Cochlear Implants

(Great Britain—The Practitioner, June 1998, p. 434.) The most common causes of sensory neuroepithelium loss in the cochlea are congenital ear defects and meningitis. Cochlear implants were developed to overcome the profound deafness resulting from interruption of input to the cochlear nerve. The three-part implant system consists of a receiving microphone worn on the ear, a speech processor worn on the body and a transmitter worn on the scalp overlying the implanted receiving package, which relays impulses into the cochlea. Cochlear implants should only be considered for profoundly deaf individuals who have an intact cochlear nerve but cannot benefit from even the most powerful hearing aids. Most centers require extensive assessment of candidates, including magnetic resonance imaging and auditory testing. Patients who have had meningitis may have significant ossification of the cochlea, which makes surgery difficult. Patients with congenital defects appear to benefit most from surgery performed before seven years of age. The surgery is technically complex, and complications include infection. The unit is usually activated about four weeks after surgery, and some patients report that the intrusion of noise is painful or disconcerting. Although late complications of surgery are rare, cochlear implantation requires extensive rehabilitation and follow-up. The success of the procedure depends on the motivation of the patient and the family, but the results may be dramatic, allowing profoundly deaf patients to communicate effectively and even use a telephone.

Tonsillectomy

(Great Britain—British Journal of General Practice, June 1998, p. 1331.) In developed countries, tonsillectomy is one of the most common surgical procedures. The most frequent indication for tonsillectomy is recurrent throat infection, but there is little objective evidence of improved clinical outcome after surgery. A review by Marshall identified a large number of studies, although only five of these investigated outcomes and met quality criteria for inclusion in the review. In all of the studies, children who underwent tonsillectomy reported approximately three fewer throat infections than control subjects in the two years following surgery, but by the third year, the differences were no longer statistically significant. No evidence indicated that tonsillectomy reduced the number of school days missed. Very little evidence was found concerning adverse effects of tonsillectomy, but the incidence of serious side effects, especially postoperative bleeding, was consistently quoted as 1 percent. No evidence of tonsillectomy benefiting adults was found.

Head Lice

(Ireland—Forum, June 1998, p. 36.) Since head lice move slowly and need scalp heat to survive, they are only transmitted by prolonged head-to-head contact. Close clustering of children during play time is the most frequent source of infestation at school, and girls seven to 12 years of age are most commonly affected. Each night, the female louse lays approximately three eggs that are glued to the hair shaft, particularly at the back of the head. Nymphs hatch after seven to 10 days, leaving the characteristic “nit” shell stuck to the hair shaft. Most infestations are asymptomatic for several weeks, by which time households and other close contacts have probably been infested. Use of a fine-toothed comb may be sufficient to control nits. If lice are detected, lotions or liquids are generally more effective for treatment than shampoos. The entire scalp should be covered. The hair should be allowed to dry naturally, since heat may inactivate medications. Thorough treatment of all contacts and rotation of products contributes to reducing resistance. Concerns have been raised about the safety of certain anti-lice preparations, especially in children.

Making Sense of Free Radicals

(New Zealand—New Zealand Family Physician, June 1998, p. 15.) Free radicals result from oxygenation, which may occur through natural metabolic processes or may be induced by chemical agents such as those found in tobacco smoke. Free radicals may cause tissue damage, including damage to DNA, which may eventually lead to malignant transformation of cells. Most of the natural mechanisms to absorb free radicals or limit their potentially damaging effects are believed to depend on the intake of specific nutrients. The most widely studied agents are vitamins C and E and beta-carotene. These agents have been credited with protective effects against degenerative cardiovascular diseases and diseases of the central nervous system and lung, in addition to having an anticancer effect. More recent research has indicated that excessive intake of antioxidants could be dangerous and that natural sources are superior to synthetic supplements.