In-Service Exam
Wound Healing Keloids - 2002





Which of the following substances has been shown to occur in higher levels in keloids and red hypertrophic scars than in pink or white hypertrophic scars?

(A) Adenosine triphosphate
(B) Creatine kinase
(C) Fibronectin
(D) Guanosine triphosphate

The correct response is Option A.

When compared with more mature pink and white scars, keloids and red hypertrophic scars have been shown to have higher levels of adenosine triphosphate. In addition, greater quantities of fibroblasts have also been found in keloid scars when compared with more mature scars. Both keloids and hypertrophic scars actively synthesize collagen fibers and have been shown to have increased activity of glycolytic enzymes in vivo.

Creatine kinase, fibronectin, and guanosine triphosphate have not been shown to be present at higher levels in keloids or red hypertrophic scars.

References
1. Glat PM, Longaker MT. Wound healing. In: Aston SJ, Beasley RW, Thorne CH, eds. Grabb & Smith's Plastic Surgery. 5th ed. Philadelphia, Pa: Lippincott-Raven; 1997:3-12.
2. Ueda K, Furuya E, Yasuda Y, et al. Keloids have continuous high metabolic activity. Plast Reconstr Surg. 1999;104:694-698.

In patients with vitamin C deficiency, which of the following physiologic findings is most likely to be decreased?

(A) Amino acid hydroxylation
(B) Fibronectin production
(C) Helical integrity
(D) Monocyte activation
(E) Prothrombin production

The correct response is Option A.

In a patient who has a vitamin C (ascorbic acid) deficiency, hydroxylation of amino acids such as lysine and proline is likely to be decreased. Hydroxylysine and hydroxyproline are the primary components of collagen, with hydroxylysine being responsible for the formation of covalent crosslinks. Vitamin C deficiency, otherwise known as scurvy, prevents collagen cross-linking and the maturation phase of wound healing, resulting in collagen breakdown. Both humans and guinea pigs are unable to manufacture vitamin C naturally.

Decreases in fibronectin production and monocyte activation are the hallmarks of vitamin A deficiency. Prothrombin production is inhibited in patients with vitamin K deficiency. Helical integrity is not affected by vitamin deficiencies.

References
1. Fink MP. The role of cytokines as mediators of the inflammatory response. In: Townsend CM Jr, ed. Sabiston's Textbook of Surgery. 16th ed. Philadelphia, Pa: WB Saunders Co; 2001:41.
2. Lawrence WT. Physiology of the acute wound. Clin Plast Surg. 1998;25:321.
3. Peacock EE Jr, Cohen IK. Wound healing. In: McCarthy JG, ed. Plastic Surgery. Philadelphia, Pa: WB Saunders Co; 1990;1:161.

For each phase of wound healing, select the most closely associated cell type (A-E).

(A) Basal epithelial cell
(B) Fibroblast
(C) Platelet
(D) Macrophage
(E) Smooth muscle cell

1) Inflammation phase

2) Proliferative phase

The correct response for Item 1 is Option D and for Item 2 is Option B.

Inflammation is the initial phase of wound healing; polymorphonuclear leukocytes (PMNs) and macrophages are primarily involved in this process. This interval typically lasts from four to six days; during this time, clots, foreign bodies, and bacteria are removed, and the wound surface closes. The proliferative phase, also known as the collagen and regenerative phase, is characterized by collagen production and increased strength within the wound. Fibroblasts are primarily responsible for the collagen production. This process begins approximately seven days after injury; its duration is approximately five weeks. Maturation, or remodeling, is the final phase and can last for more than two years. Maturation and cross linking of collagen occur during this phase.

References
1. Lawrence WT. Physiology of the acute wound. Clin Plast Surg. 1998;25:321-340.
2. Robson MC, Burns BF, Phillips LG. Wound repair: principles and applications. In: Ruberg RL, Smith DJ, eds. Plastic Surgery Ð A Core Curriculum. Saint Louis, Mo: Mosby Ð Year Book, Inc; 1994;1:5-6.

Which of the following is the most likely result following the intralesional injection of corticosteroids for treatment of keloids?

(A) Absence of adverse effects on the surrounding tissues
(B) Decreased risk for malignant degeneration
(C) Decreased risk for recurrence
(D) Lack of effectiveness on the connective tissue composition of the keloid
(E) Symptomatic relief of itching and burning

The correct response is Option E.

Intralesional corticosteroid injections are among several therapies used for treatment of keloids. Other therapeutic modalities include application of occlusive silicone dressings, use of compressive pressure earrings or dressings, interferon therapy, radiation therapy, cryosurgery, and laser or surgical excision. None of these treatments have been shown to be totally effective; however, corticosteroids have been shown to relieve the itching and burning symptoms associated with the keloids, as well as to decrease the collagen content of the keloids and subsequently decrease their size. Excision performed concomitantly with injection of corticosteroids will reduce the rate of recurrence to 30% to 50%. Low-dose radiation therapy administered postoperatively is associated with a similarly reduced rate of recurrence.

References
1. Berman B, Flores F. The treatment of hypertrophic scars and keloids. Eur J Dematol. 1998;8:591-595.
2. Sclafani AP, Gordon L, Chadha M, et al. Prevention of earlobe keloid recurrence with postoperative corticosteroid injections versus radiation therapy: a randomized, prospective study and review of the literature. Dermatol Surg. 1996;22:569-574.