The pathogenesis of symptoms in normal pressure hydrocephalus (NPH) is unclear. One theory is that in the presence of enlarged lateral ventricles, the ventricular fluid exerts increased force on the ventricular walls, the cerebrospinal fluid pressure remaining normal. This is in accordance with Pascal’s principle of F = PxA. It has not been possible to obtain direct evidence for this view.

The opportunity to gain insight into the matter arose when it was observed that two patients with symptomatic NPH were relieved of their symptoms when they developed bilateral subdural collections, one after head trauma, the other after ventriculo-peritoneal shunting for NPH.

In each case, concomitant with the subdural collections and the reversal of symptoms, the ventricular system became smaller. In the first patient, symptoms returned when the subdural collections were resorbed. In the second patient, symptoms returned when the subdural collections became excessive.

Although documentation was less thorough than desired, it was concluded that relief of symptoms was related to the decrease in the ventricular size rather than lowering of the intraventricular pressure, thus providing evidence for operation of the principle F = PxA as the mechanism of symptoms in NPH.

Carotid angioplasty and stenting is gaining popularity as an alternative to carotid endarterectomy for the treatment of carotid bifurcation stenosis. The major concern with the procedure is the risk of embolic stroke which may be initiated by balloon angioplasty of friable atherosclerotic plaque. Elimination of angioplasty may result in a lower incidence of embolic complications.

We describe a case in which a self-expanding stent alone, without balloon angioplasty, was used to successfully dilate an atherosclerotic stenosis of the carotid bifurcation.

A moderate increase in vessel diameter, from 75% to 50%, was immediately observed after stent placement alone. No embolic complications were observed and follow-up plain film and ultrasound examinations showed progressive stent enlargement with excellent anatomic and hemodynamic results.

In this case of severe carotid stenosis, the use of a self-expanding stent alone, without balloon angioplasty, resulted in excellent anatomic and hemodynamic improvement.

Symptomatic brain metastases from prostatic carcinoma are rare (0.05% to 0.5%).

A 70-year-old man presented with a homonymous hemianopsia due to brain metastatic prostatic carcinoma shortly before becoming symptomatic of prostatic disease. CT and MRI of the brain showed a tumour deep in the right hemisphere near the thalamus and involving the optic radiation.

Routine haematological and biochemical tests were normal. The prostate specific antigen level was low on two separate occasions. The prostatic and brain tumours showed identical appearances, namely of a poorly differentiated adenocarcinoma with neuroendocrine differentiation (small cell carcinoma).

A literature review suggests that small cell carcinoma of the prostate is more likely to spread to the brain compared to adenocarcinoma and that brain metastases indicate a poor prognosis. The prostate gland should be remembered as a possible cause of brain metastases and that a normal serum prostate specific antigen does not exclude this diagnosis.

Investigators use instrumental tasks for objective assessment of parkinsonian motor disability and its drug response. To date, such studies on treated parkinsonian patients have not addressed acute and long-term effects of dopaminergic drugs.

To determine the impact of long-term dopaminergic therapy within a standardized levodopa challenge test design in combination with two repeatedly performed instrumental tasks, peg insertion and tapping, in previously treated and untreated parkinsonian patients.

Tapping significantly deteriorated in previously untreated, but not in treated parkinsonian patients after levodopa intake. In contrast, motor symptoms and peg insertion significantly improved in both groups of parkinsonian patients. Results of both tests differed between parkinsonian patients and matched controls.

Worsening of cognitively less demanding tapping may result from upregulated presynaptic inhibitory feedback regulation, sedative effects of levodopa or dopamine overflow in untreated parkinsonian patients, who are sensitive to these effects in contrast to treated parkinsonian patients. Tapping is a task with autonomic repetitive performance and programming of standardised movements with a low need for cognitive effort. This autonomic functioning of attentional control and selective processing is intact in Parkinson's disease. Peg insertion depends on more complex movements and thus hypothetically on dopamine-associated cognitive processes. Therefore, impairment of peg insertion responded to dopaminergic stimulation in both groups of parkinsonian patients. Future studies on the efficacy of antiparkinsonian drugs, using instrumental tasks for objective assessment, should consider long-term impact of antiparkinsonian drug therapy and associated cognitive efforts.

Pneumocephalus can be a cause of headache, but is easily overlooked in some clinical circumstances.

A 35-year-old woman developed severe headache of abrupt onset during an epidural blood patch procedure done for a post-lumbar puncture headache. A brain CT scan showed subarachnoid air even though there was no evidence of a dural puncture having occurred during the procedure.

The experience of our patient, and a review of the literature suggests that air injected into the epidural space during use of the “loss of resistance” technique can enter the subarachnoid space if a dural puncture site from a previous lumbar puncture is present.

Pneumocephalus should be considered as a potential cause for a severe headache occurring in association with epidural procedures, and also in a number of other clinical settings. Use of a high inspired air oxygen concentration can hasten absorption of an intracranial air collection.

Carotid artery dissection resulting in occlusion or severe narrowing and massive intracranial embolism can result in life-threatening hemispheric ischemia. Aggressive endovascular and microsurgical measures may be necessary to salvage life and minimize stroke morbidity in this extreme situation.

We have treated two middle-aged women who presented within an hour of spontaneous cervical internal carotid artery (ICA) dissection causing hemiplegia, forced head and eye deviation, and declining consciousness. The first patient had a carotid occlusion through which a catheter could not be passed, so intracranial thrombolysis was achieved through a microcatheter navigated through the posterior circulation. Surgical intimectomy and thrombectomy of the dissected ICA was then carried out using an intraoperative Fogarty arterial embolectomy catheter passed up the dissected ICA, followed by endovascular stenting of the reopened cervical ICA. The second patient underwent intracranial microsurgical embolectomy and, after an unsuccessful attempt of stenting the dissected and severely narrowed cervical ICA, surgical reopening again with a Fogarty catheter. Both patients suffered basal ganglionic infarcts but most of the middle cerebral artery territories were preserved and the patients made satisfactory recoveries.

“Malignant” carotid artery dissection causing occlusion or near occlusion with intracranial embolism is an important cause of severe and life-threatening hemispheric ischemia. Treatment should include aggressive endovascular and microsurgical interventions when the hemisphere is at risk.

Ifosfamide (IFX), an alkylating agent and isomer of cyclophosphamide, is used as a single agent or a component of multi-agent chemotherapy in the treatment of ovarian, testicular, head and neck cancers, sarcomas and lymphomas. Encephalopathy is manifested by cerebellar ataxia, confusional state, complex visual hallucinations, extrapyramidal signs, seizures, and mutism.

We report two patients with non-Hodgkin’s lymphoma presenting with mutism and confusional state after IFX infusion. Nonconvulsive status epilepticus (NCSE) as the cause of confusion was diagnosed on the basis of EEG pattern and the apparent improvement following intravenous administration of diazepam.

Electroencephalogram abnormalities during IFX treatment have been described but recordings are only available in six cases. In three of them, paroxysmal alterations warranted the diagnosis of NCSE; however, most cases of IFX encephalopathy might have associated NCSE.

An outbreak of viral encephalitis occurred among pig industry workers in Malaysia in September 1998 to April 1999. The encephalitis was attributed to a new paramyxovirus, Nipah virus. This is a description of the clinical features of 103 patients treated in the Seremban Hospital with characterization of the prognostic factors.

Clinical case records and laboratory investigations were reviewed. The case definition was: patients from the outbreak area, direct contact or in close proximity with pigs, clinical or CSF features of encephalitis.

The mean age was 38 years, 89% were male, 58% were ethnic Chinese, 78% were pig farm owners or hired workers. The mean incubation period was 10 days. The patients typically presented with nonspecific systemic symptoms of fever, headache, myalgia and sore throat. Seizures and focal neurological signs were seen in 16% and 5% respectively. In the more severe cases, this was followed by drowsiness and deteriorating consciousness requiring ventilation in 61%. Autonomic disturbances and myoclonic jerks were common features. The mortality was high at 41%. Systolic hypertension, tachycardia and high fever were associated with poor outcome. On the other hand, 40% recovered fully. As for the other 19%, the residual neurological signs were mostly mild.

Nipah virus caused an encephalitis illness with short incubation period and high mortality. The prognosis for the survivors was good.

This paper highlights the hemiparkinsonism-hemiatrophy (HPHA) syndrome as a unique presentation of the parkinsonian state. Clinically relevant diagnostic and treatment aspects are reviewed.

We report a case of HPHA, in a 21-year-old, otherwise healthy, woman. Clinical and radiographic features of our case are presented. We also review the current literature on the clinical, radiological and pathophysiological mechanisms of HPHA.

In our case, despite the lack of benefit from anticholinergics and dopamine agonists (the patient declined treatment with levodopa), the patient showed a dramatic improvement with subthalamic nucleus stimulator (STN) implantation. There are no reported cases of use of STN stimulator in HPHA.

Hemiparkinsonism-hemiatrophy is a distinct entity that may be clinically and pathogenetically different from idiopathic Parkinson’s disease; hence, HPHA needs to be considered as a possible syndrome in patients that have persistent unilateral parkinsonism. As medications are reported to be unhelpful in HPHA cases, early surgical intervention may be an option, such as in our case.

Tarsal tunnel syndrome is a rare form of entrapment neuropathy. In athletes, it is usually the result of repetitive activity, local injury or a space-occupying lesion. Rarely, athletic footwear has been described as the primary cause of this syndrome.

A 37-year-old male recreational hockey player was examined clinically and electrophysiologically because of spreading numbness in the toes of his left foot while playing hockey and wearing inflatable ice hockey skates designed to promote a better fit.

Clinical and electrophysiological studies revealed evidence of left medial and lateral plantar nerve involvement. Reduced amplitudes of mixed and motor plantar nerve responses with fibrillation potentials and positive sharp waves and no evidence of conduction block suggest that the primary pathology was axonal loss. Follow-up examination showed significant clinical and electrophysiological improvement after the patient stopped wearing his inflatable ice hockey skates.

We report an unusual case of tarsal tunnel syndrome caused by an inflatable ice hockey skate. The patient improved clinically and electrophysiologically when he stopped wearing the boot.

This paper discusses the association between inflammatory and mitochondrial pathologies in patients with HIV-1/AIDS treated with zidovudine (AZT).

We present the clinical and pathological details of a 52-year-old HIV-1 positive male who presented with progressive muscle weakness. We also review the current literature and address the debated pathogenesis of the inflammatory pathology.

Muscle biopsy revealed evidence of both HIV-1 polymyositis and AZT myopathy. Six months after initiation of corticosteroid therapy and discontinuation of AZT, the patient’s symptoms had greatly improved. The biopsy was repeated to show that both pathologies had resolved.

The perceived overlap in the pathological spectra of HIV-1 polymyositis and AZT myopathy has produced some debate on causation and treatment. Unfortunately, there have been very few reports where a repeat biopsy following a drug washout period confirmed resolution of the pathology. Furthermore, affected patients have not been treated in a uniform fashion. Whether this represents one disease or two remains uncertain. The clinical relevance of this issue lies in the potential for harm from the unnecessary use of corticosteroids. This question may be best addressed by a randomized clinical trial.

There are two case reports of patients who had proximal myotonic myopathy (PROMM) / myotonic dystrophy (DM) Type 1 and parkinsonism. The combination of myotonic myopathy and parkinsonism is so rare that it may appear to be just a coincidence. However, previous neuropathological examinations of patients who had myotonic dystrophy showed that there were intracytoplasmic inclusion bodies in the nigra and striatum, which raises the possibility that myotonic myopathy may be associated with parkinsonism. In this report we describe a patient with PROMM and a clinically definite parkinsonism to highlight this possibility.

A 65-year-old man developed proximal muscle weakness, myotonia and atrophy around the age of 55 and was diagnosed as having PROMM at the age of 62. Needle electromyography and muscle biopsy supported the diagnosis. A gene study of the DM Type 1 showed a normal CTG repeat length. At age 63, he developed rest tremor, bradykinesia, hypomimia, stooped posture, and gait disturbance. The postural instability worsened rapidly. The tremor and rigidity were much worse in his right side, where myotonia was more severe. Levodopa therapy was only partially effective.

This is a case report of a patient with PROMM that shows an association with a rapidly progressive form of parkinsonism. We suggest that this may be a novel form of a neurodegenerative disorder, which we name ‘Parkinsonism- Myotonic Myopathy-Complex’.

To describe a patient who presented with a hypoglossal nerve palsy caused by a cavernous malformation, review the literature on cavernous malformations associated with cranial nerves and the differential diagnosis of hypoglossal palsy.

Partial resection of the lesion was achieved and the diagnosis of cavernous malformation proven histologically.

Involvement of a cranial nerve by a cavernous malformation is very uncommon and the facial nerve is the example most frequently reported. This case report adds another possible site for this rare occurrence.

Molybdenum cofactor deficiency (MOCOD) is a rare, progressive neurodegenerative disorder caused by sulphite oxidase enzyme deficiency. The neuropathological findings are consistent with a toxic insult to the brain that causes severe neuronal loss, reactive astrogliosis and spongiosis. The mechanisms responsible for these changes are unknown.

The case is a male infant with MOCOD who died at nine months of age from pneumonia. At autopsy, a complete neuropathological examination was performed including conventional immunohistochemical staining. In addition, brain sections were stained cytochemically with shikata and orcein which stain for disulphide bonds. The elemental composition of cortical cells was then analyzed in the scanning electron microscope using backscatter electron imaging and energy dispersive X-ray spectrometry.

Neurons demonstrated cytoplasmic staining with shikata and orcein cytochemically when compared to control sections. Energy dispersive X-ray spectrometry analysis of these neurons confirmed the presence of excess sulphur and unexpectedly revealed excess magnesium accumulation. None of these findings was found in an age-matched control.

In MOCOD we found abnormal accumulation of sulphur and magnesium in neurons. It is postulated that sulphur-containing compound(s) that are formed as a result of MOCOD cause excitotoxic neuronal injury in the presence of excess magnesium.