Resident Report 1/28 – Hemolysis

A special thank you to Dr. Lee Levitt for coming to morning report to participate in this interesting case!

Teaching Pearls:

  • Discrepancy of a low O2sat along with normal PaO2 is classically seen with methemoglobinemia.
    • Other causes include poor perfusion state such as vasoconstriction, hypothermia, or any other conditions that cause poor flow state.
    • Methemoglobin – Iron within hemoglobin exists as the oxidized state (+3), causing decreased affinity for oxygen binding.
  • Carboxyhemoglobin – when carbon monoxide binds to hemoglobin.
    • Hemoglobin has a very high affinity for CO compared to O2. Causes the oxygen dissociation curve to shift to the left, leading to decreased ability for O2 unloading.
    • Pulse oximetry cannot distinguish between carboxyhemoglobin and oxyhemoglobin.
  • Workup of anemia
    • Underproduction
    • Blood loss
    • Increased destruction (hemolysis)
  • Reticulocyte count – important to correct for degree of anemia and time of maturation.
    • High corrected reticulocyte index suggestive of blood loss or hemolysis.
    • Low corrected reticulocyte index suggestive of underproduction.
  • Hemolysis Labs
    • High LDH, low haptoglobin, indirect hyperbilirubinemia, Coombs test
  • Blood Smear
    • Schistocytes, helmet cells suggestive if microangiopathic hemolytic anemia.
    • Bite cells and Heinz bodies suggestive of G6PD deficiency.
    • Spherocytosis suggestive of either hereditary spherocytosis or autoimmune hemolytic anemia.
    • Sickle cells suggestive of sickle cell anemia
    • Target cells suggestive of liver disease (in particular obstructive liver disease), hemoglobinopathy, etc
  • Causes of Intrinsic hemolysis
    • RBC membrane defects
      • Example includes hereditary spherocytosis
    • Hemoglobinopathy
      • Examples include thalassemia, sickle cell disease, etc
    • Oxidation Problem
      • Most common example is G6PD deficiency.
  • G6PD Deficiency
    • Different variants of disease spectrum
    • X-linked disease – manifest in males
    • Hemolysis precipitated by acute insult, including infections or medications.
    • Medications associated with hemolysis include primaquine, dapsone, sulfa medications, etc.
    • Mediterranean variant associated with favism.
    • Negative G6PD test does not rule out G6PD deficiency in the setting of hemolysis.

Morning Report 1/27/16

Great Discussion today! Thanks to Mike Cruz for presenting.

  • Remember that isopropyl alcohol and ethanol causes an osmolar gap without an anion gap.
  • Beware of a normal osmolar gap in a patient with a positive volatile screen – this could reflect complete conversion of the parent compound to toxic metabolites

 

Name Anion Gap Osmolar Gap Toxicity Treatment
Methanol ELEVATED YES Retinal Toxicity from Formic Acid Fomepizole
Ethylene Glycol

(antifreeze)

ELEVATED YES Renal Failure, Oxalate crystals Fomepizole, Ethanol
Propylene Glycol

(IV Lorazepam)

ELEVATED YES Lactic Acidosis

CNS depression

HD if severe
Isopropyl Alcohol

(rubbing alcohol)

NORMAL YES Sedation Supportive Care
Ethanol NORMAL YES    

Hypocalcemia

  • MKSAP Question: Illness script for Asian female with metastatic lung adenocarcinoma – check for the EGFR mutation
  • Approach to Hypocalcemia: Check the PTH level. Causes of hypocalcemia with high PTH include Vit D resistance, pancreatitis, CKD. Causes of hypocalcemia with low PTH include destruction of the parathyroid gland (autoimmune, surgery).
  • Clinical Manifestations of Hypocalcemia: Peri-oral numbness, paresthesias, tetany, seizures, papilledema, etc
    • Tetany = neuromuscular irritability
    • Chvostek’s Sign
    • Trousseau’s Sign
  • Indications for IV Calcium drip
    • Rapid drop of total calcium to < 7.5
    • Symptomatic hypocalcemia (tetany, carpopedal spasm, seizures)
    • Prolonged QTC
  • The two main causes for hypocalcemia in ESRD are hyperphosphatemia (inability to excrete phosphorous) and lack of calcitriol production by the kidney.
  • Treatments for secondary hyperparathryoidism in ESRD include phosphorous binders, calcitriol, and calcimimetics.

Intern Report 1/27 – Hypercalcemia

Teaching Pearls:

  • Primary hyperparathyroidism and malignancy comprise of >90% of cases of hypercalcemia.
  • Primary hyperparathyroidism is the most common cause of hypercalcemia in outpatient settings.
    • Patients are often asymptomatic and/or have a history of kidney stones
  • Malignancy is the most common cause of hypercalcemia in inpatient admissions.
    • Labs often display severe hypercalcemia
    • Patients with severe hypercalcemia are often volume depleted as hypercalcemia can lead to nephrogenic diabetes insipidus
  • Initial Workup – First measure the PTH level
    • High PTH: diagnosis is likely primary hyperparathyroidism
    • High normal to mild elevation: think of primary hyperparathyroidism or Familial hypocalciuric hypercalcemia (FHH)
    • Low PTH: proceed onto further tests
  • Other work-up labs include PTHrP and vitamin D metabolites. Other considerations include SPEP/UPEP, TSH, Vitamin A, etc.
  • FHH differs from primary hyperparathyroidism in that the fractional excretion of Ca in FHH is low, whereas primary hyperparathyroidism is high.
    • Decreased fractional excretion of Calcium leads to lack of nephrolithiasis development.
  • Primary hyperparathyroidism has three different pathologic conditions:
    • Adenoma – 89-90%
    • Hyperplasia – 6.8%
    • Carcinoma – 1.2%
  • Should consider parathyroid carcinoma in patients with primary hyperparathyroidism and the following:
    • Severe elevations in calcium
    • Severe elevations in PTH
  • Management
    • IV fluids NS at 200-300cc/hour to maintain UO at 100-150cc/hour.
      • Loop diuretics only used in the setting of fluid overload
    • Calcitonin – onset of action: hours
      • Concern for tachyphylaxis
    • Bisphosphonates (pamidronate or zolendronate)
      • Onset of action >2 days

Intern Report 1/19: Sarcoidosis

Teaching Pearls:

  • Presents in 20-60 year old individuals. Diagnosis tends to occur 10 years earlier in blacks than Caucasians.
  • Over 90% present with pulmonary findings on imaging.
  • About 50% of patients with sarcoidosis are asymptomatic.
  • About 30% of patients with sarcoidosis have extrapulmonary manifestations
  • Extrapulmonary manifestations include:
    • Cutaneous – can be found on tattooed skin
    • Cardiac – monitor for conduction delays, infiltrative heart diseases
    • Lymph nodes, liver, spleen
    • GI
    • Renal
    • Systemic symptoms
  • Differential Diagnosis
    • Infectious
      • HIV, TB, fungal lung diseases
    • Occupational/environmental toxin exposure
    • Hypersensitivity pneumonitis
    • Pneumoconiosis (Beryllium)
    • Langerhans Cell histiocytosis
    • Malignancy (lymphoma)
  • Diagnosis is made with the following:
    • Clinical and radiographic findings
    • Excluding other potential causes
    • Tissue biopsy
  • Lofgren’s syndrome
    • Erythema nodosum, bilateral hilar adenopathy, fever, arthritis
    • Biopsy not needed if Lofgren’s syndrome is present (high specificity)
    • Prognosis – fantastic; treatment – NSAIDs
    • A Boards favorite topic. (Very high yield)

Resident Report 1/14 -Thrombosis

Teaching Pearls:

  • Inherited Thrombotic Diseases
    • Factor V Leiden
      • Moderate risk of thrombosis
    • Prothrombin G2120A mutation
      • Moderate risk of thrombosis
    • Protein C Deficiency (higher risk of thrombosis)
    • Protein S deficiency (higher risk of thrombosis)
    • ATIII Deficiency (higher risk of thrombosis)
  • Factor V Leiden is the most common inherited thrombotic disease
    • Occurs in 5% of Caucasians
    • Heterozygotes have 5-fold increase in thrombosis; double hit has 50-fold increase.
  • Treatments for coagulation reversal
    • FFP
      • Plasma containing normal factors
      • May take 1-2 hours for action
      • Higher volume load
    • Kcentra
      • Concentrate with factors II, VII, IX, and X
      • Immediate
    • Vitamin K
      • Duration of action approximately 4-12 hours