________________________________________________________________________ Dizziness and Vertigo
Macrolides Erythromycin has been sporadically linked to reversible ototox- icity in patients with ototoxic risk factors. Azithromycin and clarithromycin have also been suggested as possibly ototoxic [98]. Vancomycin Vancomycin is a glycopeptide antibiotic introduced in the 1950s and commonly used for efficacy in methicillin-resistant staphylococcal infections. Ototoxicity is reported in patients with other risk factors, but vancomycin monotherapy at thera- peutic doses has not shown ototoxicity [98]. Loop Diuretics Loop diuretics are used for treating congestive heart failure, renal failure, cirrhosis, and hypertension. The most effec- tive and widely used (i.e., ethacrynic acid, furosemide, and bumetanide) can cause ototoxicity [98]. Antineoplastic Agents Antineoplastic agents most associated with ototoxicity are the platinum-based compounds cisplatin and (to a lesser extent) carboplatin. Ototoxicity and nephrotoxicity are dose- proportional with both compounds [98]. Salicylates Salicylate (aspirin) can produce tinnitus and a generally revers- ible flat sensorineural hearing loss at low doses, especially in elderly patients [98]. Antiseptics Some antiseptics used for surgical preparation are ototoxic. Povidone-iodine is safe for middle ear surgeries. However, chlorhexidine is toxic if it reaches the inner ear and should not be used, and VoSol and Gentian violet also show ototox- icity [101].
DIAGNOSIS: THE “TIMING AND TRIGGERS” WORKUP
As mentioned, the prevailing clinical model in dizziness and vertigo is being replaced by the “timing and triggers” approach to streamline the differential diagnosis, increase diagnostic accuracy, and reduce unnecessary imaging tests and misdiagnosis. Publications have brought into focus the misdiagnosis of patients with stroke who present with isolated dizziness. The “timing and triggers” approach is shown to reduce this highly concerning problem largely resulting from [8]: • Over-reliance on the symptom quality approach • Lack of familiarity with key physical exam findings • Overweighting traditional stroke risk factors for patient screening (e.g., age, vascular risk factors) and not considering stroke in younger patients • Over-reliance on CT The “timing and triggers” approach departs from the Drach- man-Hart model by de-emphasizing patient descriptions of symptom quality, dropping presyncope and lightheadedness as dizziness and vertigo classes, and limiting use of the vague term “lightheadedness” [2; 7]. The term “dizziness” is used as a generic descriptor for disturbed balance or spatial orientation, vertigo, lightheaded, spinning, rocking, and others. Accurate diagnosis is an essential precondition for effective treatment of dizziness and vertigo, best ensured by defin- ing the rapidity of onset, the context, associated symptoms, intermittent or persistent nature of dizziness, and triggers of intermittent symptoms during patient history-taking. This is called the “timing and triggers” diagnostic workup. The workup is structured using the algorithm Triage-TiTrATE-Test [8; 36; 102]: • Triage: Identify dangerous causes by noting the presence of prominent associated symptoms, abnormal vital signs, altered mental status, or ancillary test results. • Timing: In the history of presenting illness, classify the pattern of dizziness attacks as episodic, acute, or chronic in duration. • Triggers: In the history and review of systems, seek an underlying pathophysiologic mechanism by searching for obvious triggers or exposures. • Targeted exam: Differentiate benign from dangerous causes within a timing-trigger category by using specific exam findings, emphasizing a targeted eye movement exam. • Test: Choose the best laboratory or imaging test when clinically relevant uncertainty remains about a dangerous cause that has not been ruled out.
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Book Code: ANCCTX2027
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