| |

Subarachnoid Haemorrhage

Byepsuadmin

Subarachnoid haemorrhages are where there is an extravasation of blood into the space between the arachnoid and pia. Subarachnoid haemorrhages often develop as a result of rupture of a cerebral aneurysm (most often arising from the circle of Willis or the middle cerebral artery bifurcation) or consequent to severe head trauma. Patients with subarachnoid haemorrhage secondary to aneurysmal bleeding often present with sudden onset severe headache which is classically described by the patient as “the worst headache of my life“.

The series of non-contrast cranial CT scans shown here (Figures 1 to 6) are from a patient who presented with sudden onset of severe headache. Subarachnoid haemorrhage is present and blood can be seen at the basal cisterns arrow_1. An urgent CT angiogram was arranged and a saccular aneurysm was noted at the left middle cerebral artery bifurcation. The Neurosurgical colleagues were then consulted urgently for neurosurgical intervention.

It should be noted that the sensitivity of a non-contrast cranial CT scan in detecting subarachnoid haemorrhage reduces significantly with time, particularly if the subarachnoid haemorrhage is small. If subarachnoid haemorrhage is strongly suspected, the patient should undergo a lumbar puncture to delineate whether the presence of xanthrochromia is present. If present, this means that there are presence of red cells in the cerebro-spinal fluid. With time, the red cells breakdown, releasing haeme, which is subsequently degraded into the yellow-green pigment bilirubin causing the characteristic yellow colour in patients with xanthochromia. In contrast, if red blood cells enter the cerebrospinal fluid due to a “traumatic tap” (i.e. a small blood vessel was damaged during the lumbar puncture), there is inadequate time for the red cells to degrade and thus xanthochromia would not be present.

The non-contrast CT scans shown here are from 2 different patients with a right-sided subarachnoid haemorrhage (Figures 7 to 15). Blood could be seen at the sulci of the right parietal lobe in both cases arrow_1 and in the latter case (Figures 8 to 15), blood could also be seen at the sulci of the right temporal lobe as well as the right sylvian fissure arrow_4.

Similar Posts

  • Multiple Sclerosis

    Byepsuadmin

    The set of cranial MRIs shown here are from a young woman with a known history of relapsing-remitting multiple sclerosis. In the first scan (T2W axial cut), we can see multiple T2 hyperintense lesions involving bilateral cerebral cortices (Figure 1). These lesions are noted to be of a juxta-cortical and also peri-ventricular distribution, which are classical of multiple sclerosis. In the next…

  • | |

    Spontaneous Parenchymal Haemorrhage

    Byepsuadmin

    There are a number of causes of spontaneous parenchymal haemorrhages. These include: hypertension, vascular malformations and aneurysms, neoplasm (primary or metastatic), cerebral amyloid angiopathy, use of antiplatelet agents or anti-coagulants, blood dyscrasias and drug abuse (e.g. amphetamine and cocaine use). Parenchymal haemorrhages could also be subdivided into deep versus lobar haemorrhages, where deep haemorrhages (basal ganglia, thalamus,…

  • Thymoma

    Byepsuadmin

    In this contrast thoracic CT scan of a middle-aged woman with newly diagnosed seropositive generalized myasthenia gravis, an abnormal thymic lesion (present in the anterior mediastinal compartment) could be seen  (Figure 1). The patient was referred to the Cardiothoracic Surgeons where she received a thymectomy via an open sternotomy. The thymic specimen was sent for histo-pathological…

  • Arterio-venous Malformations

    Byepsuadmin

    Cerebral vascular malformations can be classified by histopathology into 4 major types: Arterio-venous malformations (AVMs) Venous angiomas (developmental venous anomalies) Capillary telangiectasias and Cavernous malformations Arterio-venous malformations (AVMs) are congenital vascular lesions due to dysregulated angiogenesis. They are most often solitary but rarely could be multiple, in which case an underlying syndrome (e.g. hereditary haemorrhagic telangiectasia,…

  • Osmotic Demyelination Syndrome

    Byepsuadmin

    This is a set of cranial MRIs from a patient with osmotic demyelination syndrome, formerly called central pontine myelinolysis. Osmotic demyelination syndrome occurs when wide fluxes in serum sodium levels are induced by too rapid correction of hyponatremia. Oligodendrocytes, which forms the myelin sheaths, are particularly vulnerable to osmotic changes. If the osmotic stress is…

  • |

    Indications of a Lumbar Puncture

    Byepsuadmin

    A lumbar puncture (LP, also known as a spinal tap) is a diagnostic and at times, therapeutic medical procedure. Diagnostic indications The main diagnostic indications of performing a LP is for collection and evaluation of cerebrospinal fluid (CSF) for diagnosis and exclusion of infectious, inflammatory and neoplastic diseases affecting the central nervous system. For example,…