J Neurocrit Care.  2024 Dec;17(2):57-61. 10.18700/jnc.240012.

A case series of atraumatic nonaneurysmal perimesencephalic subarachnoid hemorrhages triggered during exertion at altitude

• Smith AT

• KMID: 2563022
• DOI: http://doi.org/10.18700/jnc.240012

Abstract

Background
Nonaneurysmal perimesencephalic subarachnoid hemorrhage (NAPH) is a form of subarachnoid hemorrhage (SAH) occurring predominantly in the perimesencephalic region, in the absence of an aneurysm or other source of bleeding on diagnostic angiography. The underlying cause of NAPH remains unclear.
Case report
Herein, we describe three patients who developed NAPH during strenuous activity in the absence of trauma after traveling to an altitude of approximately 7,500 feet. The patients were treated conservatively without any residual neurological deficits.
Conclusions
This case series suggests that hypoxia and vigorous exercise could be risk factors for NAPH. Patients traveling to higher altitudes should be counseled to increase their exercise intensity gradually.

Keyword

Subarachnoid Hemorrhage; Stroke; Neurocritical care; Wilderness medicine

Figure

• 

  Fig. 1. (A) A noncontrast computed tomography (CT) scan showing a subarachnoid hemorrhage in the basal and prepontine cisterns without evidence of hydrocephalus. (B) A CT angiogram of the brain revealing no evidence of aneurysm. (C) A diagnostic angiogram of the brain revealing no evidence of aneurysm.

• 

  Fig. 2. (A) A noncontrast computed tomography (CT) scan showing a moderate subarachnoid hemorrhage in the prepontine cistern. (B) A CT angiogram of the brain showing no evidence of aneurysm.

• 

  Fig. 3. (A) A noncontrast head computed tomography (CT) showing a subarachnoid hemorrhage within the subarachnoid space anterior to the pons extending into the interpeduncular cistern. (B) A CT angiogram of the brain revealing no evidence of aneurysm. (C) A diagnostic angiogram of the brain revealing no evidence of aneurysm.

Reference

1. van Gijn J, van Dongen KJ, Vermeulen M, Hijdra A. Perimesencephalic hemorrhage: a nonaneurysmal and benign form of subarachnoid hemorrhage. Neurology. 1985; 35:493–7.

2. Rouchaud A, Lehman VT, Murad MH, Burrows A, Cloft HJ, Lindell EP, et al. Nonaneurysmal perimesencephalic hemorrhage is associated with deep cerebral venous drainage anomalies: a systematic literature review and meta-analysis. AJNR Am J Neuroradiol. 2016; 37:1657–63.

3. Schwartz TH, Solomon RA. Perimesencephalic nonaneurysmal subarachnoid hemorrhage: review of the literature. Neurosurgery. 1996; 39:433–40.

4. Hunt WE, Hess RM. Surgical risk as related to time of intervention in the repair of intracranial aneurysms. J Neurosurg. 1968; 28:14–20.

5. Forster DM, Steiner L, Hakanson S, Bergvall U. The value of repeat pan-angiography in cases of unexplained subarachnoid hemorrhage. J Neurosurg. 1978; 48:712–6.

6. Matsumaru Y, Yanaka K, Muroi A, Sato H, Kamezaki T, Nose T. Significance of a small bulge on the basilar artery in patients with perimesencephalic nonaneurysmal subarachnoid hemorrhage: report of two cases. J Neurosurg. 2003; 98:426–9.

7. Boswell S, Thorell W, Gogela S, Lyden E, Surdell D. Angiogram-negative subarachnoid hemorrhage: outcomes data and review of the literature. J Stroke Cerebrovasc Dis. 2013; 22:750–7.

8. Canhão P, Ferro JM, Pinto AN, Melo TP, Campos JG. Perimesencephalic and nonperimesencephalic subarachnoid haemorrhages with negative angiograms. Acta Neurochir (Wien). 1995; 132:14–9.

9. Hong Y, Fang Y, Chen T, Zhang J. Recurrent perimesencephalic nonaneurysmal subarachnoid hemorrhage: case report and review of the literature. World Neurosurg. 2017; 107:877–80.

10. Piper K, Screven R, Agazzi S, Guerrero WR, Dombrowski K. Nonaneurysmal subarachnoid hemorrhage in scuba diving. World Neurosurg. 2020; 141:153–6.

11. Kohshi K, Morimatsu Y, Tamaki H, Murata Y, Kohshi K, Ishitake T, et al. Cerebrospinal vascular diseases misdiagnosed as decompression illness: the importance of considering other neurological diagnoses. Undersea Hyperb Med. 2017; 44:309–13.

12. Hida K, Iwasaki Y, Akino M. Spontaneous spinal hemorrhage during scuba diving: case illustration. J Neurosurg. 2002; 96(3 Suppl):351.

13. Litch JA, Basnyat B, Zimmerman M. Subarachnoid hemorrhage at high altitude. West J Med. 1997; 167:180–1.

14. Jehle D, Moscati R, Frye J, Reich N. The incidence of spontaneous subarachnoid hemorrhage with change in barometric pressure. Am J Emerg Med. 1994; 12:90–1.

15. Blandford J, Chalela JA. Perimesencephalic subarachnoid hemorrhage triggered by hypoxic training during swimming. Neurocrit Care. 2013; 18:395–7.