Case Study: Limb Spare

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Akiko is an almost 8 year old spayed female mixed breed dog that presented to VSH North County for evaluation of wounds suffered from a dog bite.

firstopenpaw

I evaluated Akiko the morning after she arrived through our ER. Akiko had a severe wound on the distal aspect of the left thoracic limb. The wound encompassed the entire dorsal metacarpal surface with exposure of the extensor tendons. There was a comminuted grade 3 open fracture of the 5th metacarpal bone. The wound extended to just proximal to the metacarpal pad. There was no overt instability of the carpus and manus as a whole. A dorsopalmar radiograph was obtained and delineated the MC5 fracture but no other overt bony injuries. There was conscious sensation in the digits.

I met with Akiko’s owners and discussed treatment options. They were interested in salvaging her limb if at all possible. The challenges associated with ensuring tissue health followed by obtaining closure of the wound were discussed, but limb salvage was considered feasible since enough of the weight bearing portion of the paw was not affected. We discussed that there would be an initial phase of open wound management to allow granulation tissue formation (ensuring tissue health and greatly reducing the risk of infection), followed by reconstructive procedure(s) to achieve a functional result, as the defect was considered too large to allow second intention healing and in a location that primary closure was not possible.

openpaw

The wound was managed with daily dry-to-dry bandages until a healthy granulation bed covered the majority of the wound. The dry-to-dry bandages allowed sequential mechanical debridement of the effusive wound. 9 days following initial presentation, Akiko was taken to surgery and a phalangeal fillet procedure performed. The bones of the fractured 5th metatarsal were removed along with the phalanges, but all associated skin and subcutaneous tissue from the digit was left intact. The resulting skin flap was rotated into the wound and sutured either to the adjacent skin or to the granulation bed. The digital pad was included as part of the flap to increase coverage. This procedure resulted in approximately 65% closure of the wound.  This procedure was chosen because the high-grade open fracture was at risk for infection and/or delayed healing, and because loss of the digit would not preclude weight bearing. The phalangeal fillet provides a durable skin flap that is not prone to vascular compromise.

healedpaw

The flap and remaining wound continued to be managed with a bandage using a non-adherent primary layer. At two weeks post-operatively, the flap demonstrated 100% survival including the digital pad. The remainder of the wound continued to contract and epithelialize, so no additional procedures (such as a free skin graft) were elected. The bandage was removed at approximately 5 weeks after presentation, at which time there was a slightly exuberant ~2cm granulation bed remaining on the dorsum of the paw adjacent to the transposed digital pad.

At approximately 6 weeks after initial presentation, the wound was completely closed with the exception of a ~1cm scab in the same dorsal location. Akiko demonstrated a grade 1/4 left thoracic limb lameness. The owners were instructed to wean Akiko off of her e-collar if and when she does not resort to self-trauma. No further intervention is planned.

Case Study: Thoracic Limb Lameness in French Bulldog

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Seth Mathus Ganz, DVM, DACVS

Stitch is a now 6 month old intact male French Bulldog that presented to the Veterinary
Specialty Hospital North County surgery service at 4 months of age for evaluation of left thoracic limb
lameness after jumping out of his owner’s arms. On exam, Stitch was BAR and hydrated. He exhibited a
grade 4/4 (non weight-bearing) left thoracic limb lameness with pain, swelling and crepitus in the left
elbow. Radiographs taken by the referring veterinarian demonstrated a mildly-displaced left lateral humeral condylar fracture. The treatment options were discussed with the owner. Fluoroscopic-guided closed reduction and internal fixation was elected.

Stitch was placed under general anesthesia and the left thoracic limb prepared for sterile surgery in the radiology suite. A point to point bone holding reduction forceps was used to reduce the humeral condylar fracture under fluoroscopic guidance. A selfcompressing pin was driven lateromedially through the distal humeral epiphysis. A smooth Kirschner wire was then driven from the lateral epicondyle up the lateral epicondylar crest to exit the caudomedial aspect of the diaphysis to provide rotational
stability. All of the implants were placed under fluoroscopic guidance. The implants were placed percutaneously without incisions and Stitch made an uneventful recovery from anesthesia and was discharged the following day with instructions for exercise restriction and rechecks at 2 and 6 weeks (6 weeks for radiographs). At the 2 week recheck, Stitch was ambulating without lameness and had
very good range of motion in the left elbow. At 4 weeks after surgery, Stitch represented for acute right thoracic limb lameness. A contralateral (right) lateral humeral condylar fracture was diagnosed with radiographs and repaired in a similar fashion to the left.

At this time, Stitch is fully healed from both surgeries and doing well. He did develop a seroma on the right elbow that was treated with explantation. Humeral condylar fractures are typically seen in lateral (most common, see below), medial, and bicondylar configurations. Most of these fractures are appropriately categorized as Salter-Harris IV as they propagate from the articular surface, through the
physis and into the metaphysis. There can be variable amounts of comminution present.
In our experience, humeral condylar fractures can be seen in any breed, but brachycephalic breeds and pit bull terriers seem to be over-represented. The radial head articulates chiefly with the capitulum (lateral aspect of the humeral condyle), so a jarring “jump-down” type of trauma drives the radius against the capitulum. The radial head is thought to produce a wedge effect on the intercondylar region, and the thinner lateral (compared to medial) epicondylar crest fails to produce a lateral condylar
fracture. Spaniels are heavily over-represented for a condition called incomplete ossification of the humeral condyle, which can result in chronic elbow pain or can progress to fracture. In these cases advanced imaging (CT) of the elbows and interrogation of the contralateral elbow in unilaterally-affected cases is important.

There is some clinical overlap, as spaniels can suffer true traumatic fracture and any adult dog with non-traumatic elbow-localized lameness may have IOHC. Stitch experienced minor trauma with both episodes of fracture, but his age and conformation may have contributed.
Open reduction and internal fixation has historically been recommended to perfectly restore the articular surface and provide rigid stabilization. This allows predictable and direct (without a callus) healing, avoiding osteoarthritis and impaired range of motion.
Minimally-invasive fixation is well-suited to many humeral condylar fractures because it allows excellent visualization of fracture fragments in multiple planes. This promotes accurate fracture reduction and implant placement. The other big advantage of this approach for this particular injury is that the traditional open surgical approach requires significant dissection. The closed method minimizes surgical time and trauma, allowing fast return to function.

 

Download the PDF for this case study here: Thoracic_Lameness_in_French_Bulldog.

Case Study: Incontinence in Boxer

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JULIE FISCHER, DVM, DIPLOMATE ACVIM

HISTORY AND PHYSICAL EXAM
Samson was a 4-year old MC boxer presented with a 1 month history of incontinence and abnormal urination. Samson’s owners had noted that he was leaving small puddles of urine on his beds when he rested or slept, and that they occasionally found dribbles of urine on the floor as well. When taken
outside, Samson assumed a normal leg-lifted posture to urinate and initiated a urine stream that was swiftly attenuated. He often stood in the same position without straining but without producing a urine stream for several minutes, and if permitted, would repeat this behavior several times. With the exception of the incontinence and abnormal urination behavior, Samson’s behavior, appetite, activity, and general well-being were normal and unchanging according to the owners.

Physical examination was normal with the exception of a large bladder which could not be expressed with firm pressure. Neurological examination was normal. When taken out to urinate, Samson postured normally and produced a small urine stream that was attenuated after about 5 seconds. He held the
urination posture without straining for a minute, and then repeated this process twice more. After urination attempts, the bladder was still large.

PROBLEM LIST AND INITIAL DIFFERENTIALS

  1. Urine retention: inadequate detrusor contraction (neurogenic or myogenic), inadequate sphincter relaxation, mechanical obstruction of outlet
  2. Incontinence: In the face of pathological urine retention, incontinence is de facto due to overflow (bladder hypoaccommodation, urethral irritation, polyuria with overflow, anatomical anomaly at outflow, lower motor neuron lesion are other differentials that could possibly contribute, but are unlikely to be primarily responsible).

INITIAL PLAN

  1. CBC/chemistry panel: WNL
  2. Urinalysis: color = light yellow/brown, USG = 1.026, 3+ blood, 0-3 WBC/hpf, 5-10 RBC/hpf, 3_ amorphous debris
  3. Urine culture: no growth in 72 hours
  4. Urethral catheterization: no mechanical obstruction detected; after urination attempts, 800 ml urine removed from bladder
  5. Abdominal radiographs: large bladder, normal shape and positioning, no evidence of urinary stone disease
  6. Abdominal ultrasound exam: bladder is small to medium-sized with normal wall and no apparent prostatic or urethral abnormality
  7. Retrograde and voiding urethrogram: normal urethral distension, and no intraluminal space-occupying lesion seen with retrograde study; marked bladder compression resulted in intermittent and incomplete voiding, with inadequate distension of the proximal urethral lumen/ proximal urethral narrowing

ASSESSMENT
When incontinence occurs in the face of significant urine retention, it is generally (and by definition) overflow incontinence.
This does not rule out other contributing factors such as anatomical abnormality of the outflow tract (e.g., a trigonal tumor could both cause outflow obstruction and interfere with normal closure function). In this case, mechanical obstruction was ruled out with catheterization, contrast study, and ultrasound, leaving functional obstruction (inadequate outlet opening/relaxation) as the most likely differential for this dog’s urine retention. In normal voiding, the stimulus for urethral contraction is inhibited, permitting urethral relaxation and urine outflow. Our observations of this dog’s voiding pattern suggest dyssynergic voiding, a condition in which the urethra contracts instead of relaxes in response to detrusor
contraction (in theory, usually due to a subtle supra-sacral spinal lesion). The end result of this is inadequate bladder emptying, with eventual development of detrusor atony. In general, no more than 0.5-1.0 ml urine should remain in the bladder following full voiding attempts, so the 800 ml removed from this dog is radically abnormal. This is a disease seen almost exclusively in intact and castrated male dogs, usually large to giant breeds, and often in the young. In intact dogs, exacerbation of signs is often seen with psychological or sexual excitation.
Definitive documentation of detrusor-sphincter dyssynergia requires urethral pressure profilometry performed simultaneously with cystometrography to show simultaneous urethral and detrusor contraction. Practically speaking, we diagnose it presumptively based on observation of micturition and exclusion of other differentials, as above.

TREATMENT
Therapy for dyssynergia consists of relaxation of the proximal urethra and bladder emptying. Most dogs with dyssynergia have some degree of bladder atony at the time of diagnosis, and initial therapy should include hospitalization with a urinary catheter and closed collection system for 3-5 days to help start detrusor recovery. Bladder expression is not an adequate or appropriate means of urinary care in these dogs, and owners often will have to cleanly catheterize and empty the dog’s bladder at home 2-3 times daily during initial therapy.
Contraction of the proximal urethra occurs via stimulation of alpha-1 adrenergic-innervated smooth muscle, so relaxation of the proximal urethra is achieved via alpha-1 inhibition. Several medications are available for this purpose:

  • Phenoxybenzamine: Non-selective alpha 1-alpha 2 antagonist; less potent than alternatives, with greater risk of side-effects; obsolete in human medicine for urinary applications. There is no reason at this point to use phenoxybenzamine over alternatives for urinary purposes.
  • Prazosin: Selective alpha-1 antagonist; very inexpensive; useful in both cats and dogs. Can measurably decrease blood pressure, so not recommended in hypovolemic or hypotensive animals.
  • Tamsulosin (Flomax): Potent, uroselective alpha-1 antagonist; does not decrease blood pressure at normal doses; not shown to be safe in cats yet; more expensive than prazosin.

Samson’s owners could not afford hospitalization, but agreed to catheterize him at home 3-4 times daily initially, then 2-3 times daily as needed. For financial reasons, they elected to initially try prazosin at 1 mg/15 kg q 8 hrs. This improved Samson’s voiding, but did not normalize it, and his residual urine volume stayed >300 ml. After 2 weeks the owners switched Samson to tamsulosin at 0.125 mg/10 kg q day. Samson’s residual urine volume steadily decreased and the owners were able to stop catheterizing him after 2 additional weeks. Eighteen months later he is still voiding normally on daily tamsulosin, but relapses after a few weeks if the medication is discontinued.

 

Download the PDF for this case study here: Incontinence_in_Boxer

Case Study: Feline Chronic Renal Disease vs Hyperaldosteronism

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Katherine Arnell, DVM

HISTORY:
Melvin, a 9 year old male neutered DSH, presented to the Veterinary Specialty Hospital for
evaluation of an acute onset of ataxia and cervical ventroflexion. He is strictly indoors with no
history of toxin exposure, no travel history, and no significant prior medical history.

PHYSICAL EXAM FINDINGS:
On presentation, Melvin was bright, alert and hydrated with mild cervical ventroflexion. His signs
quickly progressed to marked cervical ventroflexion, generalized weakness, reluctance to walk, and
a plantigrade stance with prolonged standing. The remainder of his neurologic examination was
unremarkable.

DIFFERENTIAL DIAGNOSES:
Melvin’s neurologic signs are consistent with neuromuscular disease. Differentials for generalized
neuromuscular disease include hypokalemic myopathy, myasthenia gravis, infectious or
inflammatory myopathy, toxin, and less likely a vascular event. Differentials for hypokalemia
include hyperaldosteronism, chronic renal disease, metabolic alkalosis, dietary deficiency,
concurrent insulin therapy, and use of medications such as penicillins, amphotericin B, and loop
diuretics.

DIAGNOSTICS:
A complete blood count was unremarkable. A chemistry panel showed hypokalemia (3.2 mmol/L),
mild azotemia (BUN 59 mg/dL and creatinine 2.9 mg/dL), hypercalcemia (11.1 mg/dL), and
hypophosphatemia (1.7 mg/dL). A urinalysis showed a USG of 1.026 with 4+ blood, few epithelial
cells, and few calcium oxalate crystals. The urine potassium concentration was elevated (69.7
mmol/L). A systolic blood pressure was mildly elevated (170 mmHg), however subsequent
measurements were normal. Abdominal ultrasound exam revealed moderate bilateral chronic
renal changes and multifocal hyperechoic splenic nodules most consistent with benign
myelolipomas.

Due to the possibility for hyperaldosteronism as a cause for Melvin’s hypokalemia, an aldosterone
level was submitted and was elevated at 1,043 pmol/L (reference range 194-388 pmol/L).

PLAN:
Melvin was treated with intravenous fluids containing potassium chloride and potassium
phosphate supplementation. Overnight, he remained stable, but his neurologic status did not
improve. Despite fluid therapy, his potassium level decreased to 2.3 mmol/L. His intravenous
potassium supplementation was increased and oral potassium gluconate was started. His
phosphorous level increased to 8.6 mg/dL, and potassium phosphate supplementation was
subsequently discontinued. Serial blood work showed marked improvement in acid-base balance
and potassium levels, with normalization of his potassium level and renal values within 72
hours. His intravenous fluids with potassium chloride supplementation were tapered and he
continued to do well. His cervical ventroflexion resolved and his overall strength improved. He
was then discharged with instructions to continue oral potassium gluconate BID and switch to a
renal diet. He was rechecked three days later, and was clinically doing well at that time. Recheck
blood work showed normokalemia (3.95 mmol/L). He was rechecked two weeks later, and was
continuing to do well. Recheck blood work showed normokalemia (4.2 mmol/L), mildly elevated
BUN (51 mg/dL), and normal creatinine (1.6 mg/dL). A repeat aldosterone concentration was
below the reference range at 67 pmol/L.

DISCUSSION:
Hypokalemia is typically defined as a serum potassium concentration below 3.6
mmol/L. Treatment depends on the severity of hypokalemia and associated clinical signs including
polyuria, polydipsia, ileus, and muscular weakness. Potassium can be supplemented both
intravenously and orally, and frequent measurement of potassium concentration is essential to
assess response to therapy and avoid iatrogenic hyperkalemia. The primary cause for the
hypokalemia should also be identified and treated appropriately.
Hyperaldosteronism generally reflects the appropriate physiologic response to counteract
hyponatremia, hyperkalemia, and hypotension. In Melvin’s case, we did not know initially if the
hyperaldosteronism was secondary to an aldosterone-secreting adenocortical adrenal tumor
(Conn’s syndrome) or secondary to renal disease given his azotemia. There was no evidence of an
adrenal tumor noted on his abdominal ultrasound exam, although changes are not always
apparent. Cats with adrenal tumors will have aldosterone concentrations ranging from 800-14,000
pmol/L and most have concentrations greater than 1000 pmol/L. Cats with renal disease can have
aldosterone concentrations ranging from 130-1,670 pmol/L. These cats will typically have bilateral
micronodular hyperplasia of the zona glomerulosa of the adrenal cortex and have
ultrasonographically normal adrenal glands.

Due to the overlap of aldosterone concentration ranges between these two diseases,
interpretation of concentrations can be challenging and other clinical parameters must also be
evaluated, including electrolytes, blood pressure, and ultrasound examination of the adrenal
glands. In Melvin’s case, we rechecked an aldosterone level approximately two weeks later and it
was below the reference range.
This finding in combination with his normal adrenal ultrasound, normal blood pressure, and
improved azotemia would suggest chronic renal disease as the cause of his previously documented
hyperaldosteronism.
Melvin is continuing to do very well clinically and loves his new renal diet. We are gradually
tapering his potassium gluconate supplementation and his renal values remain stable.

 

Download the PDF for this case study here: Feline_Chronic_Kidney_Disease

Case Study: Progressive Behavior Change in a Cat

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Tammy L. Stevenson, DVM, Diplomate ACVIM (Neurology)

HISTORY:
Chandra, a 14 year old, DSH, was presented for a 5 month history of a slowly progressive behavior
change, urinating outside the litter box, withdrawing from client, vocalizing without apparent
purpose, and a tendency to walk in circles to the left. Prior to referral, a CBC, serum chemistry
panel, urinalysis, serum T4 concentration, and a Cryptococcus titer were obtained which were
unremarkable. She was started on prednisone at 0. 5mg/kg BID, and there was initial dramatic
improvement. However, the signs would recur whenever the
medication was tapered, and now she is not responding as well to
the BID dose.

ABNORMAL EXAM FINDINGS:
Iris atrophy, nuclear sclerosis, dental disease, BCS 7/9.
Mentation: Obtunded
Cranial Nerves: absent menace on the right, others normal.
Gait: Ambulatory, tendency to circle to the left.
Conscious Proprioception (CP): unable to assess CPs, but hopping was slower on the right than the
left. The remainder of the neurological examination was normal.

NEUROANATOMIC LOCALIZATION:
Left Cerebrothalamic.

DIFFERENTIAL DIAGNOSIS:
Neoplasia, inflammatory, less likely infectious, other.

DIAGNOSITCS:
Three view thoracic radiographs—No gross evidence of metastatic disease
MRI of the brain—uniformly contrast enhancing mass associated with the meninges and
compressing the left cerebral hemisphere.

PLAN:
Left rostrotentorial craniotomy. The mass was removed and Chandra recovered uneventfully. She
was discharged within 3 days of surgery on prednisone 0.5 mg/kg BID x 7 days, then 0.5mg/kg SID
until time of recheck. The biopsy was interpreted as a psammomatous meningioma. She had an
inconsistent menace OD and an otherwise normal neurological examination at the two week
recheck.

DISCUSSION:
Meningiomas are the most common type of brain tumor in the cat. These tumors do not invade
adjacent brain tissue and typically “pop” out easily at the time of surgery. Obviously, attempting to
get clean tumor margins is not possible with brain surgery. Surprising to most clients and
veterinarians is that follow up radiation and/or chemotherapy is usually not necessary with most
feline meningiomas. Since these tumors are so slow growing, and these modalities depend on
dividing cells, they do not increase survival time. Generally, these are elderly patients that either die
of another disease process prior to regrowth, or the clients can elect to pursue a second surgery in 1-3
years if they become clinical again for their brain tumor. Clients who elect not to pursue a second surgery are usually grateful for the high quality, “bonus” time they have had with their cat. About 15% of feline meningioma patients have more than one meningioma at the time of diagnosis. Not all are surgically accessible, but removing the largest tumor can often afford clients a significant amount of quality time with their cat.
Unlike dogs with brain tumors where seizures are the most common presenting complaint, cats
are most commonly presented for behavior changes. Since the clinical signs can be very gradual in
onset and can progress slowly over several months, clients will often mistakenly interpret them as
old age and don’t bring their pet to the veterinarian until they are significantly affected. The signs
may be as subtle as lethargy, withdrawing/hiding, and sleeping a lot, or as severe as blindness,
head pressing, and compulsive pacing/circling, with or without seizures. A good response to
prednisone may further delay a definitive diagnosis and treatment. Since surgery for meningiomas
in cats is often extremely successful, motivated clients should be encouraged to seek a diagnosis.
So if presented with an elderly cat patient with behavior changes, meningioma should be on the
differential list.

 

Download the PDF for this case study here: behaviorchangeincat

Case Study: Canine Foreign Body

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Joshua Jackson, DVM, Diplomate ACVS

HISTORY:
Jake, a 2.5 year old German Shepherd, was presented for evaluation of vomiting, anorexia and
lethargy. Prior to referral, Jake had a 5 month history of vomiting, diarrhea, weight loss and
inappetence. He was treated supportively with a bland diet, maropitant and omeprazole. Although
his vomiting ceased and he began eating, Jake remained persistently lethargic. He was evaluated
five days after initiation of supportive care. A leukocytosis (17.4K) characterized by a monocytosis
and thrombocytopenia (98K) were revealed. A spec PLI was normal. Supportive care was continued
and Jake apparently improved over the next few days. His signs did not completely resolve, thus he
was presented for further evaluation.

PHYSICAL EXAMINATION FINDINGS:
Bright, Alert and Responsive
Body condition score 3/9
Very tense on abdominal palpation, but all other parameters and vitals normal.

DIFFERENTIAL DIAGNOSES:
Primary gastrointestinal disease including gastroenteritis vs. partial obstruction (foreign body) vs.
intussusception vs. mesenteric or splenic torsion vs. less likely parasitism vs. secondary to
endocrine disease such as hypoadrenocorticism. Renal, hepatic and pancreatic disease are less
given results of biochemical analysis and cPLI.

DIAGNOSTICS:
Abdominal ultrasound: A linear foreign body within the peritoneal cavity with a diffuse peritonitis
was evident. Regional intestinal mural alterations, likely secondary to inflammation or adhesion formation, were noted, as well as periaortic lymphomegaly and hypoechoic hepatomegaly.

PLAN:
Exploratory celiotomy and foreign body removal.

SURGERY REPORT:
A standard ventral midline incision was made from xiphoid to pubis. 300mls of purulent ascites was
encountered upon entry into the abdomen. Diffuse omental and intestinal adhesions were present.
A large toothpick foreign body was discovered floating free in the ascites. Adhesions were
removed and copious saline lavage performed. A closed suction drain was placed.
Closure was routine.

DISCUSSION:
Chronic peritonitis, especially septic peritonitis is not common. Animals are able to tolerate severe
abdominal inflammation and hide their clinical signs much more than people. Historical veterinary
literature suggests a mortality rate of septic peritonitis from 25-75%. It is our experience that with
aggressive medical and surgical management survival rates are much better than what has been
reported historically.
Open peritoneal drainage is almost never performed and almost all patients are managed with closed suction drainage. One of the most important components of successful postoperative management of the peritonitis patient is addressing the often severe hypoproteinemia. Early post operative enteral feeding is important. The use of nasogastric, esophagostomy, gastrostomy or jejunostomy tubes should be considered standard of care with septic peritonitis. Colloid support in addition (hetastarch, plasma, albumin) is often required.
Patients often lose tremendous volumes of fluid from the abdomen. A close watch of blood
pressure, body weight and hydration status is important and volume administration adjusted
accordingly. The use of paired blood and abdominal fluid glucose levels has not been validated in
the post operative period to determine if sepsis is present, but it is our experience that a lower
abdominal glucose than plasma in the post operative period generally suggests recurrent leakage.
A closed suction drain enables easy access for cytology to evaluate WBCs morphology and presence
of bacteria. Broad spectrum antibiotic therapy is generally utilized. We often utilize enrofloxacin
combined with ampicillin or ticarcillin.
In this case, the patient was discharged 3 days after surgery and has done well in the postoperative
period.

 

Download the PDF for this case study here: canine_foreign_body