Traumatic Tap Research Articles

AIUM Practice Parameter for the Performance of an Ultrasound Examination of the Neonatal and Infant Spine

AIUM Practice Parameter for the Performance of an Ultrasound Examination of the Neonatal and Infant Spine

AIUM Practice Parameter for the Performance of an Ultrasound Examination of the Neonatal and Infant Spine.

AIUM Practice Parameter for the Performance of an Ultrasound Examination of the Neonatal and Infant Spine.

Safety of lumbar punctures in patients with thrombocytopenia

American Association of Blood Banks guidelines recommend a minimum platelet count of 50 × 10(9) /l for LPs (lumbar puncture), but evidence is lacking. The objective of this study was to describe the range of platelet counts at which LPs are performed, and the rate of traumatic taps and haemorrhagic complications in an adult oncology population. A retrospective cohort study of patients receiving LPs over a 2-year period was carried out. Bleeding risk factors captured included anticoagulants, antiplatelets, end-stage renal disease, and other bleeding disorders. Pre-LP platelet counts were those collected ≤24 h from the time of the LP. Traumatic tap was defined as 500 or more red blood cells per high-power field in cerebrospinal fluid. One hundred and thirty-five patients underwent 369 LPs. Twenty-eight (7·6%) LPs were performed at a platelet count ≤ 50 × 10(9) /l; 18 patients received a platelet transfusion prior to the LP, with post-transfusion count available prior to LP in only one patient. Traumatic taps occurred in 16 of 113 (14·2%) LPs in patients with thrombocytopenia (platelet count < 150 × 10(9) /l) compared to 27 of 242 (11·1%) LPs in patients with a normal platelet count (P = 0·48). The presence of bleeding risk factors did not increase the incidence of traumatic taps. There were no haemorrhagic complications. Among this cohort of adult oncology patients, there were no haemorrhagic complications. Traumatic taps were not increased in patients with thrombocytopenia. The effects of platelet transfusions were rarely assessed prior to LP. Further studies should be pursued to assess whether platelet count thresholds lower than 50 × 10(9) /l are safe for lumbar puncture.

Safety of Lumbar Punctures in Adult Oncology Patients with Thrombocytopenia

Introduction: Lumbar puncture (LP) is a frequently performed diagnostic and therapeutic intervention in adult oncology patients. While thrombocytopenia is common in this patient population, the minimum "safe" platelet count required for LPs is unknown. Recent guidelines from the AABB (American Association of Blood Banks) recommend a pre-procedure platelet count of 50 x 109/L. However this recommendation is largely based on expert opinion, and there remains a paucity of studies in the adult oncology literature to address this important question.Methods: We retrospectively reviewed all oncology patients ≥18 years who underwent 1 or more LPs over a 2 year period at a single tertiary care institution to determine 1) the range of platelet counts at which LPs are performed; 2) the rate of traumatic taps; and 3) the rate of hemorrhagic complications. Laboratory, clinical, and transfusion information were extracted through the Laboratory Information System, chart review, and blood bank database, respectively. Thrombocytopenia was defined as a platelet count of < 150 x 109/L. Pre-LP platelet counts were those collected ≤24 hours from, and closest to the time of the LP. The following bleeding risk factors were documented: end stage renal disease; platelet dysfunction; von Willebrand disease; hemophilia. Anticoagulation, anti-platelet, and non-steroidal inflammatory use was also recorded, with accuracy limited by the study's retrospective nature. All patients with coagulopathy were excluded (INR ≥ 1.5, aPTT ≥ 40, fibrinogen ≤ 1.0). Traumatic tap was defined as 500 or more red blood cells per high-power field in the cerebrospinal fluid. A follow up of 1 week after LP was used to capture any hemorrhagic complications.Results: From January 2013 to December 2014, 135 oncology patients underwent 369 LPs; 64 (47.4%) patients were female, and the mean age was 59 years (range 20-87). 119 (88.1%) patients had a primary hematological diagnosis. 113 (30.6%) LPs were performed in thrombocytopenic patients. 28 (7.6%) procedures had a pre-procedure platelet count of ≤ 50 x 109/L, with 18 receiving a single platelet transfusion on the day of the LP. Of these 18 transfusions, only 1 had a post-transfusion platelet count available prior to LP with no improvement in platelet count (33 x 109/L). 15 transfusions had post-LP platelet counts within 24 hours of the transfusion (8 below 50 x 109/L with lowest 14 x 109/L), 1 had post-LP platelet count within 24-48 hours (54 x 109/L) and 1 did not have a post-transfusion platelet count. Traumatic taps occurred in 17 (15.0%) LPs in patient with thrombocytopenia, compared to 26 (11.0%) LPs in patients with a normal platelet count (fisher's exact test P=0.39). There was 1 traumatic tap in a patient with a pre-LP platelet count of ≤ 50 x 109/L; however, this patient received a pre-LP platelet transfusion for a platelet count of 42 x 109/L and had a post-LP platelet count of 66 x 109/L. Presence of bleeding risk factors did not increase the risk of a traumatic tap (present in 48.8% of traumatic taps vs. 88.3% of non-traumatic taps). There were no hemorrhagic complications.Conclusion: Among this cohort of adult oncology patients undergoing diagnostic and therapeutic LPs, there were no hemorrhagic complications. There was no significant increase in traumatic taps in patients with thrombocytopenia or bleeding risk factors. While platelet transfusions were frequently administered for patients with a platelet count of ≤ 50 x 109/L, post-transfusion platelet counts were infrequently assessed prior to the procedure. Our findings question whether a platelet transfusion threshold of 50 x 109/L is necessary for lumbar puncture. Table 1Platelet Count Pre-LP(x109/L)Number of LPsNumber of Traumatic TapsNumber of Hemorrhagic Complications0-90N/AN/A10-2030021-5070051-1003380101-1495270> 150242270Unknown1400< 50 x 109/L and received platelet transfusion on day of LP181*0Total369430*There was one traumatic tap in a patient with a platelet count of 42 x 109/L who received a platelet transfusion pre-LP. The post transfusion platelet count was 66 x 109/L. DisclosuresNo relevant conflicts of interest to declare.

Differentiation between traumatic tap and aneurysmal subarachnoid hemorrhage: prospective cohort study

Objectives To describe the findings in cerebrospinal fluid from patients with acute headache that could distinguish subarachnoid hemorrhage from the effects of a traumatic lumbar puncture.Design A substudy of a...

Infections of the Nervous System

In recent years, there have been major advancements in management of infectious diseases; however, infections that affect the central nervous system (CNS) remain a significant challenge. They are often difficult to diagnose and treat, resulting in prolonged hospitalization and high morbidity and mortality rates. With modern-day travel, outbreaks of infections can rapidly transcend the globe. Not surprisingly, several recent movies, novels, and nonfiction books have been based on encephalitis, and outbreaks have received wide attention by the popular media. The book is has 51 chapters, which are organized thematically into 10 parts and presented in >900 pages. It is an exhaustive and authoritative clinical review that is written for the practicing and academic clinician. The first part has chapters on how to approach patients with suspected CNS infections, cerebrospinal fluid (CSF) findings, and neuroradiological changes. It also has broad chapters on meningitis and encephalitis. Forty of the 51 chapters are divided by organism and cover all viruses, bacteria, spirochetes, fungi, parasites, and prions. The book also has chapters on undiagnosed and noninfectious chronic meningitis, surgical and critical care management of CNS infections, and vaccines that are relevant to these infections. This combination of a syndromic approach to the diagnosis and management of CNS infections and division of chapters by microorganisms is a unique aspect of this book. Each chapter is divided into several sections that include the epidemiology or provide a historical perspective of the infection, a brief description about the organism, clinical features, diagnosis, and management. Each of these sections has multiple subheadings, making it easy to find and focus on areas of interest to the reader. Most chapters have multiple color illustrations, as well as photomicrographs showing the pathology or neuroradiological findings. Where appropriate, tables, figures, and algorithms for management have been included. Each chapter has been written by leaders in the field, and this expertise is clearly reflected in the detail and the clinical perspective provided in each of the chapters. For example, the chapter on poliomyelitis includes a magnetic resonance imaging (MRI) scan and pathological findings, which are probably very hard to obtain as the disease is so rare these days. In the part on viral pathogens and related disorders, the chapters on herpes viruses, rabies, and prion diseases are particularly noteworthy. They are very exhaustive with multiple illustrations describing the pathophysiology, MRI and pathological findings, and approach to treatment. The chapter on encephalitis provides a very detailed approach on how to establish an etiological diagnosis in these patients and covers all aspects of unique clinical manifestations, laboratory findings, MRI findings, and pathogen isolation, comparing each of these aspects in a set of several large tables. The chapter on bacterial meningitis is extensive in scope, nearly 55 pages in length. It covers usual and unusual organisms. The diagnostic utility and interpretation of CSF findings in circumstances such as a traumatic tap or partially treated meningitis is particularly useful and so is the discussion and recommendations for adjunctive therapy and use of corticosteroids. The chapter on neurosyphilis provides excellent algorithms for diagnosis in human immunodeficiency virus–infected and uninfected subjects. Several excellent chapters have been devoted to tropical infections such as cerebral malaria, cysticercosis and other parasitic infections, tuberculosis, tick-borne diseases, trypanosomiasis, and others. Overall, the book is very well written and an important resource for all clinicians who work with patients who may develop any kind of CNS infection.

Pseudo-Froin's syndrome, xanthochromia with high protein level of cerebrospinal fluid.

Froin’s syndrome is characterized by marked cerebrospinal fluid (CSF) xanthochromia (yellow discoloration of the CSF) and hypercoagulability due to increased protein content. The cause of the high protein content of the spinal fluid is meningeal irritation and inflammation. Pseudo-Froin's syndrome has been described as stagnation of the CSF distal to a spinal block due to spinal disc bulging or tumors [1]. A 54-year-old man with paraplegia was admitted to the urology department of our institution for follow-up of a bladder wall malignancy. The patient had suffered from paraplegia for 20 years because of a thoracic spine burst fracture (T5-7) and dislocation. He had undergone operative correction to maintain the curvature of the spine. The patient was currently scheduled for a urinary bladder wall biopsy. At the time of his admission, the patient's vital signs were stable and all laboratory findings including pulmonary function tests and arterial blood gas analysis were within normal limits. Magnetic resonance imaging and computed tomography scans of the brain/spine showed no specific abnormal findings except thoracic spine destruction and dislocation. No motor or sensory abnormalities were found in the upper chest or upper extremities. Because the patient wished to maintain alertness during the operation, it was planned to perform the surgery under spinal anesthesia. The first time spinal anesthesia was performed, the CSF flow was very scanty and sticky, and the color was dark yellow. “Give” was felt, and the CSF color was judged to be due to a traumatic tap. Spinal drug administration was done after CSF confirmation by aspiration. The patient’s mental status and vital signs, especially respiration, were stable throughout the operation following the successful spinal anesthesia. No specific problems such as headache, reflex tachycardia, or sweating were observed in the perioperative period. At the second spinal anesthesia for bladder-cancer follow-up surgery, lumbar spinal pressure was measured. The CSF was observed to not drain freely due to low spinal pressure, below 1 cmH2O, and thick density. The CSF was also observed to be an extraordinarily dark yellow color and very sticky, and CSF was collected by aspiration (Fig. 1). Cell count, cytology, electrophoresis, and culture of the CSF were

High-Stakes Diagnostic Decision Rules for Serious Disorders

Diagnostic errors lead to death or disability for an estimated 150 000 patients in the United States each year.1 The emergency department is a known high-risk location for misdiagnosis.2 Missed ischemic stroke and brain hemorrhage are recognized sources of diagnostic error, with approximately 9% of cerebrovascular events missed at first emergency department contact,3 including an estimated 20% of subarachnoid hemorrhages in patients presenting with normal mental status.4 Because effective treatments are available, diagnostic delays increase morbidity and mortality 3to 8-fold,4,5 so accurate early diagnosis is important. Ratesofmissedsubarachnoidhemorrhage in the1980sand 1990s were estimated at 32%,6 although more recent estimates suggest the rate is approximately 12%, with about half occurring in the emergency department.7 Some improvement isprobably fromnewergenerationcomputed tomography(CT),7,8butmost isnot.9 The current recommended standard of care is to obtain cranial CT for patients with new, rapid-onset, severe headaches and, for those with nondiagnosticCTswhoare still suspectedofhavingpossible subarachnoid hemorrhages, to follow with diagnostic lumbar puncture.10 This “CT-LP” rule is a proven method, with sensitivity for subarachnoidhemorrhage close to 100%whenperformed correctly.11 However, because the real-world emergency department miss rate for subarachnoid hemorrhage is approximately 6%,7 the CT-LP rule either is not applied to all at-risk patients or is used incorrectly (eg, lumbar puncture is obtained too early or too late, when spinal fluid findingsmay be misleading). In this issue of JAMA, Perry and colleagues12 seek to enhance the clinical capabilities for diagnosing subarachnoid hemorrhage through validation and refinement of the Ottawa SAH Rule. The authors present the results of a prospective, cross-sectional study involving 2131 patients with acute headacheanddemonstrate that theirbestbedsidedecisionrule identified all cases of subarachnoid hemorrhage (n = 132) among emergency department patients presentingwith new, isolatedheadaches. The final rule relies on thepresenceof any 1 of 6 findings (age ≥40 years; neck pain or stiffness; witnessed loss of consciousness; onset during exertion; thunderclap headache [instantly peaking pain]; limited neck flexion on examination) and has an estimated sensitivity of 100% for detecting atraumatic subarachnoid hemorrhage. This rule offers the potential to reduce missed subarachnoid hemorrhage and decrease unnecessary, invasive diagnostic testing for patients with low-risk headaches. Is the Ottawa SAH Rule clinically useful? Any test with near-perfect sensitivity has an intrinsic appeal because a negative result effectively rules out the target disorder. The rule proposed by Perry et al also has a “rule-out power” or negative likelihood ratio (ie, extent to which the odds of having a diagnosis will change following a negative test result) of 0.024, translating to a 42-fold reduction (ie, 1.0/ 0.024) in the likelihood of subarachnoid hemorrhage. For instance, a patient with acute headache and a pretest probability of 10% who has a negative result with the Ottawa SAH rule would have a posttest probability of 0.3% (ie, convert pretest probability [10%] to pretest odds [1:9]; multiply by 0.024 to obtain posttest odds [0.024:9]; then convert back to probability: 0.024/[0.024 + 9] = 0.00266 = 0.3%. For clinicians uncomfortable converting probability to odds and back, pocket-card nomograms provide a simple graphical interpretation of pretest and posttest probabilities using likelihood ratios). This is a clinically useful result because “very low” residual risks (<1%) of dangerous disorders may be considered acceptable in the emergency department,13 particularly when shared decision-making approaches that consider patient preferences (eg, whether a patient prefers the small residual risk of missed subarachnoid hemorrhage or the risks of a false-positive lumbar puncture following a traumatic tap, including follow-up angiography) are used effectively.14 However, there are several important caveats for applicationof this decision rule. Effective use of anydecision rule requires careful attention to clinical details affecting its generalizability.Does thepatientmeet all original inclusion criteria, such as having a headache that peaked in less than an hour? Hasanexaminationbeenperformedcarefullyenough toverify that neurologic status is truly normal, including no papilledema? Is subarachnoid hemorrhage the only target diagnosis being considered, or are unstudied, rare, yet important causes of sudden-onset headache (eg, cerebral venous sinus thrombosis, pituitary apoplexy, arterial dissection) still part of the differential diagnosis? Are other unstudied variables (eg, family history of brain aneurysms) present that might complicate interpretation of the rule? In clinical practice, “rules creep” can lead to overly broad applicationofadecision rule. Suchcreep in thesettingofheadache could be toward patientswho presentwith severe headaches that are more gradual in onset. This misuse could present a problem for patients, especially if the rulewere used to Related article page 1248 Opinion

Direct Medical Costs of Traumatic Lumbar Puncture in the Setting of Possible Subarachnoid Hemorrhage

Direct Medical Costs of Traumatic Lumbar Puncture in the Setting of Possible Subarachnoid Hemorrhage

Cerebrospinal fluid analyses for the diagnosis of subarachnoid haemorrhage and experience from a Swedish study. What method is preferable when diagnosing a subarachnoid haemorrhage?

Subarachnoid haemorrhage (SAH) has a high mortality and morbidity rate. Early SAH diagnosis allows the early treatment of a ruptured cerebral aneurysm, which improves the prognosis. Diagnostic cerebrospinal fluid (CSF) analyses may be performed after a negative computed tomography scan, but the precise analytical methods to be used have been debated. Here, we summarize the scientific evidence for different CSF methods for SAH diagnosis and describe their implementation in different countries. The principle literature search was conducted using PubMed and Scopus with the search items "cerebrospinal fluid", "subarachnoid haemorrhage", and "diagnosis". CSF analyses for SAH include visual examination, red blood cell counts, spectrophotometry for oxyhaemoglobin or bilirubin determination, CSF cytology, and ferritin measurement. The methods vary in availability and performance. There is a consensus that spectrophotometry has the highest diagnostic performance, but both oxyhaemoglobin and bilirubin determinations are susceptible to important confounding factors. Visual inspection of CSF for xanthochromia is still frequently used for diagnosis of SAH, but it is advised against because spectrophotometry has a superior diagnostic accuracy. A positive finding of CSF bilirubin is a strong indicator of an intracranial bleeding, whereas a positive finding of CSF oxyhaemoglobin may indicate an intracranial bleeding or a traumatic tap. Where spectrophotometry is not available, the combination of CSF cytology for erythrophages or siderophages and ferritin is a promising alternative.

Diagnosis of Subarachnoid Hemorrhage

See related articles, p 2115 . Although the most concerning diagnosis in patients presenting with thunderclap headache (abrupt onset of a severe unusual headache) is nontraumatic subarachnoid hemorrhage (SAH), only 8% to 12% of neurologically intact patients with thunderclap headache will have SAH; most have benign causes.1 Of those with aneurysmal SAH, 40% to 50% of patients will present neurologically intact. Therefore, diagnostic testing beyond history and physical examination is necessary. The initial test of choice is a noncontrast CT scan of the brain. Although CT is an excellent test for SAH, its sensitivity is both a function of timing from the onset of the headache as well as severity of the hemorrhage.1 CT sensitivity is extremely high early but rapidly diminishes with time. Clinicians frequently encounter neurologically normal patients with a thunderclap headache and a negative CT scan. Even using third-generation scanners, CT by itself is insufficient to exclude SAH.2 Therefore, guidelines recommend that a lumbar puncture (LP) be performed in these patients whose CT scans are negative or nondiagnostic.3,4 Although LP is a relatively benign test, it adds time, patient discomfort, and, sometimes, diagnostic ambiguity from a traumatic tap. Prior studies of CT sensitivity do not adequately account for the issue of timing in the earliest hours after the hemorrhage. In this issue of Stroke , Backes et al5 present data suggesting that CT scan is 100% sensitive for SAH if performed within 6 hours of the headache onset and apart from 2 caveats, the authors recommend …

“Traumatic Tap” Proportion in Pediatric Lumbar Puncture

“Traumatic Tap” Proportion in Pediatric Lumbar Puncture

Cerebrospinal Fluid Ferritin Level, a Sensitive Diagnostic Test in Late-Presenting Subarachnoid Hemorrhage

The workup of patients with suspected subarachnoid hemorrhage (SAH) presenting late is complicated by a loss of diagnostic sensitivity of computed tomography (CT) brain imaging and cerebrospinal fluid (CSF) bilirubin levels. In this prospective longitudinal study of CSF ferritin levels in SAH, serial CSF samples from 14 patients with aneurysmal SAH requiring extraventricular drainage (EVD) were collected. The control group comprised 44 patients presenting with headache suspicious of SAH. Nine patients underwent a traumatic spinal tap. CSF ferritin levels were significantly higher in the patients with SAH compared with controls (P < .0001). The upper reference range of CSF ferritin is 12 ng/mL, and there was no significant difference between the traumatic and normal spinal taps (mean, 9.0 ng/mL vs 3.9 ng/mL; P = .59). CSF ferritin levels increased after SAH, from an average of 65 ng/mL on day 1 to 1750 ng/mL on day 11 (P < .01). Both the Fisher and Columbia CT scores were significantly correlated with CSF ferritin level. The increase in CSF ferritin level after SAH and possibly may provide additional diagnostic information in patients with suspected SAH who present late to the clinic.

"Traumatic Tap" Proportion in Pediatric Lumbar Puncture

To determine the frequency of "traumatic" or "bloody" tap when pediatric lumbar puncture is performed by a physician who has completed training and performs the procedure frequently. The author identified 100 sequential patients presenting to a pediatric emergency department requiring lumbar puncture for clinical indications. Demographic information, cerebrospinal cell counts, and other relevant data were later obtained by retrospective chart review. Cell count results were categorized according to several previously used criteria: greater than 400, greater than 1000, and greater than 10,000/unsuccessful. One procedure yielded only a small amount of bloody fluid on which no cell count was performed. The remaining 99 procedures yielded red blood cell counts less than 1000. The proportion of bloody or traumatic results from pediatric lumbar puncture reported from pediatric training centers is typically in the 20% to 30% range. This represents an overestimation of a more ideal proportion possible when the procedure is performed by a physician who has completed training and performs the procedure frequently.

Herpes Encephalitis Presenting With an Opercular Syndrome and Epilepsia Partialis Continua

The opercular syndrome is a rare form of pseudobulbar palsy that is characterized by automatic-voluntary dissociative weakness of the face in addition to weak masticatory and pharyngeal muscles. It is typically seen in the setting of an acute stroke or in association with various congenital malformations of the cortex. It has also been described rarely in association with herpes encephalitis but with an abnormal cerebrospinal fluid (CSF) cell count. We report on a 65-year-old-man with an opercular syndrome associated with epilepsia partialis continua (EPC) secondary to acute herpes simplex virus encephalitis despite an initial near normal CSF analysis. Initial EEG was unremarkable while CSF analysis revealed changes suggestive of a traumatic tap. An opercular syndrome was diagnosed based on the classic presentation of dysarthria, facial diplegia, and hypersalivation, with corresponding MRI brain changes in the operculum. During admission, EPC developed, with continuous right facial twitching and an electroencephalographic correlate in the left centrotemporal region. The EPC initially responded to intravenous lorazepam. Phenytoin was then added for seizure prophylaxis. Herpes virus DNA was later on detected in the CSF. The patient improved with antiviral treatment except for very mild residual dysarthria. Neurologists should be aware of the possible predilection of the herpes simplex virus for the opercular area and the need to empirically treat for herpes encephalitis even in the setting of near normal initial CSF studies in patients with a suggestive clinical presentation.

Traumatic Lumbar Punctures in Neonates: Test Performance of the Cerebrospinal Fluid White Blood Cell Count: Greenberg RG, Smith PB, Cotton CM, et al. Pediatr Infect Dis J 2008;27:1047–51

Traumatic lumbar puncture in neonates can make interpretation of cerebrospinal fluid (CSF) difficult. Authors performed a cohort study of 2519 traumatic lumbar punctures (≥ 500 red blood cells/mm3) in neonates ≤ 30 days to determine whether methods for adjusting CSF white blood cell (WBC) counts improve diagnostic utility. Several methods exist for adjusting WBC counts after a traumatic tap; see the referenced study for a full description. Authors found a total of 50 cases (1.8%) of meningitis among 2519 neonates with a traumatic tap.

Examination of body fluids: evaluating gross appearance; performing cell counts.

1. Leilani Collins, MS MT(ASCP)SH CLS(NCA)[⇑][1] 1. is associate professor, Clinical Laboratory Science Program, University of Tennessee Health Sciences Center, Memphis TN 1. Address for correspondence: Leilani Collins MS MT(ASCP)SH CLS(NCA), associate professor, Clinical Laboratory Science Program, University of Tennessee Health Sciences Center, 930 Madison Avenue, Suite 670, Memphis TN 38163.. (901) 448-6299. lcollins{at}utmem.edu. 1. Describe the normal appearance of cerebrospinal fluid, serous fluids, and synovial fluid. 2. Define gross findings that distinguish a traumatic tap from a pathologic bleed when a bloody CSF is encountered. 3. Name laboratory findings that aid in identifying a serous fluid as a transudate or exudate. 4. Describe how the appearance of a fluid can be used to determine the correct dilution for accurate cell counts. Evaluating gross appearance: CSF Spinal fluid is the only fluid that is normally available in quantities sufficient to sample. Adults have 90-150 mL of cerebrospinal fluid (CSF) and neonates 60-90 mL.1 The spinal fluid bathes the brain and spinal column providing nutrients to, removing waste products from, and acting as a protective cushion for the central nervous system (CNS). Since this fluid circulates around the brain and spinal column, it is an excellent source of information for the condition of the CNS. CSF is collected by lumbar puncture and, ideally, is placed into three or four sterile tubes labeled 1, 2, 3, and 4 in the order in which it is collected. If multiple tubes are received and multiple tests are ordered, tube #1 should be used for chemistry and immunology testing, tube #2 for microbiology, tube #3 for cell counts and differential, and tube #4 for any other tests.1 The normal appearance of CSF is colorless and crystal clear, resembling water. A cloudy or turbid fluid indicates increased WBCs or protein. A bloody fluid can indicate a traumatic tap in which a blood vessel is inadvertently punctured in the process of collection or blood can mean an intracranial hemorrhage or pathologic bleed. If multiple tubes are collected, there is clearing of the blood from the first tube to the last tube collected in the case of a traumatic tap but a consistent amount of blood in all tubes in the case of a pathologic bleed. If only one tube… ABBREVIATIONS: CNS = central nervous system; CSF = cerebrospinal fluid; RBC = red blood cell; WBC = white blood cell. 1. Describe the normal appearance of cerebrospinal fluid, serous fluids, and synovial fluid. 2. Define gross findings that distinguish a traumatic tap from a pathologic bleed when a bloody CSF is encountered. 3. Name laboratory findings that aid in identifying a serous fluid as a transudate or exudate. 4. Describe how the appearance of a fluid can be used to determine the correct dilution for accurate cell counts. [1]: #corresp-1

Revision of national guidelines for cerebrospinal fluid analysis in suspected subarachnoid haemorrhage

National guidelines for analysis of cerebrospinal fluid (CSF) in suspected subarachnoid haemorrhage (SAH) were published by a UK National External Quality Assessment Scheme (NEQAS) Immunochemistry Working Group in 2003. These guidelines provided recommendations on sampling requirements, spectrophotometric analysis and interpretation of results. The same group, having evolved into the UK NEQAS Specialist Advisory Group for External Quality Assessment (EQA) of CSF Proteins and Biochemistry, published in 2007 the results of the audit it conducted into current UK laboratory practice for the biochemical investigation of CSF. As a result of the findings of this audit and in the light of experience in the use of the 2003 guidelines, amendments have been made to the original guidelines and the revised guidelines are published in this journal. The main aims of the revision are threefold: to ensure that CSF is always analysed spectrophotometrically if sufficient sample is received; to downgrade the clinical significance of detecting small amounts of haemoglobin with no increase in bilirubin; and to emphasize the clinical significance of increased bilirubin with a visible oxyhaemoglobin absorbance peak irrespective of CSF protein or serum bilirubin concentrations. The National Audit of CSF Testing identified 78 laboratories which offered spectrophotometric analysis of CSF either on site or elsewhere. Twenty-one of these 78 laboratories rejected samples delivered by pneumatic tube, 17 rejected heavily blood-stained samples and 14 rejected samples taken outwith sample timing guidelines. These sample rejection policies are indefensible because useful information may be gained from spectrophotometry in all of these circumstances. CSF usually will be blood-stained following SAH – blood staining does not necessarily reflect a traumatic tap. The detection of increased bilirubin is significant irrespective of the mode of sample delivery or sample timing. Use of pneumatic tube would not be expected to cause false-negative bilirubin results. CSF is precious. Repeat sampling is invasive and interpretation of any positive results highly problematic. Laboratories are duty bound to analyse any CSF sample if sufficient is received and to interpret the results in the light of all the available information. It is the combined experience of the group over several years that the probability of SAH in a patient whose correctly timed CSF sample contains only small amounts of oxyhaemoglobin is vanishingly small. We know of one patient with a posterior communicating artery aneurysm whose CSF sample had a borderline net bilirubin absorbance (0.0067 AU) with a net oxyhaemoglobin absorbance of 0.067 AU. We are aware of no other cases of SAH where the CSF sample had a net oxyhaemoglobin absorbance ,0.1 AU and a net bilirubin absorbance 0.007 AU. The reporting comment recommended in the original guidelines for such samples ‘oxyhaemoglobin on its own has a low predictive value for SAH but does not exclude’ confuses and frustrates clinicians. We recommend that it be replaced by the less ambiguous comment ‘no evidence to support SAH’. In the original guidelines, the recommended interpretation effectively downgrades the likelihood of SAH when net bilirubin absorbance .0.007 AU but CSF protein concentration is .1 g/L. The 1 g/L cut-off is an arbitrary figure selected in recognition of the fact that high CSF protein concentrations (and therefore bilirubin absorbances) may reflect alternative pathology such as meningitis. However, it is important that biochemists realize that by its nature SAH usually results in a raised CSF protein concentration, sometimes .1 g/L. A blood-stained CSF sample with increased oxyhaemoglobin and bilirubin absorbances and CSF protein concentration .1 g/L is entirely consistent with SAH. For example, of 18 cases of SAH

Development of an integrated hardware and software platform for the rapid detection of cerebral aneurysm rupture

A cerebral aneurysm is defined as a weakened portion of an artery in the brain. Rupture of a cerebral aneurysm leads to subarachnoid hemorrhage (SAH). A significant number of patients with SAH are initially misdiagnosed and subjected to the risks associated with aneurysm re-rupture. Traditional detection methods recommended by physicians include computed tomography (CT) scan, lumbar puncture and angiography. Unfortunately, the CT scan is ineffective after 12 h, and angiography is best suited for those cases of finding the aneurysm before surgery. Physicians may therefore rely on lumbar puncture to develop a quick and objective evaluation by assessing xanthochromia. Bilirubin in the cerebrospinal fluid, resulting from the chemical decomposition of whole blood, is an indicator of hemorrhage. This metabolite can be detected after lumbar puncture, by differentiating its optical signature in the spinal fluid. In cases of traumatic spinal tap, bilirubin needs to be distinguished from whole blood. We introduce a diagnostic system based on visible spectroscopy to quickly and objectively assess low blood-volume SAH. The system integrates innovative hardware and a powerful software interface. We explore an algorithm that accounts for the noise and distortion from blood in the cerebrospinal fluid. We introduce a portable, user-friendly hardware platform composed of specific components designed for their sensitivity and specificity.

106: Differentiation of Intracranial Hemorrhage From Traumatic Lumbar Puncture Across the Age Spectrum

There is often uncertainty about whether RBCs were introduced to the cerebrospinal fluid (CSF) at the time of lumber puncture - a ”traumatic tap.” This is a particular concern in children or older adults when the procedure is technically difficult. The purpose of this study was to assess the diagnostic value of CSF xanthochromia and sequential RBC counts, the “three tube test”, to distinguish intracranial hemorrhage (ICH) from traumatic lumbar puncture (LP) across all ages.