History of Weakness

  • Before asking the patient anything, think about...
    • duration in hospital
    • preexisting neurologic conditions? (eClinician and netCARE event history are your friends)
    • patient location – general ward, or ICU?
    • any recent procedures or surgeries?
    • what medications, any recent changes?
  • Three most important items on history:
    • time of onset
    • subsequent evolution or fluctuation
    • association with sensory or cranial nerve symptoms (e.g. anything else neurological going on?)
  • Weakness impairs function. Ask about activities of daily living (ADLs):
    • Face: vision (diplopia, ptosis), drinking fluids and eating (dysphagia), speech (dysarthria or dysphonia)
    • Arms: proximal (lift arms overhead), distal (grip power)
    • Legs: rising out of a chair, standing, walking, falls
    • Use of assistive devices
    • Respiratory Function
    • The distribution of weakness is useful for diagnosis, and also to determine rehab needs and disposition
      • patients with a new inability to walk must be admitted to hospital!
    • (see table)

Physical Examination

  • Use the physical examination to differentiate non-neurologic from neurologic weakness
  • Focused neuromuscular examination:
    • Cranial nerves
      • extraocular movements (video)
      • eyelid position (presence of ptosis - example 1 - example 2)
      • facial muscle power (video)
      • palate elevation and tongue protrusion
    • Motor system
      • Muscle bulk (atrophy) - good places to look are temporalis, deltoid, hand intrinsics (FDI), quadriceps, foot intrinsic muscles (EDB)
      • Fasciculations - don't worry if you can't see them! (Put patient supine, eyes closed; FDI, back, calves are good places to look).
      • Tone - at elbow, wrist, knees, ankles. (video)
      • Power (video)
        • Neck
        • Upper extremity
        • Lower extremity
        • focus on patterns of weakness rather than exhaustive examination of muscles
        • MRC grading
    • Deep tendon reflexes (video)
      • Grading reflexes
        GradeDescription
        4+Very hyperactive; beats of clonus after initial movement
        3+Hyperactive of "brisk"; spread to neighbouring myotomes
        2+Normal (but wide variation between individuals)
        1+Hypoactive; cannot produce without reinforcement (e.g. Jendrassik)
        0Absent
    • Sensory examination (can be skipped if there is no complaint)
      • pinprick (face/hand/foot)
      • vibration (distal UE&LE)
    • Functional assessment
      • transfer
      • stance and gait
      • heel and toe walk
      • rise from squat
      • comment on use of assistive devices
  • The examination findings are essential for localization...

Localization of weakness

  • What is the pattern of weakness?
    • Facial (ocular, bulbar, or both)
    • Proximal limbs
    • Distal limbs
    • Focal (peripheral nerve or nerve root)
    • Generalized
    • terms such as quadriplegia, hemiplegia, monoplegia and paraplegia are often assumed to imply an UMN lesion
    • (see table)
  • Upper motor neuron (UMN) or lower motor neuron (LMN)?
    • Recall the corticospinal tract... (figure)
      CharacteristicUMNLMN
      ToneUpDown
      ReflexesUpDown
      PlantarsUp (extensor)Down (flexor)
      BulkNormalDown (decreased)
      FasciculationsAbsentPresent
  • What company does it keep? (e.g. other neurologic signs or symptoms)
    • Sensory signs/symptoms: think neuropathy, radiculopathy or myelopathy
    • Bowel/bladder dysfunction: think myelopathy or polyradiculopathy (e.g. Cauda Equina Syndrome)
    • Cranial nerve signs/symptoms ("3Ds and a P" - diplopia, dysarthria, dysphagia, ptosis)
      • in isolation: think neuromuscular junction
      • with other abnormalities (altered consciousness, long tract findings): think brainstem
    • Altered mental status: think brain
  • In summary:
    CharacteristicBrainStemS.C.RootPlexusNerveNMJMusc
    LevelUMNLMN
    Tone↑*↑*↑*↓↓↓N↓
    Reflexes↑*↑*↑*↓↓↓N~↓
    Plantars↑↑↑↓↓↓↓↓
    BulkN/~↓N/~↓N/~↓↓↓↓N↓
    Fasciculations---+++--
    Sensory change++++++--
    Cranial n. abN++---+++
    Sphincter dysf.--+-†----
    Altered LOC++------
    ~ = relative or mild
    * = depressed (flaccid) in acute phase
    † = spinchter dysfunction is present in cauda equina syndrome
  • If the patient has generalized weakness without anything else...
    • e.g. "Weakness with intact reflexes"
    • then it is most likely due to systemic illness, or a primary muscle disorder
    • ...and this will be the subject of the rest of the presentation

Conditions that cause Generalized Weakness

  • Asthenia, Fatigue, and Weakness of non-Neurologic Origin
  • Medical Conditions that Cause Fatigue and Weakness
  • Generalized Weakness of CNS origin
    • covered under "Localization..."
  • Generalized Weakness Due to Drugs or Toxins
  • Weakness in Patients with Renal Failure and Patients on Dialysis
    • covered under "Medical Conditions..."
  • Generalized Weakness with AIDS
    • beyond the scope of this presentation
  • Generalized Weakness in Cancer
    • beyond the scope of this presentation

Asthenia, Fatigue, and Weakness of non-Neurologic Origin

  • Are there any patients on the ward who do not complain of fatigue or weakness?
  • Differentiate exhaustion/asthenia/poor endurance from true loss of muscle power
    • on exam, the asthenic patient generates normal peak power, but fatigues rapidly ("on the count of 3... give me everything you've got!")
    • the patient with neuromuscular weakness can may produce a sustained maximal effort... but it is weak
  • Pain does not produce weakness, but it causes limitation of movement that can be misinterpreted as such.
    • do an MSK exam (i.e. passive ROM)
    • ...it sounds obvious until you see how many men with shoulder arthropathy are referred for EMG studies for ?C5 radiculopathy!
  • Psychiatric illness
    • Patients with depression and other illnesses may interpret their fatigue and lack of motivation as global weakness
    • They may present with functional weakness (preferred term instead of "psychogenic weakness")
    • There is often a mental, affective, or "psychic" component accompanying the weakness
    • Don't let a strong psychiatric history pre-empt investigation of neurologic symptoms
    • It is entirely reasonable to consult Neurology if you are unsure!

Medical Conditions that Cause Fatigue and Weakness

  • Medical illness of many organ systems can produce fatigue and weakness
    • Cardiovascular: congestive heart failure
    • Hematologic: anemia, leukemia, lymphoma
    • Renal: uremia, electrolyte abnormalities
    • Pulmonary: COPD
    • Endocrine (may cause true neuromuscular weakness as well): hypothyroidism, hyperthyroidism, hyperparathyroidism, hypogonadism, Addison disease, aldosterone deficiency, Cushing disease, hypercalcemia...
    • ...and many, many more
  • Routine laboratory evaluation for fatigue:
    • Erythrocyte sedimentation rate (ESR)
    • Complete blood cell count (CBC)
    • "Complete metabolic panel" (electrolytes including Ca2+, Mg2+, PO43-, glucose, creatinine, urea)
    • Liver function tests and liver enzymes
    • Thyroid function tests
    • Creatine kinase (CK) level (ddx of elev CK)
    • Chest x-ray

Generalized Weakness Due to Drugs or Toxins

  • Muscle is very sensitive to drugs and toxins because of its high metabolic activity
    • a daunting list of medications may produce muscle toxicity
    • they can interfere with muscle metabolism at many different sites
    • it is not useful to remember all of the drugs that can cause myopathy
    • but there are a few common offenders:
      • steroids
      • alcohol
      • statins
      • colchicine
      • (critical illness myopathy is considered a toxic myopathy, but more on this later)
  • Symptoms range from cramps and myalgias to rhabdomyolysis with severe muscle weakness and renal failure
  • Patients less able to clear drugs are at greater risk
    • Elderly, infants, ICU patients, liver and renal failure

Statin Myopathy

  • Statins cause a toxic necrotizing myopathy
    • the toxin kills muscle fibres
  • Symptoms of toxic necrotizing myopathy:
    • myalgias
    • weakness
    • hyper CK-emia
    • myoglobinuria
  • The mechanism of toxicity is unknown
  • Muscle toxicity is rare with statin use (but many patients take statins)
    • myalgias in 2% to 7% of statin users
    • elevated transaminases (assumed to come from muscle breakdown) in 0.5% to 2%
    • weakness and hyper CK-emia in 0.1% to 1%
    • severe myopathies in 0.08%
    • fatal rhabdomyolysis - 0.15 deaths per million prescriptions
  • There is a newly-described immune myopathy associated with statin use
    • Immune-mediated necrotizing myopathy (INEM)
    • Statin somehow triggers an immune-mediated myopathy
    • It appears to be rare
    • Patients develop proximal muscle weakness and hyper CK-emia that persists after statin discontinuation
    • ?immune therapies

Steroid Myopathy

  • Caused by endogenous (Cushing's) or exogenous chronic excess corticosteroid
    • risk increased with doses of prednisone >30 mg/day
    • risk seems greater with fluorinated glucocorticoids (triamcinolone > betamethasone > dexamethasone)
  • Unknown mechanism of toxicity
  • Causes proximal limb weakness and atrophy (spares cranial muscles)
  • Sometimes called a "bland myopathy":
    • CK level is usually normal
    • EMG studies tend to be normal
    • Muscle biopsy tends to be normal or have only mild non-specific abnormalities (e.g. type IIb fibre atrophy)
  • Steroid myopathy vs. relapse of inflammatory myopathy...
    • clinical presentation is similar (proximal myopathy)
    • try increasing the steroid dose, and see if weakness worsens or improves (probably safe than reducing the dose!)
    • elevated inflammatory markers and hyper CK-emia may be absent in chronic inflammatory myopathy with if muscle atrophy
    • EMG studies may be helpful as they can show evidence of active myopathy (but same limitations as above)
    • Muscle biopsy may be needed in some cases (but same limitations as above)

Alcoholic Myopathy

  • Alcohol more often causes neuropathy than myopathy
  • It causes several distinct muscle disorders:
    • acute necrotizing myopathy
      • acute muscle pain, muscle tenderness, cramping, swelling, weakness
      • markedly elevated CK, may develop myoglobinuria and acute renal failure
      • occurs in patients with history of excessive alcohol, plus a recent intense binge
    • acute hypokalemic myopathy
      • acute generalized weakness, similar to other forms of hypokalemic myopathy
      • no muscle cramping, pain, swelling, or tenderness
      • very hypokalemic (1.4-21 mEq/L)
      • resolves with treatment of hypokalemia
    • chronic alcoholic myopathy
      • insidious onset of proximal limb weakness in the setting of chronic alcohol abuse
      • it might not be a true myopathy; the weakness might be due malnutrition and/or perpiheral neuropathy
    • asymptomatic alcoholic myopathy
      • assumed to the cause of incidentally discovered elevated CK in alcoholics
      • may represent a subclinical myopathy
    • alcoholic cardiomyopathy
  • Pathologic mechanisms are unknown
  • What you need to know:
    • alcohol can cause acute or chronic myopathy
    • the CK may be elevated, or normal
    • there is often a co-existing neuropathy
    • alcoholics have many other reasons to be weak (nutritional, metabolic, etc)

Colchicine Neuromyopathy

  • Colchicine inhibits polymerization of tubulin into microtubular structures
  • It is toxic to nerves and muscle (neuromyopathy)
  • Neuromyopathy can develop with acute intoxication, or long-term use at normal doses
    • patients with chronic renal failure are at higher risk of toxicity
  • Symptoms improve with discontinuation of colchicine
    • but may take 4 to 6 months to recover

Inflammatory Myopathies

  • Many myopathies have an inflammatory component, secondary to...
    • toxic (e.g. immune-mediated necrotizing myopathy)
    • metabolic abnormalities
    • other connective tissue diseases (scleroderma, Sjögren syndrome, RA, SLE, mixed CTD)
    • ...PMR is not a myopathy (it is a vasculitis), but it produces muscle pain and weakness
  • Three "primary" inflammatory myopathies
    • Dermatomyositis
    • Polymyositis
    • Inclusion Body Myositis
  • They are pathologically distinct
    • DM is not "PM with a rash"
    • IBM is not "PM with inclusion bodies and rimmed vacuoles"
    • They differ in their response to treatment and prognosis

Polymyositis

  • PM probably isn't a single disease entity
  • PM is better defined by what it isn't, than what it is
    • Old diagnostic criteria (Bohan and Peter, 1975) didn't require muscle biopsy, and predated many immunohistochemical techniques
    • Even with muscle pathology, various disorders may be mis-labelled as PM
    • (please don't memorize this)
  • Clinical presentation:
    • Symmetric weakness, proximal > distal
    • Tender, aching muscles may be present, but usually pain isn't severe
      • "the more severe the pain, the less likely the diagnosis of polymyositis" -- Bradley's NICP
    • Cranial muscles are usually spared
      • ocular muscles are not involved
      • bulbar muscles may be involved in severe cases (dysphagia, dysarthria)
    • Tendon reflexes diminished in proportion to muscle weakness
      • which means that even patients with severe weakness should have DTRs
      • areflexia is more suggestive of neuropathy
  • Associated features:
    • all of these occur in DM, too
    • Cardiomyopathy
      • often asymptomatic
      • ECG abnormalities - conduction defects, arrythmias
      • pericarditis
      • myocarditis
      • CHF
    • Interstitial Lung Disease
      • associted with the presence of anti-Jo-1 antibodies
    • Polyarthritis
    • Malignancy
      • PM and DM both may develop as a paraneoplastic syndrome
      • association with malingnancy may be stronger in DM

Dermatomyositis

  • More than just "PM with a rash"
  • Clinical presentation:
    • Symmetric weakness, proximal > distal
    • Unlike PM, DM occurs in children
    • Unique skin manifestations in DM
      • (see gallery)
        • Heliotrope (violet-colored) rash and periorbital edema
        • Gottron's papules
        • Photosensitivity rash (shawl sign, V sign, etc)
        • Dilate nail bed capillary loops
        • Cutaneous calcinosis (more common in children)
      • skin manifestations usually accompany, or precede the onset of weakness
      • except when they lag behind the onset of weakness by months, or don't occur at all!
      • DM can still be diagnosed in the absence of rash, because of distinct findings on muscle biopsy
  • Associated features:
    • do these look familiar?
    • Cardiomyopathy
      • often asymptomatic
      • ECG abnormalities - conduction defects, arrythmias
      • pericarditis
      • myocarditis
      • CHF
    • Interstitial Lung Disease
      • associted with the presence of anti-Jo-1 antibodies
    • Polyarthritis
    • Malignancy
      • PM and DM both may develop as a paraneoplastic syndrome
      • association with malingnancy may be stronger in DM
      • it is probably worthwhile to do a malignancy work-up on all adults with PM/DM:
        • CT chest/abdo/pelvis
        • Mammograms, breast and pelvic exams in women
        • Colonoscopy for patients greater than 50 years (or with GI symptoms)

Inclusion Body Myositis

  • Pathology is uncertain, but seems to be an inflammatory myopathy
  • More common in men than women, tends to occur after 50 years
  • Unique clinical features:
    • distal > proximal asymmetric weakness (very unusual for a myopathy)
      • forearm and finger flexors, quadriceps, and tibialis anterior muscles, with profound atrophy
    • may have mild facial weakness
    • dyspaghia occurs in many patients, and may be the presenting feature
    • many have a sensory neuropathy (that is probably due to IBM, not something else)
  • Patients progress slowly over months/years
    • Most patients remain ambulatory
    • May become wheelchair or bed-bound
  • Doesn't respond to typical immunomodulatory therapy
    • some cases of "refractory" PM turn out to be IBM
  • Associated features
    • Not associated with cardiomyopathy, ILD, or malignancy
    • Autoimmune disorders coexist in up to 15% of IBM patients
      • SLE
      • Sjören syndrome
      • Scleroderma
      • Thrombocytopenia
      • Sarcoidosis

Guillain-Barré Syndrome

  • aka Acute Inflammatory Demyelinating Polyneuropathy (AIDP)
    • AIDP is the most common sub-type of GBS
    • there are other less common types of GBS (Miller-Fisher syndrome, AMAN, AMSAN, acute pandysautonomia...) that you don't need to know about
    • "Polyneuropathy" is a misnomer - more accurate term is "polycranioradiculoneuropathy"
      • ...if it's just a polyneuropathy, why is the CSF abnormal?
      • because the inflammation affects spinal nerve roots, causing raised CSF protein
      • even so, it's OK to call it a polyneuropathy
  • Clinical features:
    • Limb weakness (distal > proximal) - "ascending weakness" presentation
    • Cranial muscle weakness - facial, ocular, oropharyngeal
    • Respiratory muscle weakness
    • Sensory loss, paresthesias, pain (length-dependent)
    • Loss of deep tendon reflexes
    • Symptoms reach their nadir within 4 weeks of onset (otherwise, it's called CIDP)
  • Treatment and prognosis:
    • Patients reach their nadir, then gradually improve
    • Majority of treatment is supportive (ventilation, feeding, physiotherapy, DVT prophylaxis)
    • Intravenous immunoglobulin and plasmapheresis reduce the duration of disability
    • Many patients make complete (or near-complete) recovery, a minority have significant permanent disability

Myasthenia Gravis

  • Clinical hallmark is fatiguable muscle power
  • Typical muscles involved:
    • extra-ocular muscles, levator palpebrae superioris (ocular MG)
    • facial and oropharyngeal muscles (bulbar MG)
    • "3Ds and a P" - Diplopia, Dysarthria, Dysphagia, and Ptosis
    • limb muscle, respiratory muscle weakness (generalized MG)
  • The remainder of neurologic exam in normal...
    • Pupils are normal (it's not botulism)
    • Reflexes are normal (it's not GBS or myelopathy)
    • Sensation is normal (it's not GBS or myelopathy)
  • MG may be "unmasked" by other illness/drugs, and may trigger a myasthenic crisis
    • infection
    • electrolyte abnormalities
    • critical illness (ICU)
    • drugs (NM blockade, Botox, quinolones, etc...)
  • Diagnosis
    • nicotinic acetylcholine receptor antibody assay (a number of patients are seronegative)
    • EMG and NCS (mostly to exclude other disorders)
      • repetitive nerve stimulation (RNS) and single-fibre EMG (SFEMG) are specialized tests to look for neuromuscular junction disorders
    • it is very difficult to exclude a diagnosis of MG

Syndromic Approaches to Weakness

  • Localization - "spatial approach"
    • see Localization...
  • Time course - "temporal approach"
    • Rapidly progressive weakness
    • Flucuating weakness
    • Subacute/chronic weakness
  • Combine the two approaches to generate a differential diagnosis

Rapidly Progressive Weakness

  • What conditions produce rapidly progressive generalized weakness?
    • Polio (if you live in Afghanistan)
    • Guillain-Barré Syndrome
    • Guillain-Barré Syndrome
    • Guillain-Barré Syndrome
    • Really rare things...
      • Acute flaccid paralysis due to West Nile Virus
      • Botulism (no sensory involvement, early bulbar, pupils involved)
      • Tick paralysis (not the same thing as Lyme disease)
      • Acute intermittent porphyria
      • Ciguatera intoxication (neurotoxic marine food poisoning)
        • only let certified chefs prepared your Fugu!
  • Important "mimics"...
    • Acute (non-traumatic) myelopathy
      • Tough to diagnose in the acute phase
        • Muscle tone is flaccid
        • Reflexes are decreased/absent
        • May be mis-diagnosed as GBS
      • Certain features are present even early on:
        • Sensory level
        • Bowel or bladder dysfunction
        • Extensor plantar responses (Babinski signs)
      • Causes of acute myelopathy:
        • Inflammatory, e.g. transverse myelitis (idiopathic, post-infectious, MS, NMO)
        • Spinal cord infarction (aortic dissection, thoracoabdominal aortic surgery, cardiac arrest)
        • Mass lesion (epidural hematoma, epidural abscess, tumors...)
      • If you suspect acute myelopathy, call neurology immediately
    • Vasculitic neuropathy
      • Polyarteritis nodosa and Churg-strauss are the most likely culprits (but many others possible...)
      • The clinical hallmark is multiple focal neuropathies (mononeuritis multiplex)
      • Large, confluent multiple neuropathies may mimic diffuse or length-dependent neuropathy
      • Vasculitic neuropathies are often painful, and are accompanied by sensory loss

Fluctuating Weakness

  • Myasthenia Gravis
  • Myasthenia Gravis
  • Myasthenia Gravis
  • Periodic Paralysis
    • Hypokalemic periodic paralysis (hypoKPP)
      • A familial (genetic) channelopathy
      • Attacks begin in adolescene
        • flaccid limb weakness with absent or reduced DTRs
        • respiratory muscles spared or only midly weak
        • cranial muscles spared
        • duration is hours to days
      • Triggers
        • attacks often occur in the morning after exposure to trigger the night before
        • high salt load
        • carbohydrate load
        • during rest after strenous exercise
        • cold exposure
      • Patients may develop myopathic weakness that persists between attacks
      • Thyrotoxic hypokalemic periodic paralysis
        • A sporadic (non-genetic) disorder
          • but more common in patients of Japanese (or other Asian) origin
        • Attacks look the same as familial hypokalemic periodic paralysis
        • Associated with hyperthyroidism
        • It's important to screen thyroid function in all patients with hypoKPP
    • Hyperkalemic periodic paralysis (hyperKPP)
      • Attacks of weakness precipitated by hyperkalemia, beginning in childhood
      • During an attack:
        • mild to moderate flaccid limb weakness
        • diaphragm and cranial muscles spared
        • K+ may be normal during an attack (or even low)
        • lasts for minutes to hours
      • Triggers
        • rest after vigorous exercise
        • potassium-rich foods
        • stress
        • fatigue
      • Myotonia is present between attacks (unlike hypoKPP)
      • Patients may develop myopathic weakness that persists between attacks
    • overview of the periodic paralyses

Subacute Generalized Weakness

  • Toxic myopathy
  • Inflammatory myopathy
  • Medical conditions that cause systemic weakness
  • Lambert-Eaton myasthenic syndrome
    • a rare paraneoplastic syndrome affecting the neuromuscular junction
    • auto-antibodies against the pre-synaptic voltage-gated calcium channel (VGCC)
    • clinical features are unusual for an NMJ disorder:
      • slowly progressive proximal limb weakness
      • variable fatiguability
      • decreased DTRs
      • autonomic neuropathy (dry mouth, impotence)

Generalized Weakness in ICU patients

  • Evaluation is limited examination due to patient condition
  • Neurologic examination of critically ill patients:
    • Observation: muscle wasting, swelling, tenderness, fasciculations, myokymia, myotonia, skin lesions
    • Deep tendon reflexes are useful
    • Examination of tone and plantars not reliable with sedation
    • Unable to examine muscle power reliably
      • infer weakness from function, e.g. failure to wean from ventilator
    • Sensory exam is limited
  • May need greater reliance on electrodiagnostics (NCS and EMG)
  • Disorders that may arise after ICU admission:
    • GBS
    • spinal cord infarction (after aortic surgery)
    • myopathies (toxic, metabolic, critical illness)
    • neuropathies (toxic, metabolic, critical illness, compression)
  • Disorders that are "unmasked" or precipitated by ICU stay:
    • MG
    • porphyria
    • myopathies (toxic, metabolic, critical illness)
    • rhabdomyolysis
  • (ddx of ICU weakness)

Prolonged Neuromuscular Blockade

  • Causes weakness persisting after discontinuation of NM blockers
    • commonly-used NM blockers bind the α subunit of muscle nicotinic acetylcholine receptor and block NM transmission
    • associated with long duration NM blocker use (≥2 days)
    • caused by impaired clearance of NM blocker or its active metabolites (renal, hepatic failure, drug interactions, etc)
  • Clinical presentation
    • flaccid generalized weakness
    • cranial muscles involved - ptosis, ophthalmoplegia, facial and jaw weakness
    • DTRs decreased or absent
    • Sensation normal
    • Weakness usually resolves within several days of discontinuation of NM blocker

Critical Illness Myopathy (CIM)

  • aka acute quadriplegic myopathy
  • associated with:
    • high-dose corticosteroids
    • prolonged neuromuscular blockade
    • sepsis
    • multiorgan failure
    • ...muscle is just another end-organ
    • frequently accompanied by critical illness polyneuropathy (CIP)
  • Clinical presentation
    • failure to wean from ventilator
    • muscle wasting
    • flaccid generalized weakness
    • may have cranial muscles weakness
    • DTRs normal (unless CIP)
    • Sensation normal (unless CIP)
    • elevated CK
  • Treatment
    • No specific treatment exists
    • Avoid steroids and NM blockade if possible
    • Supportive care with early mobilization and rehabilitation may improve functional outcome

Critical Illness Polyneuropathy (CIP)

  • Generalized acute axonal sensorimotor neuropathy
  • associated with:
    • sepsis
    • systemic inflammation
    • multiorgan failure
    • parenteral nutrition
    • hyperosmolar state
    • ...nerves are just another end-organ
    • frequently accompanied by critical illness myopathy (CIM)
  • Clinical presentation
    • flaccid generalized weakness
    • cranial nerves involvement is rare
    • DTRs reduced
    • sensation impaired (but often difficult to determine)
  • Treatment
    • No specific treatment exists
    • Strict glucose control may reduce risk of CIP and its duration
    • Supportive care with early mobilization and rehabilitation may improve functional outcome
    • A few reports of IVIg being helpful, but it is unproven

Cases

  • Case One
    • 53 year old cattle rancher transferred from local hospital
    • Three month history of progressive back pain leg weakness
    • Constitutional symptoms
      • Drenching night sweats
      • Intermittent fevers
      • 40lb weight loss
    • Examination
      • EOMs full, normal facial muscle power
      • Normal tone in UE, Increased tone in LE
      • Power 5/5 in UE, Prox LE 3/5, Distal LE 2/5
      • DTRs 2+ in UE, 3+ in LE
      • Decreased pinprick and vibration from feet up to umbilicus
      • Foley in-situ
  • Case Two
    • 51 year old construction worker from Edmonton
    • Four day history of leg weakness
    • Previously well, history of alcohol abuse
    • Examination
      • EOMs full, normal facial muscle power
      • Normal tone
      • Power 5/5 in UE, Prox LE 4/5, Distal LE 3/5
      • DTRs 2+ in UE, absent in LE
      • Decreased pinprick and vibration in legs
  • Case Three
    • 34 year old lady, originally from Turkey
    • Delivered a healthy boy 2 months ago
    • Previously well
    • One month ago - diplopia; 2-3 weeks ago - dysarthria, mild dysphagia; now - feels weak and tired
    • Examination
      • EOMs full, facial muscles weak (LMN pattern), trouble swallowing water
      • Normal tone
      • Power 4/5 throughout
      • DTRs 2+ throughout
      • Normal sensation
  • Case Four
    • 62 year old man
    • 2 month history of severe headache, fatigue, myalgias, 10lb weight loss
    • PMHx of hypertension, T2DM, dyslipidemia, obesity
    • Examination
      • EOMs full, normal facial muscle power
      • Normal tone
      • Power 5/5 throughout (but gives-way easily due to pain)
      • DTRs 2+ throughout, except 1+ at ankles
      • Decreased vibration sensation at toes, normal pinprick

References

references in bold are highly recommended

  1. Busl, K. M., & Ropper, A. H. (2011). Hospital Consultation for the Patient With Generalized Weakness. Continuum Lifelong Learning Neurol, 1–23.
  2. Preston, D. C., & Shapiro, B. E. (2012). Chapter 25 - Proximal, Distal, and Generalized Weakness. Neurology in Clinical Practice (Sixth Edition. pp. 293–e33). Elsevier Inc.
  3. Amato, A. A., & Brooke, M. H. (2012). Chapter 79 - Disorders of Skeletal Muscle. Neurology in Clinical Practice (Sixth Edition. pp. 2066–e272). Elsevier Inc.
  4. Aids to the Examination of the Peripheral Nervous System, 4th edition. (2000). Saunders Limited.
  5. Liu, G. T., Volpe, N. J., & Galetta, S. L. (2010). CHAPTER 14 - Eyelid and facial nerve disorders. Neuro-Ophthalmology (Second Edition. pp. 449–489). Elsevier Inc.
  6. Hohol, M.J. The Neurologic Exam. Accessed at: http://neuroexam.med.utoronto.ca/main.htm
  7. Davis, L. E. (2005). Fundamentals of Neurologic Disease. Demos Medical Publishing.
  8. Walsh, R. J., & Amato, A. A. (2005). Toxic myopathies. Neurologic clinics, 23(2), 397–428.
  9. Jackson, C. E. (2006). A clinical approach to the patient with suspected myopathy. Continuum Lifelong Learning Neurol, 1–20.
  10. Kerchner, G. A., & ek, L. J. P. X. (2012). Chapter 64 - Channelopathies: Episodic and Electrical Disorders of the Nervous System. Neurology in Clinical Practice (Sixth Edition. pp. 1488–e210). Elsevier Inc.

Approach to Weakness

September 19th, 2013

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  • Hohol, M.J. The Neurologic Exam. Accessed at: http://neuroexam.med.utoronto.ca/main.htm
  • Hohol, M.J. The Neurologic Exam. Accessed at: http://neuroexam.med.utoronto.ca/main.htm
  • Hohol, M.J. The Neurologic Exam. Accessed at: http://neuroexam.med.utoronto.ca/main.htm
  • Hohol, M.J. The Neurologic Exam. Accessed at: http://neuroexam.med.utoronto.ca/main.htm
  • Hohol, M.J. The Neurologic Exam. Accessed at: http://neuroexam.med.utoronto.ca/main.htm
  • Neurologic examination by Juliana.