Small Ani. Med- Neuro- Neuromuscular Disease 1

drraythe's version from 2016-04-29 15:34

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 between dogs and cats?Dogs get ATROPHY and cats get HYPERTROPHY
clinical signs 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 two tests you can use to confirm your suspicions?CHEM: ELEVATED CK (mm wasting/damage). Can do Electromyography or mm bx
tx of muscular dystrophy?no tx :(
what is Labrador retriever myopathy? How do they get it? WHO gets it?Centronuclear myopathy. Autosomal recessive disease, and only YELLOW AND BLACK COATED LABS get it. can be male or female.
what are the clinical signs of lab retriever myopathy?Stiff, stilted gait with bunny hopping. Easily fatigued, Neck ventroflexion (All signs of weakness)
what does bunny hopping tell you?weakness
what does chem look like with lab retriver 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

Metabolic Myopathies/ Inflammatory Muscle Disease / Infectious Muscle Disease

Question Answer
Hypokalemic myopathy: WHO gets this? what is the pathophys?happens in CATS. The lack of K+ leads to hyperpolarization--> Refractory to depolarization
clinical signs 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 and elevated CK. Also see Electromyographic abnormalities
how do you tx hypokalemic myopathy?K+ supplementation
Cushing’s myopathy: how does this happen? what are the clinical signs?Pathophysiology is not well-understood (remember tho that steroids are catabolic to mm), will see stiff, stilted gait and generalized weakness.
what is the special Electromyographic abnormality seen with cushing's myopathy? Pseudomyotonia
prognosis of the cushing's myopathy once you start to treat the cushings?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 clinical signs 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, Electromyographic abnormalities, MM bx
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 and degeneration of muscle tissue). Pathophys is unknown but likely autoimmune.
clinical signs 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 clinical signs of hepatozoonosis?Oculonasal discharge, leukocytosis, periosteal reaction
who causes tetanus? what is the pathophys of the dz? Clostridium tetani elaborates tetanospasm toxin--> Retrograde travel into the CNS--> Inhibits glycine(inhibitory) at interneurons in the spinal cord and 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, antibiotics, supportive care includes Quiet, dark room with little stimulation
(mentioned in class) if you wanna give tetanus antitoxin what should you know?Can cause anaphylaxis- intradermal test this

Ischemic Neuromyopathy, ***myasthenia gravis

Question Answer
what is Ischemic Neuromyopathy? pathophys?Thromboembolic disease. 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 cause 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? Clinical signs/history, Abdominal and cardiac ultrasound, MRI, Creatine kinase elevation, hyperkalemia, acidosis, Paired thoracic/pelvic limb lactate and glucose
tx for ischemic neuromyopathy? prog? Anti-thrombus medication, Surgical thrombus removal. Prog is guarded ( Depends on the underlying etiology, amount of Reperfusion injury)
**pathophys of ACQUIRED FORM of MG?Antibodies form against the nicotinic ACh receptor (parasymp system). This happens in association with Dzs like: Hypothyroidism, thymoma (several other neoplasms as well), Methimazole therapy (used to tx hyperT).
which dog and 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 and 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 and neck
*CSs of the acute, fulminant form of MG?Like generalized only a peracute onset and 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 with MG?NORMAL (Electromyography (EMG) is an electrodiagnostic medicine technique for evaluating and recording the electrical activity produced by skeletal muscles. )
**what is the electrodiagnostic you use with 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 and 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 with admin). HOWEVER, Beware false positives/negatives and 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 and 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 patients have concurrent aspiration pneumonia (body can't fight infection then), Steroids can contribute to weakness
what problem associated with MG will you prolly wanna address?The megaeso and concurrent esophagitis and risk of aspiration pneumonia- give drugs to manage eso tone and 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 with MG?Avoid the use of NMJ-blocking drugs aka NO AMINOGLYCOSIDES
prog of MG? (consider type)for generalized and 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 cause of death with myesthenia gravis?Succumb to aspiration pneumonia (Or, euthanized due to constraints of dealing with 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