Background: Hyperpigmentation of dorsum of hands and fingers though considered an important diagnostic sign for Megaloblastic Anemia (MA). Objectives: To evaluate the diagnostic accuracy and reliability of hyperpigmentation for detection of Vit. B 12 deficiency among children. Study Design: A cross-sectional diagnostic study. We prospectively enrolled all children ages 2 months to 5 years presenting to inpatient or outpatient Pediatric departments. We identified the child who looks pallor, and did the hemoglobin (Hb.) and mean corpuscular volume (MCV) level. After that we included those patients who had a Hb. < 11 g/dl, and MCV > 100 fl. Study Procedure: Index test: After fulfilling the inclusion criteria, Pediatric nurse and Pediatric resident sequentially examined the knuckles and terminal phalanges of each study patient for hyperpigmentation (Index test) and the interval between the two observer’s examinations ranged between 30minutes. Reference standard: Serum Vit. B 12 level (reference standard) was performed after the clinical assessments of the children. Results: A total of 20 patients, in the age group of 2 months to 5 years were enrolled in the study. The children with Vit. B 12 deficiency was best identified by the presence of hyperpigmentation of knuckle as indicated by the high sensitivity (Pediatric resident :94% and Pediatric Nurse 82%) and satisfactory specificity ( Pediatric resident :66% and Pediatric Nurse 33%), compared with hyperpigmentation of terminal phalanges (Pediatric resident: sensitivity (Sn)=52%, Specificity (Sp)=66% & Pediatric Nurse: Sn=29%, Sp=66%). Thrombocytopenia was detected in only one case (5%). Leucopenia was detected in 3 cases (15%). Vit. B 12 deficiency was detected in 17 cases (<80 pg/ ml) out of 20 cases. Conclusion: The presence of hyperpigmentation of knuckle in the anemic children can moderately raise the probability of Vit. B 12 deficiency.
Key word: Vitamin B 12 ; Hyperpigmentation; Diagnostic accuracy; Mean corpuscular volume.
Original Article
P. 141-144
