Controversies in the Diagnosis of Subarachnoid Hemorrhage

Subarachnoid hemorrhage in the emergency department

BACKGROUND

Subarachnoid hemorrhage accounts for more than 30,000 cases of stroke annually in North America and encompasses a 4.4% mortality rate. Since a vast number of subarachnoid hemorrhage cases present in a younger population and can range from benign to severe, an accurate diagnosis is imperative to avoid premature morbidity and mortality. Here, we present a straightforward approach to evaluating, risk stratifying, and managing subarachnoid hemorrhages in the emergency department for the emergency medicine physician.

DISCUSSION

The diversities of symptom presentation should be considered before proceeding with diagnostic modalities for subarachnoid hemorrhage. Once a subarachnoid hemorrhage is suspected, a computed tomography of the head with the assistance of the Ottawa subarachnoid hemorrhage rule should be utilized as an initial diagnostic measure. If further investigation is needed, a CT angiography of the head or a lumbar puncture can be considered keeping risks and limitations in mind. Initiating timely treatment is essential following diagnosis to help mitigate future complications. Risk tools can be used to assess the complications for which the patient is at greatest.

CONCLUSION

Subarachnoid hemorrhages are frequently misdiagnosed; therefore, we believe it is imperative to address the diagnosis and initiation of early management in the emergency medicine department to minimize poor outcomes in the future.

The value of repeated lumbar puncture to test for xanthochromia, in patients with clinical suspicion of subarachnoid haemorrhage, with CT-negative and initial traumatic tap

OBJECTIVES

For the diagnosis of subarachnoid haemorrhage (SAH), the presence of cerebrospinal fluid (CSF) xanthochromia is still considered the gold standard for patients with a thunderclap headache, in the absence of blood on brain CT scan. However, a traumatic lumbar puncture (LP) typically results in high concentrations of oxyhaemoglobin in CSF, impairing the detection of xanthochromia and preventing the reliable exclusion of SAH. In this context, the value of a repeat lumbar puncture has not yet been described.

MATERIALS AND METHODS

A retrospective case series of suspected SAH patients, with a negative CT scan and initial traumatic LP, managed with a repeat LP to assess for CSF xanthochromia. Clinical notes, laboratory and imaging results were reviewed.

RESULTS

Between August 2011 and January 2020, 31 patients with suspected SAH were referred to our neurosurgical unit following negative CT and traumatic LP. A repeat LP was performed in 7 of the 31 patients, 2.4 days (±0.79 SD) after the first traumatic LP. CSF spectrophotometry analysis from repeated LP in all 7 patients was negative for xanthochromia. No adverse clinical events were recorded on average 18 months following discharge.

CONCLUSION

A repeat LP performed following a traumatic tap can still yield xanthochromia-negative CSF, thereby, excluding SAH, avoiding unnecessary invasive angiography and overall promoting the safer management of these patients.

High-Risk Chief Complaints III: Neurologic Emergencies

A careful history and thorough physical examination are necessary in patients presenting with acute neurologic dysfunction. Patients presenting with headache should be screened for red-flag criteria that suggest a dangerous secondary cause warranting imaging and further diagnostic workup. Dizziness is a vague complaint; focusing on timing, triggers, and examination findings can help reduce diagnostic error. Most patients presenting with back pain do not require emergent imaging, but those with new neurologic deficits or signs/symptoms concerning for acute infection or cord compression warrant MRI. Delay to diagnosis and treatment of acute ischemic stroke is a frequent reason for medical malpractice claims.

Clinical Policy: Critical Issues in the Evaluation and Management of Adult Patients Presenting to the Emergency Department With Acute Headache

This clinical policy from the American College of Emergency Physicians addressed key issues in the evaluation and management of adult patients presenting to the emergency department with acute headache. A writing subcommittee conducted a systematic review of the literature to derive evidence-based recommendations to answer the following clinical questions: (1) In the adult emergency department patient presenting with acute headache, are there risk-stratification strategies that reliably identify the need for emergent neuroimaging? (2) In the adult emergency department patient treated for acute primary headache, are nonopioids preferred to opioid medications? (3) In the adult emergency department patient presenting with acute headache, does a normal noncontrast head computed tomography scan performed within 6 hours of headache onset preclude the need for further diagnostic workup for subarachnoid hemorrhage? (4) In the adult emergency department patient who is still considered to be at risk for subarachnoid hemorrhage after a negative noncontrast head computed tomography, is computed tomography angiography of the head as effective as lumbar puncture to safely rule out subarachnoid hemorrhage? Evidence was graded and recommendations were made based on the strength of the available data.

New method for the determination of the net bilirubin absorbance in cerebrospinal fluid that minimizes the interference of oxyhaemoglobin and biliverdin

The presence of oxyhaemoglobin and biliverdin interferes with the method recommended by the UK NEQAS Specialist Advisory group for EQA of CSF Proteins and Biochemistry for estimating of the net bilirubin absorbance in CSF. This is easily demonstrated by using solutions with different concentrations of these three substances.The two secondary peaks of the oxyhaemoglobin spectrum at 540 nm and 577 nm are used as reference to minimize these interferences. Those peaks have the same absorbance as at 456 nm in the oxyhaemoglobin spectrum, independent of its concentration. This wavelength is very close to the maximum absorption of bilirubin and, therefore, is suitable for estimating the net bilirubin absorbance.A preliminary study with 48 spectrophotometric analyses of CSF from patients who were suspected of having subarachnoid haemorrhage were used to compare both net bilirubin absorbance estimation methods.The new method is practically free of oxyhaemoglobin and biliverdin interference. This allows for higher sensitivity and a more realistic estimation of the bilirubin concentration in a sample.A better estimation of the bilirubin concentration can have special relevance for diminishing the amount of equivocal or inconclusive cases and also to improve the prematurity of the diagnosis.

Approach to the Diagnosis and Management of Subarachnoid Hemorrhage

Headache is one of the most common reasons for presentation to the emergency department (ED), seen in up to 2% of patients.1 Most are benign, but it is imperative to understand and discern the life-threatening causes of headache when they present. Headache caused by a subarachnoid hemorrhage (SAH) from a ruptured aneurysm is one of the most deadly, with a median case-fatality of 27–44%.2 Fortunately, it is also rare, comprising only 1% of all headaches presenting to the ED.3 On initial presentation, the one-year mortality of untreated SAH is up to 65%.4 With appropriate diagnosis and treatment, mortality can be reduced to 18%.5 The implications are profound: Our careful assessment leading to the detection of a SAH as the cause of headache can significantly decrease our patients’ mortality. If this were an easy task, the 12% reported rate of missed diagnosis would not exist.6 We have multiple tools and strategies to evaluate the patient with severe headache and must understand the strengths and limitations of each tool. Herein we will describe the available strategies, as well as the ED management of the patient with SAH.

Patient with a Subarachnoid Headache

Subarachnoid hemorrhage (SAH) is a life-threatening cause of headache. The diagnostic approach to this entity continues to evolve with a recent questioning of the classic workup of computed tomography and lumbar puncture. We report a risk management case of a patient with a missed SAH resulting in a fatal outcome. When there are multiple diagnostic strategies, the patient may be involved with shared decision-making. Some of the medical and legal implications of the diagnosis of SAH will be discussed.