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LETTER TO EDITOR
Year : 2013  |  Volume : 61  |  Issue : 5  |  Page : 550--552

Retroclival subdural hematoma: An uncommon site of a common pathology

Prasad Krishnan1, Rajaraman Kartikueyan1, Siddhartha Roy Chowdhury1, Sayan Das2,  
1 Department of Neurosurgery and Radiology, Peerless Hospital, Kolkata, West Bengal, India
2 National Neurosciences Centre, Peerless Hospital, Kolkata, West Bengal, India

Correspondence Address:
Prasad Krishnan
Department of Neurosurgery and Radiology, Peerless Hospital, Kolkata, West Bengal
India




How to cite this article:
Krishnan P, Kartikueyan R, Chowdhury SR, Das S. Retroclival subdural hematoma: An uncommon site of a common pathology.Neurol India 2013;61:550-552


How to cite this URL:
Krishnan P, Kartikueyan R, Chowdhury SR, Das S. Retroclival subdural hematoma: An uncommon site of a common pathology. Neurol India [serial online] 2013 [cited 2022 Jun 29 ];61:550-552
Available from: https://www.neurologyindia.com/text.asp?2013/61/5/550/121951


Full Text

Sir,

Subdural hematomas (SDHs) of the posterior fossa are rare and there have been very few reports of retroclival SDH. Most cases of retroclival hematomas are epidural and posttraumatic. We report a case of fatal spontaneous retroclival subdural hematoma in an adult with thrombocytopenia.

A 59-year-old lady presented with history of progressive decline in sensorium with difficulty in swallowing, articulation, and weakness of all four limbs over 2 days. She was a case of chronic kidney disease (CKD) on maintenance hemodialysis twice a week. She was also diagnosed to have chronic hepatitis, hepatitis B surface antigen positive. On examination, she was flexing both upper limbs to pain. Both plantars were extensor. On admission, patient was intubated and ventilated. Investigations revealed low platelet count (18,000/cu.mm), prothrombin time of 21.2 s, and INR (International Normalized Ratio) of 1.73. Computed tomography (CT) scan of brain revealed thick collection of blood behind the clivus pushing the brain stem backward. At lower levels, blood collection was encircling the upper cervical cord [Figure 1]. The blood extended downward from the level of the dorsum sella through the foramen magnum to the C3 body space on sagittal images. Retrocerebellar blood was also seen [Figure 2]. Laterally, the blood was more on the right side but did not extend beyond the internal acoustic meatus [Figure 3]. An acute subdural hematoma over the left frontoparietal region was also seen [Figure 4]. Transfusion of platelets and fresh frozen plasma transfusion was given; however, her neurological condition worsened rapidly and she died within 6 h of admission.{Figure 1}{Figure 2}{Figure 3}{Figure 4}

Posterior fossa (infratentorial) SDHs are rare and account for 0.3% of all SDHs. [1],[2] Mostly they are on the cerebellar convexity. No data is available on what proportion of these SDHs are retroclival. The majority of retroclival hematomas are epidural and some cases are interdural. PubMed search using the words retroclival and hematoma and recovered 29 records and search using the terms retroclival, subdural, and hematoma recovered only 6 records.

The source of bleeding in both supratentorial compartment and cerebellar convexity SDHs is supposed to be the bridging veins that traverse the "potential" space between the arachnoid and the inner layer of the dura or from injured cerebral cortex. The retroclival subdural space is an "actual" space bounded anteriorly by the clival dura and posteriorly by the anterior pontine membrane (APM), a thickened condensation of arachnoid [Figure 5], which comes in contact with the dura only at points of exit of the cranial nerves. [3] The basilar venous plexus is contained within the subarachnoid space bounded by the thick APM. The retroclival subdural space is, hence, relatively bloodless. This may account for the rarity of acute SDHs in this location. The source of bleeding in nontraumatic cases in this location is unclear. Another reason for the rarity of this condition may be the rapid redistribution of blood from the retroclival into the spinal subdural space. [3],[4],[5] Small quantities of blood and poor resolution scanners are the causes put forth for the infrequent reporting of these lesions. [5]{Figure 5}

Literature review retrieved nine cases of retroclival acute SDHs, [Table 1] six of which were traumatic [1],[3],[4],[5],[6] and 1 was due to a pituitary apoplexy. [2] The other two patients were anticoagulant-related. [7],[8] About 10% of patients on anticoagulants for at least 1 year, develop serious complications and 1% of them are fatal. [8] In our patient, the bleed may be related to thrombocytopenia and also mild coagulation abnormalities which could be attributable to chronic hepatitis and CKD.{Table 1}

The diagnosis of the location of a retroclival hematoma as subdural or extradural is difficult with a CT scan alone. In this patient, we could not do magnetic resonance imaging. However, tracking of blood upto the lower border of C3 and absence of blood in front of the transverse ligament suggests the subdural location of haemorrhage. An extradural hematoma would dissect inferiorly upto the attachment of the membrana tectoria to the C2 body but no further downward. [1] This is because the posterior [inner] layer of the clival dura is continuous with the spinal dura, while the anterior [periosteal] layer is continuous with the upward extension of the posterior longitudinal ligament, that is, the tectorial membrane.

All posttraumatic cases were young, [5] while nontraumatic cases were elderly. Rarity of the condition defies establishment of proper management protocols. All the reported cases of retroclival SDHs, except one, had been successfully management by conservative means and surgery is considered only in patients with progressive neurological deficits. [1],[5]

In conclusion, retroclival SDHs are rare and it could be posttraumatic or spontaneous due to abnormal coagulation. This is a difficult area to approach surgically. However, most cases can probably be managed conservatively as the clot decompresses into the spinal subdural space. Surgery has a role only if there is life-threatening compression of posterior fossa structures. Awareness of this pathology and establishing the diagnosis early on CT scan will help in monitoring such patients for neurological deterioration and institution of appropriate management strategies.

References

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