Canis ISSN: 2398-2942

Intracranial hemorrhage

Synonym(s): Cerebrovascular accident, CVA, Stroke

Contributor(s): Rodney Bagley, Laurent Garosi

Introduction

  • Rare cause of neurological disease → rapid cerebral dysfunction.
  • In contrast to the high incidence in man, intracerebral hemorrhage resulting from spontaneous rupture of vessels is rare in dogs.
  • Cause: trauma (subarachnoid or intracranial hemorrhage), rupture of congenital vascular abnormalities, primary or secondary brain tumors, vasculitis, systemic hypertension, intravascular lymphoma, hemorrghagic infarction, impaired coagulation.
  • Predisposed to by hypertension ( → sub-arachnoid bleeding), hypothyroidism, thromboembolic disease, coagulopathy, vasculopathy, radiation therapy.
  • Signs: acute onset, diverse neurological deficits depending on site and type of hemorrhage.
  • Diagnosis: imaging techniques, cerebrospinal fluid (CSF) analysis.
  • Prognosis: depends upon the extent of hemorrhage and the area of the nervous system involved.
  • See cerebral concussion/contusion Brain: cerebral concussion / contusion.

Pathogenesis

Etiology

Predisposing factors

General

Pathophysiology

  • Blood leaks directly into the brain, forming a hematoma within the brain parenchyma, or into the subarachnoid or subdural space, leading to physical disruption of the tissue and pressure on the surrounding brain. This alters CNS volume/pressure relationships, with the possibility of increasing intracranial pressure (ICP) and decreasing cerebral blood flow (CBF).
  • As a hematoma develops, ICP may remain constant due to a system of compensation. Within the skull, a change in the volume of one intracranial component (brain tissue, arterial blood, venous blood, CSF) will be balanced by a compensatory change in another.
  • Exhaustion of the compensating mechanisms for an intracranial space occupying lesion results in further increases in the volume of the hematoma, producing massive elevations in ICP.
  • Due to mechanical autoregulation, CBF remains constant even though cerebral perfusion pressure (CPP) may vary between 40 and 120 mmHg.
  • The normal autoregulation of CBF may be impaired following intracranial bleed, causing blood flow to damaged regions to become directly dependent on systemic blood pressure. Such animals may be unable to compensate for reductions in mean arterial pressure, causing decreased CPP in the presence of increased ICP.
  • In these circumstances, systemic hypotension can result in inadequate perfusion of the brain, which leads to cerebral ischemia and secondary neuronal injury.
  • Raised intracranial pressure Intracranial pressure measurement ultimately leads to brain herniation Brain: tentorial herniation.

Types of brain herniation

  • Subfalcal.
  • Caudal transtentorial.
  • Foramen magnum (can cause respiratory depression).
  • Rostral transtentorial.
  • Intracranial disease processes may result in mechanical disruption of intracranial tissues (primary injury). This primary injury may initiate a number of secondary pathophysiological sequelae such as:
    • Metabolic alterations in neuronal or glial cells.
    • Impairment of vascular supply to normal tissue (ischemia).
    • Impairment of cerebrovascular autoregulation.
    • Hemorrhage (intraparenchymal, intraventricular, extradural or subdural).
    • Irritation (seizure generation).
    • Obstruction of the ventricular system.
    • Edema formation.
    • Production of physiologically active products.
    • Increased intracranial pressure (ICP).
  • See pathophysiology of brain trauma Brain: trauma.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Lowrie M et al (2012) Concurrent medical conditions and long-term outcome in dogs with nontraumatic intracranial hemorrhage. Vet Radiol Ultrasound 53 (4), 381-388 PubMed.
  • Garosi L S (2010) Cerebrovascular disease in dogs and cats. Vet Clin North Am Sm Anim Pract 40 (1), 65-79 PubMed.
  • Hillock S M et al (2006) Vascular encephalopathies in dogs: diagnosis, treatment and prognosis. Comp Cont Educ Pract Vet 28 (3), 208-218 VetMedResource.
  • Garosi L S, Platt S R, McConnell J F, Wray J D & Smith K C (2005) Intracranial hemorrhage associated with Angiostrongylus vasorum infection in three dogs. JSAP 46 (2), 98-99 PubMed.
  • Thomas WB et al (1997) Magnetic resonance imaging appearance of intracranial hemorrhage secondary to cerebral vascular malformation in a dog. Vet Radiol Ultrasound 38 (5), 371-375 PubMed.
  • Elrifai A M et al (1996) Characterization of the cardiac effects of acute subarachnoid hemorrhage in dogs. Stroke 27 (4), 737-741 PubMed.
  • Dunn K J et al (1995) Intracranial hemorrhage in a Dobermann puppy with von Willebrand's disease. Vet Rec 136 (25), 635-636 PubMed.

Other sources of information

  • Garosi L S, Platt S R (2009) Treatment of cerebrovascular disease. In: Bonagura J D & Twedt D C (eds) Current Veterinary Therapy XIV. St Louis, Missouri, Saunders Elsevier. pp 1074-1077.
  • Braund KG (1994) Clinical Syndromes in Veterinary Neurology. 2nd edn. St. Louis: Mosby.
  • Bagley R S (1994) Pathophysiological effects of central nervous system tumor. Proceedings of the 12th Annual Veterinary Medical forum, Washington DC. pp 928-930.
  • Kornegay J N (1993) Pathogenesis of diseases of the central nervous system. In: Textbook of Small Animal Surgery. 2nd edn. Ed D Slatter. Philadelphia: W B Saunders. pp 1022-1037.
  • Shores A (1989) Craniocerebral trauma. In: Current Veterinary Therapy, 10th ed. Ed R W Kirk. Philadelphia: W B Saunders. pp 847-853.


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