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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We recently demonstrated a direct relationship between autoregulation-related changes in renal vascular resistance (RVR) and renal interstitial ATP concentrations. To assess the possible role for extracellular ATP in the regulation of tubuloglomerular feedback (TGF)-mediated autoregulatory adjustments in RVR, renal interstitial ATP concentrations were measured with microdialysis probes in anesthetized dogs at different renal arterial pressures (RAPs) within the autoregulatory range during augmented and diminished activity of the TGF mechanism. Stepwise reductions in RAP from ambient pressure (129+/-3 mm Hg) to 102+/-2 mm Hg (step 1) and 75+/-1 mm Hg (step 2) resulted in significant decreases in ATP concentrations from 9.0+/-0.8 to 6.3+/-0.6 nmol/L in step 1 and to 4.2+/-0.5 nmol/L in step 2. Changes in RVR were highly correlated with changes in ATP concentrations (r=0.86, P<0.001, n=12). Acetazolamide (100 microgram. kg(-1). min(-1), n=6), which increases solute delivery to the macula densa, thus augmenting TGF activity, significantly decreased renal blood flow (RBF) by -16+/-2% and glomerular filtration rate (GFR) by -22+/-4% and increased ATP concentrations from 8.4+/-0.7 to 15.5+/-1.4 nmol/L. Although basal RBF and GFR levels were reduced by the acetazolamide infusion, autoregulation efficiency was maintained, and interstitial ATP concentrations were significantly decreased in response to reductions in RAP by -36+/-4% in step 1 and by -54+/-2% in step 2. The relationship between changes in RVR and interstitial ATP concentrations was preserved during acetazolamide treatment (r=0.80, P<0.01). Inhibition of the TGF mechanism by furosemide significantly increased RBF by 33+/-6% and GFR by 13+/-2% and decreased ATP concentrations from 8.9+/-1.4 to 5.0+/-0.8 nmol/L (n=6). Furosemide caused marked impairment of RBF and GFR autoregulatory efficiency (by -14+/-3% and -11+/-3% in step 1 and by -26+/-2% and -18+/-4% in step 2, respectively). In the furosemide-treated kidneys, interstitial ATP levels remained low and were not altered during reductions in RAP (4.7+/-0.7 nmol/L in step 1 and 4.7+/-0.8 nmol/L in step 2), and changes in RVR did not exhibit a correlation with changes in ATP concentrations (r=0.22, P=0.30). These data support the hypothesis that extracellular ATP contributes to autoregulatory adjustments in RVR that are mediated by changes in activity of the TGF mechanism.
Hypertension 2001 Feb
PMID:Renal interstitial atp responses to changes in arterial pressure during alterations in tubuloglomerular feedback activity. 1123 Mar 69

Summary The case is described of a 12-year-old girl presenting with raised intracranial pressure without ventricular dilatation and a type 1 Chiari malformation. This was taken to be a coincidental association of pseudotumour cerebri and the Chiari malformation. Treatment of the pseudotumour with Diamox gave rapid and sustained relief of the intracranial hypertension without change in the Chiari malformation. In addition, a series of 156 cases of pseudotumour cerebri was reviewed for evidence of the Chiari malf ormation. An overall incidence of 1.3%, rising to 2.7% in patients with MR scanning [excluding the case described] was found.
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PMID:Pseudotumour cerebri occurring in association with the Chiari malformation. 1174 33

Pseudotumor cerebri is a condition of intracranial hypertension without localizing signs except for papilledema with normal intracranial contents and normal cerebrospinal fluid constituents. It is seen more frequently in women than in men (8:1) especially women are of childbearing age, and in 90% of cases of obesity. The most common symptoms are headache and visual obscuration. Other symptoms include pulsatile tinnitus, shoulder and arm pain. The papilledema present in almost all PTC patients can lead to decreased vision and blindness. One third of the large series had substantial visual loss including loss of visual field. Treatment has been directed toward preserving vision. Medications that reduce intracranial pressure such as diuretics like Acetazolamide have some success. When vision is threatened, these individuals may undergo optic nerve sheath decompression or lumbar peritoneal shunt to preserve vision. Even with prompt intervention, visual loss can occur.
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PMID:[Pseudotumor cerebri (PTC--an update)]. 1194 27

A 34-year-old obese woman developed blurred vision in both eyes soon after large-volume liposuction of the dorsum and gluteus region bilaterally associated with abdominal dermolipectomy. An ophthalmic examination revealed severe bilateral visual loss and pallid optic disc edema. The patient gave a history of transient obscurations of vision in the past. Neuroimaging studies were non-revealing, but a lumbar puncture disclosed a markedly elevated intracranial pressure. The patient was diagnosed as having had bilateral ischemic optic neuropathy superimposed on pre-existing idiopathic intracranial hypertension (IIH). Acetazolamide treatment was used. Some visual improvement occurred, and optic disc edema evolved into severe optic disc pallor. This case shows that visual loss from optic disc infarction may be a devastating complication of high-volume liposuction in patients with underlying IIH. Because liposuction is frequently performed on obese patients, physicians should screen for signs and symptoms of IIH before undertaking this procedure.
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PMID:Bilateral visual loss complicating liposuction in a patient with idiopathic intracranial hypertension. 1651 64

Acetazolamide (AZD), a sulfa-like moiety, is a potent, nonspecific inhibitor of carbonic anhydrase (CA) enzymes and has been demonstrated to decrease lipogenesis in adipose cells in in vitro cell culture studies. In contrast, topiramate (a sulfamate moiety) appears to inhibit specific (CA) enzymes II and V. Four placebo-controlled trials with topiramate have demonstrated positive results in weight loss. There is only anecdotal evidence that AZD may cause weight loss. The following case is of a 49-year-old African-American woman with a long history of schizoaffective disorder, hypertension, diabetes type II, stress incontinence, and obesity (body mass index, 45.5 kg/m2). Previous trials of topiramate demonstrated temporary but significant weight loss before AZD use. A 4 week washout period occurred before starting AZD, 250 mg twice daily. Significant weight loss of 11.5 lbs was seen over 4 weeks. During washout periods of either topiramate or AZD, her total mean weight was approximately 2 to 7 lbs higher than when she was treated with AZD. Although tolerance and side effects may limit the use of AZD as a safe and effective strategy for medication-related weight gain, the pharmacology may provide research insights into the causes and treatments of obesity.
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PMID:Is acetazolamide similar to topiramate for reversal of antipsychotic-induced weight gain? 1809 Aug 83

The patient (woman), 54 years of age, treated for p-ANCA positive vasculitis, hypertension, and thyroid gland hypofunction was referred to our Department due to the decrease of the visual acuity of her left eye. Since the year 2003, she was followed-up in the Department of Neurology due to the idiopathic intracranial hypertension (the opening pressure of the intracranial liquid was 480 -500 mm of H2O column), treated by acetazolamide tablets (Diluran) 1/2 tablet once daily. She was followed-up for the bilateral persistent papilledema by the local ophthalmologist. Due to the progression of the visual acuity loss the decompression (fenestration) of the optic nerve sheath was performed, and the neurosurgeon recommended the lumbo-peritoneal shunting. Adequate indication and choice of the surgical treatment helped to stabilize visual functions.
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PMID:[Benefit of the surgical treatment of the idiopathic intracranial hypertension--a case report]. 2005 24

The cause of idiopathic intracranial hypertension (IIH) remains unknown, and no consensus exists on how patients should be monitored and treated. Acetazolamide is a common treatment but has never been examined in a randomised controlled trial. The objectives of this pilot trial are to prospectively evaluate the use of acetazolamide, to explore various outcome measures and to inform the design of a definitive trial in IIH. Fifty patients were recruited from six centres over 23 months and randomised to receive acetazolamide (n = 25) or no acetazolamide (n = 25). Symptoms, body weight, visual function and health-related quality-of-life measures were recorded over a 12-month period. Recruited patients had typical features of mild IIH and most showed improvement, with 44% judged to have IIH in remission at the end of the trial. Difficulties with recruitment were highlighted as well as poor compliance with acetazolamide therapy (12 patients). A composite measure of IIH status was tested, and the strongest concordance with final disease status was seen with perimetry (Somers' D = 0.66) and optic disc appearance (D = 0.59). Based on the study data, a sample size of 320 would be required to demonstrate a 20% treatment effect in a substantive trial. Clinical trials in IIH require pragmatic design to involve sufficiently large numbers of patients. Future studies should incorporate weighted composite scores to reflect the relative importance of common outcome measures in IIH.
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PMID:A randomised controlled trial of treatment for idiopathic intracranial hypertension. 2116 Dec 60

Vestibular migraine is considered to be the second most common cause of vertigo and the most common cause of spontaneous episodic vertigo. The duration of attacks varies from seconds to days, usually lasting minutes to hours, and they mostly occur independently of headaches. Long-lasting individual attacks are treated with generic antivertiginous and antiemetic drugs. Specific antimigraine drugs are unlikely to be very effective for rescue. The mainstay of the management of vestibular migraine is prophylactic medication. To date, there are no controlled trials available; the body of knowledge builds on case series and retrospective or observational studies. Most drugs are also used for the prevention of migraine headaches. The choice of medication should be guided by its side effect profile and the comorbidities of patients. Betablockers such as propanolol or metoprolol are preferred in patients with hypertension but in the absence of asthma. Anticonvulsants include topiramate when patients are obese, valproic acid and lamotrigine. Lamotrigine is preferred if vertigo is more frequent than headaches. Calcium antagonists include verapamil and flunarizine. If patients have anxiety, tricyclic antidepressants such as amitryptiline or nortryptiline or SSRIs and benzodiazepines such as clonazepam are recommended. Acetazolamide is effective in rare genetic disorders related to migraine-like episodic ataxia; however, its place in vestibular migraine is still to be established. Nonpharmacological measures such as diet, sleep, hygiene and avoidance of triggers are recommended as they are for migraine. Vestibular rehabilitation might be useful when there are complications such as loss of confidence in balance or visual dependence.
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PMID:Management of vestibular migraine. 2169 18

To investigate the etiological and clinical features of pseudotumour cerebri (PTC) in children, features of 12 children with PTC were documented. The etiology could be clarified in 6 patients. The other 6 patients were accepted as idiopathic intracranial hypertension (primary PTC). Acetazolamide was used as the first drug and was effective in only 4 patients who had no underlying cause. Repeated lumbar punctures (LP) were performed in 6 patients and 5 of them were unresponsive. Prednisone was used in 3 patients and was effective in only one patient. The CSF pressure continued to be high in five patients and could be normalized only by withdrawing of the precipitating drug in three patients and by ventricular-peritoneal shunting in two patients with cerebral venous thrombosis. Although, medical treatment and repeated LP are usually effective in children with PTC, clarifying and solving the underlying cause can be crucial.
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PMID:Pseudotumour cerebri in children: etiological, clinical features and treatment modalities. 2205 Aug 95

Considering the high prevalence of the obstructive sleep apnea syndrome (OSA), it is expected that many patients with the disorder are traveling to altitude. However, this may expose them to the risk of pronounced hypoxemia, exacerbation of nocturnal breathing disturbances by frequent central apneas, impaired daytime performance, and high blood pressure. Recently, randomized studies specifically investigated the effects of altitude (1630-2590 m) in OSA patients and the optimal treatment in this setting. The results indicate that patients should continue to use continuous positive airway pressure therapy (CPAP) when sleeping at altitude. Since CPAP alone does not control central sleep apnea emerging at altitude, combined treatment with acetazolamide and CPAP should be considered, in particular, in patients with severe OSA and co-morbidities. Supplemental oxygen combined with CPAP might be advantageous in patients with OSA and concomitant cardiopulmonary disease by preventing hypoxemia and central sleep apnea. In patients unable to use CPAP or if electrical power is not available, an optimally fitted mandibular advancement device might be an alternative treatment option that can be combined with acetazolamide during altitude sojourns. Acetazolamide alone is also beneficial and better than no treatment at all, since it improves oxygen saturation, breathing disturbances, and the excessive blood pressure elevation in OSA patients traveling to altitude.
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PMID:How to treat patients with obstructive sleep apnea syndrome during an altitude sojourn. 2220 52


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