THE PATHOPHYSIOLOGY OF THE EAR.pdf
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Allergic rhinitis is a common disorder that is strongly linked to asthma and conjunctivitis. It is usually a long-standing condition that often goes undetected in the primary-care setting. The classic symptoms of the disorder are nasal congestion, nasal itch, rhinorrhea and sneezing. A thorough history, physical examination and allergen skin testing are important for establishing the diagnosis of allergic rhinitis. Second-generation oral antihistamines and intranasal corticosteroids are the mainstay of treatment. Allergen immunotherapy is an effective immune-modulating treatment that should be recommended if pharmacologic therapy for allergic rhinitis is not effective or is not tolerated, or if chosen by the patient. This article provides an overview of the pathophysiology, diagnosis, and appropriate management of this disorder.
Comprehensive and widely-accepted Canadian guidelines for the diagnosis and treatment of allergic rhinitis were published in 2007 [1]. This article provides an overview and update of the recommendations provided in these guidelines as well as a review of current literature related to the pathophysiology, diagnosis, and appropriate management of allergic rhinitis.
Posner-Schlossman Syndrome (PSS), also known as glaucomatocyclitic crisis, is a disease typified by acute, unilateral, recurrent attacks of elevated intraocular pressure (IOP) accompanied by mild anterior chamber inflammation. The pathophysiology is still unknown, although there are several theories proposed, ranging from autoimmune to infectious. Treatment management is focused on controlling the intraocular pressure and decreasing inflammation. While an attack usually resolves without sequelae, repeated attacks over time may lead to long-term glaucomatous damage (a secondary glaucoma).
The exact pathophysiology of PSS is still unknown. However, one case of a patient with PSS who underwent trabeculectomy for uncontrolled IOP on medical therapy demonstrated presence of mononuclear cells in the trabecular meshwork of an intra-operative specimen[5]. On electron microscopy, mononuclear cells were seen intercalated in the trabecular meshwork with long pseudopods, possibly impeding the outflow of aqueous (see Figure 1). The origin of these mononuclear cells is still unknown.
There are various views regarding the pathophysiology of this condition. Lance [2] suggested that the syndrome is induced in patients with cervical disorders, predominantly C3 root discharge causing antidromic release of vasodilator peptides (peripheral mechanism). He proposed that the primary mechanism is activation of the trigeminovascular system. He pointed out, and Hirsch [9] reiterated, that parasympathetic vasodilatation is greater in the nose and cheek than in the ear; therefore, red ears must be mediated primarily by inhibition of sympathetic vasoconstriction or activation of sympathetic vasodilatation. Thus, the presence of RES suggests an underlying dysregulation of sympathetic outflow. Purdy [10] noted that, in RES, there is pain in and around the ear associated with autonomic phenomena, including erythema of the ear ipsilateral to the pain. He suggested that the condition be labeled auriculoautonomic cephalalgia or be placed in the trigeminal autonomic cephalgia group. Several authors, including Kumar and colleagues [5], have used brainstem trigeminovascular activation to explain RES associated with migraine. Lambru and colleagues suggested that it is possible that trigeminoautonomic parasympathetic activation occurs with sympathetic deficit. The imbalance between parasympathetic and sympathetic systems thus may facilitate inhibition of sympathetic tone of the ear. Sympathetic dysregulation, not parasympathetic activation as formerly believed, may be the predominant mechanism of RES [1].
RES is a rare syndrome of diverse pathophysiology which is difficult to treat. To our knowledge, our present report is the first to describe a dietary trigger of RES. Successful management with lifestyle modifications and avoidance of migraine triggers gives insight into the pathogenesis of primary migraine-associated RES. 2b1af7f3a8