Kenny Caffey syndrome
Overview
A very rare inherited skeletal disorder involving thickening of the long bones of the body and head abnormalities.
Symptoms
* Tetanic convulsions * Delayed physical development * Myopia * Small eyes * Farsightedness * Swelling of optic disk * Vascular tortuosity * Macular crowding * Dwarfism * Large anterior fontanel * Underdeveloped nails * Narrow long-bone shafts * Thickening of long bones * Thin marrow bone cavities of long bones * Craniofacial disproportion * Transient hypocalcemia * High level of phosphates in blood * Microcytic anemia * Reduced number of neutrophils in blood * Neonatal liver disease
Causes
Hypoalbuminemia commonly results in a “pseudohypocalcemia” –Results in decreased total serum Ca2+ but normal free, ionized (active) Ca2+ –Does not result in sequelae of hypocalcemia * Hypoparathyroidism –Often occurs after thyroidectomy or parathyoidectomy –Infiltrative diseases of the parathyroid gland (e.g., hemochromatosis, Wilson's disease, sarcoidosis, tuberculosis) –Pseudohypoparathyroidism (parathyroid hormone resistance) –Idiopathic (autoimmune) * Medications (e.g., diuretics, heparin, foscarnet, cimetidine, glucagon, phosphates, aminoglycosides, theophylline, cisplatin) * Vitamin D deficiency –Poor oral intake and/or absent sun exposure –Malabsorption –Hepatic and/or renal failure –Anticonvulsant use * Pancreatitis * Alkalosis (especially respiratory alkalosis) * Sepsis * Shock * Burns * Magnesium deficiency (often seen in alcoholism) * Hyperphosphatemia * Alcoholism (may directly suppress PTH and/or deplete magnesium) * Postoperative (usually transient) * Post-blood transfusion * Malignancy –Medullary carcinoma of the thyroid –Osteoblastic metastases * Familial hypocalcemia * DiGeorge's syndrome (congenital absence of the parathyroid glands) * Polyglandular autoimmune syndrome, type I (hypoparathyroidism, adrenal insufficiency, and mucocutaneous candidiasis) * Rickets
Treatment
* Asymptomatic patients can be treated with oral calcium supplements plus vitamin D * If severe symptoms are present, administer 10% IV calcium gluconate and recheck calcium levels frequently * Change causative medications if possible * Treat underlying diseases as necessary (e.g., sepsis, pancreatitis, renal failure) * Correct other electrolyte abnormalities (e.g., hypomagnesemia) * Hypoalbuminemia may improve with adequate nutrition; however, there is no need to correct serum Ca2+, because the ionized calcium is normal * Hypoparathyroidism: Calcium carbonate supplementation of 1–2 g per day plus vitamin D supplementation * Vitamin D deficiency: Oral vitamin D or calcitriol (1,25-hydroxyvitamin D)