiomer harbors the antitubercular activity. This enantiomer is 500 and 12 fold more potent than the (R,R)-ethmabutol and the meso-form respectively. On the other hand, all the three isomers are equipotent in terms of the major side-effect of the drug, optic neuritis.