Introduction 

   Achondroplasia is a hereditary, congenital disturbance of epiphyseal chondroblastic growth and mutation with the characteristic appearance of disproportionate short stature. The well-recognized neurosurgical implications of achondroplasia include spinal cord compression and acute or progressive hydrocephalus. 
   We report a case of a 26-year-old woman with achondroplasia who developed aneurysmal subarachnoid hemorrhage (SAH) and review the relevant literatures. 

Case Report 

   A 26-year-old woman presented with sudden, excruciating headache. For several years, she occasionally had been suffered occipital and suboccipital headache that was controlled by usual analgesics. On admission, she was drowsy, however, did not show any focal neurological deficits. Physical examination revealed short stature (134 cm), shortened limbs and fingers, whereas relatively normal torso, in addition to the hypoplastic midface (Fig. 1A). Nevertheless, the patient denied any previous noteworthy medical problems. 
   Cranial computed tomography demonstrated diffuse SAH primarily located within the basal cisterns without significant hydrocephalus (Fig. 1B). Catheter angiography revealed an aneurysmal dilatation at the anterior communicating artery (Fig. 1C). No additional cerebrovascular anomaly was detected. She underwent the right pterional craniotomy for obliteration of the ruptured aneurysm. Following careful arachnoid dissection, anteriorly protruded aneurysm was found. Because the aneurysm had no discernible neck, it was wrapped with muslin patch and glue. 
   She had an unremarkable postoperative course, including radiographic disappearance of aneurysm. Molecular analysis of the fibroblastic growth factor receptor-3 (FGFR-3) gene on short arm of the 4th chromosome showed one point mutation at G1138C. Counseling by the genetic experts revealed that two of her family members (father and her sibling) also showed the same external features. However, they refused to conduct screening test for stroke, because they didn’t have any bit of clues for cerebrovascular symptoms. Two weeks following the operative procedure, she was discharged uneventfully. 

Discussion 

   Achondroplasia, characterized by the congenital dwarfism and rhizomeric micromelia, is known to be associated with severe neurological conditions including hydrocephalus, small skull base, cervicomedullary compression and spinal stenosis.¹⁾⁴⁾⁵⁾ All these features are characteristics of the genetically inherited, autosomal dominant abnormality of endochondral ossification.⁴⁾⁷⁾ 
   In the present case, the patient exhibited megaencephaly and several facial deformities, in addition to the common stigmata of achondroplasia. The degree of hydrocephalus and contraction of posterior fossa, however, was not so significant. 
   Intracranial hemorrhage could occur in achondroplastic patients, albeit seldom reported. However, such literatures described only autopsy-proven, mainly nonsurgical hemorrhage caused by arteriovenous malformation and aneurysm, therefore, clinical detail has not been reported.²⁾⁶⁾ 
   Another report, perioperative hemorrhage in the cerebellar hemisphere, assumed this phenomenon is primarily attributable to the rapidly developed venous hypertension.¹⁾³⁾ Aneurysmal SAH, in general, is not caused by venous hypertension from small basal foramen and subsequent impaired drainage. 
   Accordingly, if achondroplasia is exclusively an abnormality of chondroblastic bone formation, precise pathogenic mechanisms of the aneurymal SAH still remain enigmatic and, this correlation seems to be rather incidental. Nonetheless, this case emphasizes the need to include aneurymal SAH in the differential diagnosis of sudden mental deterioration in achondroplastic patients. Because the patient did not show any symptoms that draw neurological attention, except intermittent headache, her initial clinical presentation should have been quite unusual, as shown in the current case. Atypical, severe headache such as trigeminal neuralgia might be developed in an achondroplastic patient with asymmetric skull base,⁶⁾⁸⁾ but this can be differentiated with ours. Prompt recognition and proper surgical interventions guarantees the long-term promising outcome to these patients. 

Conclusion 

   We present this rare case with a review of the literature and highlight the importance of including aneurymal SAH in the differential diagnosis of sudden mental deterioration in achondroplastic patients. 

REFERENCES

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