The warning leak in subarachnoid hemorrhage and the importance of its early diagnosis.

A 40-year-old man had a severe headache of sudden onset and progressive palsy of the third cranial nerve from a minor subarachnoid hemorrhage. Despite assessment by two primary care physicians the possibility of serious neurologic disease was not raised and the urgency of the situation not appreciated. Two weeks after the onset of the headache the patient was urgently admitted to hospital at the request of a neuro-ophthalmologist. Cerebral angiography revealed an aneurysm of the posterior communicating artery, which was surgically occluded with a clip. The patient had a satisfactory recovery, with almost complete return of nerve function by the time of discharge from hospital. Such "warning leaks" in subarachnoid hemorrhage are discussed, and a protocol for their assessment is recommended.     

老年蛛网膜下腔出血的治疗方法和预后分析

目的:探讨70岁以上老年蛛网膜下腔出血患者的治疗方法和预后。方法:回顾性分析我院2006-2012年收治的49例老年蛛网膜下腔出血患者的临床资料及其预后。结果:49例患者入院时Hunt-Hess分级:Ⅰ级14例,Ⅱ级8例,Ⅲ级6例,Ⅳ级6例,Ⅴ级15例,其中14例采用开颅动脉瘤夹闭术,10例采用血管内介入栓塞术,25例采用内科保守治疗。治疗后6月,根据ADL量表评价预后(ADL≥60分为预后良好):内科保守治疗者仅3例预后良好,手术及栓塞术者17例预后良好。结论:对于老年蛛网膜下腔出血患者而言,影响患者预后的原因主要是出血导致的脑损伤和症状性脑血管痉挛,通过手术或栓塞术积极治疗破裂动脉瘤是预后良好的重要因素。     

CEREBRAL COMPLICATIONS INCURRED DURING PREGNANCY AND THE PUERPERIUM

In a statistical study of maternal mortality cases in Franklin County, Ohio, with a total of 170 deaths in a ten-year period (1948-1957), there were 36 fatal cases with cerebral complications of various types. Intracranial hemorrhage was the cause of death in 17 cases; subarachnoid hemorrhage in eight; intracerebral hemorrhage in eight and subdural hemorrhage in one case. There were nine cases of intracranial tumor with fatality. In a miscellaneous group of ten “cerebral deaths” infectious processes were the cause in eight cases, including tuberculous meningitis, purulent meningitis, brain abscess, acute (cerebromedullary) poliomyelitis, “viral” encephalitis, toxoplasmosis and tetanus.In a smaller clinical (nonfatal) group with cerebral complications occurring during pregnancy and the puerperium, two patients with subarachnoid hemorrhages made spontaneous recovery. A diagnosis of intracerebral hemorrhage was made in three instances, in two of which operation was done and evacuation of blood clots was accomplished. One patient recovered spontaneously from a minimal hemorrhage.Five other persons had cerebral thrombosis, three in the third month of pregnancy and two in the immediate puerperium. All recovered, with some residual deficits.Three patients with intracranial tumor were successfully treated surgically but with disappointing results ultimately (one case each of cerebellar medulloblastoma, cerebral astrocytoma and supratentorial meningioma).Only when the obstetrician, neurologist and the neurosurgeon are fully aware of the signs, symptoms, and many times the rapid course of these cerebral complications of pregnancy, can there be any material lowering of the morbidity and mortality. Emphasis should be placed on the early investigation of all neurological complaints during pregnancy and the puerperium, with immediate institution of an aggressive diagnostic and therapeutic regimen.     

Tranylcypromine Cephalgia

Tranylcypromine, a useful antidepressant agent, has been linked with a clinical syndrome of undetermined incidence characterized by exceedingly severe and prolonged headache. Associated phenomena may include paroxysmal hypertension, pallor, chest pain and collapse. This violent reaction does not seem to be related to age, sex, duration of treatment, or pre-existing cardiovascular disease; nor is it possible to predict in whom it will occur. The clinical picture may sometimes be quite similar to that produced by subarachnoid hemorrhage or by pheochromocytoma. The mechanism of action is not known, although it is possible that the syndrome may be due to an amphetamine-like effect; i.e., that tranylcypromine influences the adrenergic component of the reticular activating system. The occurrence of severe headache in the course of tranylcypromine therapy is an indication for immediate withdrawal of the drug. Tranylcypromine cephalgia should be considered as part of the differential diagnosis of sudden, violent and prostrating headache.     

Radiological Findings of Sexual Intercourse Related Emergency Department Admissions: A First Overview

Objectives

Sexuality is an essential aspect of human function, well-being and quality of life. Many people have sex without complications. However, there are some people who need to seek emergency medical help for related health problems. The aim of this study was to present a first overview of patients who received a radiological examination related to sexual intercourse based emergency department admission.

Methods

Our centralized electronic patient record database was reviewed for patients who had been admitted to our emergency department with an emergency after sexual intercourse between 2000 and 2011. The database was scanned for the standardized key words ‘sexual intercourse’ or ‘coitus’ retrospectively. For all patients identified in the electronic patient record database the radiological examinations were searched for manually in our Radiology Information System, and reviewed by three independent radiologists.

Results

One hundred and twenty nine out of 445 (29,0%) patients received a radiological examination after immediate emergency department admission related to sexual intercourse. Fifty two out of 129 (40.3%) patients had positive radiological findings while 77 (59.7%) did not. Eighty point seven percent (n = 42) of the radiological findings were a sexual intercourse-associated pathology and 19.2% (n = 10) were considered to be incidental findings. Age and male sex positively correlated with radiological imaging workup (p<0.001, respectively p<0.037). The most common sexual intercourse-associated pathology was headache attributed to cerebrovascular insult (n = 21, 40.3%) followed by epididymitis (n = 7, 16.6%) and obstructive uropathy (n = 5, 11.6%). Of the patients with headache attributed to non-traumatic intracranial hemorrhage, subarachnoid hemorrhage (n = 14, 66.6%) was the most common, followed by intracerebral bleeding (n = 4, 19.0%) and one subdural hemorrhage.

Conclusions

Pathological findings are manifold. Cerebral imaging is the most common type of radiological imaging performed. Further prospective and standardized studies should be performed to better evaluate the significance of radiological imaging in this patient collective with the aim to gain better knowledge on what patients profit from what type of radiological imaging when presenting with a sexual intercourse related emergency.

Advances in Knowledge

The present study provides a first overview on radiological findings of sexual intercourse related emergency department admissions.     

Gonadotropin-Releasing Hormone Agonist-Induced Pituitary Apoplexy in Treatment of Prostate Cancer: Case Report and Review of Literature

ObjectiveTo describe a case and review the literature on the rare complication of pituitary apoplexy after administration of a gonadotropin-releasing hormone agonist (GnRHa) for treatment of patients with prostate cancer.MethodsWe present a detailed case report of a patient with immediate signs of pituitary apoplexy after receiving a GnRHa and review the 6 previously reported cases in the literature.ResultsA 60-year-old man presented to a local hospital with severe headache, nausea, vomiting, and diplopia. Prostate cancer had recently been diagnosed, and he had received his first dose of a GnRHa 4 hours before this presentation. On physical examination, he was confused and had ptosis of the left eye. A head computed tomographic scan without contrast enhancement showed soft tissue filling the sella, without intracranial hemorrhage or mass effect. He was discharged with the diagnosis of viral meningitis. Three weeks later, he presented again with severe headache and diplopia. He had confusion, lethargy, disorientation, a blood pressure of 88/64 mm Hg, and left cranial nerve III, IV, and VI paralysis. Magnetic resonance imaging of the brain revealed an enhancing pituitary mass with hemorrhage extending to the optic chiasm, consistent with pituitary apoplexy. Laboratory results were consistent with panhypopituitarism. Surgical excision revealed a necrotic pituitary macroadenoma with hemorrhage. Tumor immunohistochemical staining was positive only for luteinizing hormone.ConclusionWe describe a rare adverse effect of GnRHa therapy, which unmasked a gonadotropin-secreting pituitary macroadenoma. This case adds to the 6 previously reported cases of GnRHa administration inducing pituitary apoplexy in men with prostate cancer. (Endocr Pract. 2007;13:642-646)     

Hypothalamo-pituitary dysfunction in patients with chronic subdural hematoma

Relatively frequent pituitary hormone deficiencies are observed after traumatic brain injury (TBI) and subarachnoid hemorrhage (SAH) and according to the published studies the neuroendocrine consequenses of traumatic brain injury are underdiagnosed. In a cohort of 59 patients (49 males, mean age 68.3 years, 36-88 years) after evacuation of subdural hematoma (SDH) were evaluated hypothalamo-pituitary functions one week after surgery, after three months and after one year. Hypogonadism was present in 26 % of patients in an acute phase, but in the majority had a transient character. Less than half of patients was GH deficient (GHD) according to the GHRH+arginine test. We did not find any serious case of hypocortisolism, hypothyroidism, diabetes insipidus centralis nor syndrome of inappropriate secretion of ADH (SIADH). Transient partial hypocortisolism was present in two cases, but resolved. We did not find relation between extension of SDH or clinical severity and development of hypopituitarism. In conclusion, in some patients with SDH growth hormone deficiency or hypogonadism was present. No serious hypocortisolism, hypothyroidism, diabetes insipidus nor SIADH was observed. The possibility of neuroendocrine dysfunction should be considered in patients with SDH, although the deficits are less frequent than in patients after TBI or SAH.     

In-hospital cerebrovascular complications following orthotopic liver transplantation: A retrospective study

Background

Cerebrovascular complications are severe events following orthotopic liver transplantation (OLT). This study aimed to observe the clinical and neuroimaging features and possible risk factors of in-hospital cerebrovascular complications in the patients who underwent OLT.

Patients and methods

We retrospectively reviewed 337 consecutive patients who underwent 358 OLTs. Cerebrovascular complications were determined by clinical and neuroimaging manifestations, and the possible risk factors were analyzed in the patients with intracranial hemorrhage.

Results

Ten of 337 (3.0%) patients developed in-hospital cerebrovascular complications (8 cases experienced intracranial hemorrhage and 2 cases had cerebral infarction), and 6 of them died. The clinical presentations were similar to common stroke, but with rapid deterioration at early stage. The hematomas on brain CT scan were massive, irregular, multifocal and diffuse, and most of them were located at brain lobes and might enlarge or rebleed. Infarcts presented lacunar and multifocal lesions in basal gangliar but with possible hemorrhagic transformation. The patients with intracranial hemorrhage had older age and a more frequency of systemic infection than non-intracranial hemorrhage patients. (P = 0.011 and 0.029, respectively).

Conclusion

Posttransplant cerebrovascular complications have severe impact on outcome of the patients who received OLT. Older age and systemic infection may be the possible risk factors of in-hospital intracranial hemorrhage following OLT.     

鞘内注射脐带间充质干细胞治疗神经系统疾病的安全性和疗效研究

目的：探讨腰穿鞘内注射脐带间充质干细胞治疗神经系统疾病的安全性和疗效并且分析腰穿治疗过程中遇到的各种技术 难题。方法：2008 年12 月至2011年5 月88 例伴有神经系统疾病的患者给予鞘内注射干细胞治疗,并且评价其在治疗过程中的 技术难题,采用HAI评分系统对这些患者神经功能的恢复情况进行评估,定期观察患者的临床症状、生物学指标和影像学检查观 察其治疗前后的变化。结果：88 例患者中具有技术难题的患者有20 例,主要表现为在鞘内注射脐带间充质干细胞的过程中需要 行全麻补充、腰穿定位困难等,18 例患者在治疗过程中出现副作用（头痛、低热、腰痛和下肢痛）,但这些副作用在48 小时内经过 系统治疗后完全缓解。随访1 年,50 例患者神经功能得到一定改善,包括15 例脊髓损伤患者、10 例脑瘫患者、10例脑外伤后综合 征患者、5 例脑梗死后综合征患者、5 例脊髓小脑共济失调患者和5 例运动神经元病患者。结论：鞘内注射脐带间充质干细胞治疗 神经系统疾病是安全和有效的,由于随访时间较短,有必要对这种治疗模式进行扩大的、双盲、安慰剂对照研究来进一步推广其 临床应用。     

Thrombocytopenia-absent radius (tar) syndrome: a case with agenesis of corpus callosum, hypoplasia of cerebellar vermis and horseshoe kidney

The thrombocytopenia-absent radius (TAR) syndrome (MIM 274000) is a congenital malformation syndrome characterised by bilateral absence of the radii with present thumbs, hypomegakaryocytic thrombocytopenia and a number of additional features including skeletal and cardiac anomalies. Mental retardation, reported in about 7% of patients, is usually secondary to intracranial hemorrhage. In 1994 there was a single report of a girl with TAR syndrome and hypoplasia of the cerebellar vermis and corpus callosum and in 2003 another case of TAR syndrome with cerebellar dysgenesis has been reported. In 2000 there was first report of horseshoe kidney in association with TAR syndrome followed by a clinical study of 34 cases with TAR syndrome in 2002 where horseshoe kidney was noted in two cases. Here we report of a girl with TAR syndrome, severe mental retardation, agenesis of corpus callosum, hypoplasia of cerebellar vermis and horseshoe kidney. There is no previous report of a child with TAR syndrome and all those associated anomalies in the same patient.     

Leptin as a marker for severity and prognosis of aneurysmal subarachnoid hemorrhage

Leptin has been identified as a plasma marker for outcomes in traumatic brain injury and intracerebral hemorrhage. We further investigated whether leptin might serve as a marker for severity and prognosis in aneurysmal subarachnoid hemorrhage. One hundred and eight consecutive patients and 108 sex and age – matched healthy subjects were recruited. Plasma leptin levels were measured by enzyme-linked immunosorbent assay. Clinical severity was assessed using World Federation of Neurological Surgeons score and Fisher score. Mortality and poor long-term outcome (Glasgow outcome scale scores of 1–3) at 6 months were recorded. Plasma leptin levels on admission were substantially higher in patients than in healthy controls, and were significantly associated with the clinical severity. There was also a significant association between leptin levels and clinical outcomes at 6 months in multivariate logistic regression analysis. Using receiver operating characteristic curves, we calculated areas under the curve for clinical outcomes at 6 months. The predictive performance of leptin was similar to, but did not obviously improve those of World Federation of Neurological Surgeons score and Fisher score. Thus, leptin may indicate clinical severity of the initial bleeding and also have prognostic value for clinical outcomes in aneurysmal subarachnoid hemorrhage and may therefore help in guiding treatment decisions in the setting of aneurysmal subarachnoid hemorrhage.     

Brain stem insufficiency in acute ischemia and cerebral hemorrhage]

Consciousness disorders are closely related to the general dysfunction of the brain stem, and called by some authors brain stem insufficiency. To evaluate the degree of brain stem dysfunction, an original scale has been elaborated. Each group of brain stem functions are scored. Consciousness being the most important symptom of the brain stem insufficiency is scored about 50% in a 63-score scale. Scores are used to achieve the most objectivity in the clinical monitoring of the brain stem insufficiency. Its utility was examined in 75 patients with either ischemia or cerebral hemorrhage. Patients of both groups with severe insufficiency below 33 scores and persisting over 24 hours had no chance to survive. The authors suggest that the scores may successfully be used in the clinical monitoring of all disorders producing consciousness disturbances. Survival of patients with brain stem insufficiency in the course of cerebral ischemia or hemorrhage depends on the degree and duration of the brain stem insufficiency.     

Neurosurgical Aspects of Unexplained Unconsciousness

Neurosurgical experiences and diagnostic difficulties with unconscious patients without diagnosis included cases of intracranial neplasia, cerebral arteriosclerosis, subdural hematoma, traumatic subcortical hemorrhage, subdural abscess, rheumatic encephalitis, spontaneous subarachnoid hemorrhage, subacute bacterial endocarditis and emboli, myocardial infarction and emboli, spontaneous subcortical hemorrhage, fat embolism, meningitis, drug intoxication, uremia, cases in which the cause of death was not clearly established, and phycomycosis of the central nervous system.     

甲状腺素对动脉瘤性蛛网膜下腔出血大鼠脑缺氧诱导因子-1α表达的影响及其机制*

目的:探讨甲状腺素(T4)对动脉瘤性蛛网膜下腔出血后大鼠脑缺氧诱导因子-1α(HIF-1α)表达的调节及其机制。方法:72只雄性成年SD大鼠随机分为以下4组:蛛网膜下腔出血模型组(SAH)(n=18)、蛛网膜下腔出血+甲状腺素组(SAH+T4)(n=18)、蛛网膜下腔出血+溶剂组(SAH+溶剂组)(n=18)、假手术组(n=18)。颈内动脉穿刺法建立蛛网膜下腔出血的模型,术后行颅脑CT平扫,建模后立即开始给药,按3 μg/100 g腹腔注射,每隔24 h一次,连续3 d,SAH+T4组予甲状腺素干预,SAH+溶剂组予等体积溶剂干预,均在建模后72 h处死;各组6只大鼠经多聚甲醛灌注处死后石蜡包埋切片行免疫组化染色检测HIF-1α及p-Akt蛋白、6只用TUNEL法检测凋亡,6只用干湿重法做脑水肿含量检测。结果:建模成功后SAH组及SAH+T4组、SAH+溶剂组大鼠的脑组织肿胀明显,蛛网膜下腔可见暗红色血凝块。SAH组神经行为学评分、脑含水量、凋亡率、HIF-1α蛋白、p-Akt蛋白均较假手术组明显增高(P＜0.05);SAH+T4组神经行为学评分、HIF-1α蛋白、p-Akt蛋白均较SAH组明显增高,其脑含水量、凋亡均较SAH组明显减少(P＜0.05)。结论:使用T4替代治疗可以上调动脉瘤性蛛网膜下腔出血后大鼠脑HIF-1α蛋白表达水平,可能是通过激活三磷酸肌醇激酶／蛋白激酶B(PI3K/Akt)信号通路,使凋亡率减小,最终大鼠行为学得以改善,对大鼠脑产生保护作用。     

Meningeal Carcinomatosis

Meningeal carcinomatosis without gross tumour in the substance of the brain or spinal cord has been reported rarely. Two cases observed at the Victoria General Hospital, Halifax, presented a bizarre clinical picture consisting of signs of meningeal irritation without fever, and psychotic behaviour. Examination of the cerebrospinal fluid revealed low sugar concentration and increased pressure, protein and cells. In one case these cells were readily identified as malignant on stained smears. At autopsy the surfaces of the cerebral hemispheres, cerebellum and brain stem were covered by an opalescent film and on section the subarachnoid space was densely packed with malignant cells. Both primary tumours were adenocarcinomas, one originating in the gallbladder and one in the rectum. The diagnosis of meningeal carcinomatosis must be considered in patients presenting with profound mental changes and meningeal irritation without fever. Diagnosis may be confirmed by cytological examination of the cerebrospinal fluid. The primary tumour is most commonly an adenocarcinoma. There is no satisfactory treatment available.     

诊断性脑血管造影的术后并发症及其风险因素(附437例临床分析)

目的:观察脑血管造影患者的术后并发症,并分析影响并发症的风险因素。方法:437例动脉粥样硬化脑血管病、脑肿瘤、蛛网膜下腔出血、动脉瘤、动静脉畸形、癫痫、血管炎等的患者接受脑血管造影,观察术后24h以内发生的神经系统和局部并发症。用多因素分析方法确定与术后并发症相关的因素。结果:15例(3.43%)发生神经系统并发症,其中2例发生脑卒中并遗留永久残疾;2例死亡。手术造影侧穿刺部位血肿是最常见的并发症。与神经系统并发症相关的危险因素增包括动脉粥样硬化脑血管病,蛛网膜下腔出血,频繁TIA发作。结论:诊断性脑血管造影并发症发生率较低。具有并发症风险因素的患者应尽量减小手术创伤,加强术后观察。     

6-OHDA-induced ectopia of external granule cells in the subarachnoid space covering the cerebellum

The present report describes the genesis, development and topographical distribution of ectopic cells of the external granular layer in the subarachnoid space covering the rat cerebellum. Following one intracisternal injection to newborn rats of 100 micrograms 6-hydroxydopamine (6-OHDA), the meningeal cells degenerate and are removed by phagocytosis within 24 h post injection (p.i.), leaving the cerebellar cortex without a pia-arachnoid cover. Defects appear in the basal lamina investing the cerebellar cortex 3 to 5 days p.i., and both external granule cells and 'sprouts' from Bergmann-glia endfeet grow into the subarachnoid space. The latter form large, flat glial lamellae and cover extensive areas of the denuded cerebellar surface, although they do not form a glial scar over the exposed neuropil of the cerebellar cortex. The numbers of ectopic external granule cells increase within the subarachnoid space both by proliferation and a continuous efflux of cells from the cerebellar cortex. They migrate, aggregate, and ultimately develop into granule, stellate and basket cells, the morphology of which is indistinguishable from their counterparts in situ; they make specific afferent and efferent connections, both among themselves and with the underlying cerebellar cortex and brainstem. The distribution of ectopic external granule cells and their derivatives is restricted to the anterior vermal fissures and the vermal-hemispheric junctions. The present results indicate that external granule cells and their derivatives are capable of both differentiating normally and surviving in the subarachnoid space if they become associated with glial cells and establish synaptic connections.     

ENZYMES ASSOCIATED WITH THE METABOLISM OF CATECHOLAMINES, ACETYLCHOLINE AND GABA IN HUMAN CONTROLS AND PATIENTS WITH PARKINSON''S DISEASE AND HUNTINGTON''S CHOREA

—Tyrosine hydroxylase (TH), dopa decarboxylase (DDC), glutamic acid decarboxylase (GAD), choline acetyltransferase (CAT), and acetylcholinesterase (AChE) were measured in 18–55 areas of brain from humans post mortem. Individuals meeting sudden and unexpected death (22), patients dying in hospital with non–neurological illness (6), Parkinson's disease (12), Huntington's chorea (8), terminal coma (6) or head injury (2) were included in the series. The absolute values obtained compared favourably with some previous human studies where high values for these enzymes were obtained, as well as with monkey and baboon data. The regional distributions of the enzymes were also comparable to those previously reported in human and animal studies. A number of important points with regard to human tissue seemed to emerge from the study. The mode of death was not a factor in enzyme levels in non–neurological and non-coma cases. Post mortem delay did not seem to be a major factor either even though a substantial decline in GAD, TH and DDC could be demonstrated in rats left several hours between sacrifice and removal of the brain for assay. Age had a highly significant effect in certain areas of brain. The decline typically followed a curvilinear pattern (activity = A/age + B with the sharpest drops being in the younger age groups). DDC seemed to be the enzyme most severely affected by age but all the enzymes showed declines in certain brain areas, while in other areas there was no significant decline. All the enzymes were very depressed by coma from illness except AChE. TH and DDC in the brain stem were, however, not affected in the head injury cases. The Parkinsonian cases showed a sharply decreased TH activity in the substantia nigra, caudate and putamen. There were decreases in GAD in the globus pallidus (GP) and substantia nigra with marginal decreases in the neostriatum. CAT levels in the extrapyramidal nuclei were normal. In Huntington's chorea there was a substantial decrease in GAD in all the extrapyramidal structures. There was a patchy loss of CAT in the neostriatum and locus coeruleus.     

Effect of aging on neurotransmitter receptor binding in rat and human brain.

β-Adrenergic and GABA receptor binding were measured in brain areas of rats 3 to 24 months of age. While GABA receptor binding was not significantly different across age in any area, β-adrenergic receptor binding was significantly reduced in the cerebellum and brain stem, but not cerebral cortex, of 24-month-old animals. The loss in β-adrenergic receptor binding does not correlate in a temporal fashion with the reported decrease in norepinephrine-stimulated cyclic AMP accumulation in the cerebellum which occurs as early as 12 months of age. An age-related reduction in β-adrenergic binding was also noted in human cerebellar tissue obtained at autopsy, suggesting that the cerebellar dysfunction seen with aging may be related to a loss of cerebellar neurons which receive noradrenergic input.     

Postmortem Human Brain pH and Lactate in Sudden Infant Death Syndrome

Lactate and pH were measured in frontal and temporal cortex, cingulate gyrus, and caudate nucleus in brains from sudden infant death syndrome (SIDS) cases, control infants, and control adults. Both the lactate levels and the pH values were significantly correlated (p less than 0.001) between the four brain areas, whereas lactate and pH values were significantly correlated within each brain area (p less than 0.001) with a value of pH 7.2 for zero lactate. The lactate concentration in heart blood was significantly correlated with brain lactate (p less than 0.001). Adult sudden death cases (heart attacks) had low lactate and high pH values, whereas agonal state cases had high lactate and low pH values. Control infants who had died because of accidents also had low lactate and high pH values, but infants who might have been exposed to hypoxia before death had high lactate and low pH values. SIDS cases fell into two groups: the first, consisting of all victims over 30 weeks of age and about one-half to two-thirds of those aged less than 30 weeks, had low lactate and high pH values; the second group, consisting of about one-third to one-half of those less than 30 weeks old, had high lactate and low pH values. The changes in lactate levels and pH values indicate that the majority of SIDS cases had died suddenly, but that a sizeable minority had been exposed to hypoxia prior to death.