Severe acute respiratory syndrome phobia with hyponatremic seizure

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Severe acute respiratory syndrome phobia with
hyponatremic seizure 

• Su-Yu Chen
• Division of Endocrinology and Metabolism,
  Departement of Internal Medicine, ChiMei Medical
  Center , Tainan, Taiwan

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Case report

• A 30-year-old single woman was sent to our
  hospital in the middle of May 2003. She is easy
  anxious in character and used to over-concern
  about dust or contagions, so she changes her
  clothes and takes a bath whenever she goes home
  form outside. She felt thats adequate and
  necessary, although her family disagreed.
  However, she denied any physical no psychological
  suffering for this condition.

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• She visited a teaching hospital in Taipei city
  due to dog-bite and stayed there for half one
  hour where a few SARS probable cases were
  detected in the patient in the middle of April
  2003. She felt very anxious for infection of SARS
  virus after that event. She checked her
  temperature several times per day and visited
  other hospitals to asked examinations to rule out
  the possible of infection. Although no fever nor
  any laboratory finding support her worry, she
  still called for help and sough information by
  phones and internet. Difficult to fall asleep,
  poor concentration and deteriorated job
  performance developed during this period.

4

• Under the impression that water could clean our
  body, she began to drink lots of water. In
  average, she drank 5000 ml of water in each day
  within two weeks before this admission.
• She developed light-headedness and general
  weakness one day before admission. On
  transportation to hospital she began to vomit
  repeatedly. Upon arrival, she was alert and
  oriented, but soon thereafter she had a
  generalized seizure..

5

• Laboratory data(5/19)
• Na 117 mEq/L,K 2.97 mEq/L, CL79 mEq/L,serum
  osmolality 245 mOsm/kg
• Arterial blood gas PH7.236 PCO238
• PO2100 HCO316.1 BE-10.6
• Computed tomography of the head and chest
  radiography were normal
• BUN/Cr3.6/0.58mg/dl GOT/GPT17.6/9.3, CK74
  LDH326 IU/L, Hb10.9 g/dl

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• Laboratory data(5/20)
• Na 140 mEq/L,K 3.88 mEq/L,
• Arterial blood gas no acidosis
• Ketone bodynegative Lactat2.4mmol/L

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• Laboratory data(5/26)
• Na 134mEq/L,K 3.96 mEq/L
• Arterial blood gas PH7.410 PCO235
• PO280 HCO321.8 BE-2.2
• BUN/Cr4.8/0.44mg/dl GOT/GPT27.4/19.1, CK1699
  LDH364 IU/L, Hb11.7 g/dl

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• After one day, her electrolytes became
  normalized. She was discharged without
  neurological deficits. Her daily water
  consumption decreased to 1 liter since discharge.
  Severn days later she visited our ER with the
  complaint of chest discomfort. Her serum sodium
  was 134 mEq/L.

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Discussion

• Polydipsia can be defined as an impulsive
  behavior leading to absorption of large amounts
  of water (4 to 20 liters a day), without any
  underlying organic disease.
• The most common etiology factor is psychotic
  polydipsia. Its incidence in a population of
  chronic psychiatric patients can be as high as
  42.
• Episodic polydipsia and hyponatremia occur in 3
  to 5 of institutionalized patients with metal
  illness
• 80 cases is schizophrenia patients
• Biol Psychiatry.40(1)28-34,1996
• Biol Psychiatry 198913709-723

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Discussion

• Hyponatremia associated with much water intake
  also has been reported in endurance athletes ,
  recreational hiker and soldiers .
• Iatrogenic hyponatremic seizure has been found in
  individuals who have consumed large amounts of
  water for examination.(urological and pelvic
  ultrasound evaluation)

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Discussion

• Polydipsia alone is unlikely to cause severe
  hyponatremia because of the large capacity of the
  kidney to excrete free water(18 liter).
• Most cases have, in addition to polydipsia , some
  abnormality in water excretion

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Discussion

• Ingestion of water lead not only dilution of the
  serum concentration of sodium but also to the
  expansion of total body water with consequent
  minimal expansion of the extracellular fluid
  volume.
• The most important response during normal
  physiologic circumstance is to the minimal
  hyponatremia the synthesis and secretion of the
  ADH are inhibited, decreasing the concentrations
  of the ADH in the blood perfusing the kidney.
• gta gradual development of impermeability in the
  most distal portions of the nephron
  segment(collecting duct and collecting tubules in
  part from the closing of microtubular channels
  dependent on ADH

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Discussion

• The minimal volume expansion is enough to maitain
  or incresed renal plasma flow and the
  GFRgtdecreased in the filtration
  fractiongtincrease in the delivery of filtered
  Na,Cl and water to the distal portion of the
  nephrongtWater can be reabsorbed, it is excreted
  in increasing quantities in a progressively more
  dilute urine.

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Discussion

• In state of maximal water diuresis, the the
  urinary osmolar concentration (urine osmolarity)
  may decreased to as low as 50 mOsm/L, and urine
  flow may reach or exceed 500 ml/h.gtIntake of
  water up to 12 to 15 liter per day can be
  excreted by a healthy individual without the
  development of water retention or hyponatremia.

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Normal water hemeostasis

• Total body water is distributed in two major
  compartment2/3 ICF 1/3 ECF(intravascularintersti
  tial space14
• Osmolality is the solute or particle
  concentration of fluid
• Disorder of vasopressin secretion and action
  occur commonly in both the outpatient and in
  patient settings.

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Normal water hemeostasis

• Plasma osmolality is maintained within narrow
  limits by osmotically regulated arginine
  vasopressin(AVP) secretion and thirst.
• Despite large variations of water intake, the
  osmolality of body fluid in healthy individuals
  is maintained within relatively narrow ranges(275
  to 295 mOsm/ kg H2O)
• To maintain plasma osmolality at constant level,
  AVP secretion must in vary in response to small
  changes in plasma osmolality which is achieved
  through osmoreceptors located in the anterior
  hypothalamus.

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Water intake and Hyponatremia(1)

• Several steps are required for the kidney to
  excrete a water load
• Impaired glomerular filtration(Renal failure)
• Impaired delivery water and electrolytes to the
  dilute sites of the nephron because of increased
  proximal reaborption
• Depletion of ECF (often from vomiting with
  continued ingestion of water)
• Decreased effective circulating arterial
  volume, leading to increased thirst and
  vasopressin level Edematous status(eg, CHF ,
  cirrhosis, nephrotic syndrome)

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Water intake and Hyponatremia(2)

• Impaired renal diluting mechanism(Thiazide
  dieruetics)
• Maintenance of a dilute urine (impermeabilty of
  the collecting duct to water in the absence
  vasopressin) SIADH and endocrine disorder

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Glomerular filtration rate

• In general, a GFR reduced to approximately 20 of
  normal results in sufficient impairment of
  excretion of water to result in frequent
  hyponatremia.
• Hyponatremia may develop at levels of less
  impairemtn of GFR in intake of water is high.

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Impaired delivery water and electrolytes to the
dilute sites of the nephron because of increased
proximal reabsorption

• If a large proportion of glomerular filtrate is
  reabsorbed proximally, then sufficient water
  cannot reach the distal nephron to be excreted.
• Increased proximal reabsoption of glomerular
  filtrate can lead to retension of water and
  consequent hyponatremia

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Impaired delivery water and electrolytes to the
dilute sites of the nephron because of increased
proximal reabsorption

• Although depletion of ECF volume may arise from
  many causes, the most common cause associated
  with hyponatremia is gastric losses from vomiting
  with concomitant ingestion of water.
• Severe depletion of ECF volume also results in
  release of ADH

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Impaired renal diluting mechanism(Thiazide
dieruetics)

• In the distal tubule, sodium and chloride are
  transported out of the lumen by sodium chloride
  cotransporter that plays a critical role in the
  production of dilute urine.
• This transporter is block by thiazide diuretic
  agents.
• Such hyponatremia may be severe if intake of
  solute is low or intake of water is high.
• Thiazide agent are generally contraindicated in
  all patients with hyponatremia regardless of the
  underlying cause because thiazide agents can
  further impair the ability of the kidney to
  excrete water.

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Hyponatremia Associated with a Normal ECF Volume

• SIADH
• Glucocorticoid deficiency and hypothyroidism
• Phmacological agents
• Physical and emotional stress
• Acute hypoxia and hypercapnia
• Primary polydipsia

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Physical and emotional stress

• Physical and emotional stress are often
  associated with vasopressin release, possibly
  secondary to nausea or hypotension or both,
  associated with stress-induced vasovagal reaction

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Water Intolerant

• Any of these states that impair excretion of
  water can produce hyponatremia in a patient with
  an initially normal serum concentration of NA if
  sufficient free water is suppliedgtmay be
  considered to be water intolerant
• Such a patient is at risk for developing
  hyponatremia if given hypotonic intravenous fluid
  or a large oral water load.

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Conclusion

• Lots of beverage commercial have been emphasizing
  that drinking plenty of water can accelerate
  clearance in human body.
• When people face the SARS epidemic, it is
  understandable that they drink more water to get
  rid of virus.
• SARS outbreaks might occur again in the future so
  we come up with this case study as an alert.