1 / 23

Lab Rounds

Lab Rounds. Juliette Sacks CCFP-EM August 10, 2006. Case. L.W. 49 y.o. Female 3-4 day hx of: disorientation dysarthria progressing ataxia dysphagia no vomiting acute on chronic diarrhea no hx of trauma, seizures or LOC no drug or EtOH abuse. Case cont’d. FHx: adopted

clarice
Download Presentation

Lab Rounds

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Lab Rounds Juliette Sacks CCFP-EM August 10, 2006

  2. Case • L.W. 49 y.o. Female • 3-4 day hx of: • disorientation • dysarthria • progressing ataxia • dysphagia • no vomiting • acute on chronic diarrhea • no hx of trauma, seizures or LOC • no drug or EtOH abuse

  3. Case cont’d • FHx: adopted • Collateral Hx: from pt’s daughter who is primary caregiver • NKDA • Meds: • Lithium 120mg qhs • Zyprexa 10mg at noon and 20mg qhs • Zopiclone 22.5mg qhs • Propanolol 40mg at noon and 40mg qhs

  4. Case cont’d: • PMHx/Sx: • Bipolar disorder • Chronic diarrhea • Multiple laparotomies with ileostomy • Px: • Tremulous, dysarthric • 118/56 61 18 36.7C 02 sats 97% on 3L by NP • Chest clear • CVS N • Abdo distended but nontender • CN intact, clonus, incr. DTRs, generalized muscle weakness

  5. Results • Na 133, K 3.9 • Troponin, CK, LFTs N, Cr 100 • EtOH, APAP, ASA negative • Hgb 136, WBC 5.2, Plt 272 • Li 3.96 • EKG: Anterior T wave depression • AXR: ++ dilated loops of large bowel with air fluid levels; no free air • CT head: N

  6. Lithium • Commonly used to treat depressive and bipolar affective disorder • Low therapeutic index • Intoxication seen with acute and chronic use • Multisystem dysfunction with intoxication • T1/2: 29h

  7. Lithium Dosing • Therapeutic indices: • 0.6 - 1.2 mEq/L (prophylactic control) • 1.0 - 1.5 mEq/L (acute mania) • Oral administration only • Absorbed from GIT 2-4h postingestion • Minimally protein bound • Steady state plasma levels achieved in 5d

  8. Lithium Excretion • Excreted through the kidneys therefore dosing is dependent on: renal function, volume status, age • Reabsorbed in the proximal tubule • 20% is excreted in urine • Lireabsorption follows Na reabsorption but may be reabsorped preferentially to counter Na losses in volume depleted pts

  9. More about Li… • Lithium alters the cation transport across cell membranes in nerve and muscle cells • Influences reuptake of serotonin and epinephrine • Inhibits second messenger systems involving phosphatidylinositol cycle • Inhibits postsynaptic D2 receptor sensitivity

  10. Factors predisposing to Li Toxicity(courtesy of Tintinalli) • Renal failure • Volume depletion • Hyperthermia/NMS • Infection • CHF • Diabetes mellitus • Gastroenteritis • Surgery • Cirrhosis • Decreased Na intake

  11. Drug interactions with Li(courtesy of Tintinalli) • Major: Haloperidol • Moderate: • ACEI - Methyldopa • Anorexiants - Metronidazole • Benzodiazepines - NSAIDs • Caffeine - Phenytoin • CCB - Tetracyclines • Carbamazepine - Theophyllines • Clozapine - Thiazide diuretics • Fluoxetine - Urea • Iodide salts - Succinylcholine • Loop diuretics - Nondepolarizing muscle paralytics • Phenothiazines - TCAs Minor: Carbonic anhydrase inhibitors, sympathomimetics

  12. Clinical Manifestations • GI: • Nausea and vomiting • Diarrhea • CNS: • Weakness and fatigue • Lethargy and confusion • Tremor (coarse, irregular) • Ataxia • Seizures • Neuromuscular excitability/fascicular twitching • Stupor • Coma

  13. Clinical Manifestations 2 • Renal: • May cause acute renal failure • Decreased CrCl • Nephrogenic diabetes insipidus • With polyuria and polydipsia • CV: • Hypotension • Sinus bradycardia • Ventricular dysrhythmias (including complete heart block) • EKG findings in chronic Li use: depressed ST segments and T wave flattening/inversion; QTc prolongation • CV collapse and respiratory failure

  14. Clinical Manifestations 3 • Neurological sequelae: • 10% risk of permanent damage • Truncal and gait ataxia • Nystagmus • Short term memory deficits • Dementia

  15. Lithium Toxicity(chronic ingestion)

  16. Treatment • ABCs • iv fluids, cardiac monitoring • EKG • Identification of agents and amount ingested (get the pill bottles if possible) • Beware sustained release preparations! • Rule out co-ingestions • Serum Li with 2nd sLi 2h later • Lytes, Cr, BUN, tox screen • Hx and Px • +/- CT head depending on neurological presentation

  17. Treatment cont’d • Restore fluid volume and correct electrolyte abnormalities • Oral charcoal does not bind Li but may bind other drugs taken • Whole bowel irrigation may be considered especially with SR preparations • If given within 1h of ingestion may remove 60% of drug

  18. Hemodialysis • For severe lithium toxicity • When? • s[Li] >4.0 mEq/L regardless of clinical status • s[Li] >2.5 mEq/L with symptoms; with renal insufficiency or other factor(s) that limit Li excretion • s[Li] 2.5-4.0 mEq/L asymptomatic patient but who is not expected to have s[Li] <1.0mEq/L w/i 36h

  19. Goal: decrease sLi levels to <1 mEq/L within 6-8h post dialysis • Li clearance of 70-170 ml/min • Use of continuous venovenous hemofiltration reduces the post dialysis rebound in sLi level • Addition of bicarbonate to dialysate may improve Li extraction

  20. Adjuncts • Consult renal service • Consult psychiatric service • Consult poison control/toxicology service

  21. What about L.W.? • After 4h of fluid replacement, Li level was 3.53 but she remained symptomatic • Sent for hemodialysis • No role for gastric lavage, whole bowel irrigation • Serial Li levels and >1 course of dialysis • Persistent neurological deficits despite s[Li] of 1.0-1.1 mEq/L • Lithium discontinued; replaced by olanzepine

More Related