Hyponatremia in pregnancy
Nadia Barghouthi, Jessica Perini in Endocrine Diseases in Pregnancy and the Postpartum Period, 2021
Mild hyponatremia is a common finding in pregnancy. Both serum osmolality and sodium levels drop by a predictable amount due to hormonal, renal, and vascular effects leading to a reset osmostat. Mild, euvolemic hyponatremia is common in pregnancy secondary to a reset osmostat, which is a change in the set point of anti-diuretic hormone (ADH) release and stimulation of thirst. The syndrome of inappropriate ADH can occur in pregnancy, typically associated with nonosmotic stimuli such as hypovolemia, nausea, and pain, promoting the release of ADH. Under nonpregnant conditions, serum osmolality is maintained within a narrow range of 275–295 mOsm/L. Hyponatremia during labor is now thought to be primarily associated with overdrinking. Increased free water intake either due to stress or social encouragement may overcome the kidney’s ability to excrete the water load.
The viva: the non-operative clinical practice of neurosurgery
Vivian A. Elwell, Ramez Kirollos, Syed Al-Haddad in Neurosurgery, 2014
The non-operative clinical practice of neurosurgery is an important aspect of the oral and clinical examination. The majority of candidates spend an enormous effort memorizing precise values, ranges and units for certain neurosurgical conditions. Intracranial pressure is the pressure exerted by the intracranial content. The Monro–Kellie hypothesis states that the sum of the intracranial volumes of blood, brain, cerebrospinal fluid, and other components is constant, and that an increase in any one of these must be offset by an equal decrease in another, or else the overall pressure will rise. Diabetes insipidus is a result of low circulating levels of antidiuretic hormone (ADH). The insufficiency of ADH results on the excessive renal loss of water and electrolytes. Patients have a high output of dilute urine with normal or high serum osmolality.
Renal
Faye Hill, Sash Noor, Neel Sharma, Tiago Villanueva in Medical and Surgical Emergencies for Students and Junior Doctors, 2021
Low urine output, failure to produce urine, thirst, dizziness, confusion, blood in urine, fever, rash, joint pain, urinary urgency, urinary hesitancy, abdominal pain, muscle weakness, sensory loss. Patients with acute renal failure or acute kidney injury should undergo blood investigations namely a full blood count, urea and electrolytes and C-reactive protein. Urine and bloods should be sent for culture if infection is suspected. With regard to urinary electrolytes, in pre-renal failure there is typically increased urinary sodium reabsorption and increased urinary urea absorption with low urine sodium concentrations. Patients with acute renal failure or acute kidney injury should be appropriately fluid resuscitated according to volume status, typically with 0.9% sodium chloride. Patient medication should be reviewed to ensure any nephrotoxic drugs are ceased and vital drugs should be dosed in accordance with altered renal kinetics. Investigations of choice include a urine osmolality, serum osmolality, urinary sodium concentration, thyroid function tests and serum cortisol.
Acute sensorineural hearing loss in hemodialysis patients
Published in Acta Oto-Laryngologica, 2020
Tzu-Yu Li, Po-Wen Cheng, Yi-Ho Young
Background: Approximately, 30–40% of patients experienced hearing loss under regular hemodialysis. Objective: This study reviewed our experience on treating acute hearing loss in patients under regular hemodialysis over the past two decades. Methods: Twenty-six patients having acute hearing loss under hemodialysis were divided into two groups based on their etiologies. Sixteen patients (16 ears) with sudden sensorineural hearing loss (SSHL) were assigned to Group A and 10 patients (13 ears) with endolymphatic hydrops (EH) were assigned to Group B. Results: No significant difference was noted between Groups A and B, regardless of hemodialysis duration, clinical manifestation, underlying systemic diseases, blood examination, and vestibular test battery. In contrast, serum osmolality was significantly lower in Group B (292 ± 11 mOsm/kg) than in Group A (310 ± 11 mOsm/kg). Furthermore, Group B (40 ± 14 dB) had better mean hearing level than Group A (87 ± 21 dB) in the initial audiogram, and a higher hearing improvement rate (69%) than Group A (19%). Conclusions and significance: Both SSHL and EH are major causes for precipitating acute hearing loss in hemodialysis patients. Compared to SSHL, the less deteriorated MHL and lower serum osmolality in EH provide two clues for differentiating acute hearing loss in hemodialysis patients.
Serum Osmolality In Patients With Meniere'S Disease
Published in Acta Oto-Laryngologica, 1973
C. Angelborg, I. Klockhoff, J. Stahle
Hyperosmolality in serum was found in 19 of 56 patients with Menière's disease. The cause of the moderately elevated serum osmolality has not yet been identified. The serum sodium and potassium concentrations were within normal limits. The hyperosmolality may indicate that Menière's disease is a disorder afflicting the entire organism. Hyperosmolality alternating with normal osmolality was seen in several patients, a phenomenon which may be in accordance with the general fluctuating character of the disease. The elevation of serum osmolality after the peroral consumption of glycerin in patients with Menière's disease was studied and related to the hearing loss, and no correlation was found.
Hyponatremia in Hospitalized Patients: The Potential Role of Tolvaptan
Published in Hospital Practice, 2011
Steven B. Deitelzweig, Linda McCormick
Hyponatremia (typically defined as serum sodium level < 135 mEq/L) is a common electrolyte abnormality among hospitalized patients. Whether present at admission or acquired during hospitalization, hyponatremia is associated with higher mortality and longer hospital stays. Failure to adequately investigate and treat hyponatremia may also be associated with adverse outcomes. The presence and severity of clinical symptoms largely depend on the rate and extent of the decline in serum sodium; rapid or large decreases may cause serious neurologic complications. The approach to treatment depends on the presence and severity of symptoms, the timing of their onset, the underlying etiology, and the patient's volume status. Patients with euvolemic or hypervolemic hyponatremia usually have inappropriately elevated levels of arginine vasopressin, which stimulates water reabsorption even in the presence of low serum osmolality. Tolvaptan is an orally active, selective V2-receptor antagonist that blocks the effects of arginine vasopressin in the renal collecting duct to promote aquaresis without increasing sodium or potassium excretion; as a result, it increases serum sodium in a controlled manner. Tolvaptan offers a mechanism-based treatment option for patients with euvolemic or hypervolemic hyponatremia who have serum sodium levels < 125 mEq/L or persistent symptoms resistant to fluid restriction.