Neuromuscular Neuromuscular EmergenciesEmergencies

Hanni BoumaHanni Bouma

R3 NeurologyR3 Neurology

OutlineOutline Approach to neuromuscular Approach to neuromuscular

respiratory failurerespiratory failure Signs & SymptomsSigns & Symptoms InvestigationsInvestigations Knowing when (to ask someone else) to Knowing when (to ask someone else) to

intubateintubate Overview of:Overview of:

Myasthenic crisisMyasthenic crisis GBSGBS BotulismBotulism

True or false? Regarding GBS…True or false? Regarding GBS…

~10% of pts will require intubation.~10% of pts will require intubation. All cases of suspected GBS should be All cases of suspected GBS should be

treated with either IVIG or PLEX.treated with either IVIG or PLEX. Normal CSF protein precludes the diagnosis.Normal CSF protein precludes the diagnosis. Hypertension is the most common Hypertension is the most common

autonomic complication.autonomic complication.

Case 1Case 1 A 32-yo M with MG since age 20, on stable A 32-yo M with MG since age 20, on stable

dose of pred 40, Imuran, and Mestinon, is dose of pred 40, Imuran, and Mestinon, is admitted to hospital for elective bowel admitted to hospital for elective bowel surgery (complications of diverticulitis)surgery (complications of diverticulitis)

Pt. has persistent diplopia and mild Pt. has persistent diplopia and mild fatigable weakness at the deltoidsfatigable weakness at the deltoids

The surgery team calls you the morning of The surgery team calls you the morning of his scheduled surgery to ask if they should his scheduled surgery to ask if they should do anything for his myasthenia. do anything for his myasthenia.

Case 1Case 1 You should:You should: A) Suggest switching to equivalent dosage A) Suggest switching to equivalent dosage

of IV steroids while NPOof IV steroids while NPO B) Review med list & advise re: drugs that B) Review med list & advise re: drugs that

might trigger a crisis (ie. Antibiotics!!)might trigger a crisis (ie. Antibiotics!!) C) Kindly recommend postponing the C) Kindly recommend postponing the

surgery for pre-op IVIG or PLEX surgery for pre-op IVIG or PLEX D) All of the aboveD) All of the above

Case 2Case 2

A 10-month-old infant presents with A 10-month-old infant presents with constipation and poor feeding constipation and poor feeding followed by progressive hypotonia, followed by progressive hypotonia, descending weakness, dilated pupils, descending weakness, dilated pupils, and bilateral ptosis. and bilateral ptosis.

What is the likely diagnosis?What is the likely diagnosis? How was it likely acquired?How was it likely acquired? How would you treat him?How would you treat him?

Case 3Case 3

You are called to see a patient in ICU You are called to see a patient in ICU with known diagnosis of MG, recurrent with known diagnosis of MG, recurrent crises leading to ICU admissions, on crises leading to ICU admissions, on stable dose of pred 60 mg qd and stable dose of pred 60 mg qd and Imuran. Admitted with MG crisis, Imuran. Admitted with MG crisis, intubated then trach’ed. Now, 2 weeks intubated then trach’ed. Now, 2 weeks later, “doing better” as per ICU. They later, “doing better” as per ICU. They want to start tapering his prednisone. want to start tapering his prednisone. What do you advise them to do?What do you advise them to do?

Case 3Case 3

1) Agree with their plan to begin a 1) Agree with their plan to begin a slow tapering course by 10 mg qweek slow tapering course by 10 mg qweek initially.initially.

2) Discuss the patient with their 2) Discuss the patient with their treating neurologist.treating neurologist.

3) Advise them to avoid rapid tapering 3) Advise them to avoid rapid tapering of steroids given the risk of recurrent of steroids given the risk of recurrent crisis.crisis.

4) Both 2 & 3.4) Both 2 & 3.

Part 1: Part 1: Neuromuscular Respiratory Neuromuscular Respiratory

FailureFailure

Respiratory Failure BasicsRespiratory Failure Basics

Type I:Type I: Hypoxia without hypercapniaHypoxia without hypercapnia Usually associated with ↑ WOBUsually associated with ↑ WOB V/Q mismatch most commonV/Q mismatch most common

Vascular disease/shunts (PE, Vascular disease/shunts (PE, Pulm. HTN, R->L shunts)Pulm. HTN, R->L shunts)

Interstitial lung disease (ARDS, Interstitial lung disease (ARDS, cardiogenic pulmonary edema, cardiogenic pulmonary edema, pneumonia)pneumonia)

Pneumothorax, atelectasisPneumothorax, atelectasis

Type II:Type II: Hypercapnia with or w/o hypoxia Hypercapnia with or w/o hypoxia A.k.a. hypoventilationA.k.a. hypoventilation

Neuromuscular conditionsNeuromuscular conditions Deformities (kyphoscoliosis)Deformities (kyphoscoliosis) Reduced breathing effort (extreme Reduced breathing effort (extreme

obesity, drug effects, brainstem lesion obesity, drug effects, brainstem lesion affecting respiratory drive)affecting respiratory drive)

Increased airway resistance (asthma, Increased airway resistance (asthma, COPD)COPD)

Neuromuscular CausesNeuromuscular Causes Spinal cord lesionSpinal cord lesion

Cervical cord compression, transverse myelitisCervical cord compression, transverse myelitis Motor neuron lesionMotor neuron lesion

ALSALS Peripheral nerve lesionPeripheral nerve lesion

GBSGBS, CIDP, critical illness polyneuropathy, Lyme , CIDP, critical illness polyneuropathy, Lyme disease, tick paralysis, toxicdisease, tick paralysis, toxic

NMJ disorderNMJ disorder MG, MG, LEMS, LEMS, botulismbotulism, organophosphate poisoning, organophosphate poisoning

Muscle lesionMuscle lesion Polymyositis, dermatomyositis, critical illness Polymyositis, dermatomyositis, critical illness

myopathy, hyperthyroidism, congenital myopathy myopathy, hyperthyroidism, congenital myopathy (muscular dystrophy), mitochrondrial myopathy(muscular dystrophy), mitochrondrial myopathy

HistoryHistory Time course?Time course?

progressive weakness over hours to days progressive weakness over hours to days GBS GBS fluctuating weakness (on an hourly basis) present fluctuating weakness (on an hourly basis) present

for weeks/months for weeks/months MG MG Distribution of weakness?Distribution of weakness?

Proximal > distal (MG & GBS)Proximal > distal (MG & GBS) Ascending in GBSAscending in GBS

Sensory Sx.?Sensory Sx.? Distal paresthesias common in GBSDistal paresthesias common in GBS No sensory inv’t in MGNo sensory inv’t in MG

HistoryHistory +FH?+FH? Pain?Pain?

Low backache frequently in GBS; neck pain: C-Low backache frequently in GBS; neck pain: C-spine lesion?spine lesion?

Antecedent illness?Antecedent illness? 60% of GBS triggered by viral URT illness or 60% of GBS triggered by viral URT illness or

C.jejuniC.jejuni gastro gastro 40% of myasthenic crises triggered by 40% of myasthenic crises triggered by

infectioninfection MedicationsMedications Exposure to fertilizers & pesticides?Exposure to fertilizers & pesticides?

Organophosphate poisoningOrganophosphate poisoning Recent dietRecent diet

Botulism from home-canned goodsBotulism from home-canned goods

ExamExam Long, thin face? (myotonic dystrophy? Long, thin face? (myotonic dystrophy?

Congenital?)Congenital?) Skin rash (dermatomyositis?Skin rash (dermatomyositis? CNsCNs

Pupils: Pupils: Reactivity may be lost in botulism or Miller-Reactivity may be lost in botulism or Miller-

Fisher variant of GBSFisher variant of GBS EOM: EOM:

Opthalmoparesis or ptosis (MG? Opthalmoparesis or ptosis (MG? mitochondrial D/O? MFS?)mitochondrial D/O? MFS?)

Presence or absence of bulbar weakness?Presence or absence of bulbar weakness? Motor exam: Motor exam:

Fasciculations? (ALS, organophosphate Fasciculations? (ALS, organophosphate poisoning); tone; power (fatigable weakness? poisoning); tone; power (fatigable weakness? Distribution proximal vs. distal?)Distribution proximal vs. distal?)

ExamExam Sensory: Sensory:

Normal in MGNormal in MG Distal sensory loss in GBS, esp vib/propDistal sensory loss in GBS, esp vib/prop Sensory level at C-spine level w/ quadriparesis Sensory level at C-spine level w/ quadriparesis

= C-spine lesion= C-spine lesion Coordination:Coordination:

Ataxia in MF variant of GBSAtaxia in MF variant of GBS Reflexes:Reflexes:

AreflexiaAreflexia in GBS; preserved in MG in GBS; preserved in MG

MechanismsMechanisms1)1) Bulbar dysfunction: Bulbar dysfunction:

Facial, oropharyngeal, laryngeal weakness Facial, oropharyngeal, laryngeal weakness upper airway obstruction in supine upper airway obstruction in supine position position

Impaired swallowing Impaired swallowing aspiration aspiration2) 2) Inspiratory muscle Inspiratory muscle

weakness/diaphragmatic paralysisweakness/diaphragmatic paralysis atelectasis atelectasis V/Q mismatch V/Q mismatch hypoxia hypoxia

3) 3) Expiratory muscle weaknessExpiratory muscle weakness hypoventilation hypoventilation AND AND weak cough/poor weak cough/poor secretion clearance secretion clearance aspiration, pneumonia aspiration, pneumonia

4) 4) Acute complicationsAcute complications PE PE

SymptomsSymptoms If subacute (ie. GBS): dyspnoea and orthopnoeaIf subacute (ie. GBS): dyspnoea and orthopnoea

Easy to overlookEasy to overlook If gradual onset, inadequate respiration usually If gradual onset, inadequate respiration usually

occurs first during sleepoccurs first during sleep Symptoms of nocturnal hypoventilation: Symptoms of nocturnal hypoventilation:

a broken sleep pattern, nightmares, nocturnal a broken sleep pattern, nightmares, nocturnal confusion, morning headache, daytime fatigue, confusion, morning headache, daytime fatigue, mental clouding and somnolence. mental clouding and somnolence.

SOBOE less common in NMDs than in those SOBOE less common in NMDs than in those with other Cardioresp D/O (reduced mobility)with other Cardioresp D/O (reduced mobility)

Dyspnoea when lying flat or immersed in water Dyspnoea when lying flat or immersed in water suggests weakness of the diaphragmsuggests weakness of the diaphragm

Warning signsWarning signs Rapid, shallow breathingRapid, shallow breathing StridorStridor Bulbar weaknessBulbar weakness

weak cough, nasal voice, pooling of saliva weak cough, nasal voice, pooling of saliva Orthopnea Orthopnea Staccato speechStaccato speech Abdominal paradoxAbdominal paradox

http://http://www.youtube.com/watch?vwww.youtube.com/watch?v==RFGzdNFuXIMRFGzdNFuXIM

Weakness of neck & trapezius musclesWeakness of neck & trapezius muscles Single-breath countSingle-breath count

Mehta, S. “Neuromuscular disease causing acute respiratory failure.” Respiratory Care, 2006. 51 (9): 1016-1023.

InvestigationsInvestigations Bedside PFTs:Bedside PFTs: “20/30/40 rule”“20/30/40 rule”

Vital capacity (max exhaled volume after full Vital capacity (max exhaled volume after full inspiration). Normal = 60 ml/kg (4 L in 70 kg inspiration). Normal = 60 ml/kg (4 L in 70 kg person). person). VC < 20 ml/kg (or 1 L) means VC < 20 ml/kg (or 1 L) means intubationintubation

Max inspiratory pressure. Index of ability to avoid Max inspiratory pressure. Index of ability to avoid atelectasis. Normal = >atelectasis. Normal = > 80 cm H2O (male), >70 80 cm H2O (male), >70 cm H2O (female)cm H2O (female). . MIP >-30 means intubationMIP >-30 means intubation

Max expiratory pressure. Index of ability to Max expiratory pressure. Index of ability to cough/clear secretions. Mean MEP = 140 cm H2O cough/clear secretions. Mean MEP = 140 cm H2O (male), 95 cm H20 (female). (male), 95 cm H20 (female). MEP <40 means MEP <40 means intubationintubation

InvestigationsInvestigations ABG: ABG:

Hypercarbia (PCOHypercarbia (PCO2 2 > 45 mmHg)> 45 mmHg)

• PCOPCO2 2 often normal or low until late in often normal or low until late in NM resp failureNM resp failure

• Established resp failure from NMDs: low pO2, Established resp failure from NMDs: low pO2, normal pH, elevated bicarb & pCO2 normal pH, elevated bicarb & pCO2

• Elevations of bicarb & pH with normal pO2 & Elevations of bicarb & pH with normal pO2 & pCO2 suggest pCO2 suggest nocturnal hypoventilationnocturnal hypoventilation

Hypoxia (POHypoxia (PO2 2 < 75 mmHg) = usually < 75 mmHg) = usually atelectasis or pneumonia in acute settingatelectasis or pneumonia in acute setting

Basic labs (CBC, SMA-10, LFTs, CK)Basic labs (CBC, SMA-10, LFTs, CK) CXRCXR

Predictors of need for MVPredictors of need for MV

20/30/40 rule20/30/40 rule

or reduction in VC, MIP, MEP by >30%or reduction in VC, MIP, MEP by >30%

POPO22 <70 mmHg on RA or PCO <70 mmHg on RA or PCO22 >50 >50 mmHg w/ acidosismmHg w/ acidosis

Dysarthria, dysphagia, impaired gag Dysarthria, dysphagia, impaired gag reflexreflex

Intubation: things to think Intubation: things to think aboutabout

Code status?Code status? Call ICU if signs of imminent resp Call ICU if signs of imminent resp

failurefailure

Identify Identify earlyearly to avoid emergency to avoid emergency intubation…elective intubation always intubation…elective intubation always preferredpreferred Minimizes atelectasis/pneumoniaMinimizes atelectasis/pneumonia Minimizes complications of intubation specific to Minimizes complications of intubation specific to

NMDsNMDs Avoid depolarizing NM blockersAvoid depolarizing NM blockers

NPPV?NPPV?

Few studies on its use in GBS & MGFew studies on its use in GBS & MG Inappropriate if upper airway Inappropriate if upper airway

function severely impairedfunction severely impaired More often used in chronic NMDs More often used in chronic NMDs

(ALS, muscular dystrophies) for (ALS, muscular dystrophies) for chronic hypoventilationchronic hypoventilation

General careGeneral care Serial PFTs (MIP/MEP/FVC) Serial PFTs (MIP/MEP/FVC) bid to qidbid to qid Electrolytes: low potassium, high Electrolytes: low potassium, high

magnesium & low phosphate magnesium & low phosphate exacerbate exacerbate muscle weaknessmuscle weakness

Chest physio, suctioning & incentive Chest physio, suctioning & incentive spirometryspirometry

DVT prophylaxisDVT prophylaxis HOB elevationHOB elevation NPO if bulbar weakness; NG or Dobhoff NPO if bulbar weakness; NG or Dobhoff

feedingfeeding

Part 2:Part 2:

MGMGGBSGBS

BotulismBotulism

MGMG

Ab-mediated attack on nicotinic Ach rec Ab-mediated attack on nicotinic Ach rec defective transmission across NMJ defective transmission across NMJ

Bimodal: F 20-30 yo; M 50-60 yoBimodal: F 20-30 yo; M 50-60 yo 2 autoimmune forms2 autoimmune forms

Ach receptor Ab+: 80% with generalized MG Ach receptor Ab+: 80% with generalized MG & 50% with ocular MG& 50% with ocular MG

Anti-MuSK Ab+: 50% of patients who are Anti-MuSK Ab+: 50% of patients who are Ach rec Ab negative; typically female with Ach rec Ab negative; typically female with prominent bulbar weaknessprominent bulbar weakness

PresentationPresentation Motor:Motor:

Fluctuating, fatigable weaknessFluctuating, fatigable weakness involving involving eyes (90%), face/neck/oropharynx (80%), limbs eyes (90%), face/neck/oropharynx (80%), limbs (60%)(60%)

Limbs rarely affected in isolationLimbs rarely affected in isolation Rest restores strength (at least partially)Rest restores strength (at least partially)

Sensory: normalSensory: normal Reflexes: preservedReflexes: preserved Thymic abnormalities:Thymic abnormalities:

Malignant thymoma in 10-15% (more severe Malignant thymoma in 10-15% (more severe disease)disease)

Thymic hyperplasia in 50-70%Thymic hyperplasia in 50-70%

InvestigationsInvestigations

Ach receptor AbsAch receptor Abs Anti-MuSK AbsAnti-MuSK Abs Edrophonium (Tensilon) test: obsoleteEdrophonium (Tensilon) test: obsolete EMG:EMG:

Repetitive nerve stimulationRepetitive nerve stimulation: >10% : >10% decrement in amplitude betw 1decrement in amplitude betw 1stst & 5 & 5thth CMAP CMAP

Single-fiber: Single-fiber: “jitter” “jitter” Sens >95% for MG but not specificSens >95% for MG but not specific

Management: generalManagement: general Symptomatic therapy Symptomatic therapy (mild-moderate weakness)(mild-moderate weakness)::

Cholinesterase inhibitors (Cholinesterase inhibitors (MestinonMestinon)) Short-term disease suppression:Short-term disease suppression:

To hasten clinical improvement in hospitalized pts w/ To hasten clinical improvement in hospitalized pts w/ crisis or impending crisis; pre-operatively; chronic crisis or impending crisis; pre-operatively; chronic refractory diseaserefractory disease

PLEX PLEX oror IVIG IVIG Long-term immunosuppression:Long-term immunosuppression:

When weakness is inadequately controlled by MestinonWhen weakness is inadequately controlled by Mestinon PrednisonePrednisone AzathioprineAzathioprine (if steroid failure or excessive SE) (if steroid failure or excessive SE) Cyclosporine, Mycophenolate mofetil…Cyclosporine, Mycophenolate mofetil…

Myasthenic CrisisMyasthenic Crisis

Defined by resp failure requiring Defined by resp failure requiring ventilatory assistanceventilatory assistance

Occurs in 20-30%; mortality 5%Occurs in 20-30%; mortality 5% Common precipitants:Common precipitants:

Infection in 40% (esp respiratory)Infection in 40% (esp respiratory) MedicationsMedications SurgerySurgery PregnancyPregnancy AspirationAspiration

Drugs that exacerbate MGDrugs that exacerbate MG

AntibioticsAntibiotics: (**Penicillins : (**Penicillins like Tazocin are OK!)like Tazocin are OK!) Aminoglycosides (genta, Aminoglycosides (genta,

tobra)tobra) Fluroquinolones (cipro)Fluroquinolones (cipro) Macrolides Macrolides

(erythromycin, azithro, (erythromycin, azithro, tetracycline, tetracycline, doxycycline)doxycycline)

Cardiac:Cardiac: All beta-blockersAll beta-blockers Calcium channel Calcium channel

blockersblockers Anticonvulsants:Anticonvulsants:

Phenytoin, CBZPhenytoin, CBZ

Antipsychotics, lithiumAntipsychotics, lithium Thyroid hormonesThyroid hormones Magnesium toxicityMagnesium toxicity Iodinated contrast Iodinated contrast

agentsagents Muscle relaxants Muscle relaxants

BaclofenBaclofen Long-acting benzosLong-acting benzos

**Too much **Too much anticholinesteraseanticholinesterase

Myasthenic crisis: Myasthenic crisis: managementmanagement

GeneralGeneral Determine if resp failure is imminent!!Determine if resp failure is imminent!! Stop any meds that may be contributingStop any meds that may be contributing

Mestinon usually stopped as wellMestinon usually stopped as well May contribute to increased airway secretions in May contribute to increased airway secretions in

intubated patientsintubated patients Treat any infectionTreat any infection

Myasthenic Crisis: Myasthenic Crisis: managementmanagement

SpecificSpecific PLEX or IVIG: PLEX or IVIG:

start one or the other, quicklystart one or the other, quickly Comparable efficacyComparable efficacy

Evidence somewhat limited…TBD laterEvidence somewhat limited…TBD later Earlier response seen with PLEX, but more Earlier response seen with PLEX, but more

adverse eventsadverse events Preference somewhat individualized…Preference somewhat individualized…

Myasthenic crisis: Myasthenic crisis: managementmanagement

PLEXPLEX Removal of anti AChR and antiMuSK AbsRemoval of anti AChR and antiMuSK Abs 1 session/day x 51 session/day x 5

No superiority of PLEX qd x 5 vs qod x 5No superiority of PLEX qd x 5 vs qod x 5 Rapid onset of action (3-10 days)Rapid onset of action (3-10 days) Need central line with associated complicationsNeed central line with associated complications

PTX, hemorrhage, line sepsisPTX, hemorrhage, line sepsis Caution in pts with sepsis, hypotension; may Caution in pts with sepsis, hypotension; may

lead to increased bleeding and cardiac lead to increased bleeding and cardiac arrhythmiasarrhythmias

Myasthenic crisis: Myasthenic crisis: managementmanagement

IVIGIVIG 0.4g/kg/day x 5 days0.4g/kg/day x 5 days Easily administered and widely availableEasily administered and widely available Long duration of action Long duration of action

May last as long as 30 daysMay last as long as 30 days Side effectsSide effects

Anaphylaxis in IgA deficiencyAnaphylaxis in IgA deficiency Renal failure, pulmonary edemaRenal failure, pulmonary edema Aseptic meningitisAseptic meningitis Thrombotic complications and strokeThrombotic complications and stroke

Myasthenic crisis: Myasthenic crisis: management management

Therapeutic effect of PLEX & IVIG is short-Therapeutic effect of PLEX & IVIG is short-lived…lasts weekslived…lasts weeks

Therefore, glucocorticoids started at high Therefore, glucocorticoids started at high dose (60 to 80 mg qd) as welldose (60 to 80 mg qd) as well

Onset of benefit at 2-3 wks, peaks at 5.5 mosOnset of benefit at 2-3 wks, peaks at 5.5 mos Initiation ass’d with transient worsening of Initiation ass’d with transient worsening of

weakness, serious in up to 50%weakness, serious in up to 50% Occurs 5-10 days after initiation & lasts 5-6 daysOccurs 5-10 days after initiation & lasts 5-6 days Resp failure requiring MV in up to 10%Resp failure requiring MV in up to 10% Concomitant use of PLEX or IVIG helps to prevent Concomitant use of PLEX or IVIG helps to prevent

this transient worseningthis transient worsening

GBSGBS Most common cause of acute or subacute Most common cause of acute or subacute

gen’d paralysisgen’d paralysis Monophasic AIDP: autoimmune attack against Monophasic AIDP: autoimmune attack against

surface antigens on peripheral nervessurface antigens on peripheral nerves Develops 5 days to 3 weeks after resp/GI Develops 5 days to 3 weeks after resp/GI

infection in 60%infection in 60% Campylobacter jejuniCampylobacter jejuni (26%) (26%) Viral URTI, influenzaViral URTI, influenza EBV, CMV, VZV, HIV, hep A & B, coxsackieEBV, CMV, VZV, HIV, hep A & B, coxsackie

Other precipitants: immunization, pregnancy, Other precipitants: immunization, pregnancy, surgery, Hodgkin’s diseasesurgery, Hodgkin’s disease

PresentationPresentation Sensory: Sensory:

distal paresthesias/numbness (earliest Sx.)distal paresthesias/numbness (earliest Sx.) Reduced vibration/proprioceptionReduced vibration/proprioception

Motor:Motor: SymmetricSymmetric; evolves over days to 1-2 wks; evolves over days to 1-2 wks AscendingAscending: LE before UE; : LE before UE; proximalproximal> distal> distal

Reflexes: reduced, then absentReflexes: reduced, then absent Autonomic instabilityAutonomic instability

Other: low backache very common, myalgiasOther: low backache very common, myalgias

InvestigationsInvestigations NCS/EMG:NCS/EMG:

Reduced conduction velocitiesReduced conduction velocities Loss of F wavesLoss of F waves Conduction block in motor nervesConduction block in motor nerves Reduced motor amplitudes: 2° axonal damage Reduced motor amplitudes: 2° axonal damage worse worse

Px.Px.

CSF: CSF: High protein (may be normal in first 2 days)High protein (may be normal in first 2 days) No cells or few lymphsNo cells or few lymphs

10% have 10-50 lymphs10% have 10-50 lymphs

ManagementManagement

Admit for observation (potential for Admit for observation (potential for deterioration)deterioration)

Determine if resp failure imminentDetermine if resp failure imminent

IVIG IVIG (0.4g/kg/d x 5 d) or (0.4g/kg/d x 5 d) or PLEX PLEX (4-6 Rx. q1-(4-6 Rx. q1-2d)2d) Equally effective (2012 AAN guideline)Equally effective (2012 AAN guideline) PLEX useful in first 2 weeks; benefit less PLEX useful in first 2 weeks; benefit less

clear after that…also more adverse effectsclear after that…also more adverse effects Steroids no proven benefitSteroids no proven benefit

Predictors of need for MV in Predictors of need for MV in GBSGBS

Time from onset to admission < Time from onset to admission < 7 days7 days

Inability to coughInability to cough Inability to standInability to stand Inability to lift elbows or headInability to lift elbows or head LFT increasesLFT increases Presence of autonomic dysfxnPresence of autonomic dysfxn

Sharshar T, Chevret S, Bourdain F, Raphael JC. Early predictors of mechanical ventilation in Guillain-Barre´ syndrome. Crit Care Med 2003;31(1):278–283.

CourseCourse Progression over 1-4 weeksProgression over 1-4 weeks Recovery: few wks to monthsRecovery: few wks to months Mortality 3-5%Mortality 3-5% Poor prognosis:Poor prognosis:

Resp failure requiring intubation Resp failure requiring intubation Advanced ageAdvanced age Very low distal motor amplitudes (axonal Very low distal motor amplitudes (axonal

damage)damage) Rapidly progressive weakness over 1 weekRapidly progressive weakness over 1 week

BotulismBotulism Toxin is a presynaptic blocker of Ach release

Onset of Sx. 12-36 hours after ingestion Prodrome: N/V, abdo pain, diarrhea, dry mouth Symmetric neurologic deficits

First develop acute cranial neuropathies (opthalmoplegia, can be total; B/L ptosis, dysphagia, dysarthria, facial weakness)

Blurred vision secondary to pupillary dilatation Descending muscle weakness No sensory deficits apart from blurred vision

Urinary retention/constipation (smooth muscle paralysis) Respiratory failureRespiratory failure is primary cause of death is primary cause of death

““Dozen Ds” of BotulismDozen Ds” of Botulism

dry mouthdry mouth diplopiadiplopia dilated pupilsdilated pupils droopy eyesdroopy eyes droopy facedroopy face diminished gag diminished gag

reflexreflex

dysphagiadysphagia dysarthriadysarthria dysphoniadysphonia difficulty lifting difficulty lifting

head head descending descending

paralysisparalysis diaphragmatic diaphragmatic

paralysisparalysis

Botulism Botulism Investigation: Investigation:

Foodborne: serum analysis for toxin by bioassay in mice

Analysis of stool, vomitus, and suspected food items may also reveal toxin

Infantile: isolation of C.botulinum spores & toxin detection in stool

EMGEMG Treatment: Treatment:

Equine serum heptavalent botulism antitoxin Children older than 1 year of age and adults

Human derived botulism immune globulin (BIG-IV or BabyBIG)

Infants less than 1 year of age

Key pointsKey points

20/30/40 rule20/30/40 rule Identify pts at risk for resp failure Identify pts at risk for resp failure

EARLY to avoid emergency intubationEARLY to avoid emergency intubation Don’t wait for pts to complain of Don’t wait for pts to complain of

dyspnea before doing bedside PFTsdyspnea before doing bedside PFTs