Metabolism & Endocrine Flashcards
This deck covers Chapters 116-120 in Rosens, compromising all of endocrinology, electrolyte disturbances, and acid-base physiology.
What is Conn’s syndrome? Is the K elevated?
Conn’s Syndrome
- Primary hyperaldosteronism
- Hypernatremia
- Hypokalemia
- Hypertension
List 8 causes of hypophosphatemia
- Malnourished
- EtOH abuse
- Hyperventilation
- Sepsis
- NMS
- Insulin
- Diuretics
- Burns
- Hyperparathyroidism
List FOUR tests that can help diagnose adrenal insufficiency
To Diagnose
- AM Cortisol
-
AM ACTH
* Differentiates 1* from 2* (1* = high ACTH) -
ACTH Stimulation Test
* Baseline cortisol
* Give 250mcg of ACTH, measure again at 30/60m
* If cortisol <20, gland doesn’t work (Primary AI)
* Normal patient should double cortisol - 24h Urine for 17-OH Steroids
If in doubt re: diagnosis, give dexamethasone because hydrocortisone has mineralocorticoid activity.
List SIX causes of a high osmolar gap
- EtOH
- Methanol
- Isopropyl Alcohol
- Ethylene Glycol
- DKA
- Mannitol/Sorbitol
- Hyperlipidemia
- CKD
Outline your management of hypercalcemia in the ED
- Fluids, fluids, fluids
- Diuretics are contentious: if you give any, make it Lasix
- Bisphosphonates
- Calcitonin 4 IU/kg
- Hydrocortisone (if granulomatous dz, not cancer)
- Remove offending agent/treat underlying condition
What is the formula for the anion gap? What is the correction for albumin?
Anion Gap
- Na+ - (HCO3- + Cl-)
For every 10 g/L drop in albumin remove 2.5 from expected AG
How would you approach severely symptomatic hyponatremia and how quickly would you correct the serum sodium?
Severe Hyponatremia
- Hypertonic (3%) saline 100ml over 10 mins
- Will inrease Na+ 2-3 mmol/L
- 3% saline = 513mEq/L OR about 0.5 mEq/mL
- Repeat q10min until seizures stop
Sodium Correction
- Target: 120 mEq/L or until not seizing
- Acute: 1 mEq/L/h
- Chronic: 0.5 mEq/L/h, max 12mEq/day
- Administer D5W and DDAVP if corrected too rapidly
How can the measured sodium in patients with hyperglycemia be corrected?
↑ Glucose 10 mmol/L causes ↓ Na+ 3 mmol/L
Differentiate activated hyperthyroidism from unactivated (apathetic) hyperthyroidism
Activated Hyperthyroidism
- 4th decade
- Duration of symptoms: 8 months
- Weight loss: 10 lbs
- Thyroid weight 70 g
- Eye findings: Frequent
- CHF: Common
- Afib: 1/3 of patients
- Depression: Uncommon
Apathetic Hyperthyroidism
- 7th decade (ELDERLY)
- Duration of symptoms: 26 months
- Weight loss: 40 lbs
- Thyroid weight: 45 g
- Eye findings: Rare
- CHF: Common
- AFib: ¾ of patients
- Depression: Common
Differentiate primary and secondary adrenal insufficiency. List FIVE causes of each.
Primary AI = the gland has failed
- Acute
1. Addison’s disease (MCC in the West)
2. TB (MCC worldwide)
3. Waterhouse-Friederich (Neisseria)
4. Trauma
5. Anticoagulation - Chronic
1. Addison’s
2. TB
3. HIV
4. Adrenal mets
5. Adrenalectomy
6. Etomidate
Secondary AI = the pituitary has failed
- Acute
1. Sheehan syndrome
2. Pituitary apoplexy
3. TBI
4. Sepsis - Chronic
1. Pituitary tumor
2. Surgery
3. Steroids
4. Empty Sella
5. Brain rads
List SIX causes of increased ADH
SIADH and Normal
- Increased osmolarity (Na+)
- Decreased BP
- SAH
- Pain
- Medications (SSRI)
- Low pressure, low volume
- Caffeine
The anion gap takes into consideration chloride and bicarb. What are FIVE classic unmeasured anions?
- Albumin
- Lactate
- Ketones
- Sulfate
- Phosphate
- Organic acids
What is the pathophysiology of rhabdomyolysis?
- Depletion of ATP (exercise, drug, trauma) causing…
- ATP-dependent ion channel failure causing…
- Huge increase in intracellular calcium causing…
- Increased muscle contractility
- Protease activity
- Mitochondrial dysfunction causing O2 free radicals
- Apoptosis
List the 6 progressive ECG changes of hyperkalemia
- Peaked T waves
- Loss of P waves
- Widening of QRS
- Sine wave
- Vfib
- Asystole
List 6 causes of hyperkalemia
- Hemolysis
- Renal failure
- Drugs (Spironolactone, ACEi, NSAIDs)
- Tumour lysis syndrome
- Rhabdomyolysis
- Digoxin toxicity
- Amiloride
- Iatrogenic
Give FOUR causes for falsely low anion gap
High levels of unmeasured cations:
- Lithium
- Hypergammaglobulinemia (MM)
- Hypertriglyceridemia
- Bromide toxicity
- Hypoalbuminemia
List SIX triggers for DKA
The 8 “I’s”
- Initial
- Insulin non-compliance
- Infarct (MI/CVA)
- Infection
- Incision (surgery)
- Insemination (pregnancy)
- Intoxication
- Iatrogenic (medication changes)
List SIX symptoms consistent with thyrotoxicosis
List SIX signs consistent with thyrotoxicosis
Symptoms
SOB, exercise intolerance, palpitations, weight loss, appearance change, hair loss, anxiety, temperature intolerance, restless, oligomenorrhea
Signs
Afib, proptosis, tachycardia, CHF, fever, neck swelling, bruit, tremor, hyperreflexia
In regards to the serum glucose, how is diabetes diagnosed?
- Random plasma glucose >11.1 mmol/L
- Fasting plasma glucose >7 mmol/L
List 6 drugs that have been associated with rhabdomyolysis
- Barbiturates
- Benzodiazepines
- Colchicine
- Corticosteroids
- Isoniazid
- Lithium
- MAOIs
- Narcotics
- Neuroleptics
- Phenothiazines
- Salicylates
- Serotonergics
- Statins
- Theophylline
- TCAs
List EIGHT causes of respiratory alkalosis
Central
- Head Injury
- Stroke
- Anxiety
- Pain
- ASA
- Pregnancy
- High-altitude
- Anemia
Pulmonary
- Hypoxia
- PE
- Pneumonia
- Asthma
- Pulmonary edema
- Mechanical ventilation
Explain the phenomenon of paradoxical worsening of ketosis as AKA/DKA is treated.
- AKA/DKA is mostly β-hydroxybutyrate
- As its treated, it is converted to acetoacetate
- Urine dipstick tests acetoacetate, not β-hydroxybutyrate
- Dip looks more positive as treatment starts
List TEN causes of hypercalcemia
Malignancy
- Lung
- Multiple Myeloma
- Bone mets
Endocrine
- Hyperparathyroidism
- Hyperthyroidism
- Vitamin D excess
Granulomatous
- Sarcoidosis
- TB
- Crohn’s
Drugs
- Thiazides
- Iatrogenic calcium
Miscellaneous
- Paget’s
- Dehydration
- Rhabdomyolysis
What is the management of hyponatremia in the asymptomatic or mild-mod symptomatic patient?
Hypovolemic hyponatremia
- NS 0.9% to correct deficit
Euvolemic hyponatremia
- Free-water restriction
Hypervolemic hyponatremia
- Free-water restriction and diuresis +/- dialysis
List SIX causes of metabolic alkalosis
CLEVER PD
- Contraction
- Licorice
- Endocrine (Conn’s, Cushing’s)
- Vomiting
- Excess alkali (Antacids)
- Refeeding/Renal
- Post-hypercapnia
- Diuretics
When would you treat hyponatremia acutely?
Both of:
- Sodium <120 mEq/L
- Altered, focal neuro deficits, or seizing
Treatment
- 3% saline 100 cc IV over 15 minutes (raises Na 2-3 mEq)
List 5 precipitants of myxedema coma
Who is the typical patient that will present with myxedema coma? What will their vitals be like?
Precipitants
- Infection
- Infarction
- Incision (Surgery)
- GI bleed
- Hypoglycemia
- Hypothermia
- Medications
Typical Patients
- Older women
- Thyroidectomy
Vitals
- Hypothermic
- Bradycardic
- Hypotensive
- Altered
What are the ECG changes in hypocalcemia?
- Short PR
- Long QT
- ST depression
- TWI
- U wave
Arrhythmia is uncommon.
Describe the clinical presentation of hypocalcemia
Neuromuscular
- Paresthesias
- Muscle weakness
- Muscle spasm
- Tetany
- Chvostek’s and Trousseau’s signs
- Hyperreflexia
- Seizures
Cardiovascular
- Bradycardia
- Hypotension
- Cardiac arrest
- Digitalis insensitivity
- QT prolongation
Pulmonary
- Bronchospasm
- Laryngospasm
Psychiatric
- Anxiety
- Depression
- Irritability
- Confusion
- Psychosis
- Dementia
How do you calculate how much hypertonic saline to administer to a patient who has severe symptoms but is not actively seizing?
Step 1: Calculate sodium deficit
- NaDeficit = TBW * (NaDesired - NaMeasured)
- Assume TBW = 60% of weight
- Assume NaDesired = 120 mEq/L
Step 2: Calculate volume of 3% saline needed
- 3% saline = 513 mEq/L
- Volume (cc) = (NaDeficit/ 513) * 1000
Step 3: Calculate desired rate of infusion
- Rate = Volume (cc) / [(NaDesired - NaMeasured)*2]
- Assumes max safe rate = 0.5 mEq/hr
Example
A 70kg man presents twitching with a sodium of 112. Assuming this is chronic, how much and how fast will you correct him?
Step 1:
- NaDeficit = TBW * (NaDesired - NaMeasured)
- NaDeficit = (0.6*70) * (120 - 112)
- NaDeficit = 42 * 8
- NaDeficit = 336 mEq
Step 2:
- Volume (cc) = (NaDeficit/ 513) * 1000
- Volume (cc) = (336/ 513) * 1000
- Volume (cc) = 655 cc
Step 3:
- Rate = Volume (cc) / [(NaDesired - NaMeasured)*2]
- Rate = 655 / [(120 - 112)*2]
- Rate = 655 / 16
- Rate = 41 cc/hr for 16 hours
List EIGHT causes of high anion gap metabolic acidosis
MUDPILES CAT
- Methanol/Metformin
- Uremia
- DKA
- Propylene glycol/Paraldehyde
- Iron, INH
- Lactate
- Ethylene Glycol
- Salicylates
- CO, Cyanide
- Alcoholic Ketoacidosis
- Toluene
How is acid sensed in the body? How is H+ maintained?
pH Sensing
- Central = Medulla
- Peripheral = Carotid body
H+ Homeostasis
- H/K+ renal antiporter
- Carbonic anhydrase
- Buffering capacity
What is a delta gap? How do you calculate it?
Used to assess if more than just HAGMA
- Delta Gap: Change in AG / Change in Bicarb
- Remember alphabetical A(G) before B(icarb)
The ratio gives one of four results:
- <0.4 due to a pure NAGMA
- 0.4 – 0.8 due to a mixed NAGMA + HAGMA
- 0.8 – 2.0 due to a pure HAGMA
- >2.0 due to a mixed HAGMA + metabolic alkalosis
Here’s a worked example:
- Hgb 142 WBC 17 Plt 355
- Na 136 K 5.3 Cl 115 HCO3 7 Urea 28.6 Cr 522 Glc 5.5
- Ca 2.49 PO4 1.52 Mg 1.02 Albumin 36
- EtOH < 1 Acetaminophen < 13 Salicylates < 0.1
- VBG: pH 6.94 pCO2 30 HCO3 6 BE -26
- Lactate 2.4
- B-hydroxybutyrate 1.55
Calculate the delta ratio
- Delta ratio = [AG-12] / [24-HCO3]
- Delta Ratio = (14-12) / (24-7)
- Delta Ratio = 0.117