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SA Med - Neuro - Neuro Dz 1

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drraythe's version from 2017-10-02 04:53

NM DZ: Intro, Congenital/Developmental Myopathies

Question Answer
3 types of NM Dzs?Myopathies
Junctionopathies
Neuropathies
What is Muscular dystrophy?Deficient or abnormal myofiber proteins (e.g., dystrophin)
How do you get muscular dystrophy, what is the signalment of who gets thisX-linked Dz so usually golden retrievers, males!
How does muscular dystrophy differ btwn dogs & cats?Dogs get ATROPHY & cats get HYPERTROPHY
CSs of muscular dystrophy?Progressive muscle atrophy (cats get hypertrophy tho. bc cats.)
Stilted
Bunny hopping gait
Dysphonia
Hypertrophy of the tongue base
Dysphagia/ptyalism
Trismus (lockjaw)
What is Trismus?Lockjaw!
How can muscular dystrophy look like on chem, what are 2 tests you can use to confirm your suspicions?CHEM: ELEVATED CK (mm wasting/damage). Can do Electromyography or mm biopsy
Tx of muscular dystrophy?No Tx :(
What is Labrador retriever myopathy? How do they get it? WHO gets it?Centronuclear myopathy. Autosomal recessive Dz, & only YELLOW & BLACK COATED LABS get it. Can be male or female.
What are the CSs of lab retriever myopathy?Stiff, stilted gait w/ bunny hopping
Easily fatigued
Neck ventroflexion (All signs of weakness)
What does bunny hopping tell you?Weakness
What does chem look like w/ lab retriever myopathy? What 3 tests can you do to confirm?CHEM: Elevated creatine kinase
TESTS: Electromyography, Muscle biopsy, Genetic test (VetGen)
Tx for lab myopathy? Prog?No Tx, but they are functional pets! Better prog than the x-linked muscular dystrophy in Goldens
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Metabolic Myopathies/ Inflammatory Muscle Dz / Infectious Muscle Dz

Question Answer
Hypokalemic myopathy: WHO gets this? What is the pathophys?Happens in CATS. The lack of K+ leads to hyperpolarization → Refractory to depolarization
CSs of hypokalemic myopathy?Neck ventroflexion (CLASSIC sign of weakness, esp in cats)
Generalized weakness
Stiff, stilted gait
How do you Dx hypokalemic myopathy?On CHEM you will see Hypokalemia & elevated CK. Also see Electromyography abnormalities
How do you Tx hypokalemic myopathy?K+ supplementation
Cushing’s myopathy: how does this happen? What are the CSs?Pathophysiology is not well-understood (remember tho that steroids are catabolic to mm), will see stiff, stilted gait & generalized weakness
What is the special Electromyography abnormality seen w/ cushing's myopathy?Pseudomyotonia
Prognosis of the Cushing’s myopathy once you start to treat the Cushing’s?Guarded for resolution of myopathic signs
Masticatory muscle myositis → what is the pathophys of this?Autoimmune disorder where the Type IIM muscle is targeted (only found in masticatory mms)
What are ACUTE CSs of masticatory mm myositis? CHRONIC?ACUTE: Painful swelling of masticatory muscles, Trismus, exophthalmos, fever
CHRONIC: Atrophy/fibrosis/contracture of masticatory muscles
How do you Dx MMM?Antibody titers
CK elevation
Electromyography abnormalities
MM biopsy
How do you Tx MMM? Prog?Immunosuppression!! Its autoimmune! (in class she said long tapering dose) - fair prog
What is Polymyositis? What is the pathophys?Generalized myositis (inflammation & degeneration of muscle tissue). Pathophys is unknown but likely autoimmune.
CSs of polymyositis?Generalized weakness
Exercise intolerance
Myalgia (mm pain - pain on palpation)
Muscle swelling (acute) or atrophy (chronic)
(Dx is the same as for everything else)
What is the word for mm pain?Myalgia
Tx for polymyositis? Prog?Immunosuppression (suspected autoimmune pathophys). Guarded prog
Possible etiological agents of infectious mm Dz?
(7)
Toxoplasma gondii
Neosporum canis
Hepatozoon spp.
RMSF, E. canis, Leptospira spp.
Clostridia spp.
What CSs in almost pathognomonic for neospora infxn in puppies?Rigid pelvic limb extension
Where is (geographically) Hepatozoon?Gulf coast
Common CSs of hepatozoonosis?Oculonasal discharge
Leukocytosis
Periosteal Rxn
Who czs tetanus? What is the pathophys of the Dz?Clostridium tetani elaborates tetanospasmin toxin → Retrograde travel into the CNS → Inhibits glycine(inhibitory) at interneurons in the spinal cord & brainstem → Uncontrolled muscle contraction (so inhibit the inhibitor → spasm)
CSs of tetanus?Rigid limb extension
Trismus
Risus sardonicus
Erect ears
Enophthalmos
Elevated 3 rd eyelids
Opisthotonus
How do you Tx tetanus?Antitoxin
Wound care
ABx
Supportive care inclds Quiet
Dark room w/ little stimulation
(Mentioned in class) If you wanna give tetanus antitoxin what should you know?Can cz anaphylaxis - intradermal test this
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Ischemic Neuromyopathy, ***Myasthenia gravis

Question Answer
What is Ischemic Neuromyopathy? Pathophys?Thromboembolic Dz. Predisposing Dz (see other card) leads to Thrombus in the distal aorta → Ischemic injury to peripheral nerves/muscle of the pelvic limb
Explain Dzs which cz ischemic neuromyopathy in DOGS VS CATSCATS: Hypertrophic cardiomyopathy, thyrotoxic cardiomyopathy
DOGS: Cushing’s syndrome, renal failure, pancreatitis, IMHA, etc... for both, leads to: Thrombus in the distal aorta
CSs of Ischemic Neuromyopathy?Acute onset of paraparesis/paraplegia → Hypalgesia/analgesia of the distal limbs. Rectal hypothermia, cool paws, cyanotic nail beds, absent femoral pulses. In DOGS, also see patellar areflexia (absent reflex)
Diff ways you can Dx ischemic neuromyopathy?CSs/Hx
Abdominal & cardiac ultrasound
MRI
Creatine kinase elevation
Hyperkalemia
Acidosis
Paired thoracic/pelvic limb lactate & glucose
Tx for ischemic neuromyopathy? Prog?Anti-thrombus medication
Surgical thrombus removal
Prog is guarded (Depends on the underlying etiology, amt of Reperfusion injury)
**Pathophys of ACQUIRED FORM of MG?Antibodies form against the nicotinic ACh receptor (parasymp system). This happens in association w/ Dzs like: Hypothyroidism, thymoma (several other neoplasms as well), Methimazole therapy (used to Tx hyperT).
Which dog & cat breeds are prone to ACQUIRED MG?Abyssinian
Akita
German Shepherd
Golden Retriever
**What is the pathophys of the CONGENITAL form of MG? Which breeds of dogs are prone to this form?Lack of or dysfunctional nicotinic ACh receptors. Jack Russell terrier, smooth-haired fox terrier, Dachshund, Samoyed are prone
**What are the GENERALIZED CSs of MG?Exercise intolerance
Megaesophagus (regurgitation, aspiration pneumonia)
Ptyalism
Dysphonia
Fatigable palpebral reflexes (harder & harder for them to close their eye when you continually tap on it)
Neck ventroflexion (cat)
Normal myotactic reflexes
**What are the FOCAL CSs of MG?Megaesophagus (regurgitation, aspiration pneumonia)
Dysphonia
Ptyalism
Dropped jaw
Fatigable palpebral reflexes
*What is the focalized form of MG?Basically affects only head & neck
*CSs of the acute, fulminant form of MG?Like generalized only a peracute onset & very severe. ....Including muscles of respiration :( :( (May require ventilatory support)
*What will thoracic radiographs (can use to Dx MG) look like of MG? (3 major things to see or look for)Megaesophagus
Pneumonia (aspiration pneumonia)
Thymic or other thoracic mass
**What will electromyography look like w/ MG?NORMAL (Electromyography (EMG) is an electrodiagnostic medicine technique for evaluating & recording the electrical activity produced by skeletal muscles. )
**What is the electrodiagnostic you use w/ MG?(Electromyography will be NORMAL) Repetitive nerve stimulation will show a decremental response (can do it at first but then slowly gets worse )
*What is the GOLD STANDARD TEST for Dx ACQUIRED MG?Acetylcholine receptor antibody titers
*Best way to Dx CONGENITAL MG?Muscle biopsy & immunohistochemistry
*What is a Tensilon test? Explain how it worksUse Edrophonium chloride, which is an ANTIcholinesterase test (so inc ACH in synapse to try to counteract the fact not all the nicotinic ACH receptors are working. should see improvement of CSs w/ admin). HOWEVER, Beware false pos/negs & severe side effects (SLUDGE: salivation, lacrimation, urination, diaphoresis (sweating), GI upset (incld diarrhea), emesis (vomiting) ) (she isnt fond of this test)
What are some anticholinesterase drugs you can use to Tx MG? (2). Precautions?Pyridostigmine, Neostigmine
Beware SLUD signs, so start at the low end of the dose & titrate therapy appropriately
3 drugs you can use for immunosuppressive therapy to Tx MG? Precautions?Prednisone
Cyclosporine
Azathioprine

However this is a controversial Tx bc: Some dogs undergo spontaneous remission, Many PTxs have concurrent aspiration pneumonia (body can't fight Infxn then), Steroids can contribute to weakness
What problem associated w/ MG will you prolly wanna address?The megaeso & concurrent esophagitis & risk of aspiration pneumonia- give drugs to manage eso tone & esophagitis (she didn't mention what they were)...can also provide nutritional support via stomach tube, or try the bailey chair
****Which drugs should you avoid in a dog w/ MG?Avoid the use of NMJ-blocking drugs aka NO AMINOGLYCOSIDES
Prog of MG? (Consider type)For generalized & focal the prog is guarded (Some cases undergo spontaneous remission, but megaeso might never go away → lots of aspiration pneumonia). Acute, fulminant type: grave prognosis
What is the most common cz of death w/ myasthenia gravis?Succumb to aspiration pneumonia (Or, euthanized due to constraints of dealing w/ repeated bouts of aspiration pneumonia)
How do you know if their MG is in remission?Monitor serum antibody titers q6-8wk: Remission achieved when titers return to normal
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