Pedro André Kowacs

Leão's cortical spreading depression From experimental “artifact” to physiological principle

Cortical spreading depression was described in 1943 by Aristides Leão, a Brazilian neurophysiologist. Initially considered to be a mysterious event as it was discovered serendipitously, its nature has become progressively better known. Cortical spreading depression is now accepted as the mechanism underlying migraine aura and has became known as either Leãos spreading depression or cortical spreading depression. Recent studies have suggested a role for Leãos cortical spreading depression in the pathogenesis and symptomatology of neurologic disorders such as transient global amnesia, head injury, and cerebrovascular diseases.

Infection of the CNS by Scedosporium apiospermum after near drowning. Report of a fatal case and analysis of its confounding factors

This report describes a fatal case of central nervous system pseudallescheriasis. A 32 year old white man presented with headache and meningismus 15 days after nearly drowning in a swine sewage reservoir. Computerised tomography and magnetic resonance imaging of the head revealed multiple brain granulomata, which vanished when steroid and broad spectrum antimicrobial and antifungal agents, in addition to dexamethasone, were started. Cerebrospinal fluid analysis disclosed a neutrophilic meningitis. Treatment with antibiotics and amphotericin B, together with fluconazole and later itraconazole, was ineffective. Miconazole was added through an Ommaya reservoir, but was insufficient to halt the infection. Pseudallescheria boydii was finally isolated and identified in cerebrospinal fluid cultures, a few days before death, three and a half months after the symptoms began. Diagnosis was delayed because of a reduction in the lesions after partial treatment, which prevented a stereotactic biopsy. Physicians should be aware of this condition, and provide prompt stereotactic biopsy. Confirmed cases should perhaps be treated with voriconazole, probably the most effective, currently available treatment for this agent.

Cox-2 Inhibitor for the Treatment of Idiopathic Stabbing Headache Secondary To Cerebrovascular Diseases:

The idiopathic stabbing headache (ISH) is characterized by a stabbing pain of short duration, variable localization and an errant evolution pattern. As its biological mechanisms are unknown and the treatment options are little effective, this disorder shows a strong impact on the patients life. Two females and one male, aged 76, 66 and 72 years, respectively, started presenting ISH within 20 days after the onset of a stroke. All the patients were treated for the ISH with celecoxib, a COX-2 specific inhibitor, with full recovery from ISH up to 6 days after it was first administered. The interruption of the drug 60 days after the treatment with celecoxib induced again the appearance of algic symptoms in two patients. We concluded that cerebrovascular diseases (CD) can lead to ISH and that the COX-2 inhibitor can be an effective prophylactic drug for ISH after CD.

Influence of lamotrigine over the sunct syndrome: one patient follow-up for two years

The SUNCT syndrome is characterized by a short-lasting headache in the first division of the trigeminal nerve, associated with ipsilateral autonomic symptoms. It is highly refractory to prophylactic medication. We describe a case where lamotrigine reduced the intensity, duration, and frequency of attacks and increased the remission period of this disorder. Over a two-year period, the attacks came back immediately whenever the patient reduced the dose or neglected treatment. We concluded that lamotrigine is effective in treating SUNCT syndrome when used in high doses for a prolonged period of time.

Central nervous system Aspergillus fumigatus infection after near drowning

Aims: To report the case of a 26 year old white man, who developed chronic meningitis and intracerebral granulomata 15 days after an episode of near drowning in a swamp. Methods:Aspergillus fumigatus was isolated from cerebrospinal fluid cultures. Results: The patient died 70 days after the symptoms were first noticed, and seven days after a subarachnoid haemorrhage. Aspergillus has never been reported before as a cause of intracranial infection after near drowning. Conclusions: Physicians must be aware of this possibility when confronted with such a situation, because there are now effective therapeutic options for systemic aspergillosis.

Massaging over the greater occipital nerve reduces the intensity of migraine attacks: evidence for inhibitory trigemino-cervical convergence mechanisms

Activation of the trigemino-cervical system constitutes one of the first steps in the genesis of migraine. The objective of this study was to confirm the presence of trigemino-cervical convergence mechanisms and to establish whether such mechanisms may also be of inhibitory origin. We describe a case of a 39-years-old woman suffering from episodic migraine who showed a significant improvement in her frontal headache during migraine attacks if the greater occipital nerve territory was massaged after the appearance of static mechanical allodynia (cortical sensitization). We review trigemino-cervical convergence and diffuse nociceptive inhibitory control (DNIC) mechanisms and suggest that the convergence mechanisms are not only excitatory but also inhibitory.

Prevalência e características da cefaléia idiopática em punhaladas em uma população de migranosos

Idiopathic stabbing headache is a quite unknown disorder. Its main features consist of brief stabbing pains, lasting few seconds. In most cases, idiopathic stabbing headache is underdiagnosed. We have followed up migraine patients during a period of 12 months, aiming to determine the prevalence and main features of idiopathic stabbing headache while occuring apart from migraine attacks. Two hundred and thirty-three of the 280 patients initially surveyed were included in the analysis of the results. Ninety-four patients presented idiopathic stabbing headaches (40.4%), being 72 of them females (76.5%). For migraine with idiopathic stabbing headaches, mean age, age of beginning of migraine and years with migraine were 33, 22.5 and 10.6 years, respectively. Mean duration of the idiopathic stabbing headaches was reported to be 1.42 seconds [ 1 second by 68 patients (72.4%), 2 seconds by 17 (18.1%), 3 seconds by 6 (6.3%), 4 seconds by 1 (1.05%) and 5 seconds by 2 (2.15%)]. Pain paroxysms were reported to be unilateral by 86 (91.4%) and bilateral by 8 (8.6%) of the cases. They were reported to be temporal by 56 patients (60%), occipital by 15 (15.6%), frontal by 8 (8.5%), temporo-occipital by 7 (7.4%), parietal by 5 (5.3%), fronto-temporal by 1 (1.06%), cervical by 1 (1.06%) and ocular by 1 patient (1.06%). The study confirms a high prevalence of idiopathic stabbing headaches in migraineurs. Its main clinical features could be well determined during the interval between migraine attacks.

Cerebellar ataxia in non-paraneoplastic Lambert-Eaton myasthenic syndrome.

Lambert-Eaton myasthenic syndrome (LEMS) is an immune-mediated disorder of the neuromuscular junction that rarely is associated with cerebellar ataxia (CA). We describe two patients with non-paraneoplastic LEMS associated with CA who showed high levels of anti-P/Q-type voltage-gated calcium channels antibodies in the serum and cerebrospinal fluid, and reduced CMAP with increment after brief maximum voluntary contraction in electrophysiological studies. We suggest that LEMS should be considered in the differential diagnosis of patients with CA.

The role of the irritative zone and of the number and distribution of calcifications in the severity of epilepsy associated with intracranial calcifications

OBJECTIVE To determine the influence of the location of the irritative zone, and the number and the distribution of the intracranial calcifications in the severity of epilepsy associated with intracranial calcifications. METHOD We studied 47 patients with epilepsy and intracranial calcifications, 24 with normal (Group A) and 23 with abnormal interictal EEGs (Group B), a control group (n=21) with abnormal interictal EEGs and normal CT-scans (Group C). Clinical, electroencephalographic and neuroradiological features were compared among groups. RESULTS Temporal lobe interictal EEG abnormalities were found in 23/24 Group B patients, and in all Group C patients. Most Group B and Group C patients presented temporal lobe seizure symptomatology, whereas in most Group A patients symptomatology was rolandic (p=0.0001). Epilepsy was more severe in Group B and Group C patients than in Group A patients (p=0.0001 and p=0.0054). No relationship was found between the number of calcifications and epilepsy severity. CONCLUSION An irritative zone at the temporal lobe is more relevant in determining the severity, symptomatology and frequency of seizures than the number and location of calcifications.

Critical flicker frequency in migraine. A controlled study in patients without prophylactic therapy

The critical flicker frequencies (CFF) of individuals with migraine with and without aura were determined and compared to those of normal controls. Twenty-six migraine patients, 12 with aura and 14 without aura and 30 healthy controls were included. Migraineurs were tested during a migraine-free period, through both the continuous flicker method (CFM) and the forced choice method (FCM). Migraineurs presented a mean flickering fusion threshold lower than healthy controls with the CFM (40.45 vs. 44.33, respectively; P = 0.019) and with the FCM (34.16 Hz vs. 38.5 Hz, respectively, P = 0.019). Both groups of migraineurs had significantly lower thresholds as compared to controls, migraineurs with aura presenting the lowest thresholds for the fusion of flickering (P = 0.008 and P = 0.0001 with the CFM and the FCM, respectively). Results confirmed and extended previous observations of abnormal flicker fusion thresholds in migraineurs. We hypothesize that this finding might be related to a shorter cortical stimulation silent period.