A nice CATCH!
Indhirajanti, S., Alsma, J., Daele, P.L.A. van
Voorzitter(s): dr. P.M. Netten, ‘s-Hertogenbosch & dr. L.J.M. Reichert, Arnhem
Locatie(s): Auditorium 1
Categorie(ën):
Case report: A 42-year old Caucasian man presented at the emergency department with a painful shoulder with restricted movement. His complaints had started spontaneously and traumatic injury was absent. His medical history revealed mental retardation and cardiac anomalies; a ventricular septal defect corrected at the age of two, an aortic coarctation and an aorta valve stenosis. Despite previous testing no specific syndrome had been found.
Physical examination not only revealed signs of a fractured shoulder, but also subtle facial dysmorphisms (hypertelorism and hyperplastic gingivae) and prominent pulsations on the right side of the neck. Auscultation of the heart revealed a systolic murmur in accordance to the aortic valve stenosis.
Laboratory results included a severe serum hypocalcaemia of 1.41 mmol/l (normal range 2.20 - 2.65 mmol/l). Ionized calcium was 0.67 mmol/l (1.15 - 1.29 mmol/l). Serum albumin level was normal. Serum phosphate was high at 1.91 mmol/l (0.80 - 1.40 mmol/l). There were a mild thrombocytopenia and anemia. His white blood cell count was slightly elevated with a normal differentiation. Renal function was normal. Both urinary calcium and parathyroid hormone (PTH) concentration were low (0.10 mmol/l (1.0 - 5.0 mmol/l) respectively 1.2 pmol/l (1.4 – 7.3 pmol/l)). Furthermore 25-OH-D was low. A shoulder X-ray revealed a fractured humerus.
The diagnosis of hypoparathyroidism was made. The combination of hypoparathyroidism, facial dysmorphisms and cardiac anomalies were highly suggestive for 22q11.2 deletion syndrome. Calcium and vitamin D suppletion were initiated and the patient underwent surgery for the humerus fracture without any complications. The result of the chromosomal analysis to confirm the diagnosis is awaited.
Discussion: The 22q11.2 deletion syndrome affects between 1 in 2000 and 1 in 4000 live births. The microdeletion leads to a defective development of the pharyngeal pouch system. The acronym CATCH-22 summarizes the clinical features Cardiac Abnormality, Abnormal facies, Thymic aplasia, Cleft palate and Hypocalcemia/ Hypoparathyroidism, where "22" represents the affected chromosome. However, there is a great variety in clinical presentation. The classic combination of hypoparathyroidism, thymic hypoplasia and facial dysmorphism is also called diGeorge syndrome. Although 22q11.2 deletion syndrome is fairly common the diagnosis is often missed as physicians are unaware of the syndrome or see only one part of the cardinal features.
Conclusion: The finding of hypocalcaemia in a patient with a considerable medical history should trigger one to think of a 22q11.2 deletion syndrome, even at the age of 42.