Patho Exam 3 part 2 Flashcards
(35 cards)
Hyponatremia
-Stages?
Hyponatremia stages
mild - Na 125-134
moderate - Na 115-124
severe - Na 110-114
Hyponatremia
-epidemiology
Hyponatremia epidemiology
- most common electrolyte disorder
- 28% of hospitalized patients
- 7% of patients in community clinics
Hyponatremia
-risk factors?
Hyponatremia risk factors
- certain medications
- advancing age > 30
- increased intake of hypotonic fluids
- -PO water in martathon water
- -PO water or hypotnic IV fluids in nurisng home patients
- smaller body size in women
Clinical Presentation of Hypoatremia
-stage symptoms?
Clinical Presentation of Hypoatremia
Mild - Nausea, malaise
Moderate - HA, lethargy, restlessness, disorientation
severe - seizures, coma, respiratory arrest, brainstem herniation, death
Clinical Presentation of Hypoatremia
-acute vs chronic symptoms?
Clinical Presentation of Hypoatremia
chronic - > 48hours, frequent asymptomatic, may have impaired attention, posture, gait
rapid onset - HA, lethargy, restlessness, disorientation, seizures, coma, respiratory arrest, brainstem herniation, death
depends on volume status
Clinical Presentation of Hypoatremia
-magnitude of hypoatremia?
- SOsm decreases in proportion to SNa
- as SOsm decreases, water movement into brain cells increase
Clinical Presentation of Hypoatremia
-rapidity of onset?
- Brain cells can adjust intracellular osmolality to minimize cellular changes to volume changes
- compensation begins within minutes
- maximal compensation takes 48 hours
- -therefore more acute changes are not yet compensated and are more likely to be associated with symptoms
Hyponatremia
-Diagnosis?
Asymptomatic patient - Routine labs
Symptomatic patient - Chem-7 (including Na+) and other screening laboratories are drawn
–serum osmolality, urine Na, serum glucose, lipids, renal function, thyroid function
-physical exam
-history of present illness
-past medical history
-home medications
Hyponatremia diagnosis approach?
- Assess the serum osmolality
- hypertonic
- isotonic
- hypotonic - Assess the volume status
- volume overload
- euvolemic
- dehdrated
- volume depleted - assess acuity and severity
- acute vs chronic
- mild vs severe
Isotonic Hypoatremia
- SosM
- other thing
Isotonic Serum Osmolality
- Sosm - 280 mOsm/kg
- Lab Artifact - Seen in patients with hyperlidemia or hyperproteinemia when a specif lab technique is used
Hypertonic Hypoatremia
-SOsm
-Symtpoms?
-
Hypertonic Hypoatremia
- SOsm > 280
- Excess effective osmoles in ECF
- -elevated glucose
- –for every 100mg/dl increase in glucose, Na increases by 1/7 mEq/L
- mannitol, glycine, sorbitol, polyethylene glycol
- -associated with osmolal gap
- -measured SOsm - calculated SOsm
Hypotonic Hypoatremia
- SOsm?
- how to assess etiology?
- causes?
Hypotonic Hypoatremia
- SOsm <280
- most common cause of hypoatremia
- many causes
- must assess volume status to determine etiology
- -euvolemic hypotonic hypnatremia
- -hypervolimic hypotonic hypoatremia
- -hypovolemic hypotonic hyponatremia
Hypovolemic Hypotonic Hyponatremia
- what is it?
- causes?
Hypovolemic Hypotonic Hyponatremia
-ECF volume contraction –> loss of hypotonic fluids
- -diarrhea
- -excessive sweating
- -Thiazide diuretics
- –usually mild, asymptomatic
- –within 2 weeks of initiaton
- –elderly women at greater risk
Hypovolemic Hypotonic Hyponatremia
-initally?
Hypovolemic Hypotonic Hyponatremia
- initally, transient hypernatremia
- osmotic AVP release, stimulation of thirst
- if salt and water losses continue, more AVP released
- if patient drinks water or are given hypotonic IV fluids, they retain water and hyponatremia develops
Hypovolemic Hypotonic Hyponatremia
- clinical presentation ?
- laboratories?
Hypovolemic Hypotonic Hyponatremia
- Clinical Presentation
- orthostasis, hypotension, tachycardia, dry mucous membranes, CNS changes - Laboratories
- Hyponatremia
- Uosm usually >450
- UNa will help determine cause
Euvolemic Hypotonic Hyponatremia
-causes?
Euvolemic Hypotonic Hyponatremia
- Most common cause is syndrome of inappropriate antidiuretic hormone (SIADH)
- Nonosmotic or nonphysiologic increase in AVP release and/or enhanced sensitivity of kindey to AVP
- -water intake exceeds kidneys capacity to excrete water
- -UOsm > 100
- -UNa > 20 due to ECF volume expansion - When SIADH is suspected, need to rule out hypothyroidism, hypocortisolism, and renal failure
- UOsm > 100
- UNa > 20
Euvolemic Hypotonic Hyponatremia
-Causes of SIADH?
Causes of SIADH
- Lung or pancreatic cancer
1. CNS disorders - -Head trauma, ischemic or hemorrhagic stroke, meningitis, tumor
- Pulmonary disorders
- -Pneumonia (PNA), Tuberculosis (TB), acute respiratory distress syndrome (ARDS) - Medications
- carbamazepine, oxcarbazepine
- SSRIs, tricyclic antidepressants, typical antiphyshotics, MAOI inhibitors
- ecstasy
- chemotherapeutic agents
Euvolemic Hypotonic Hyponatremia
-Other causes than SIDAH
- Primary or psychogenic polydipsia
- PO water intake > kidneys ability to excrete solute-free water
- -usually > 20 L /day
- -dilulation - UNa < 20 mEq/L
- UOsm < 100 mOsm
Euvolemic Hypotonic Hyponatremia
- clinical presentation?
- labortories?
Euvolemic Hypotonic Hyponatremia
- Depends on magnitude of hypoatremia and rapidity of onset of hypoatremia
- Mild: Nausea, malaise, or asymptomatic
- Mod: HA, Lethargy, restlessness, disorientation
- Severe: seizures, coma, respiratory arrest, brainstem herniation, death
2.Labs- Una and UOsm will help determine etiology
Hypervolemic Hypotonic Hyponatremia
- What is it?
- Compensating mechanisms?
- decreased effective arterial blood volume (EABV)
- cirrhosis
- heart failure (CHF)
- nephrotic syndrome - Comp
- impaired renal sodium and water exretion = ECF volume expansion, edema
- nonosmotic AVP release
- -Water retention > NA retetntion
Hypervolemic Hypotonic Hyponatremia
- clinical presentations?
- laboratories?
- Symptoms due to ECF volume expainsion
- edema (peripheral or pulmonary) - Depends on magnitude of hyponatremia & rapidity of onset of hypoatremia
- Mild: Nausea, malaise, or asymptomatic
- Mod: HA, lethargy, restlessness, disorientation
- Severe: seizures, coma, respiratory arrest, brainstem herniation, death
Laboraties
- UNa < 20
- UOsm > 100
Hypervolemic Hypotonic Hyponatremia
-Clinical Outcomes?
- Worse for women than men
- Worse for children than adults
- severe risk factor for morbidity and mortality in patients with HF and cirrhosis
Hypervolemic Hypotonic Hyponatremia
-treatment?
Hypervolemic Hypotonic Hyponatremia
- Depends on
- magnitude
- rapidity
- patients volume status
Hypernatremia
- Serum Na?
- Risk factors?
- outcome?
- Na > 145
- always associated with hyperosmolality & cellular dehydration - Risk factors
- impaired thirst response
- lack of access to water
- -elderly, infants, children, disabled, comatose
- latrogenic
- -too little free water or too much hypertonic solution plus increased renal free water loss - Outcomes in adults
- High mortality rate in chronic acute cases
