Vestibular Disorders after Kidney Transplantation: Focus on the Pathophysiological Mechanisms Underlying the Vertical Nystagmus Associated with Tacrolimus-Related Hypomagnesamia.

The purpose of this paper is to present the case of a patient undergoing kidney transplantation who developed limb tremor dizziness and vertical nystagmus (ny) during Tacrolimus (TAC) therapy and to investigate the pathophysiological mechanisms underlying the balance disorder. This case study regards a 51-year old kidney transplant male patient with hand tremors and lower limbs asthenia associated with dizziness and nausea. The symptoms started two months after the beginning of intravenous TAC for renal transplantation. The pure-tone audiometry showed a mild symmetrical high-frequencies down-sloping sensorineural hearing loss. Acoustic emittance measures showed a normal tympanogram; stapedial reflexes were normally elicited. The Auditory Brainstem Responses (ABR) and Cervical Vestibular Evoked Myogenic Potentials (c-VEMPs) were bilaterally normally evoked. The bedside vestibular examination showed spontaneous down-beating stationary persistent, omni-positional nystagmus, not inhibited by fixation. The Head-Shaking Test accentuates the spontaneous ny. The horizontal clinical head impulse test was negative, bilaterally. A biochemical blood test revealed a decrease in Magnesium (Mg) levels (0.8 mg/dL; normal range 1.58-2.55). The integration of Mg induced both a plasma levels normalization and an improvement of clinical symptoms. This case suggests that TAC treatment can induce a Mg depletion that caused the transient cerebellar lesion. Therefore, the monitoring of serum electrolytes during immunosuppressive treatment appears to be a useful tool in order to reduce the central system symptomatology.

Tinnitus and equilibrium disorders in COVID-19 patients: preliminary results.

PURPOSE: Tinnitus and equilibrium disorders such as dizziness and vertigo have been reported by patients with COVID-19; however, they have been rarely investigated. The aim of this study was to study the prevalence of subjective tinnitus and dizziness in a sample of COVID-19 patients using an online 10-item close-ended questionnaire. METHODS: A multicentric study that included 15 Italian hospitals in different regions was conducted using an online 10-item close-ended questionnaire developed to identify the presence of tinnitus and balance disorders in patients with COVID-19 between May 5 and June 10, 2020. The questionnaire was administered to 185 patients in a period of > 30 - < 60 days after diagnosis of COVID-19; responses were recorded in an online Excel spreadsheet. The questionnaire was composed of three sections: (1) demographic information; (2) presence and characteristics of tinnitus and dizziness after COVID-19 diagnosis; (3) possible association with migraine. RESULTS: Thirty-four patients (18.4%) reported equilibrium disorders after COVID-19 diagnosis. Of these, 32 patients reported dizziness (94.1%) and 2 (5.9%) reported acute vertigo attacks. Forty-three patients (23.2%) reported tinnitus; 14 (7.6%) reported both tinnitus and equilibrium disorders. CONCLUSION: This study suggests that the presence of subjective otoneurological symptoms such as tinnitus and balance disorders can affect COVID-19 patients; further studies are necessary to investigate the prevalence and pathophysiological mechanisms underlying these subjective symptoms in COVID-19 patients.

[Case of sialadenitis by iodinated contrast medium in a dialysis patient].

BACKGROUND: Sialadenitis by iodinated contrast medium (i.c.m) oriodine mumps (IM) is a rare and late benign manifestation that occurs independently of intravenous or endoarterial administration modality. If renal function is normal, i.c.m. does not reach salivary glands concentrations able to induce sialadenitis. However, a critical glomerular filtration reduction may lead to salivary ducts edema and glandular swelling after i.c.m. injection. We report a rare case report of IM in a patient on chronic hemodialysis. METHODS: A 72-year-old woman affected by chronic kidney disease on chronic hemodialysis, underwent to endoscopic removal of a rectal cancer. For disease staging, a total body TC with i.c.m. was performed. The following morning, patient showed a soft and aching bilateral paroditidis swelling. Salivary glands ultrasound was diagnostic for sialadenitis. The patient was rapidly treated with betamethasone following by a 240 minutes post-dilution online hemodiafiltration session. RESULTS: Within the next 24h, a complete remission of IM was obtained. CONCLUSION: In our patient, a compensatory hyperactivity of the sodium / iodine symporter (NIS) on salivary gland cells may have played a crucial role in IM induction. An high efficiency hemodialysis session within the few following hours after i.c.m injection is a fundamental tool in patients on renal replacement treatment to prevent IM that is an epiphenomenon of i.c.m. accumulation.