Journal Club!

Quick rundown of the articles we talked about today in morning report:

  1. ANDROMEDA-SHOCK trial, JAMA 2019: RCT of 424 patients with septic shock randomized to capillary refill vs lactate to target resuscitation efforts.  Primary outcome of interest was 28 day mortality.  While the difference between the two groups was not statistically significant, the study may have been underpowered.  Interestingly, there were lower rates of organ dysfunction at 72 hours with the cap refill guided resuscitation than lactate.  So keep doing your cap refill bedside exam!
  2. E-cigarettes vs nicotine-replacement therapy (NRT): Multi-center RCT in the UK that randomized 886 people to e-cigarettes or NRT of their choice for 3 months.  Outcome of interest was abstinence from smoking at 6 months and 1 year.  They found a significantly higher rate of abstinence in the e-cigarette group than the NRT group.  However, while only 9% of the abstinent NRT users were still using NRTs at 1 year, over 80% of the abstinent e-cigarette users were still using e-cigarettes at the end of the study period!  Together with the alarmingly high incidence of e-cigarette use amongst adolescents, the results of this study would have to be interpreted cautiously.
  3. EAGLES trial. Lancet. 2016: Multi-center, double-blind, RCT looking at neuropsychiatric effects of varenicline (Chantix), bupropion, or nicotine patch or placebo involving ~4k people without psych history and 4k people with psychiatric history.  Study found that Chantix resulted in the highest rates of sustained abstinence across all study arms.  In the psychiatric cohort, there were no differences between the treatment groups in terms of rates of psychiatric events. Bottom line: use Chantix whenever you can to help your patients trying to quit smoking!
  4. EXTEND trial. NEJM. 2019: Multi-center, randomized, placebo-controlled trial of 225 patients who presented with ischemic stroke within 4.5-9 hours after onset of symptoms with radiologic evidence of salvageable brain tissue randomized to receive tPA vs conservative management.  The primary outcome of interest was functional status at 90 days and was significantly better for the intervention group vs control arm.  Caveats are that symptomatic intracranial hemorrhage was six times higher in the intervention group than the control arm.  65% of the patients in the study woke up with neurologic deficits and had an unknown time of onset.
  5. Thyroid hormone replacement for subclinical hypothyroidism (Feller et al. JAMA. 2018): Meta-analysis of 21 RCTs with 2192 patients randomized to hormone replacement or no replacement.  The study found no significant difference in qualify of life, thyroid replacement symptoms, fatigure/tiredness, depression, cognition, or SBP after 12 months of therapy.  Based on this study, the new guidelines state that in patients with no symptoms of hypothyroidism or non-specific symptoms of hypothyroidism who have fT4 within normal limits and TSH <20, thyroid hormone therapy is strongly recommended against.

Bacteroides bacteremia

Some key learning points from our M&M case discussion today:

  • Ertapenem is a slow acting antibiotic and not an ideal empiric treatment in a patient who presents with sepsis or is acutely ill.  So if you want to use a carbapenem for empiric coverage, pick meropenem or imipenem instead.
    • Fun fact: ertapenem is actually more expensive than mero/imi.  The only use for ertapenem is in transitioning patients from hospitalization to home where its daily dosing is more favorable than the TID dosing of meropenem.
  • For diabetic foot ulcers, please refer to our SCVMC algorithm to help you figure out empiric antibiotics.  Simply open the HHSConnect browser and type in diabetic foot in the search bar to pull up the algorithm.
  • If blood cultures take a longer time to speciate (in our patient, over 5 days), expect anaerobes because anaerobes are difficult to culture and are sent out for speciation.  E coli is an organism that should speciate quickly and would grow in aerobic and anaerobic bottles.  If a species is only growing in anaerobic bottles, then it’s probably not E coli.
  • Levofloxacin is the only fluoroquinolone that has a role in outpatient treatment of GNR bacteremia, other fluoroquinolones (like cipro) are less effective.
  • Avoid using fluoroquinolones for empiric treatment of E coli bacteremia or pyelonephritis because our VMC antibiogram shows ~25% resistance with fluoroquinolones.

Hypercalcemia of malignancy

Thanks to John for presenting the case of a middle-aged woman with metastatic renal cell carcinoma who presented with subacute diffuse weakness and constipation, found to have symptomatic hypercalcemia, treated with IV fluids and zoledronic acid.


Clinical Pearls

  • A third of patients with malignancy develop hypercalcemia in their disease course.  Hypercalcemia of malignancy is associated with very poor prognosis (~50% 30 day mortality).
  • Constipation plus polyuria is the most specific symptom combination for hypercalcemia
  • Denosumab is superior to zoledronic acid in treating hypercalcemia of malignancy and is safe to use in renal failure.
  • One way to quickly determine the etiology of hypercalcemia from your chemistry panel is to look at the chloride to phosphate ratio.  A ratio > 33 is highly suggestive of a PTH or PTHrP mediated process.

Hypercalcemia ddx:

Hypercalcemia algorithm

** Primary hyperPTH is the most common cause of hypercalcemia in the outpatient setting.  Malignancy is the most common cause of hypercalcemia in the inpatient setting.

Treatment of hypercalcemia:

Ca <12

  • No treatment if asymptomatic
  • Avoid exacerbating factors

Ca 12-14

  • If chronic/asymptomatic ⇒ same tx as Ca <12
  • If acute/symptomatic ⇒ same tx as Ca 14-18

Ca 14-18

  • IVF – lots!
  • Lasix only if concurrent renal/heart failure
  • Calcitonin
  • Bisphosphonate (zoledronic acid >>pamidronate if malignancy. Denosumab if refractory to ZA or severe renal impairment)

Ca >18

  • Above PLUS
  • Hemodialysis

Hypercalcemia treatment chart

Aspirin toxicity

We discussed the case of a middle aged woman admitted with AMS, found to have AGMA and respiratory alkalosis with work up revealing ASA toxicity, managed with HD!


Clinical Pearls

  • In suspected ASA toxicity, check serum levels every 2 hours until two consecutive levels decrease from peak value
  • The goal in treatment of ASA overdose is to keep ASA in its charged and deprotonated state which has less end organ toxicity.
    • Give bicarb with the goal of maintaining urine pH of 7.5-8 and serum pH <7.60.
    • Treat hypokalemia aggressively (see below).
  • Patients with ASA overdose have a high minute ventilation so avoid intubation if possible to allow them to maintain their minute ventilation.
  • Call renal early for HD if indicated ⇒ AMS, cerebral/pulmonary edema, fluid overload, kidney injury, severe acidemia, ASA level >100 mg/dL, or clinical deterioration in spite of aggressive management

Management of ANY patient with suspected toxic ingestion:

  • ABCs (Airway, Breathing, Circulation)
  • Call Poison Control! (1800 222-1222)
  • Can patient get Activated Charcoal? (usually only within 1 hour of ingestion)
  • Check Utox, Salicylate screen, acetaminophen screen, +- alcohol and volatile screen if suspected. You don’t want to miss a potential co-ingestion! 

ASA overdose

  • Remember that ASA can be found in other compounds like topical salicyclic acid, herbal medications, bismuth subsalicyclate (part of Pepto-Bismol), and Oil of Wintergreen so don’t forget about those topical medications!
  • Most sensitive vital sign abnormality in early ASA overdose is tachypnea with hyperventilation. 
  • Classic acid/base abnormality is anion gap metabolic acidosis with respiratory alkalosis (see below)

How does ASA work?

  • Inhibition of cyclooxygenase results in decreased synthesis of prostaglandins, prostacyclin, and thromboxanes. This contributes to platelet dysfunction and gastric mucosal injury
  • Stimulates the chemoreceptor trigger zone to cause Nausea and Vomiting
  • Activates the respiratory center in the medulla leading to hyperventilation and respiratory alkalosis
  • Interferes with cell metabolism (Krebs cycle and decouples oxidative phosphorylation) leading to metabolic acidosis

Metabolism

  • Reaches peak concentration within 1 hour of ingestion. Takes longer with the enteric coated formulations
  • Detox occurs normally by the liver and then metabolites are excreted by the kidney. In OD, liver is overwhelmed so more of the drug becomes dependent on renal excretion (slow and can take up to 30 hours).

Clinical features

  • Tinnitus
  • Vertigo
  • Nausea and vomiting
  • Diarrhea
  • Hyperpnea (tachypnea and hyperventilation)
  • Hyperthermia (due to disturbances with oxidative phosphorylation)
  • Lethargy and confusion

Making the diagnosis

  • Check salicylate level and if elevated, check levels every two hours until two consecutive levels decrease from peak , value is less <40, and patient is asymptomatic.
    • <30 = therapeutic, >40 = toxic, >100 = absolute indication for HD regardless of symptoms
  • Check serum creatinine– ASA is renally excreted so significant renal failure will change management.
  • Check potassium level-need to treat hypokalemia aggressively (see below)

Other labs that can support diagnosis but not required

  • Coagulation studies (large overdose can cause hepatotoxicity and interfere with Vit K metabolism)
  • Lactate (can be elevated due to uncoupling of oxidative phosphorylation)
  • CXR if concern for pulmonary edema (potential complication of ASA overdose)

Treatment ASA overdose

  • Goal: keep salicylate (weak acid) in its charged and deprotonated form to prevent it from crossing into the blood brain barrier by maintaining alkalemia
  • ABCs
  • Fluids
  • Activated Charcoal if <1 hour from ingestion
  • AVOID intubation if possible (remember that these patients have high minute ventilation (RR x TV) due to ASA effect on the medulla and this can be hard to reproduce on the ventilator without causing significant auto-peep)
  • Volume resuscitation (be careful of pulmonary edema/cerebral edema)
  • Alkalinize urine with sodium bicarbonate
    • Sodium Bicarbonate 1-2 meQ/kg IV bolus followed by 100-150 meQ/D5W and titrated to maintain urine pH of 7.5 to 8.0 and continued until salicyclate level <30. It is OK to continue sodium bicarbonate even with alkalemia as long as pH<7.60Alkalinizing the urine keeps ASA in the non-acidic form (Sal-), thus avoiding a lot of the complications of ASA overdose.
  • Treat hypokalemia aggressively to maintain alkalinization. If hypokalemia is not corrected, the body will reabsorb potassium and acidify the urine, which is the opposite of what we want.
  • Consider giving glucose for neuro-glycopenic symptoms (controversial but patient can have neuro-glycopenic symptoms due to low CNS glucose even with a normal serum glucose)
  • Call renal early if patient may need hemodialysis 
    • Indications
      • AMS
      • Cerebral edema/pulmonary edema
      • Fluid overload
      • Acute or chronic kidney injury
      • Severe acidemia
      • ASA level >100 mg/dL
      • Clinical deterioration despite aggressive care

RCA infarct, bradycardia, & hyperkalemia!

Today, we discussed the case of an elderly woman with significant history of vasculopathy and ESRD who presented with weakness, found to be bradycardic to 30s, hypotensive, and hyperkalemic to 7.2.  Her hyperkalemia was treated with dialysis but she underwent cardiac cath due to up trending troponins, found to have a 100% occlusion of the RCA!


Clinical Pearls

  • First step in managing a patient with bradycardia is ABCs!
  • First medication for symptomatic bradycardia is atropine.  Remember that atropine works at the level of the AV node and higher so if the block is occurring somewhere below the AV node, then atropine will not be effective.
  • Other pharmaceutical agents are dopamine, epi, or isoproterenol
  • Anyone with bradycardia and unstable hemodynamics in spite of above treatments should receive transcutaneous pacing.  This buys you time until you can place a transvenous pacemaker (less painful, more effective)
  • ECG has a low sensitivity but high specificity for hyperkalemia-induced cardiomyocyte instability.
  • ECG changes associated with hyperkalemia in progressive severity:
    • Peaked T waves
    • P wave widening, PR prolongation, P wave disappearance
    • QRS widening, AV block, bradycardia
    • Sine wave
    • VF/asystole/PEA

Bradycardia approach

1. ABCs!

  • Pharmaceutical agents
  • Atropine (0.5 mg – 1 mg q3-5 mins for a total of 0.03 mg/kg)
  • If no improvement, consider dopamine or epi
  • If still symptomatic, then start transcutaneous pacing

2. Find underlying cause and treat it 

  • Meds: BB, CCB, amio, digoxin, clonidine, lithium, acetylcholinesterase inhibitors
  • Ischemia (up to 25% of patient with acute MI present with bradycardia)
  • ↑ vagal tone: if young, athlete
  • Metabolic: hypoxia, sepsis, ↓T4, hypothermia, hypoglycemia, hyperkalemia
  • OSA
  • Elevated ICP
  • Infections: legionella, lyme, Q fever, typhoid, malaria, RMSF, yellow fever, leptospirosis, dengue, Chagas disease
  • Infiltrative processes: sarcoid, amyloid, hemochromatosis

In our patient, the cause was severe hyperkalemia as well as an RCA infarct.  Given her clinical instability, and the potential for worsening hyperkalemia from cardiac catheterization alone, the team normalized her serum potassium before performing cardiac cath which led to the RCA MI diagnosis.

Hyperkalemia

  • ECG changes are not sensitive for hyperkalemia and can miss up to 39% of patients even with a K of 7-9.
  • Sweet spot for potassium appears to be a mean K of 3.5 to 4.5 mEq/L. There is not a well-defined treatment threshold.
  • Bottom line for management: if you have the kidneys available, use the kidneys to excrete as much potassium as possible.
  • Newer agents like sodium zirconium and patiromer. Mix with water. Well tolerated and highly effective.

Agents that reduce serum potassium via transient intracellular shift:

  • Insulin: give with D50 if normoglycemic to avoid hypoglycemia and be sure to check FSG hourly for 4 hours after to ensure no hypoglycemia develops
  • Albuterol (10-20 mg) nebs: this is significantly higher than the dose we give in COPD (2.5 mg) and is equal to ~8 treatments! So make sure to continue the nebs when the patient arrives on the floor from the ER if they are still hyperkalemic.
  • NaHCO3: best for management of chronic hyperkalemia in the outpatient setting.  In the acute management of hyperkalemia, alkalinization of serum with a large bicarb load can lead to a reduction in serum calcium levels.  Lower serum calcium can lead to more cardiac membrane instability and fatal arrhythmias!

Agents that eliminate potassium from the body:

  • Loop diuretics: first choice if a functioning kidney is available!
  • Cation exchange binders: preferred when kidneys are not available
    • Patiramer (available at VMC), much more tolerable than kayexalate and highly effective at lowering serum potassium.  Like kayexalate, it works over hours to days.
    • Sodium zirconium: similar to patiramer but not currently available
    • Kayexalate: not pleasant to take orally. Also carries with it the slight risk of colonic ischemia especially in post renal transplant patients and those with baseline colonic dysfunction (due to infection or inflammation).
  • Dialysis

Indication for using calcium gluconate: when EKG changes are noted.  Repeat doses (maximum 3) until EKG changes have resolved.

EKG Changes in Hyperkalemia:

  • K > 5.5 ⇒ repolarization abnormalities:
    • Peaked T waves are the earliest sign
  • K > 6.5 ⇒ progressive paralysis of the atria:
    • P wave widens and flattens
    • PR segment lengthens
    • P wave eventually disappears
  • K > 7.0 ⇒ conduction abnormalities and bradycardia:
    • QRS widens
    • High-grade AV block, slow junctional and ventricular escape rhythms
    • Any kind of conduction block (bundle branch blocks, fascicular blocks)
    • Sinus bradycardia or slow AF
    • Sine waves
  • K > 9.0 ⇒ cardiac arrest:
    • Asystole
    • Ventricular fibrillation
    • PEA with bizarre, wide complex rhythm

Multiple Myeloma

Thanks to Erica for presenting the case of a middle aged man who presented with acute back pain and B symptoms after trauma to his back, found to have stage 3B multiple myeloma.


Clinical Pearls 

  • Remember that majority of cases of acute low back pain (<6 weeks) is due to musculoskeletal etiologies that spontaneously improve on their own.  Imaging and further diagnostic work up is not indicated unless there are red flags (see below).
  • A straight leg test is more useful when negative as it has a high negative predictive value for ruling out radiculopathy.  False positive rates are quite high.
  • Unexplained anemia and worsening renal function in the outpatient setting should trigger a work up for multiple myeloma.
  • The most common presenting symptoms for MM are anemia (73%), bone pain (58%), and renal insufficiency (48%).
  • In diagnosing MM, sensitivity increases with each added test: SPEP (82%) → IFE (93%) → FLC/UPEP (97%).  The other 3% that would not be diagnosed with these tests have a non-secretory MM (monoclonal increase in plasma cells in bone marrow that do not produce immunoglobulins or light chains).

Red flags for acute low back pain:

  • Focal neurologic complaints/deficits
  • History of cancer
  • Age >50 years
  • Fever not explained by another cause
  • History of recent bacteremia or IVDU
  • Steroid use
  • Weight loss
  • Pain that is worse at night
  • No relief with bed rest or pain lasting >1 month

Multiple Myeloma: refer to this prior blog post.  Other info below:

Diagnostics:

  • SPEP: picks up M protein or elevated immunoglobulins (heavy + light chain) in the serum.  You can diagnose over 80% of patients with MM using an SPEP.
  • IFE: identifies the specific type of immunoglobulin that is elevated with its light chain.
  • Free light chains (FLC): measures the amount of free light chains not bound to a heavy chain floating around in the blood.  Normally people have about a 2:1 ratio of kappa to lambda chains.  In light chain only multiple myeloma, there is a disproportionate increase in one type over the other and the ratio will be off.  If there is an increase in both light chains but the ratio is normal, think kidney disease!
    • Keep in mind that the reason to check FLC when you suspect MM is to diagnose those people who are only producing light chains and not whole immunoglobulins that would have been picked up by SPEP/IFE.
  • UPEP: measures light chains dumped in the urine (Bence Jones protein)

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Status Epilepticus & Serotonin Syndrome

Today we talked about the case of a young woman who presented after suicide attempt by ingestion of multiple prescription medications, found to be obtunded, initially in status epilepticus and later with exam findings concerning for serotonin syndrome.


Clinical Pearls

  • Continuous EEG is indicated if a patient is not returning to baseline mentation 15 mins after a seizure to rule out non-convulsive status epilepticus.
  • Status epilepticus is defined as a seizure lasting > 5 mins or > 2 discrete seizures between which there is incomplete recovery of consciousness.
  • Treatment of status epilepticus involves acute management with IV/IM benzos, urgent long-term control with IV fosphenytoin (preferred), phenytoin, or valproic acid.  Remember that keppra is more useful in suppressing future seizures than treating an acute episode.
  • Serotonin syndrome is a clinical diagnosis and manifests with neuromuscular activation like tremors, hyperreflexia, and clonus (generally worse in lower extremities).  Use Hunter’s criteria to help with diagnosis.

Status Epilepticus

  • When is continuous EEG needed?
    • If patient is not returning toward baseline in 15 mins after a seizure, goal is to rule out nonconvulsive seizures
  • How to define status?
    • > 5 mins OR
    • > 2 discrete seizures between which there is incomplete recovery of consciousness
  • Non-convulsive status epilepticus
    • Suspect if LOC not improving by 10 mins after cessation of movement
    • Mental status remains abnormal for 30-60 mins after movement cessation
    • Dx requires a 24-hour EEG (we don’t have one ☹)
    • Treatment is the same as generalized status epilepticus, but prognosis is worse (mortality 65% vs 27%)
  • Treatment of status
    • Assessment and supportive treatment
    • Initial pharmacologic therapy
      • Ativan (2 mg IV q1-2 mins), total dose 0.1mg/kg
        • Watch out for respiratory depression and hypotension
        • Alternatives: versed 0.2mg/kg IM, valium 0.2mg/kg IV
    • Urgent long-term control
      • Fosphenytoin (preferred): 20 mg/kg at 150mg/min
        • Give extra 10 mg/kg if not responding
        • Dephosphorylates into phenytoin.  It’s more soluble in water and less likely to precipitate in the skin and vessels.
      • Phenytoin: 20mg/kg at 50mg/min (slower than fospheny)
        • If infused too fast, can irritate skin/vessels causing skin necrosis
      • Valproic acid: 20mg/kg at 5 mg/kg/min
        • Sometimes the preferred choice in patients with known generalized epilepsy b/c phenytoin can provoke absence seizures in that population.
      • What about Keppra?
        • Technically not FDA approved for status.  It has weak evidence to support its use.  More useful in suppressing subsequent seizures after status has been controlled.

Serotonin syndrome:

  • Clinical diagnosis. Serum serotonin concentrations do not correlate with clinical findings.
  • Severe disease can lead to DIC, rhabdo, renal failure, and ARDS.
  • Diagnostic criteria: use Hunter’s (84% sensitive, 97% specific)Hunter's decision rule
  • DDx
    • NMS
    • Anticholinergic toxicity
    • Malignant hyperthermia
    • Sympathomimetic intoxication
    • Sedative-hypnotic withdrawal
    • Meningitis
    • Encephalitis
  • Serotonin syndrome may be distinguished from other causes of agitated delirium on the basis of neuromuscular findings. Whereas patients with serotonin syndrome show signs of neuromuscular activation (eg, tremor, hyperreflexia and clonus that are greater in the lower extremities, ocular clonus, and increased muscle tone), patients with sympathomimetic toxicity or infections of the central nervous system lack these findings.
  • Treatment
    • Supportive care and sedation
      • Chemical sedation preferred over physical restraint
    • Autonomic instability
      • High BP: esmolol or nitroprusside (Short acting). Avoid longer acting agents
      • Low BP: neo or epi. Avoid idirect agents like dopamine because they are converted to epi and norepi.  When monoamine oxidase is inhibited, epi and norepi production at the cellular level is not controlled and could lead to an exaggerated HD response.
    • Hyperthermia
      • No benefit to Tylenol b/c increase in body temp is due to increased muscular activity rather than alteration in the hypothalamic temperature setpoint.
      • If temp >41.1, then sedate, paralyze, intubate
    • Antidote: cyproheptadine
      • Histamine receptor antagonist. Also has weak anticholinergic activity
      • 12 mg loading dose, then 2 mg q2h until clinical response is seen.
      • Is sedating (good) and can also cause transient hypotension.

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