Bedside transcranial sonography monitoring in a patient with hydrocephalus post subarachnoid hemorrhage

Hydrocephalus in patients with subarachnoid hemorrhage (SAH) is a frequent cause of clinical deterioration. In addition to clinical evaluation, computed tomography (CT) scans are used regularly to monitor for the appearance of hydrocephalus. The use of bedside ultrasound for imaging has expanded to multiple clinical applications especially in the acute critical patient care. We describe a case for which we used a hand-held two-dimensional (2D) transcranial sonography (TCS) probe to follow-up a patient with hydrocephalus after subarachnoid hemorrhage demonstrating high accuracy and clinical correlation. Permission to use the following figures was granted by the patient’s family.

Hydrocephalus is a common problem after subarachnoid hemorrhage SAH [3]. It is a devastating complication and can occur in up to 30% of patients. Its onset can be acute, within 48 h of SAH or, less frequently chronic, developing weeks or even months after SAH. The pathophysiology is most likely due to acute or chronic obstruction of cerebrospinal fluid (CSF) flow either by clot burden or induced inflammation and arachnoiditis. There are no current guidelines on how to manage or follow these patients in the acute stage and how to prevent the development of chronic symptomatic hydrocephalus. CT scan is used frequently in the management and monitoring of acute hydrocephalus of SAH as these patients often comatosed or sedated and clinical examination is not the safest method to monitor for hydrocephalus. According to the Food and Drug Administration, there is no amount of radiation that is completely without risk of radiation related cancer [4]. Moreover, transfer from and to intensive care units pose a real problem to medical care staff. Therefore, alternative monitoring strategies should be developed. The role of TCS has evolved as an imaging modality for the brain parenchyma in the setting of multiple pathologies, including movement disorders, parkinsonism and follow up of vasospasm post SAH using transcranial Doppler [5]. The diagnosis and monitoring for hydrocephalus has been used in young children because of the possibility of using the fontanelle as an acoustic window to the brain. The advantages of TCS in the management of hydrocephalus in adult have not been fully studied to date. But according to sporadic papers, the advantages of using TCS even in adults to follow hydrocephalus could encompass ease of use, low cost, wide acceptance by patients, no radiation risk, high mobility and relative independence from movement artifacts. Specifically, bedside availability and reliability has made critical care intensivists interested to use it with increasing frequency [6].

The accuracy of ultrasound compared to CT scan is not well established in adults and no known large studies confirming or infirming the utility of ultrasound in adults with hydrocephalus. Most of the literature comparing ultrasonography and computed tomography has been done in infants and children because of the natural acoustic windows of the brain through the fontanelles [7–12]. A report in 1984 by Rubenstein describes 19 adult patients the correlation between ultrasound images of the brain obtained post-operatively through a burr-hole and computed tomography [13]. The quality of the image was, however, much inferior to what we are able to see now. Recently, a comparison of the two techniques was performed in 15 brain-injured patients [14]. In 15 patients with brain injury, the 3rd ventricle was 35.5 ± 12 mm using TCS versus 33.1 ± 14 mm with computed tomography with an intraclass correlation of 0.88 and 95% confidence interval of 0.63–0.96, p < 0.01. There were no systematic biais using the Bland–Altman plot. In our case, the craniectomy site allowed direct skin dura matter contact which helps clarify more the brain structures and decreases the distance and eliminates artifacts caused by bone. To our knowledge, so far not many case reports and or case series evoked the possibility to use ultrasound instead of CT scan to monitor these patients’ hydrocephalus. Recently, a case series was published and showed that TCS using B-sonography mode was effective in decision making regarding removal of external ventricular drainage in patients with post-hemorrhagic malabsorption hydrocephalus with good specificity and sensitivity [15, 16].

This case illustrates the usefulness of hand-held bedside ultrasound for follow-up of patients with subarachnoid hemorrhage as a non-invasive, simple and safe method to monitor for the development of hydrocephalus and may be to guide management.

Patients with SAH and particular those with a craniotomy can be monitored easily at the bedside with hand-held TCS for the development of hydrocephalus. Further studies with larger number of patients should be performed to evaluate the feasibility, sensitivity and specificity of TCS in the detection of hydrocephalus in adult patients after SAH.