Ruptured aneurysm of the circle of Willis in a case of polycystic disease of the kidneys.
Congenital anomalies are often multiple and tend to occur in certain combinations. Polycystic kidney disease is frequently found with anomalies involving other organs of the body. An association, reported a number of times, but not given much clinical emphasis, is that of Polycystic disease of the kidneys and aneurysm of the circle of Willis.
A 45 year old male was admitted with history of sudden onset of headache associated with vomiting 8 days prior to hospitalisation. He developed progressive drowsiness and was admitted in a semiconscious state.
On examination, he was febrile, normotensive (B.P.: 130/90 mm Hg) and stuporose. Fundi were normal. He had hypotonia of all four limbs and marked neck stiffness. There was no focal neurological deficit.
Per abdomen, both kidneys were found to be markedly enlarged. Liver and spleen were not palpable. A complete haemogram, urine examination, renal functions and liver function tests were normal.
CSF examination revealed frank xanthochromia with proteins 200 mg%, RBCs 11000/ C.mm and 60 leucocytes/C.mm.
ECG and X-ray chest were normal. A diagnosis of Polycystic kidney disease with subarachnoid haemorrhage was made. The patient dramatically improved with parenteral dexamethasone and supportive management and had an uncomplicated hospital stay without any residual deficit.
An ultrasound study confirmed the presence of Polycystic kidneys with kidney sizes: the right: 10 x 8.5 cm, left: 23 x 7.5 cm. Liver ultrasound scan did not reveal any evidence of Polycystic disease.
Four vessel angiography demonstrated a multilobular aneurysm of the anterior communicating artery in the circle of Willis [Fig. 1].
An aortogram with a selective renal arteriogram showed splaying and distortion of the renal vasculature around radiolucencies on both the sides, further confirming the diagnosis [Fig. 2].
Selective hepatic and splenic arteriograms were normal.
The patient refused neuro-surgical treatment for his aneurysm and took discharge at request.
Adult Polycystic disease (APCD) is by far the most common hereditary disorder to affect the kidney and the third most common cause of progressive renal failure. Its frequency is between 1 in 500 to 1 in 1500 in the general population. It differs in pathological anatomy, natural history and mode of inheritance from a form of polycystic disease in infants called infantile polycystic disease (IPCD).
APCD is inherited as an autosomal dominant character with very high penetrance while IPCD is inherited as an autosomal recessive trait. About one third of all patients with APCD have one or a few cysts in the liver. Epithelium-lined cysts of other viscera are much less common and when present are almost invariably asymptomatic. About 5% have one or more cysts of the pancreas.
The abnormality of major clinical significance associated with APCD of kidneys is the occurrence of saccular aneurysms of the cerebral arteries. The majority of intracranial aneurysms are of congenital origin and are distinctly saccular in shape. They are known as `berry' aneurysms because of their shape and smooth dark coats. They most frequently appear at or near the bifurcation of the larger cerebral arteries, occurring 4 times as often in the anterior half as in the posterior half of the circle of Willis. Usually single, they may be multiple. Our patient had a single multilobular aneurysm of the anterior communicating artery.
The origin of these berry aneurysms is not definitely known. They may develop because of congenital defect of the media, with thinning out of the elastica, or because of persistent remnants of the embryonic capillary network.
The association of APCD and intracranial aneurysm was cited by Dunger in four autopsy cases as early as 1904. In Brown's report (1951), 8 patients (22.4%) out of 36 with APCD died of sub-arachnoid haemorrhage from ruptured berry's aneurysm.
Past theories of polycystic disease have included intra-uterine and renal infection accompanied by tubular obstruction, and non-union of the branches of the ureteric bud with the nephrogenic blastoma, neither of which has been verified. This latter pathogenetic possibility was disproved by Lambert.
Obstruction due to polypoid and papillary hyperplasia of tubular epithelium may play a part in the initiation of cyst formation both in experimental models of the disease, such as the diphenylamine induced polycystic disease of rats, and in the human disease. Acquired obstruction of this kind may possibly lead to cystic dilatation of the tubules because of a change in the composition of the tubular basement membrane that causes it to split and renders it less resistant to distension. APCD may, indeed, be due to an abnormality of the genetic locus that determines the structure of the collagen of the glomerular and tubular basement membranes and defects in these membranes may be related to a single enzyme deficiency., 
Recently it was seen that patients with congenital cerebral aneurysms were type III collagen deficient. This might directly influence the properties of arterial walls in such a way as to encourage aneurysm formation at the point of known arterial weakness.
Is it the same genetic defect which leads to changes in the collagen of basement membrane of kidney tubules and collagen of cerebral arteries in patients with APCD and associated aneurysm of intracranial arteries?
Approximately 12% of patients with polycystic renal disease die of subarachnoid haemorrhage while about 3%. Of patients who die of subarachnoid haemorrhage have polycystic renal disease.
Most of the reports indicate that the patients with combined anomalies die from rupture of aneurysm and that APCD kidney is frequently an incidental autopsy finding. Our patient presented with subarachnoid haemorrhage and polycystic kidneys were found on routine examination. Relatively few patients die of renal failure with an unruptured congenital aneurysm being found at autopsy.
Unruptured intracranial saccular aneurysms that are less than 10 mm in diameter have a very low probability of subsequent ruptures. Patients with aneurysm 10 mm or greater in size should be considered for intracranial surgery, to isolate the aneurysm from the circulation as soon as possible, since nearly half may rupture within 2½ months of diagnosis. Other factors entering into a decision regarding surgery include the general condition of the patient and the accessibility of a neurosurgeon who is experienced in aneurysmal surgery.
Antifibrinolytic agents have been used in the management of ruptured intracranial aneurysm. They decrease the risk of rebleeding. Aminocaproic acid has proved useful in this context. It acts as an antagonist of activators for plasminogen. It has been found to reduce the subarachnoid rebleeding rate from 20 to 13% with a consequent fall in mortality from 20 to 12%.
Our patient did not receive aminocaproic acid and did not have a rebleed for 3 weeks.
We are thankful to the Bombay Port Trust Hospital for doing Ultrasound studies on this patient and to the Dean, Seth G.S. Medical College. and K.E.M. Hospital for giving permission to publish this case.