Calcineurin Inhibitor‐Induced Headache: Clinical Characteristics and Possible Mechanisms

Two-Pore Domain Potassium Channel in Neurological Disorders

K2P channel is the leaky potassium channel that is critical to keep up the negative resting membrane potential for legitimate electrical conductivity of the excitable tissues. Recently, many substances and medication elements are discovered that could either straightforwardly or in a roundabout way influence the 15 distinctive K⁺ ion channels including TWIK, TREK, TASK, TALK, THIK, and TRESK. Opening and shutting of these channels or any adjustment in their conduct is thought to alter the pathophysiological condition of CNS. There is no document available till now to explain in detail about the molecular mechanism of agents acting on K2P channel. Accordingly, in this review we cover the current research and mechanism of action of these channels, we have also tried to mention the detailed effect of drugs and how the channel behavior changes by focusing on recent advances regarding activation and modulation of ion channels.

Neurologic Toxicities Associated with Tumor Necrosis Factor Inhibitors and Calcineurin Inhibitors

The calcineurin inhibitors cyclosporine and tacrolimus are used for their immunosuppressive effects. Neurotoxic side effects include tremor, paresthesia, and headache. Rarer neurotoxicities include seizure, posterior reversible encephalopathy syndrome, and encephalopathy. Tacrolimus tends to be more neurotoxic than cyclosporine. Management of toxicities associated with calcineurin inhibitors includes dose reduction, switching between calcineurin inhibitors, or switching to a calcineurin-free regimen. Tumor necrosis factor (TNF) inhibitors are used in autoimmune diseases. Management of demyelinating conditions among patients treated with anti-TNF should follow standard of care and withdrawal of the anti-TNF. This drug class should be avoided in patients with a history of demyelinating conditions.

Chronic pain 1-5 years after heart transplantation-A nationwide cross-sectional cohort study

Aim

To provide a multidimensional assessment of self-reported chronic pain 1-5 years after heart transplantation and its relationship with self-reported well-being, fatigue, recovery, self-efficacy and socio-economic factors and to explore differences between heart recipients and a cohort of lung recipients.

Design

This multicentre, cross-sectional, cohort study is a part of the Swedish national Self-management after thoracic transplantation study.

Methods

Six questionnaires were distributed at the heart recipients yearly follow-up (1-5 years) at three Swedish university hospitals 2014-2017.

Results

The study group comprised of 79 heart recipients, 25 women and 54 men with a mean age of 52.68 years. Chronic pain among heart recipients was common and those not in paid employment as well as those with low psychological well-being and high general fatigue reported significantly more pain. Female heart recipients were more affected by pain. General health and vitality, general fatigue, physical fatigue and reduced activity were related to the pain intensity score.

Relevance to clinical practice

As it is the duty of the healthcare system to provide adequate pain treatment, screening for pain should be a mandatory part of long-term follow-up.

Pain, fatigue and well-being one to five years after lung transplantation - a nationwide cross-sectional study

RATIONALE AND AIM

Little is known about persistent pain after lung transplantation. Therefore, the aim was to present a multidimensional assessment of self-reported pain 1-5 years after lung transplantation and its relationship with fatigue and transplant-specific well-being.

METHODS

This nationwide, cross-sectional cohort study is part of the self-management after thoracic transplantation study. A total of 117 lung recipients, all White, who were due for their annual follow-up at one (n = 35), two (n = 28), three (n = 23), four (n = 20) and 5 years (n = 11) after lung transplantation were included. We used three instruments; the Pain-O-Meter (POM), which provides information about pain intensity, sensation, location and duration, the MFI-19 fatigue instrument and the Organ Transplant Symptom and Well-being Instrument (OTSWI). Permission to carry out this study was granted by the Regional Ethical Review Board in southern Sweden (D-nr 2014-124).

RESULTS

The prevalence of pain was 51% after 1 year, 68% after 2 years, 69.5% after 3 years, 75% after 4 years and 54.5% after 5 years. Women experienced more pain than men. Lung recipients with pain reported lower well-being and higher symptom distress but were not more fatigued than those without pain.

STUDY LIMITATIONS

The limitations of this study are due to the cross-sectional design. The recruitment of patients during the study period was probably affected by the different conditions regarding staffing at the outpatient lung transplant clinic in the two thoracic transplant centres in Sweden. The slightly different approach to the care of these patients in the pre, peri and postoperative setting contributes to the heterogeneity of the study population.

CONCLUSION

Chronic bodily pain up to 5 years after lung transplantation reduces perceived well-being. Lung recipients with pain report higher symptom distress than those without pain.

Brain natriuretic peptide constitutively downregulates P2X3 receptors by controlling their phosphorylation state and membrane localization

BACKGROUND

ATP-gated P2X3 receptors are important transducers of nociceptive stimuli and are almost exclusively expressed by sensory ganglion neurons. In mouse trigeminal ganglion (TG), P2X3 receptor function is unexpectedly enhanced by pharmacological block of natriuretic peptide receptor-A (NPR-A), outlining a potential inhibitory role of endogenous natriuretic peptides in nociception mediated by P2X3 receptors. Lack of change in P2X3 protein expression indicates a complex modulation whose mechanisms for downregulating P2X3 receptor function remain unclear.

RESULTS

To clarify this process in mouse TG cultures, we suppressed NPR-A signaling with either siRNA of the endogenous agonist BNP, or the NPR-A blocker anantin. Thus, we investigated changes in P2X3 receptor distribution in the lipid raft membrane compartment, their phosphorylation state, as well as their function with patch clamping. Delayed onset of P2X3 desensitization was one mechanism for the anantin-induced enhancement of P2X3 activity. Anantin application caused preferential P2X3 receptor redistribution to the lipid raft compartment and decreased P2X3 serine phosphorylation, two phenomena that were not interdependent. An inhibitor of cGMP-dependent protein kinase and siRNA-mediated knockdown of BNP mimicked the effect of anantin.

CONCLUSIONS

We demonstrated that in mouse trigeminal neurons endogenous BNP acts on NPR-A receptors to determine constitutive depression of P2X3 receptor function. Tonic inhibition of P2X3 receptor activity by BNP/NPR-A/PKG pathways occurs via two distinct mechanisms: P2X3 serine phosphorylation and receptor redistribution to non-raft membrane compartments. This novel mechanism of receptor control might be a target for future studies aiming at decreasing dysregulated P2X3 receptor activity in chronic pain.

Metabolische Störungen

Im folgenden Kapitel werden die verschiedenen metabolischen Störungen betrachtet. Zunächst wird auf die allgemeinen und spezifischen neurologischen Komplikationen bei Organtransplantation eingegangen. Dann geht es um die metabolischen Enzephalopathien: Störungen der Gehirntätigkeit bei angeborenen und erworbenen Stoffwechselerkrankungen im engeren Sinn, Elektrolytstörungen, Hypovitaminosen, zerebrale Folgen einzelner Organdysfunktionen, zerebrale Hypoxien, Endotheliopathien und Mitochondropathien. Anschließend werden das Alkoholdelir und die Wernicke-Enzephalopathie erörtert. Bei zahlreichen akuten Erkrankungen von Gehirn, Rückenmark und peripherem Nervensystem treten typische Störungen vegetativer Systeme auf, deren Erkennung und Therapie insbesondere bei Intensivpatienten eine vitale Bedeutung haben kann: die autonomen Störungen. Bei der zentralen pontinen Myelinolyse kommt es zu einer akuten, vorwiegend fokal-symmetrischen Demyelinisierung im Hirnparenchym. Auch Basalganglienerkrankungen können intensivmedizinisch relevant werden. Und schließlich wird die akute Stressreaktion betrachtet, die aufgrund der vielfältigen metabolischen und endokrinen Veränderungen bei kritischen Erkrankungen entsteht. Gerade das RCVS als neuere Krankheitsentität und wichtige Differenzialdiagnose zur Vaskulitis des ZNS verdient einen eigenen Platz, in diesem Unterkapitel werden ebenfalls verwandte Syndrome wie die hypertensive Enzephalopathie und das PRES abgehandelt.

A Role for K2P Channels in the Operation of Somatosensory Nociceptors

The ability to sense mechanical, thermal, and chemical stimuli is critical to normal physiology and the perception of pain. Contact with noxious stimuli triggers a complex series of events that initiate innate protective mechanisms designed to minimize or avoid injury. Extreme temperatures, mechanical stress, and chemical irritants are detected by specific ion channels and receptors clustered on the terminals of nociceptive sensory nerve fibers and transduced into electrical information. Propagation of these signals, from distant sites in the body to the spinal cord and the higher processing centers of the brain, is also orchestrated by distinct groups of ion channels. Since their identification in 1995, evidence has emerged to support roles for K2P channels at each step along this pathway, as receptors for physiological and noxious stimuli, and as determinants of nociceptor excitability and conductivity. In addition, the many subtypes of K2P channels expressed in somatosensory neurons are also implicated in mediating the effects of volatile, general anesthetics on the central and peripheral nervous systems. Here, I offer a critical review of the existing data supporting these attributes of K2P channel function and discuss how diverse regulatory mechanisms that control the activity of K2P channels act to govern the operation of nociceptors.

A dominant-negative mutation in the TRESK potassium channel is linked to familial migraine with aura

Migraine with aura is a common, debilitating, recurrent headache disorder associated with transient and reversible focal neurological symptoms. A role has been suggested for the two-pore domain (K2P) potassium channel, TWIK-related spinal cord potassium channel (TRESK, encoded by KCNK18), in pain pathways and general anaesthesia. We therefore examined whether TRESK is involved in migraine by screening the KCNK18 gene in subjects diagnosed with migraine. Here we report a frameshift mutation, F139WfsX24, which segregates perfectly with typical migraine with aura in a large pedigree. We also identified prominent TRESK expression in migraine-salient areas such as the trigeminal ganglion. Functional characterization of this mutation demonstrates that it causes a complete loss of TRESK function and that the mutant subunit suppresses wild-type channel function through a dominant-negative effect, thus explaining the dominant penetrance of this allele. These results therefore support a role for TRESK in the pathogenesis of typical migraine with aura and further support the role of this channel as a potential therapeutic target.

Familial hemiplegic migraine Ca(v)2.1 channel mutation R192Q enhances ATP-gated P2X3 receptor activity of mouse sensory ganglion neurons mediating trigeminal pain

BACKGROUND

The R192Q mutation of the CACNA1A gene, encoding for the α1 subunit of voltage-gated P/Q Ca2+ channels (Ca(v)2.1), is associated with familial hemiplegic migraine-1. We investigated whether this gain-of-function mutation changed the structure and function of trigeminal neuron P2X3 receptors that are thought to be important contributors to migraine pain.

RESULTS

Using in vitro trigeminal sensory neurons of a mouse genetic model knockin for the CACNA1A R192Q mutation, we performed patch clamp recording and intracellular Ca2+ imaging that showed how these knockin ganglion neurons generated P2X3 receptor-mediated responses significantly larger than wt neurons. These enhanced effects were reversed by the Ca(v)2.1 blocker ω-agatoxin. We, thus, explored intracellular signalling dependent on kinases and phosphatases to understand the molecular regulation of P2X3 receptors of knockin neurons. In such cells we observed strong activation of CaMKII reversed by ω-agatoxin treatment. The CaMKII inhibitor KN-93 blocked CaMKII phosphorylation and the hyperesponsive P2X3 phenotype. Although no significant difference in membrane expression of knockin receptors was found, serine phosphorylation of knockin P2X3 receptors was constitutively decreased and restored by KN-93. No change in threonine or tyrosine phosphorylation was detected. Finally, pharmacological inhibitors of the phosphatase calcineurin normalized the enhanced P2X3 receptor responses of knockin neurons and increased their serine phosphorylation.

CONCLUSIONS

The present results suggest that the CACNA1A mutation conferred a novel molecular phenotype to P2X3 receptors of trigeminal ganglion neurons via CaMKII-dependent activation of calcineurin that selectively impaired the serine phosphorylation state of such receptors, thus potentiating their effects in transducing trigeminal nociception.

Repeated, severe headache in a lung transplant patient: a case report

We report a patient in whom a double lung transplantation has been performed for end-stage bronchiectasis due to IgG2 deficiency, under treatment with monthly intravenous immunoglobulins (IVIG) and Later switched to subcutaneous (SC) IG on her request. After the transplantation procedure which was uneventful, she continued to receive weekly SCIG. She developed repeated episodes of aseptic meningitis, which was finally resolved by switching again to monthly IVIG (slower infusion rate) in combination with low dose sodium valproate. This is to our knowledge the first case of aseptic meningitis due to SC IG treatment after lung transplantation.

Spontaneous intracranial hypotension-hypovolemia associated with tacrolimus

There is little precedent for a medication-induced spontaneous intracranial hypotension/cerebrospinal fluid (CSF) hypovolemia (SIH). This case history of a woman with low CSF pressure, orthostatic headache, and radiographic findings consistent with SIH but without a detectable leak was notable for its association, both onset and resolution, with the use of the calcineurin inhibitor tacrolimus (FK506). A literature review for potential causes of a tacrolimus-induced CSF hypotension suggests many potential mechanisms of action, including effects on blood brain barrier and dural compliance, and supports further vigilance for this condition in the medically complex setting of tacrolimus use.

Molecular background of leak K+ currents: two-pore domain potassium channels

Two-pore domain K(+) (K(2P)) channels give rise to leak (also called background) K(+) currents. The well-known role of background K(+) currents is to stabilize the negative resting membrane potential and counterbalance depolarization. However, it has become apparent in the past decade (during the detailed examination of the cloned and corresponding native K(2P) channel types) that this primary hyperpolarizing action is not performed passively. The K(2P) channels are regulated by a wide variety of voltage-independent factors. Basic physicochemical parameters (e.g., pH, temperature, membrane stretch) and also several intracellular signaling pathways substantially and specifically modulate the different members of the six K(2P) channel subfamilies (TWIK, TREK, TASK, TALK, THIK, and TRESK). The deep implication in diverse physiological processes, the circumscribed expression pattern of the different channels, and the interesting pharmacological profile brought the K(2P) channel family into the spotlight. In this review, we focus on the physiological roles of K(2P) channels in the most extensively investigated cell types, with special emphasis on the molecular mechanisms of channel regulation.

Low-dose cyclosporine treatment for sight-threatening uveitis: efficacy, toxicity, and tolerance

Aim:

To ascertain the effectiveness, tolerability, and safety of low-dose cyclosporine in the management of sight-threatening uveitis.

Materials and Methods:

This was a retrospective clinical case series of patients using oral low-dose cyclosporine for the management of sight-threatening uveitis in the uvea clinic (UC). Patients receiving cyclosporine were identified from the clinic database. Main outcome measures were degree of intraocular inflammation, visual acuity and dose reduction of oral steroid for effectiveness and adverse symptoms, systemic hypertension, and raised serum creatinine for tolerability and safety.

Results:

Intraocular inflammation was improved or stable in 97% of patients, visual acuity was improved or stable in 91%, and oral steroid dosage was reduced in 73% (by half or more in 51%). Adverse symptoms were almost universal, the commonest being peripheral paresthesia/burning in 70% and fatigue in 67%. Significant systemic hypertension developed in 27% and raised creatinine in 30%, necessitating dose reduction. Cyclosporine was discontinued in 35%, being intolerable in 20% and ineffective in 15%.

Conclusions:

Cyclosporine was found to be effective in reducing inflammation and protecting vision in sight-threatening uveitis. It was safe with proper monitoring, including in children. It had a significant toxicity profile and a high incidence of adverse symptoms which required close supervision, and a prompt dose reduction or drug exchange.

Nitric oxide-induced changes in endothelial expression of phosphodiesterases 2, 3, and 5

OBJECTIVE

To investigate nitric oxide (NO)-mediated changes in expression of cyclic nucleotide degrading phosphodiesterases 2A (PDE2A), PDE3B, and PDE5A in human endothelial cells.

BACKGROUND

Nitric oxide induces production of cyclic guanosine monophosphate (cGMP), which along with cyclic adenosine monophosphate (cAMP) is degraded by PDEs. NO donors and selective inhibitors of PDE3 and PDE5 induce migraine-like headache and play a role in endothelial dysfunction during stroke. The current study investigates possible NO modulation of cGMP-related PDEs relevant to headache induction in a cell line containing such PDEs.

METHODS

Real time polymerase chain reaction and Western blots were used to show expression of PDE2A, PDE3B, and PDE5A in a stable cell line of human brain microvascular endothelial cells. Effects of NO on PDE expression were analyzed at specific time intervals after continued DETA NONOate administration.

RESULTS

This study shows the expression of PDE2A, PDE3B, and PDE5A mRNA and PDE3B and PDE5A protein in human cerebral endothelial cells. Long-term DETA NONOate administration induced an immediate mRNA up-regulation of PDE5A (1.9-fold, 0.5 hour), an early peak of PDE2A (1.4-fold, 1 and 2 hours) and later up-regulation of both PDE3B (1.6-fold, 4 hours) and PDE2A (1.7-fold, 8 hours and 1.2-fold after 24 hours). Such changes were, however, not translated into significant changes in protein expression indicating few, if any, functional effects.

CONCLUSIONS

Long-term NO stimulation modulated PDE3 and PDE5 mRNA expression in endothelial cells. However, PDE3 and PDE5 protein levels were unaffected by NO. The presence of PDE3 or PDE5 in endothelial cells indicates that selective inhibitors may have functional effects in such cells. A complex interaction of cGMP and cAMP in response to NO administration may take place if the mRNA translates into active protein. Whether or not this plays a role in the headache mechanisms remains to be investigated.

Headache in children and adolescents after organ transplantation

The prevalence and characteristics of headache were studied in a national cohort of 177 pediatric patients with kidney, liver, and heart transplants. All patients received triple drug immunosuppression with CsA, Aza, and MP. Data on headaches were collected by sending two questionnaires and reviewing the medical records. Statements on headache were found in the medical records of 46% of the patients. According to a questionnaire, two thirds had experienced headaches sometime after transplantation, and 40% had present headaches. The episodes had significantly affected the quality of life in a third of the patients, and resulted in neurological examination in 15%. Most of the subjects (61%) described typical episode as mild or moderate, and 39% as severe or very severe. The usual episodes lasted <4 h in 73% of the patients and >4 h in 27%. The headache could be classified as migraine, probable migraine or headache without specific features in 33%, 31%, and 36%, respectively. Most patients (82%) had used pain-killers, mainly acetaminophen and ibuprofen. Headache episodes may significantly impair the quality of life in children and adolescents after organ transplantation.

Focus on headache as an adverse reaction to drugs

There are a large number of drugs inducing headache as an adverse reaction. Nevertheless, headaches as adverse reactions to drugs have received limited attention. Non-serious adverse reactions, such as headache, are not quantified and described as accurately as serious, life threatening ones. However, non-serious reactions can also be extremely troublesome, above all when they are chronic: they can affect patients' quality of life and contribute to non-compliance. It is absolutely possible that the number of patients with headache as an adverse reaction, which is going to increase, considering the growing use of medications. Physicians should, therefore, be aware of this issue. Indeed, it is difficult to attribute the diagnosis of adverse drug reaction to a condition, headache, which is also a very common symptom in general population.

Methotrexate and cyclosporine treatments modify the activities of dipeptidyl peptidase IV and prolyl oligopeptidase in murine macrophages

Analysis of the effects of cyclosporine A (25–28 mgkg⁻¹) and/or methotrexate (0.1 mgkg⁻¹) treatments on dipeptidyl peptidase IV (DPPIV) and prolyl oligopeptidase (POP) activities and on algesic response in two distinct status of murine macrophages (Mφs) was undertaken. In resident Mφs, DPPIV and POP were affected by neither individual nor combined treatments. In thioglycolate-elicited Mφs, methotrexate increased DPPIV (99–110%) and POP (60%), while cyclosporine inhibited POP (21%). Combined treatment with both drugs promoted a rise (51–84%) of both enzyme activities. Only cyclosporine decreased (42%) the tolerance to algesic stimulus. Methotrexate was revealed to exert prevalent action over that of cyclosporine on proinflammatory Mφ POP. The opposite effects of methotrexate and cyclosporine on POP activity might influence the availability of the nociceptive mediators bradykinin and substance P in proinflammatory Mφs. The exacerbated response to thermally induced algesia observed in cyclosporine-treated animals could be related to upregulation of those mediators.

Metabolische Störungen

Bei fortgeschrittenem Organversagen von Niere, Herz, Leber oder Lunge stellt eine Organtransplantation meist das einzige kurative Therapieverfahren dar. Auch eine Knochenmarktransplantation wird bei sonst unheilbaren Leukämien oder Lymphomen eingesetzt. Nach Organtransplantation treten bei 30–60% der Patienten neurologische Komplikationen auf. Differenzialdiagnostisch müssen vorbestehende, durch die Grunderkrankung bedingte, Störungen von intraoperativen Komplikationen, von metabolisch bedingten neurologischen Störungen und von Nebenwirkungen der notwendigen immunsuppressiven Medikation abgegrenzt werden. Immunsuppressiva können dabei sowohl eine direkte Neurotoxizität als auch indirekt vermehrt Infektionen des Zentralnervensystems (ZNS) und sekundäre ZNS-Malignome verursachen. Während metabolische Enzephalopathien oder opportunistische ZNS-Infektionen bei allen Patienten nach Transplantation etwa gleich häufig auftreten können, sind andere neurologische Syndrome für bestimmte Organtransplantationen typisch.

Recurrent headache as the main symptom of acquired cerebral toxoplasmosis in nonhuman immunodeficiency virus-infected subjects with no lymphadenopathy: the parasite may be responsible for the neurogenic inflammation postulated as a cause of different types of headaches

Headache and/or migraine, a common problem in pediatrics and internal medicine, affect about 5% to 10% children and adolescents, and nearly 30% of middle-aged women. Headache is also one of the most common clinical manifestations of acquired Toxoplasma gondii infection of the central nervous system (CNS) in immunosuppressed subjects. We present 11 apparently nonhuman immunodeficiency virus-infected children aged 7 to 17 years (8 girls, 3 boys) and 1 adult woman with recurrent severe headaches in whom latent chronic CNS T. gondii infection not manifested by enlarged peripheral lymph nodes typical for toxoplasmosis, was found. In 7 patients, the mean serum IgG Toxoplasma antibodies concentration was 189 +/- 85 (SD) IU/mL (range 89 to 300 IU/mL), and in 5 other subjects, the indirect fluorescent antibody test titer ranged from 1:40 to 1:5120 IU/mL (n= <1:10 IU/mL). Some of the patients suffered also from atopic dermatitis (AD) and were exposed to cat and/or other pet allergens, associated with an increased IL-4 and decreased IFN-gamma production. These cytokine irregularities caused limited control of cerebral toxoplasmosis probably because IL-4 down-regulated both the production of IFN-gamma and its activity, and stimulated production of a low NO-producing population of monocytes, which allowed cysts rupture, increased parasite multiplication and finally reactivation of T. gondii infection. The immune studies performed in 4 subjects showed a decreased percentage of T lymphocytes, increased total number of lymphocytes B and serum IgM concentration, and impaired phagocytosis. In addition, few of them had also urinary tract diseases known to produce IL-6 that can mediate immunosuppressive functions, involving induction of the anti-inflammatory cytokine IL-10. These disturbances probably resulted from the host protective immune reactions associated with the chronic latent CNS T. gondii infection/inflammation. This is consistent with significantly lower enzyme indoleamine 2,3-dioxygenase (IDO) activity reported in atopic than in nonatopic individuals, and an important role that IDO and tryptophan degradation pathways plays in both, the host resistance to T. gondii infection and its reactivation. Analysis of literature information on the subjects with different types of headaches caused by foods, medications, and other substances, may suggest that their clinical symptoms and changes in laboratory data result at least in part from interference of these factors with dietary tryptophan biotransformation pathways. Several of these agents caused headache attacks through enhancing NO production via the conversion of arginine to citrulline and NO by the inducible nitric oxide synthase enzyme, which results in the high-output pathway of NO synthesis. This increased production of NO is, however, quickly down-regulated by NO itself because this biomolecule can directly inactivate NOS, may inhibit Ia expression on IFN-gamma-activated macrophages, which would limit antigen-presenting capability, and block T-cell proliferation, thus decreasing the antitoxoplasmatic activity. Moreover, NO inhibits IDO activity, thereby suppressing kynurenine formation, and at least one member of the kynurenine pathway, 3-hydroxyanthranilic acid, has been shown to inhibit NOS enzyme activity, the expression of NOS mRNA, and activation of the inflammatory transcription factor, nuclear factor-kB. In addition, the anti-inflammatory cytokines IL-4 and IL-10, TGF-beta, and a cytokine known as macrophage deactivating factor, have been shown to directly modulate NO production, sometimes expressing synergistic activity. On the other hand, IL-4 and TGF-beta can suppress IDO activity in some cells, for example human monocytes and fibroblasts, which is consistent with metabolic pathways controlled by IDO being a significant contributor to the proinflammatory system. Also, it seems that idiopathic intracranial hypertension, pseudotumor cerebri, and aseptic meningitis, induced by various factors, may result from their interference with IDO and inducible nitric oxide synthase activities, endogenous NO level, and cytokine irregularities which finally affect former T. gondii status 2mo in the brain. All these biochemical disturbances caused by the CNS T. gondii infection/inflammation may also be responsible for the relationship found between neurologic symptoms, such as headache, vertigo, and syncope observed in apparently immunocompetent children and adolescents, and physical and psychiatric symptoms in adulthood. We therefore believe that tests for T. gondii should be performed obligatorily in apparently immunocompetent patients with different types of headaches, even if they have no enlarged peripheral lymph nodes. This may help to avoid overlooking this treatable cause of the CNS disease, markedly reduce costs of hospitalization, diagnosis and treatment, and eventually prevent developing serious neurologic and psychiatric disorders.

Entzündliche Erkrankungen des ZNS sowie immunmodulatorische Therapie und ihr Einfluss auf primäre Kopfschmerzen

Headaches are a well known symptom in systemic or local inflammatory diseases such as pneumonia or meningitis. These headaches may mimic primary headaches and are thought to be generated by inflammatory mediators acting directly on nociceptors or indirectly - via facilitation of neurons. Apart from prostaglandin and nitric oxide also cytokines (TNF-alpha or interleukin-6) may play a role. In primary headaches such as migraine inflammatory mechanisms also have been acclaimed to contribute to pain generation. The recently observed increase of migraine attacks under immunmodulatory therapy in multiple sclerosis has focussed attention on primary headaches in states of altered immunity, for instance in autoimmune disorders like lupus erythematosus, rheumatoid arthritis, or in patients treated with immunosuppressants. This article describes the standard of knowledge and tries to shed light on possible mechanisms of pain generation in the respective conditions.

Transient Ischemic Attack After Rizatriptan Administration in a Liver Transplant Recipient: A Case Report

We report the case of a male liver transplant recipient who developed de novo migraine while on tacrolimus therapy. Considering the inadequate control of pain using nonsteroidal antiinflammatory drugs, rizatriptan benzoate (10 mg orally) was administered (double administration). After both administrations a clinically transient ischemic attack (TIA) occurred. Rizatriptan was discontinued, the patient recovered without sequelae from both episodes of TIA. Remission of migraine occurred after discontinuation of tacrolimus and substitution with cyclosporine. We suggest that the association of rizatriptan and tacrolimus could potentially lead to an excessive risk of cerebral vasospasm and should be used with caution. A change in immunosuppressive therapy (from tacrolimus to cyclosporine or sirolimus) may improve migraine and should be the first choice. Further prospective comparative randomized trials are needed to establish the best therapeutic option in this particular subset of patients.