Category: USMLE Step 2 CK

Baker Cysts

Baker cyst: aka popliteal cyst, is an extrusion of synovial fluid from knee joint space into the gastrocnemius/semimembranous bursa. Precipitated by

  1. Increased production in synovial fluid such as during inflammation states or any intra-articular pathology
  2. A communication formation between the joint and bursa

Image result for baker cyst

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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 – main 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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