Clinical Features

The early manifestations are irritability, loss of appetite, low-grade fever, and tenderness in the legs. These signs and symptoms are followed by leg swelling—most marked at the knees and the ankles—and pseudoparalysis. The infant might lie in the “pithed frog” position, with the hips and knees semiflexed and the feet rotated outward. Subperiosteal hemorrhages in the lower limb bones sometimes acutely increase the swelling and pain, and the condition might mimic acute osteomyelitis or arthritis. A “rosary” at the costochondral junctions and depression of the sternum are other typical features (Fig. 47-1). The angulation of scorbutic beads is usually sharper than the angulation of a rachitic rosary. Gum changes are seen in older children after teeth have erupted and are manifested as bluish purple, spongy swellings of the mucous membrane, especially over the upper incisors (Fig. 47-2). Anemia, a common finding in infants and young children with scurvy, is related to impaired iron absorption and coexistent hematopoietic nutrient deficiencies including iron, vitamin B₁₂, and folate. Hemorrhagic manifestations of scurvy include petechiae, purpura, and ecchymoses at pressure points; epistaxis; gum bleeding; and the characteristic perifollicular hemorrhages (Fig. 47-3). Other manifestations are poor wound and fracture healing, hyperkeratosis of hair follicles, arthralgia, and muscle weakness.

Figure 47-1 Scorbutic rosary.

(Courtesy of Dr J.D. MacLean, McGill Centre for Tropical Diseases, Montreal.)

Figure 47-2 Gingival lesions in advanced scurvy.

(From Nutrition, ed 4, Kalamazoo, MI, 1980, The Upjohn Company, p 80. Used with permission of Pfizer, Inc.)

Figure 47-3 Perifollicular petechiae in scurvy.

(From Weinsier RL, Morgan SL: Fundamentals of clinical nutrition, St Louis, 1993, Mosby, p 85.)

Laboratory Findings and Diagnosis

The diagnosis of vitamin C deficiency is usually based on the characteristic clinical picture, the radiographic appearance of the long bones, and a history of poor vitamin C intake. The typical radiographic changes occur at the distal ends of the long bones and are particularly common at the knees. The shafts of the long bones have a ground-glass appearance due to trabecular atrophy. The cortex is thin and dense, giving the appearance of pencil outlining of the diaphysis and epiphysis. The white line of Fränkel, an irregular but thickened white line at the metaphysis, represents the zone of well-calcified cartilage. The epiphyseal centers of ossification also have a ground-glass appearance and are surrounded by a sclerotic ring (Fig. 47-4). The more specific but late radiologic feature of scurvy is a zone of rarefaction under the white line at the metaphysis. This zone of rarefaction (Trumerfeld zone), a linear break in the bone that is proximal and parallel to the white line, represents area of debris of broken-down bone trabeculae and connective tissue. A Pelkan spur is a lateral prolongation of the white line and may be present at cortical ends. Epiphyseal separation can occur along the line of destruction, with either linear displacement or compression of the epiphysis against the shaft. Subperiosteal hemorrhages are not visible using plain radiographs during the active phase of scurvy. However, during healing the elevated periosteum becomes calcified and radiopaque, giving a dumbbell or club shape to the affected bone (Fig. 47-5). MRI can demonstrate acute as well as healing subperiosteal hematomas along with periostitis, metaphyseal changes, and heterogeneous bone marrow signal intensity.

Figure 47-4 Radiographs of a leg. A, An early scurvy “white line” is visible on the ends of the shafts of the tibia and fibula; sclerotic rings (Wimberger sign) are shown around the epiphyses of the femur and tibia. B, More advanced scorbutic changes; zones of destruction (ZD) are evident in the femur and tibia. Pelkan spur is also seen at the cortical end.

Figure 47-5 Calcified subperiosteal hematoma (SH) is seen along the midshaft of left femur of an infant with advanced scurvy; pathologic fractures (PF) are seen in the shafts of right tibia and fibula with bowing of fibular shaft and periosteal reaction along the tibia.

(Courtesy of Prof. Anita Khalil.)

Biochemical tests are not very useful in the diagnosis of scurvy, because they do not reflect the tissue status. A plasma ascorbate concentration of <0.2 mg/dL usually is considered deficient. Leukocyte concentration of vitamin C is a better indicator of body stores, but this measurement is technically more difficult to perform. Leukocyte concentrations of ≤10 µg/10⁸ white blood cells (WBCs) are considered deficient and indicate latent scurvy, even in the absence of clinical signs of deficiency. Saturation of the tissues with vitamin C can be estimated from the urinary excretion of the vitamin after a test dose of ascorbic acid. In healthy children, 80% of the test dose appears in the urine within 3-5 hr after parenteral administration. Generalized nonspecific aminoaciduria is common in scurvy, whereas plasma amino acid levels remain normal.

Differential Diagnosis

Scurvy is often misdiagnosed as arthritis, osteomyelitis, battered child syndrome, or acrodynia. The early irritability and bone pain are sometimes attributed to nonspecific pains or other nutritional deficiencies. Copper deficiency results in a radiographic picture very similar to that of scurvy. Henoch-Schönlein purpura, thrombocytopenic purpura, or leukemia is sometimes suspected in children presenting with hemorrhagic manifestations.

Treatment

Vitamin C supplements of 100-200 mg/day orally or parenterally ensure rapid and complete cure. The clinical improvement is seen within a week in most cases, but the treatment should be continued for up to 3 months for complete recovery.

Prevention

Breast-feeding protects against vitamin C deficiency throughout infancy. In children consuming milk formula, fortification with vitamin C must be ensured. Children consuming heat-treated milk should consume adequate vitamin C–rich foods in infancy. Dietary or medicinal supplements are required in severely malnourished children.