Infectious and inflammatory myelopathies Flashcards
1
Q
Discospondylitis definition
A
- Infection of the IVD and adjacent vertebral end plates
2
Q
What is most common etiology of discospondylitis?
A
- bacterial infection
- Fungal organisms possible as well as algal, but less likely
3
Q
Which bacteria are most common with discospondylitis?
A
- Staphylococcus spp most common***
- E. coli
- Brucella* (don’t forget!)
4
Q
Which fungal organisms could cause discospondylitis?
A
- Aspergillus
5
Q
Routes of infection for discospondylitis?
A
- Hematogenous spread
- Foreign body migration (e.g. grass awn)
- Iatrogenic (post op or post-injection)
6
Q
What is most common route of infection for discospondylitis?
A
- Hematogenous
7
Q
Source for hematogenous discospondylitis
A
- UTI thought to be the source
8
Q
Signalment of discospondylitis
A
- Often seen in older patients, medium to large breed dogs
- Often hunting dogs
9
Q
Most common sites and number of sites for discosponydlitis
A
- L7-S1 most common site
- Single site more common than multiple sites
- 40% per one study have multiple sites affected
10
Q
Presenting complaint for discospondylitis
A
- Painful
- Febrile
- ADR
- Neuro deficits depend on localization
11
Q
Diagnosis of discospondylitis
A
- CBC/Chem/UA (leukocytosis, hyperglobulinemia, UTI )
- Radiographs**
- CT
scan - MRI
12
Q
Appearance of discospondylitis on radiograph
A
- Jagged
- Evidence of lysis around the vertebral end plate
13
Q
How to diagnose the organism in discospondylitis?
A
- Blood cultures (important to make sure it’s not fungal and make sure we are better antibiotic stewards)
- Urine cultures
- Disc culture (percutaneous)
- Surgical cultures ($$$$)
14
Q
Treatment of discospondylitis
A
- Antibiotics based on culture and sensitivity for bacterial infection (1st gen cephalosporins, penicillin or amoxicillin to start)
- Aspergillus (itraconazole or flucaonazole)
- Brucella (tetracyclines and aminoglycosides)
- May need to start with a few IV doses
- Tx lasts for a months
- Should see improvement within the first week
- Can do surgery to consider decompression and/or stabilization
15
Q
When should you see improvement with discospondylitis?
A
- Within the first week
16
Q
How long does treatment last for discospondylitis?
A
- 6-12 months
17
Q
Which breeds are predisposed to Aspergillus?
A
- German Shepherds are predisposed likely due to T cell immunodeficiency
- Poor prognosis
18
Q
General signalment for non-infectious myelopathies
A
- Think of younger patients, but never rule out in older patients
- Can be acute onset, or several week history
19
Q
Clinical sign classic with meningitis
A
- Pain
20
Q
Clinical signs classic with myelitis
A
- Neurological deficits
21
Q
CSF in non-infectious myelopathies in general
A
- pleocytosis (increased WBC in general)
- > 5/µL
- Also should have negative infectious disease titers
22
Q
Steroid responsive meningitis/arteritis underlying pathophysiology
A
- Immune mediated disease - attacks leptomeninges and blood vessels
23
Q
Who gets steroid responsive meningitis/arteritis?
A
- Young dogs around 1 year of age
- Boxers, Beagles, GSP, Goldens, Burnese Mountain Dogs
24
Q
Clinical signs of steroid responsive meningitis/arteritis
A
- Fever and cervical pain
25
Exam findings of steroid responsive meningitis/arteritis
- Cervical pain only
- Neck guarding
- Pain on palpation (EXTREME PAIN)
26
Blood work with steroid responsive meningitis/arteritis
- Leukocytosis (neutrophilia)
27
Major dfdx for meningitis/arteritis
- Polyarthropathy
- Discospondylitis
- meningomyelitis, bacterial meningitis
28
Diagnosis of steroid responsive meningitis/arteritis
- Based on CSF analysis
- Cervical MRI
- +/- joint taps
- Infectious disease titers neg
29
CSF with steroid responsive meningitis/arteritis
- Neutrophilic pleocytosis (from IL-8)
| - IgA levels increased also
30
Treatment of steroid responsive meningitis/arteritis
- Immunosuppression (steroids, cyclosporine, mycophenolate, etc.)
- may have concurrent IMPA
31
Granulomatous meningomyelitis
- Similar to disease that we learned about in the brain with granulomatous meningoencephalitis
32
Infectious causes of granulomatous meningomyelitis?
- Bacteria (Straph, Strep, coliforms)
- Fungal (Cryptococcus, Coccidiomycosis, Blastomycoses)
- Rickettsial
- Protozoal (toxoplasmosis and neospora you have to do electron microscopy to differentiate)
33
Etiology of tetanus
- Clostridium tetani
| - Anaerobic, spore forming bacterium (very hard to get rid of)
34
Where are Clostridium tetani spores?
- Ubiquitous in the environment
35
How common is tetanus in dogs and cats?
- Uncommon overall
| - Cats are 10x more resistant
36
What causes tetanus infection?
- Spore being introduced in a wound
- Penetrating wounds, contaminated body cavity surgeries (like OVH or castration)
- Must germinate to produce the toxin
37
WHat is the primary toxin in tetanus**?
- Tetanospasmin
38
Tetanospasmin toxin travel
- Enters nerve via telodenra (nerve endings) at motor end plate either locally or hematogenously
- Toxin is transported retrograde to the CNS
- Primary target is the Renshaw cell = inhibitory interneuron in the spinal cord
- Interferes with release of glycine and GABA (inhibitory neurotransmitters) resulting in extensor tone
- Causes uncontrolled contraction of extensor muscles
39
What is the primary target of tetanospasmin?
- Renshaw cell (inhibitory interneuron in the spinal cord)
| - Interferes with release of glycine and GABA
40
Clinical signs of tetanus
- Focal or generalized (often progresses to generalized ultimately)
- Muscle stiffness
- Sardonic grin, lock-jaw, sawhorse posture
41
When do signs of tetanus start?
- 5-10 days after infection
42
Hallmark of tetanus
- Muscle stiffness
43
Diagnosis of tetanus
- Clinical features and history of a previous wound/surgery
- May be quite difficult to find a wound
- Look for signs of an infection on blood work (high white cell count, hyperglobulinemia)
- May see systemic effects - respiratory difficulties, cardiac arrhythmias, hyperthermia (PNS or SNS signs suggest worse prognosis)
44
Treatment goals for tetanus
- Halt toxin production (need to find the source)
| - Supportive care
45
Treatment of tetanus
- Supportive care (nursing care, recumbency, bladder management, feeding tubes, sedation as auditory and tactile stimuli will worsen signs)
- Antibiotic therapy with Penicillin G (metronidazole, clindamycin, and tetracyclines are helpful)
- If wound is found, clean/debride and can use H2O2 to generate O2
- Can also locally infuse Abx
- Antitoxin will prevent further binding of toxin (but may lead to anaphylaxis)
46
Antibiotics for tetanus?
- Penicillin G is abx of choice
| - Metronidazole is also effective
