Category: USMLE Step 2 CK

Hyponatremia: Primary polydipsia

Hyponatremia is excess of water relative to sodium and almost always due to increased ADH.

  • SIADH: inappropriate increase (Conrad: any lung, brain, drugs and cancer)
  • SADH: appropriate increase such as in hypovolemia or hypervolemia with decreased effective arterial volume

Evaluation of hyponatremia begins with the following laboratory datas

  1. Plasma osmolality: to determine if the patient really has hyponatremia
    • Pseudohyponatremia: will be high in patients with osmotic substances that draw water to dilute the concentration of sodium
  2. Urine osmolality: useful in limited circumstances  -> Uosm will be < 100
    • malnutrition(decrease solute intake)
    • primary polydipsia(increase water intake)
  3. Urinary sodium: used to determine the kidney’s concentrating capabilities(basically how the body is responding to this state, or did it cause it)
    • Normally should be low < 20

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Lead poisoning

Symptoms and signs:

  1. GI: abdominal pain, constipation, anorexia, lead lines on gum(Burton’s lines)
    Image result for lead lines gum lead poisoning
  2. Neurological : headache, neurocognitive deficits(forgetfullness, encephalopathy, behavior problems, language regression; childrens especially susceptible due to incomplete BBB maturation), motor/sensory peripheral neuropathies(stocking-glove pattern ddx with GBS, DM… etc, extensor weakness)
  3. Hematologic:al microcytic anemia(99% bound to erythrocytes and can disrupt heme synthesis)
  4. Nonspecific signs: fatigue, irritability, insomnia,
  5. Chronic s/s: hypertension, nephropathy

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Intrapartum fetal heart rate monitoring

Cardiotocography aka electronic fetal monitor, monitors the fetal heartbeat and uterine contractions during pregnancy Рmain purpose is for peripartum fetal heart rate monitoring.

Besides accelerations, there are 3 types of decelerations that need to be differentiated as they have different etiologies, prognosis and managements – Early, Late and Variable.

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