A 51-year-old woman developed skeletal symptoms due to histologically proved osteomalacia. The etiology could not be determined until a history of factitial diarrhea due to long-term phenolphthalein (Ex-Lax) ingestion was finally elicited. Normal bowel habits returned after the use of phenolphthalein was discontinued and the osteomalacia showed signs of healing. Surreptitious ingestion of cathartics should be considered as a causal factor in patients with unexplained osteomalacia.The overuse of phenolphthalein (Ex-Lax) may cause diarrhea and result in a variety of metabolic disturbances. Hypocalcemia has been observed in such cases, but to our knowledge osteomalacia has not pre¬ viously been recorded. The purpose of this communication is to cite the occurrence of biopsy proved severe osteomalacia in a patient with factitial diarrhea due to phenolphthalein.
Patient SummaryA 51-year-old white obese woman was seen in the orthopedic clinic with back and hip pain of six months' duration. She was hostile, combative, and a poor historian. To one observer the patient admitted to hav¬ ing three to four loose stools daily, but later denied this. Her history and family history were otherwise unremarkable. On physical examination, there was moderate obesity, skeletal tenderness over the spine and hips, and emotional lability.Laboratory results were as follows: hemoglobin, 15.5 gm/100 ml; white blood cell count, 8,000/cu mm; and negative results of venereal disease research laboratory test for syphilis (VDRL). The serum creatinine level was 1.2 mg/100 ml. Serum electrolyte values were sodium, 135 mEq/liter; potassium, 3.1 mEq/liter; chlo¬ ride, 98 mEq/liter; and carbon dioxide combining power, 24 mEq/liter. Values for the serum calcium were 7.7, 7.8, and 8.0 mg/100 ml and for serum inorganic phosphate 3.1, 3.1, and 3.0 mg/100 ml. Se¬ rum alkaline phosphatase levels were 13.1 and 12.0 Bodansky units/100 ml. Serum protein electrophoresis determinationshowed an albumin value of 3.4 gm/100 ml and normal levels of globulin. A 24-hour urine sample contained 105 mg of calcium in a volume of 2,100 ml. The serum caro¬ tene level was 56µg/100 ml and the serum magnesium level was 1.9 mEq/liter. Re¬ sults of a 25-gm four-hour xylose absorp¬ tion test on three occasions averaged 1.8 gm. Skeletal roentgenograms demon¬ strated essentially normal bone density, but pseudofractures of both femoral necks were noted (Fig 1, left). A left 11th rib specimen was removed for study following the administration of a double bone-label with demeclocycline hydrochloride (Declomycin). A review of the histologie changes and bone remodel¬ ing data in the removed bone specimen demonstrated changes of florid os¬ teomalacia (Fig 2). Osteoid seam numbers were markedly increased and the mineral appositional rate was decreased (Table).The etiology of the osteomalacia was