Further Outpatient Care
See the list below:
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Kearns-Sayre syndrome (KSS) can involve many systems and organs. Clinicians must maintain comprehensive surveillance. Be especially alert for signs or symptoms of diabetes mellitus and for heart block; the latter may develop at any stage.
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Annual ECG, echocardiography, audiometry, and biochemistry to screen for common endocrine disturbances are recommended. [34]
Complications
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Heart block is a significant and preventable cause of mortality.
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Deterioration has been reported after local anesthesia with articaine. [35]
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Avoid the use of drugs known to be toxic to mitochondria, such as valproic acid, tetracyclines, biguanides, chloramphenicol, barbiturates, phenothiazines, and zidovudine. [36]
Prognosis
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Kearns-Sayre syndrome is a progressive disorder, and the prognosis for patients with the condition is poor. Death is common in the third or fourth decade of life. [37]
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Disease progression can be predicted to some extent by the size and location of the deletion and the degree of skeletal muscle heteroplasmy. [38]
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As in other mtDNA deletion disorders, women who have Kearns-Sayre syndrome have an increased risk of clinically affected offspring. The risk is currently estimated at approximately 1 per 24 births. [16] Genetic counselling is recommended so options for affected women considering pregnancy can be discussed. [39]
Patient Education
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Participation in an exercise-training program can lead to a subjective improvement in muscle-related symptoms, enhanced aerobic exercise capacity, and increased muscle strength.
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Patients can access the Kearns-Sayre Syndrome Information Page maintained by the National Institute of Neurological Disorders and Stroke for information on the disorder and support organizations.
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Skeletal muscle stained for both cytochrome oxidase (COX) and succinic dehydrogenase (SDH), two mitochondrial respiratory chain enzymes. Fibers that stain only for SDH and are COX-negative appear blue. Original magnification X 50.
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Bilateral ptosis and external ophthalmoplegia. Top: patient looking straight ahead. Below: patient is being asked to look in the direction of the arrow in each case. Restriction of eye movements in each direction is demonstrated.
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Modified Gomori Trichrome stain showing ragged red fibres. These show red staining round the periphery as well as within the sarcoplasm, giving a speckled appearance. Of the two affected muscle fibres pictured here, the one on the right shows a more extreme degree of mitochondrial proliferation and also some degeneration/vacuolation than the one on the left.
