• Cause: unknown, few reports exist. Trauma has been postulated as a cause. Aneurysms have only been described in Bearded dragons (Pogona vitticeps) and in one Burmese python (Python molurus bivittatus). Hypertension, underlying cardiovascular disease or genetic predisposition may play a role. Encephalitozoon pogonae infection was implicated in one Bearded dragon case. Spirorchid flukes may cause aneurysms in Green sea turtles (Chelonia mydas).
• Signs: soft fluid filled subcutaneous swelling often in the dorsolateral neck or over the head, sudden death with no previous illness, lethargy, blepharospasm, hyporexia, anorexia.
• Diagnosis: often based on presentation or made on post-mortem, computed tomography, magnetic resonance imaging or doppler ultrasonography of a swelling may be helpful in establishing possible cause.
• Treatment: conservative management if the aneurysm isn’t too large can be considered. Reports of good surgical outcomes of cranial aneurysms in bearded dragons can be found. Aspiration of these aneurysms is generally contraindicated – the swellings refill quickly suggesting communication with a high-pressure vessel.
• Prognosis: good to poor depending on location of the aneurysm and time of presentation.

• Soft fluid filled subcutaneous swelling usually in the dorsolateral neck or over the head although can be elsewhere, sudden death with no previous illness, lethargy, blepharospasm, hyporexia, anorexia.
• Exophthalmos secondary to an orbital varix has been described in a Green iguana (Iguana Iguana).

• Sudden onset swelling, usually over the dorsolateral neck or dorsal cranium.
• Sudden death.

• Worldwide.

• Captive Bearded dragons Bearded dragon appear overrepresented.

• Unknown, unlikely zoonotic potential.

• Initial stabilization, cost of supportive treatment, fluid therapy, hematobiochemistry, hospitalization, diagnostic imaging – in particular advanced imaging (MRI or CT) and Doppler ultrasonography

• Depending on the size of swelling ongoing bleeding may pose a risk of cardiovascular crisis.
• Patients are likely to be unstable during anesthesia if attempting surgery and may require a transfusion before or after the procedure.
• As reptile blood donors may be difficult to obtain sterile collection of blood and autotransfusion may be considered.

• Unknown.
• Aneurysms usually arise from either the internal carotid artery or from the aorta.
• Trauma, genetic predisposition and underlying cardiovascular disease may all play a role:
  • It has been suggested that the carotid arteries, because of their shallow position in the dorsolateral pharynx, may be exposed to trauma during feeding.
  • In a recent pathological review of aneurysms in bearded dragons, aneurysms were found in five locations; cephalic, cranial coelom, caudal coelom, limbs and tail, with the cranial coelom being the most common. It may be that the cephalic ones are diagnosed more antemortem given their visible location.
• One report describes a generalized vasculitis with pharyngeal aneurysm development associated with systemic E. pogonae infection in a bearded dragon.

General

• Trauma Traumatic injuries resulting from handling or fighting with another individual, dropping from a height, underlying cardiovascular disease Heart disease.

• Largely unknown.
• A recent pathological review of cases in bearded dragons has suggested that the vascular dilations and ruptures observed likely associated with weakness of the vessel walls caused by degenerative changes in the intimal and medial tunics.
• Stranded Green turtles infested with spirorchid flukes (Hapalotrema mehrai, Hapalotrema postorchis and Neospirorchis schistosomatoides) may suffer secondary aneurysms resulting from the parasitism. Endocarditis, arteritis and thrombosis may also be present.

• Aneurysms appear to develop and progress quickly.
• In the author’s experience they often appear overnight.

• Unknown.

Refereed papers

• Recent references from PubMed and VetMedResource.
• Ortega J, Wyneken J & Garner M M (2023) Aneurysm associated with vascular wall degeneration in Bearded dragons (Pogona vitticeps). Vet Pathol 3009858231214025 PubMed.
• Kaiser N C, Greenwood S J, Gouchie G M & Martinson S A (2021) Encephalitozoon pogonae – Associated systemic vasculitis in a Central Bearded dragon (Pogona vitticeps). J Herpetol Med Surg 31 (3),  168-172 VetMedResource.
• Raiti P (2012) Husbandry, diseases and veterinary care of the Bearded dragon (Pogona vitticeps). J Herpetol Med Surg 22 (3-4), 117-131 BioOne.
• Rush E M, Donnelly T M & Walberg J (2001) What’s your diagnosis? Cardiopulmonary arrest in a Burmese python. Aortic aneurysm. Lab Anim 30 (3), 24-27 PubMed.
• Gordon A N, Kelly W R & Cribb T H (1998) Lesions caused by cardiovascular flukes (digenea: spirorchidae) in stranded green turtles (Chelonia mydas). Vet Pathol 35 (1), 21-30 PubMed.
• Whittaker C, Schumacher J & Bennett R (1997) Orbital varix in a green iguana (Iguana iguana). Vet Comp Ophthal 7 (2), 101-104 VetMedResource.

Other sources of information

• Barten S & Simpson S (2019) Differential Diagnoses by Clinical Signs – Lizards. In: Mader’s Reptile and Amphibian Medicine and Surgery. 3rd edn. Eds: Divers S & Stahl S. Elsevier, USA. pp 1259.
• Hynes B & Girling S (2019) Cardiovascular and Haemopoietic Systems. In: BSAVA Manual of Reptiles. 3rd edn. Eds: Girling S & Raiti P. BSAVA, UK. pp 338.