Knuckle Pigmentation: A Clue to Systemic Illness

Excerpt

A 50-year-old female, consuming mixed non-vegetarian diet, presented to our out-patient department with easy fatigability, tiredness and dyspnea of 3 months duration. On examination she had severe pallor but systemic examination of the cardiovascular, respiratory, gastrointestinal and neurological systems were within normal limits. Detailed general examination revealed hyperpigmentation of skin over the knuckles of both hands (Fig. 1). Investigations showed hemoglobin of 73 g/L with mean corpuscular volume (MCV) of 116.7 fL, mean corpuscular hemoglobin of 38.8 pg, mean corpuscular hemoglobin concentration of 38.8 % and red cell distribution width of 30.6 %. She also had mild thrombocytopenia (137 × 10⁵/µL). Total leukocyte count was 4100/µL and reticulocyte count was 4 % (Corrected reticulocyte count—1.95 %). Peripheral smear examination showed marked anisopoikilocytosis with macroovalocytes and hypersegmented neutrophils (Fig. 2). Serum lactate dehydrogenase (LDH) was 840 IU/L (normal <480 IU/L). Serum chemistries were within the normal range. Her plasma cyanocobalamin was 144 pg/mL (normal: 187–883 pg/mL). Gastroduodenoscopy and antral biopsy showed features of atrophic gastritis. Her serum tested positive for anti-parietal cell antibody, hence confirming the diagnosis of addisonian pernicious anemia. She symptomatically improved with parenteral hydroxycobalamine—1000 µg intra muscular (im) injection given every third day for seven injections. Her hemoglobin at 1 month follow up improved to 94 g/day and MCV 100.1 fl with improvement in thrombocytopenia (256 × 10⁵/µL). She was put on lifelong vitamin B12 prophylaxis (1000 µg im every month) and asked to follow up yearly with complete blood count and red cell indices.

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