Moya Moya Disease: A rare disease with a common presenting symptom in a chronic kidney disease patient

Moya Moya Disease (MDD) is a rare cerebrovascular pathology. It is non atherosclerotic cerebrovascular disease characterized by bilateral internal carotid stenosis or occlusion, and abnormal vascular network at the base of the brain. Here we report a case of young female who presented in emergency with complaints of jerky movements of limbs for six months and history of recently developed unusual high blood pressure which was followed by uremic symptoms. Her workup revealed severe renal dysfunction required kidney replacement therapy (KRT) i.e., hemodialysis. During hospital stay her mental status deteriorated with a drop in GCS. Brain imaging performed and she found to have MMD. Her clinical course continued to deteriorate despite of extensive work up and aggressive management, she died eventually.


INTRODUCTION
Moya Moya Disease (MMD) is a rare, chronic and progressive cerebrovascular disease, characterized by stenosis of bilateral internal carotid arteries with abnormal network at the base of brain. 1 Extra cranial vessels mainly involve renal artery. 2 It is rare disease with reported incidence of 0.086 per 100,000 population 3 , more common in East Asian countries like, Japan, Korea and China with slight female predominance (2:1).It has bimodal age of onset, with Coma Scale (GCS) was 15/15.Chest examination revealed bilateral crepitations on auscultation and a gallop sound at precordial area.Abdomen was soft and non-tender with no visceral enlargement.Laboratory parameters revealed grossly abnormal kidney functions with serum creatinine of 13.5 mg/dl, urea 191mg/dl, Na 133mEq/L, K 4.1mEq/L, Cl 91mEq/L and HCO3 15mEq/L, Hemoglobin was 7.2g/dL, TLC 10.2 x10 9 /L, Platelet 424 x 10 9 /L.On ultrasonography kidney were measured as 7cm each, with increased echogenicity.Chest roentgenogram revealed signs of pulmonary edema.She was commenced on hemodialysis with temporary dialysis catheter.
During her hospital stay she developed generalized tonic clonic seizures (GTCs) multiple times and dropped her conscious level, GCS declined to 7/15.She was electively intubated and kept on mechanical ventilation.During workup for the cause of GTCs her metabolic profile found normal and cerebrospinal fluid analysis was inconclusive.Brain imaging performed, CT scan brain done, which raised the suspicion of bilateral parietal regions infarct, this was confirmed with MRI brain, which showed bilateral parietal lobe infarct as evidenced by hyper intense signals in T1 images (Fig. 1).CT angiogram of brain revealed nonvisualization of bilateral middle cerebral, anterior cerebral arteries and Circle of Willis.Numerous collaterals from posterior carotid and extra carotid circulation supplying anterior portion of brain were found and these findings are suggestive of Moya Moya disease (Fig. 2).Unfortunately, CT angiogram of abdomen could not have done to rule out renal artery stenosis as patient did not survive.

DISCUSSION
MMD is a chronic, progressive, cerebrovascular disease characterized by occlusion of bilateral internal carotid arteries at their distal portions. 4As a result, collateral network of leptomeningeal vessel formed at the base of brain giving appearance of 'puff of smoke' known as Moya Moya in Japanese. 5There are four defined types of MMD, ischemic, hemorrhagic, epileptic and other.It has unique clinical features with two peaks of age distribution at age of five years and at 40.Our patient was different in a way that she was not at any of this peak.The cause of chronic kidney disease remained unclear from history in our patient, but we as a routine see many young patients presenting in our emergency room with advanced uremia and small kidneys indicating a long term pathology going on.
Pediatric population usually have ischemic attack where as adults have both hemorrhagic and ischemic. 6t is more common in females as compared to males and has highest incidence in Japan. 4MMD has some genetic association linked to chromosome 17 in Japanese as well as with other demographics. 5t can present with recurrent TIA, epilepsy, stroke (hemorrhagic or infarct), hemiparesis, dysarthria, aphasia, and cognitive impairment. 7Reno vascular hypertension is considered to be one of the important causes of hypertension in patients with MMD. 8 It

Fig. 2 :
Fig.2: CT angiogram of brain showing coiled network of vessels at the base of brain giving puff of smoke appearance "Moya Moya".(Picture courtesy: Dr. M. Farid, Dept. of Radiology, SIUT)