Catecholamine-induced cerebral vasospasm and multifocal infarctions in pheochromocytoma

Summary We report the case of a 76-year-old male with a remote history of papillary thyroid cancer who developed severe paroxysmal headaches in the setting of episodic hypertension. Brain imaging revealed multiple lesions, initially of inconclusive etiology, but suspicious for metastatic foci. A search for the primary malignancy revealed an adrenal tumor, and biochemical testing confirmed the diagnosis of a norepinephrine-secreting pheochromocytoma. Serial imaging demonstrated multiple cerebral infarctions of varying ages, evidence of vessel narrowing and irregularities in the anterior and posterior circulations, and hypoperfusion in watershed areas. An exhaustive work-up for other etiologies of stroke including thromboembolic causes or vasculitis was unremarkable. There was resolution of symptoms, absence of new infarctions, and improvement in vessel caliber after adequate alpha-adrenergic receptor blockade for the management of pheochromocytoma. This clinicoradiologic constellation of findings suggested that the etiology of the multiple infarctions was reversible cerebral vasoconstriction syndrome (RCVS). Pheochromocytoma remains a poorly recognized cause of RCVS. Unexplained multifocal cerebral infarctions in the setting of severe hypertension should prompt the consideration of a vasoactive tumor as the driver of cerebrovascular dysfunction. A missed or delayed diagnosis has the potential for serious neurologic morbidity for an otherwise treatable condition. Learning points: The constellation of multifocal watershed cerebral infarctions of uncertain etiology in a patient with malignant hypertension should trigger the consideration of undiagnosed catecholamine secreting tumors, such as pheochromocytomas and paragangliomas. Reversible cerebral vasoconstriction syndrome is a serious but reversible cerebrovascular manifestation of pheochromocytomas that may lead to strokes (ischemic and hemorrhagic), seizures, and cerebral edema. Alpha-adrenergic receptor blockade can reverse cerebral vasoconstriction and prevent further cerebral ischemia and infarctions. Early diagnosis of catecholamine secreting tumors has the potential for reducing neurologic morbidity and mortality in patients presenting with cerebrovascular complications.

Acute oedema associated with risperidone use: a report

Risperidone acts by potent serotonergic, dopaminergic and alpha adrenergic receptor antagonism. The most common side effects reported are extrapyramidal symptoms, dizziness, sedation, insomnia, headache, anxiety, nausea, constipation and weight gain. Oedema associated with risperidone use is a rare side effect. Here we present a report on pedal oedema associated with use of oral risperidone 4 mg per day for acute-onset psychotic illness. Through this case report we want to make clinicians aware about this important side effect as it can affect patients’ compliance and quality of life.

Phenylephrine induces relaxation of longitudinal strips from small arteries of goat legs

Alpha adrenergic stimulation is known to produce vasoconstriction. We have earlier shown that, in spiral strips of small arteries Phenylephrine (PE) caused vasorelaxation under high nitric oxide (NO) environment. However on further experimentation it was realized that the PE-induced vasorelaxant response occurred only with longitudinal strips of small arteries even under normal NO environment while circular strips showed contraction with PE even under high NO environment. Such PE-induced vasorelaxation of longitudinal strips was blocked by Phentolamine, an alpha-adrenergic receptor blocker. On delineation of specific receptor subtype, PE-induced relaxation was found to be mediated through alpha 1D receptor. However, this phenomenon is specific to small artery, as longitudinal smooth muscle of aorta showed only contractile response to adrenergic stimulation. There is no prior report of longitudinal smooth muscle in small artery up to our knowledge. The results of this study and histological examination of vessel sections suggest the presence of longitudinal smooth muscle in small artery and their relaxant response to alpha adrenergic stimulation is a novel phenomenon.

Apraclonidine in the unlicensed treatment of eyelid ptosis

Eyelid ptosis is a complication that may occur following injection of botulinum toxin type A. It generally presents within 3–7 days of treatment. A drooping or lowering of the eyelid may be severe to the point that it leads to restriction of vision, or it may be subtle, with just the feeling of a heavy lid or, more typically, difficulty in being able to apply eye make-up. There is currently no licensed treatment for eyelid ptosis. Apraclonidine hydrochloride, commonly known as Iopidine is an alpha-adrenergic receptor agonist and causes the contraction of the Muller's muscle, which may result in an eyelid lift of 1–3 mm. There are factors that may lead to an increased risk of this complication, and there are also ways in which to help prevent it from occurring. Thorough consultations should always be given and practitioners should always ensure that they have in-depth knowledge of facial anatomy and musculature and use good injection technique.