L15: Downer Cow Syndrome (Risco) Flashcards
Syndrome =
An aggregate of symptoms and signs, not necessarily due to one specific cause, which when considered together, characterize a disease or lesion
Compartment Syndrome
pressure damage within an osteofacial compartment
-Pressure in hamstring muscles depends on pelvis roation
Classic head in the flank position seen in:
Parturient paresis (milk fever)
Crush syndrome
Systemic effect of muscle damage. Downer cows will develop brown urine (myoglobinuria), renal failure, and hyperkalemia –> cardiac arrhythmias
Calving paralysis
- large lumbar roots of both sciatic and obturator nerves are vulnerable to compression damage
- obturator n. Most commonly affected
- intrapelvic trauma and exhaustion
Chars. Of lymphosarcoma from mets to vertebral canal
- usually in lumbar region L1 to L6
- “wandering metastatic cells” from uterus or other abd. viscera carried to vertebral canal via anastomosis from draining caudal vena cava and vertebral venous sinuses
- Dx: remove lumbar part of axial skeleton and freeze. Fat around dural tube becomes hard, whereas LSA tissue will be pink and soft
- most common in older cows, not close to PP period**
Non-systemic secondary causes of downer syndrome
-myoneural damage due to recumbency
Most common metastatic tumor in the uterus
LSA
Most common primary tumor in the uterus
Myosarcoma (rare)
Myoneural damage due to recumbency results in:
- pale ischemic muscles
- hemorrhagic torn muscles
- medial thigh (adductor region) usually affected
- scar tissue around sciatic nerve due to compression against the femur (at the level of where nerve wraps around hip joint)
Sciatic n. Branches into:
Tibial (caudal) and common peroneal (cranial) nerves
Why are forelimbs usually spared in compartment syndrome?
- forelimbs not under body in sternal recumbency
- brisket bears most of the weight
Damage to common peroneal nerve occurs where?
Where nerve crosses the stifle when hindlimbs positioned under the abdomen
Sciatic nerve damage –> ***
Femur dislocates and usually moves craniodorsal *** towards greater sciatic foramen. Can also dislocate ventrally into obturator foramen
What determines the ability to stand or become recumbent?**
Determined by amount of muscle function lost and location of lesion
