Aneurysmal subarachnoid hemorrhage complications
Vasospasm is an important cause for mortality following aneurysmal subarachnoid hemorrhage aSAH affecting as many as 70% of patients. It usually occurs between 4th and 21st days of aSAH and is responsible for delayed ischemic neurological deficit (DIND) and cerebral infarction
It is one of the factors that can most significantly worsen the prognosis despite different treatments.
Transcranial doppler (TCD) evidence of vasospasm is predictive of delayed cerebral ischemia (DCI) with high accuracy. Although high sensitivity and negative predictive value make TCD an ideal monitoring device, it is not a mandated standard of care in aneurysmal subarachnoid hemorrhage (aSAH) due to the paucity of evidence on clinically relevant outcomes, despite recommendation by national guidelines. High-quality randomized trials evaluating the impact of TCD monitoring on patient-centered and physician-relevant outcomes are needed 1).
A greater proportion of aneurysmal subarachnoid hemorrhage patients, are surviving their initial hemorrhagic event but remain at increased risk of a number of complications, including delayed cerebral ischemia, epilepsy, nosocomial infections, cognitive impairment, shunt dependent hydrocephalus, and shunt related complications 2).
Intracranial complications including delayed cerebral ischemia (vasospasm), aneurysm rebleeding, and hydrocephalus form the targets for initial management. However, the extracranial consequences including hypertension, hyponatremia, and cardiopulmonary abnormalities can frequently arise during the management phase and have shown to directly affect clinical outcome.
Although the intracranial complications of SAH can take priority in the initial management, the extracranial complications should be monitored for and recognized as early as possible because these complications can develop at varying times throughout the course of the condition. Therefore, a variety of investigations, as described by this article, should be undertaken on admission to maximize early recognition of any of the extracranial consequences. Furthermore, because the extracranial complications have a direct effect on clinical outcome and can lead to and exacerbate the intracranial complications, monitoring, recognizing, and managing these complications in parallel with the intracranial complications is important and would allow optimization of the patient’s management and thus help improve their overall outcome 3).
Aneurysmal subarachnoid hemorrhage is complicated by intracerebral hemorrhage in 20—40 %, by intraventricular hemorrhage in 13-28%, and by subdural blood in 2-5% (usually due to posterior communicating aneurysm when over convexity, or distal anterior intracerebral artery (DACA) aneurysm with interhemispheric subdural).
The intracranial effects of aSAH causing death and disability are from vasospasm, direct effects of the initial bleed, increased intracranial pressure (ICP) and rebleeding 4).
Early brain injury and hydrocephalus (HCP) are important mediators of poor outcome in subarachnoid hemorrhage (SAH) patients. Injection of SAH patients’ CSF into the rat ventricle leads to HCP as well as subependymal injury compared with injection of control CSF 5).
Fever is a common occurrence (70%) especially in poor grades, contributes to adverse outcome and may not always respond to conventional treatment.
Persistent hyperglycemia (>200 mg/dl for >2 consecutive days) increases the likelihood of poor outcome after aSAH.
Management of patients following aSAH includes four major considerations:
(1) prediction of patients at highest risk for development of DCI,
(2) prophylactic measures to reduce its occurrence,
(3) monitoring to detect early signs of cerebral ischemia,
(4) treatments to correct vasospasm and cerebral ischemia once it occurs 6).
Delayed cerebral ischemia
Subarachnoid hemorrhage (SAH) is often accompanied by pulmonary complications, which may lead to poor outcomes and death.
Sympathetic activation of the cardiovascular system in aneurysmal subarachnoid hemorrhage not only triggers the release of atrial and brain natriuretic peptides it can also lead to increased pulmonary venous pressures and permeability causing hydrostatic pulmonary edema 9).
see Neurogenic pulmonary edema.
Cardiac manifestations of intracranial subarachnoid hemorrhage patients include mild electrocardiogram variability, Takotsubo cardiomyopathy, non-ST elevation myocardial infarction, ST-elevation myocardial infarction and cardiac arrest, but their clinical relevance is unclear.
Among patients suffering from cardiac events at the time of aneurysmal subarachnoid hemorrhage, those with myocardial infarction and in particular those with a troponin level greater than 1.0 mcg/L had a 10 times increased risk of death 10).
Acute kidney injury
Hypokalemia is a common electrolyte disorder in the intensive care unit. Its cause often is complex, involving both potassium losses from the body and shifts of potassium into cells.
We present a case of severe hypokalemia of sudden onset in a patient being treated for subarachnoid hemorrhage in the surgical intensive care unit in order to illustrate the diagnosis and management of severe hypokalemia of unclear cause. The patient received agents that promote renal potassium losses and treatments associated with a shift of potassium into cells. Ibanez et al. outline the steps in diagnosis and management, focusing on the factors regulating the transcellular distribution of potassium in the body 11).
The clinical outcome after aneurysm rupture is at least in part determined by the severity of IVH. Knowledge of the effect of IVH may help guide physicians in the care of patients with aneurysmal bleeding 12).
Deep vein thrombosis
Overall rates of VTE (Deep vein thrombosis DVT or PE), DVT, and PE were 4.4%, 3.5%, and 1.2%, respectively. On multivariate analysis, the following factors were associated with increased VTE risk: increasing age, black race, male sex, teaching hospital, congestive heart failure, coagulopathy, neurologic disorders, paralysis, fluid and electrolyte disorders, obesity, and weight loss. Patients that underwent clipping versus coiling had similar VTE rates. VTE was associated with pulmonary/cardiac complication (odds ratio [OR] 2.8), infectious complication (OR 2.8), ventriculostomy (OR 1.8), and vasospasm (OR 1.3). Patients with VTE experienced increased non-routine discharge (OR 3.3), and had nearly double the mean length of stay (p<0.001) and total inflation-adjusted hospital charges (p<0.001). To our knowledge, this is the largest study evaluating the incidence and risk factors associated with the development of VTE after aSAH. The presence of one or more of these factors may necessitate more aggressive VTE prophylaxis 13).
Short course (<48h) administration of EACA in patients with aneurysmal subarachnoid hemorrhage is associated with an 8.5 times greater risk of Deep vein thrombosis (DVT) formation 14).
Routine compressive venous Doppler ultrasonography is an efficient, noninvasive means of identifying Deep vein thrombosis (DVT) as a screening modality in both symptomatic and asymptomatic patients following aneurysmal SAH. The ability to confirm or deny the presence of DVT allows one to better identify the indications for chemoprophylaxis. Prophylaxis for venous thromboembolism in neurosurgical patients is common. Emerging literature and anecdotal experience have exposed risks of complications with prophylactic anticoagulation protocols. The identification of patients at high risk-for example, those with asymptomatic DVT-will allow physicians to better assess the role of prophylactic anticoagulation 15).
Deep vein thrombosis (DVT) formation most commonly occurs in the first 2 weeks following aSAH, with detection in a cohort peaking between Days 5 and 9. Chemoprophylaxis is associated with a significantly lower incidence of DVT 16).
Patient should be ideally monitored in the NICU for at least 1st 24 h after surgery. Anticonvulsants, osmotherapy and nimodipine must be continued. Hydrocephalus, vasospasm, seizures, and electrolyte disturbances can occur necessitating close observation and prompt management. One of the major challenges in the management of aSAH is identifying potential or ongoing perfusion deficits. Ischemic insults can occur following ictus, or due to raised ICP, hypotension and vasospasm. Early identification and appropriate treatment of postictal intracranial (ICP, TCD flow velocities) and cardiovascular (cardiac output, ECG, BP, CVP) changes is possible in dedicated NICU and is crucial for improving outcomes. Heuer et al. observed that raised ICP (>20 mmHg) occurred in >50% of patients after aSAH and was associated with poor outcomes. Factors associated with raised ICP included poor clinical and radiological grades of aSAH, intraoperative brain swelling, parenchymal and intraventricular bleed and rebleeding.