Pseudohypoparathyroidism

Postcoarctectomy syndrome was developed in a boy with Williams syndrome. Angiogram revealed widespread changes of visceral arteries and extravasation of the contrast material from the right inferior phrenic artery. Emergency laparotomy was successful. This unusual complication makes clear that the mesenteric arteritis after coarctectomy can cause aneurysm with a risk of rupture.

(Chest 1994; 106:1290-91)

Postcoarctectomy syndrome presents as severe abdominal pain, beginning 24 h to 8 days after coarctectomy, and can include mesenteric arteritis. Williams syndrome is characterized by hypercalcemia, a congential heart defect, mental retardation, and elfin face. We report an unusual complication of rupture of the right inferior phrenic artery aneurysm due to mesenteric arteritis following coarctectomy in a boy with Williams syndrome.

CASE REPORT

A 10-year-old boy was admitted to the hospital with edema and proteinuria on March 9, 1989. The patient was diagnosed as having primary osteoma cutis and pseudohypoparathyroidism at 7 months of age.

At the time of hospital admission, the boy weighed 25.4 kg and was 121.7 cm tall. He had elfin face and was mentally retarded. On physical examination, a continuous murmur (Levine second degree) was heard in the fourth intercostal space at the left sternal border, and a diastolic murmur (Levine third degree) was heard at the apex. Blood pressure in the upper extremities was 160/100 mm Hg, but pulses were barely palpable in the lower extremities. Subcutaneous calcified nodules were noted on the thighs, hips, and abdomen. Laboratory data were normal except urinary protein, 167 mg/100 ml (2.5 g/d),and serum albumin, 2.0 g/dl. Ellesworth-Howard test showed type 2 abnormality with an increase in cyclic adenosine monophosphate levels. Cardiac catheterization revealed coarctation of the aorta with a pressure gradient of 80 mm Hg, and mild aortic regurgitation.

Coarctectomy with end-to-end anastomosis was performed on July 13, 1989. Immediately after surgery, arterial pulsation became normal in the lower extremities. However, hypertension continued (150 to 170/80 to 90 mm Hg), and the patient was given nifedipine, hydralazine, and other antihypertensive drugs. [beta]-Blocker was not administered due to bradycardia. By these medcations, blood pressure was gradually normalized on the third postoperative day; however, the patient complained of nausea and a stomach ache and vomited. On the fourth postoperative day, abdominal distention became obvious. The next day the platelet count fell to 10,000/[mm.sup.3], and the patient developed melena and went into shock. Gastroscopy revealed acute gastric mucosal lesions, and abdominal paracentesis revealed hemoperitoneum. Angiogram of the abdominal aorta and its branches revealed widespread club-like dilatation, segmental spastic constriction, and stretching. The right inferior phrenic artery was dilated, and extravasation of the contrast material was noted (Fig 1).

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We performed an emergency laparotomy. Blood was spurting from the area of the right diaphragm, and hemostasis was achieved by suture ligation of the inferior phrenic artery. Stomach and intestines were edematous and filled with blood; numerous petechiae were observed on the serosa of intestines and the mesenterium. Total amount of hemorrhage was estimated to be about 850 ml. The patient recovered rapidly after laparotomy.

Three weeks after surgery, the patient's systolic arterial pressure was 100 to 120 mm Hg, and the diastolic murmur had disappeared. Two months after surgery, angiography revealed resolution of pathologic changes, except for two small aneurysms in the jejunal and ileal arteries (Fig 2). The patient experienced no further cardiovascular complications or abdominal symptoms.

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DISCUSSION

The mechanisms of paradoxic hypertension following repair of coarctation is thought to be due to hormonal (increased cathecholamine release and activation of reninangiotensin system) or neural disorders.(1) It disappears for a few days with or without treatment in most of the patients, thus patients who require laparotomy are extremely rare. Pathologic findings of postcoarctectomy mesenteric arteritis include intestinal hemorrhage, and arterial and venous thrombosis.(2) The pathogenesis of mesenteric arteritis following coarctectomy is thought to be similar to that of malignant hypertension. Nemes et al(3) have suggested that progressive elevation of blood pressure induces vasoconstriction by autoregulation and release of vasopressor agents that resulted in necrosis of smooth muscle and endothelial cells.

Reduction of paradoxic hypertension by using propranolol and other antihypertensive drugs has been successful in preventing mesenteric arteritis following repair of coarctation of the aorta. Although this patient showed moderate hypertension and became normotensive on the third postoperative day, mesenteric arteritis that resulted in disseminated intravascular coagulation and rupture of the inferior phrenic artery still developed. It is speculated that once mesenteric arteritis occurred, sequential pathologic changes such as transmural inflammatory cell infiltration, fragmentation of the internal elastic lamina, and intravascular thrombosis below the repaired coarctation are inevitable in some cases.(2)(3)(4) However, presence of abnormal calcium metabolism and initial treatment of hypertension by a calcium channel blocker in this case may contribute to the development and acceleration of a vascular lesion; exact mechanisms of formation of the aneurysm and its repture remain to be defined. Angiographic findings were compatible to the reported changes in postcoarctectomy syndrome, including segmental constriction, dilatation, and stretching of the mesenteric arteries, and certainly distortion of normal vascular architecture predisposes the artery to rupture.(4)(5)

To our knowledge, this is the first report of rupture of the inferior phrenic artery aneurysm associated with postcoarctectomy syndrome. Surgeons should be aware that arteritis with a risk of rupture may be present after coarctectomy in any branches that arise from the aorta distal to coarctation.

ACKNOWLEDGMENT: We thank Drs. S. Shimazu and N. Arai, Department of Surgery, Hokushin General Hospital, for accomplishment of laparotomy.

REFERENCES

(1)Parker FB Jr, Farrell B, Streeten DHP, Blackman MS, Sondheimer HM, Anderson GH Jr. Hypertensive mechanism in coarctation of the aorta: further studies of the renin-angiotensin system. J Thorac Cardiovasc Surg 1980; 80:568-73

(2)Ho ECK, Moss A. The syndrome of 'mesenteric arteritis' following surgical repair of aortic coarctation. Pediatrics 1972; 49:40-5

(3)Nemes Z, Diets R, Mann JFE, Luth JB, Gross F. Vasoconstriction and increased blood pressure in the development of accelerated vascular disease. Virchows Arch Pathol 1980; 386:161-73

(4)Singleton AO Jr, McFinnis LMS, Earson HR. Arteritis following correction of coarctation of the aorta. Surgery 1959; 45:665-73

(5)Kawauchi M, Tada Y, Asano K, Sudo K. Angiographic demonstration of mesenteric arterial changes in postcoarctectomy syndrome. Surgery 1985; 98:602-04

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