Meet the expert - Ipernatremia...Meet the expert - Ipernatremia Marco Faustini Fustini IRCCS Istituto delle Scienze Neurologiche di Bologna (ISNB) ... Durante la visita medica in reparto

Roma, 7-9 novembre 2014

Meet the expert - Ipernatremia

Marco Faustini Fustini IRCCS Istituto delle Scienze Neurologiche di Bologna (ISNB)

Ospedale Bellaria [email protected]


Relazione a forma di U tra la [Na+] nel plasma al ricovero e la mortalità in ospedale1

Adattato da: Wald R, et al. Arch Intern Med. 2010;170(3):294-302.

[Na+] nel siero al ricovero mEq/L

Prob

abili

tà p

rede

tta d

ella

m

orta

lità

in o

sped

ale

110 115 120 125 130 135 140 145

0.05

0.10

0.15

0.20

n=53.236

Curva cubica restrittiva

Intervallo di confidenza 95%

Wald, R. et al. Arch Intern Med 2010;170:294–302.


Hypernatraemia

Hypernatraemia (serum sodium > 145 mmol/L) is a hype-osmolar disorder, in which there is a deficit of body water relative to body solutes.

Hypernatraemia is always synonymous with

hyperosmolality, because Na+ is the main constituent of plasma osmolality,

but hyperosmolality can exists without hypernatraemia when there is an excess of non-sodium solute. This occurs most often with marked elevation of plasma glucose, as in patient with non-ketotic hyperglycaemic hyperosmolar coma.

Verbalis J 2003


Durante la visita medica in reparto ti viene chiesto quale soluzione usare in un paziente “disidratato”

•  A) Soluzione salina 0.9% (“fisiologica”) •  B) Soluzione glucosata 5% •  C) Soluzione salina 0.45% •  D) Soluzione ipertonica 3% •  E) Ringer lattato •  F) Soluzione elettrolitica “reidratante”


Durante la visita medica in reparto ti viene chiesto quale soluzione usare in un paziente “disidratato”

•  A) Soluzione salina 0.9% (“fisiologica”) •  B) Soluzione glucosata 5% •  C) Soluzione salina 0.45% •  D) Soluzione ipertonica 3% •  E) Ringer lattato •  F) Soluzione elettrolitica “reidratante”

1) Una delle soluzioni elencate, indifferentemente 2) Una delle soluzioni elencate, tranne la soluzione ipertonica 3) Una delle soluzioni elencate, tranne la soluzione glucosata 5% 4) Non so


Revisiting dehydration:

what a difference a word makes


Dehydration vs. (extracellular fluid) volume depletion

•  The terms dehydration and volume depletion are used interchangeably at the bedside.

•  This habit may be pernicious, because the two conditions describe clearly different disturbances.

•  The proper use of the terms dehydration and volume depletion should improve patient care.

•  Dehydration associated with hypertonicity = a principal loss of body water from the intracellular and interstitial compartments.

•  Extracellular fluid volume depletion = a fluid deficiency that clinically affects the vascular tree.

N Engl J Med 1977 297: 1444 J Clin Invest 1958 37: 1236 N Engl J Med 1962 267: 77 Science 1952 115: 447


Body fluid compartments in man

J Verbalis, 2003

Volemia

EABV Intravascular fluid



•  The physiologic concept of dehydration, at first glance, might subsume the definition of volume depletion.

•  This erroneous assumption, made by investigators about

seventy years ago, was corrected by physiologists in the era after World War II, but today has insidiously resurfaced because volume depletion has become a shorthand for extracellular fluid volume depletion, and the first two words of the latter phrase make all the difference.

N Engl J Med 1977 297: 1444 Ann Intern Med 1997 127 N Engl J Med 1962 267: 77 Science 1952 115: 447



•  When water is lost from the skin, gut, or kidney, the hypertonicity created in the ECF is directly transferred to the larger intracellular space.

•  Worsening hypertonicity therefore has its biggest impact on the size of the ICF and, to a lesser extent, on interstitial spaces.

•  To dehydrate is to lose this intracellular water and stimulate thirst.

N Engl J Med 1977; 297: 1444 Ann Intern Med 1997; 127 N Engl J Med 1962; 267: 77 15: Science 1952; 115: 447


N Engl J Med 2005

1)  Increased plasma osmolality: osmoreceptor stimulation of AVP 2)  Decreased arterial circulating volume: decreased effective arterial blood volume (EABV)

Baroreceptor stimulation of AVP

Decreased distal delivery of filtrate to the tip of the loop of Henle


Physiological relationships among plasma osmolality, plasma AVP concentrations, urine osmolality, and urine volume in man.

Robertson, 1985



Hypernatremia: clinical manifestations

Infants (outpatients): - hyperpnea, muscle weakness, restlessness, high-pitched cry, insomnia, lethargy, convulsions (rarely), and coma.

Elderly patients (outpatients): - few symptoms until the serum sodium exceeds 160 mmol/L; - thirst, which dissipates as the disorder progresses and is absent in patients with hypodipsia; - muscle weakness, confusion, and coma are sometimes manifestations of coexisting disorders rather than of the hypernatremia itself.

N Engl J Med 2000 342: 1493



In patients of all ages - orthostatic hypotension and tachycardia reflect marked hypovolemia; - rapid sodium loading can cause convulsions and coma.

In hospitalised patients

- clinical manifestations are even more elusive, because they often have preexisting neurologic dysfunction.

N Engl J Med 2000 342: 1493



Brain shrinkage induced by hypernatremia can cause vascular rupture, with cerebral bleeding, subarachnoid hemorrhage, and permanent neurologic damage or death.

Brain shrinkage is countered by an adaptive response that is initiated promptly and consists of solute gain by the brain that tends to restore lost water.

This response leads to the normalization of brain volume and accounts for the milder symptoms of hypernatremia that develops slowly.

N Engl J Med 2000 342: 1493


N Engl J Med 2000 342: 1493



However, the normalization of brain volume does not correct hyperosmolality in the brain.

In patients with prolonged hyperosmolality, aggressive treatment with hypotonic fluid may cause cerebral edema, which can lead to coma, convulsions, and death.

Recommendation: a 8-10 mmol per liter per day for all patients except those in whom the disorder has developed over a period of hours.

N Engl J Med 2000 342: 1493


Caso 1

•  Paziente di 8 anni ricoverata per una voluminosa formazione endo e sovrasellare; poliuria e polidipsia da qualche mese; deficit visivo severo (2/10 OD e 3/10 OS). La sodiemia è 142 mmol/L.

•  La paziente viene operata per via transfenoidale con rimozione molto ampia della lesione, anche se non radicale. L’esame istopatologico depone per un craniofaringioma adamantinomatoso.

•  Nel periodo postoperatorio (nelle prime 48 ore la paziente è trasferita nel reparto di Rianimazione) la paziente non sviluppa poliuria e polidipsia. Tuttavia, si assiste a un progressivo incremento della sodiemia, fino al valore di 159 mmol/L.


Caso 1

•  Trasferita nuovamente nel reparto di Neurochirurgia, la bambina appare polipnoica e agitata.

•  Non ci sono segni clinici di deplezione di volume extracellulare. Non c’è edema.

•  Il medico di guardia (ore 16) richiede per il giorno successivo un controllo degli esami di routine.

•  Il mattino successivo viene eseguito il prelievo venoso. Poco dopo, compare una crisi epilettica.

•  La sodiemia (ore 10) è 173 mmol/L.

•  Quale potrebbe essere la causa dell’ipernatremia? •  Come proponi di agire in questo caso?


Hypernatraemia – first assessment

Hyper-osmolality Hypertonic hypernatraemia

ECF volume

Normal ECF (loss of free water)

Decreased ECF (loss of free water and sodium: hypotonic solutions)

Increased ECF (gain of free water and sodium: gain of hypertonic solutions)

0.9% saline until vital signs stable, along with free water

free water replacement loop diuretics and free water replacement; hemodialysis if nothing works

Roma, 7-9 novembre 2014 HYPERNATREMIA

Hypernatremia, a deficiency of body water relative to body solute.

Causes: -  net water loss; -  hypertonic sodium gain


Causes of hypernatremia: net water loss

Pure water loss: - unreplaced insensible losses (dermal and respiratory) - hypodipsia - neurogenic diabetes insipidus - congenital nephrogenic diabetes insipidus - acquired nephrogenic diabetes insipidus: - renal diseases (medullary cystic disease…) - hypercalcemia or hypokalemia - drugs (lithium, demeclocycline, foscarnet, methoxyflurane,

amphotericin B, vasopressin V2-receptor antagonists) Hypotonic fluid loss:

- renal causes (loop diuretics, osmotic diuresis, postobstructive diuresis, poliuryc phase of acute tubular necrosis…);

- gastrointestinal causes (vomiting, nasogastric drainage, enterocutaneous fistula, diarrhea, osmotic cathartic agents);

- cutaneous causes (burns, excessive sweating)

N Engl J Med 2000 342: 1493


Causes of hypernatraemia: hypertonic sodium gain

- hypertonic sodium bicarbonate infusion - hypertonic feeding preparations - ingestium of sodium chloride - ingestium of sea water - sodium chloride-rich emetics - hypertonic saline enemas - intrauterine injection of hypertonic saline - hypertonic sodium chloride infusion - hypertonic dialysis - primary hyperaldosteronism - Cushing’s syndrome N Engl J Med 2000 342: 1493


Hypernatremia – first assessment

Hyper-osmolality Hypertonic hypernatremia

ECF volume

Normal ECF (loss of free water)

Decreased ECF (loss of free water and sodium: hypotonic solutions)

Increased ECF (gain of free water and sodium: gain of hypertonic solutions)

0.9% saline until vital signs stable, along with free water

free water replacement loop diuretics and free water replacement; hemodialysis if nothing works


Mange, K. et. al. Ann Intern Med 1997;127:848-853

Effect of a 1-L Infusion of Water or 0.9% Saline on Virtual Body Fluid Spaces




Hypernatremia: principles of treatment

•  Search the initial cause. •  There is no drug for the treatment of

hypernatremia. •  Whenever it’s possible, prefer hydration by

mouth (especially in childhood). •  Use hypotonic solutions in severe cases, with

caution.

























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Meet the expert - Ipernatremia...Meet the expert - Ipernatremia Marco Faustini Fustini IRCCS Istituto delle Scienze Neurologiche di Bologna (ISNB) ... Durante la visita medica in reparto