Cerebrospinal Fluid Myelin Basic Protein as a Prognostic Biomarker in Dogs with Thoracolumbar Intervertebral Disk Herniation

Background: Release of myelin basic protein (MBP) into the cerebrospinal fluid (CSF) is associated with active demyelination and correlates with outcome in various neurological diseases. Hypothesis/Objectives: To describe associations among CSF MBP concentration, initial neurological dysfunction, and long‐term ambulatory outcome in dogs with acute thoracolumbar intervertebral disk herniation (IVDH). Animals: Five hundred and seventy‐four dogs with acute thoracolumbar IVDH and 16 clinically normal dogs. Methods: Prospective case series clinical study. Signalment, initial neurological dysfunction as determined by a modified Frankel score (MFS), and ambulatory outcome at >3‐month follow‐up were recorded. Cisternal CSF MBP concentration was determined by an ELISA. Associations were estimated between CSF MBP concentration and various clinical parameters. Results: Dogs with thoracolumbar IVDH that did not ambulate at follow‐up had a higher CSF MBP concentration (median, 3.56 ng/mL; range, 0.59–51.2 ng/mL) compared with control dogs (median, 2.22 ng/mL; range, 0–3.82 ng/mL) (P= .032). A CSF MBP concentration of ≥3 ng/mL had a sensitivity of 78% and specificity of 76% to predict an unsuccessful outcome based on receiver‐operating characteristics curve analysis (area under the curve =0.688, P= .079). Affected dogs with a CSF MBP concentration ≥3 ng/mL had 0.09 times the odds of ambulation at follow‐up compared with affected dogs with CSF MBP concentration <3 ng/mL when adjusted for initial MFS (95% confidence interval 0.01–0.66, P= .018). Conclusions and Clinical Importance: These results would suggest that CSF MBP concentration may be useful as an independent prognostic indicator in dogs with thoracolumbar IVDH.     

Prevalence of Urinary Tract Infection in Dogs after Surgery for Thoracolumbar Intervertebral Disc Extrusion

Background: Urinary tract infection (UTI) is a common complication in people with spinal cord injury (SCI). Dogs with acute intervertebral disc extrusion (IVDE) have similar risk factors for UTI when compared with human SCI patients and have a high perioperative prevalence of UTI. Objectives: Determine the prevalence of UTI in dogs for 3 months after surgery for thoracolumbar IVDE and identify risk factors for development of UTI. Animals: Twenty‐five dogs treated surgically for 26 acute disc extrusions. Methods: Prospective study. Urinalysis and urine culture were performed perioperatively. At home, owners monitored urine with dipsticks every 48 hours for 1 month then once a week until 3 months. Dogs returned for assessment of motor function, urinalysis, and urine culture at 1 and 3 months after surgery. Presence of UTI over the 3‐month period was correlated to potential risk factors. Results: Ten dogs (38%) developed 12 UTIs over the 3‐month period, with the majority occurring between weeks 1 and 6; 60% of the UTIs were occult. Hematuria in the absence of pyuria or UTI was a common finding in the perioperative period. Sex, breed, and ambulatory status influenced the risk of developing a UTI. Conclusions and Clinical Importance: There is a high prevalence of UTIs, many of which are occult, in the 3 months after surgery for thoracolumbar IVDE. These dogs should be routinely monitored for UTI with urine culture regardless of urinalysis results.     

Urinary Tract Infection in Dogs with Thoracolumbar Intervertebral Disc Herniation and Urinary Bladder Dysfunction Managed by Manual Expression,Indwelling Catheterization or Intermittent Catheterization

Objective— To evaluate risk factors for lower urinary tract infection (UTI) in dogs with intervertebral disc disease (IVDD) that had manual expression (ME), indwelling catheterization (IDC) or intermittent catheterization (ITC) for urinary bladder management. Study Design— Randomized‐clinical trial. Animals— Dogs (n=62) treated with urinary bladder dysfunction requiring surgery for IVDD and control dogs (n=30) that had surgery for reasons other than IVDD. Methods— Treated dogs were randomly assigned to ME, IDC, or ITC. Urine was collected for culture and antimicrobial susceptibility testing before and after treatment. Incidence and risk factors for UTI were evaluated. Bacterial isolates and antimicrobial resistance patterns were described. Results— Mean (±SD) time to urination was significantly longer for IDC dogs (7.4±2.75 days) than ME dogs (4.2±2.63) and ITC dogs (4.9±3.12). Thirteen treated dogs (21%) and no control dogs developed UTI: 4/25 (16%) ME, 8/25 (32%) IDC, and 1/12 (8%) ITC. Enterobacter sp. was most frequently isolated (4/13; 31%). Duration of treatment was the only risk factor for UTI and each additional day of treatment increased the risk of UTI 1.5 times. Conclusion— For dogs with acute IVDD, the duration of required urinary bladder management establishes the risk of UTI, not the urinary bladder management technique. Clinical Relevance— Duration of treatment for urinary bladder dysfunction is a risk factor for UTI in dogs recovering from acute IVDD. Treatment for urinary bladder management should be limited where possible and no method of treatment is preferred. For dogs managed by IDC, voluntary urination might occur before clinically suspected.     

Surgical Decompression in Dogs with Thoracolumbar Intervertebral Disc Disease and Loss of Deep Pain Perception: A Retrospective Study of 46 Cases

The case details and outcome after surgical decompression of 46 dogs with thoracolumbar intervertebral disc disease with loss of deep pain perception prior to surgery were reviewed. Nineteen dogs (41.3%) recovered with a median follow-up period of 12.5 months. Recovery was defined as an ambulatory paraparesis, or better, with urinary and fecal continence. There was a better outcome in dogs with loss of deep pain for less than 24 hours prior to surgery (19/41; 46.3% recovered) than in dogs without deep pain perception for more than 24 hours (0/5; 0% recovered). Dogs with deep pain perception present at two weeks postoperatively had significantly higher success rate (8/12; 66.7% recovered) than dogs without deep pain perception at this time period (1/10; 10.0% recovered). The return of deep pain perception by two weeks postoperatively can be a useful positive prognostic indicator.     

Spinal Cord Swelling as a Myelographic Indicator of Prognosis: A Retrospective Study in Dogs With Intervertebral Disc Disease and Loss of Deep Pain Perception

The association of myelographic spinal cord swelling with neurological outcome was examined in 46 dogs with intervertebral disc disease and absence of deep pain perception (DPP). Spinal cord swelling was measured by calculating a ratio of the length of the loss of the myelographic dye column to the length of the second lumbar vertebra (L2). A positive neurological outcome was defined as return of voluntary motor function. A cut-off value for swelling:L2 of 5.0 was established by the creation of a receiver operator characteristic curve. Using a swelling:L2 ratio of 5.0 as a cutoff for indication of neurological recovery yielded a sensitivity of 74% and a specificity of 61%. Overall neurological recovery rate was 43%. Dogs with spinal cord swelling: L2 ratios less than 5.0 had a recovery rate of 61%, whereas dogs with a ratio greater than or equal to 5.0 had a recovery rate of 26%. Evaluation of these data by chi square analysis confirmed that a ratio less than 5.0 was associated with a positive outcome, and a ratio greater than or equal to 5.0 was associated with a negative outcome, ( P <.05). Although other factors, such as duration of neurological signs, affect neurological outcome in dogs with no DPP, evaluation of myelographic spinal cord swelling can assist in establishing a prognosis.     

Serial Evaluation of Abdominal Fluid and Serum Amino‐terminal pro‐C‐type Natriuretic Peptide in Dogs with Septic Peritonitis

Background

Serum N‐terminal pro‐C‐natriuretic peptide (NT‐proCNP) has shown promise as a diagnostic biomarker for sepsis. Its sensitivity to detect dogs with septic peritonitis (SP) is reportedly low, perhaps attributable to the compartmentalization of NT‐proCNP in the abdominal cavity.

Objectives

To evaluate the use of an ELISA for the measurement of NT‐proCNP in canine abdominal fluid and to describe the peri‐operative pattern of abdominal fluid and serum NT‐proCNP concentrations in dogs with SP.

Animals

Five client‐owned dogs with nonseptic abdominal effusion of varying etiologies and 12 client‐owned dogs with SP undergoing abdominal surgery and placement of a closed‐suction abdominal drain (CSAD). Six dogs were included upon hospital admission; 6 were included the day after surgery.

Methods

Prospective pilot study. A commercially available ELISA kit was analytically validated for use on canine abdominal fluid. The NT‐proCNP concentrations were measured in the abdominal fluid of control dogs, and in serum and abdominal fluid of dogs with SP from admission for CSAD removal.

Results

In dogs with SP, admission abdominal fluid NT‐proCNP concentrations were lower than the concurrent serum concentrations (P = 0.031), and lower than control canine abdominal fluid concentrations (P = 0.015). Postoperatively, abdominal fluid NT‐proCNP concentrations remained lower than serum concentrations (P < 0.050), except on day 4.

Conclusions and Clinical Importance

The ELISA kit was able to measure NT‐proCNP in canine abdominal fluid. In dogs with SP, low serum NT‐proCNP concentrations cannot be explained by abdominal compartmentalization.     

Evaluation of the Cortisol‐to‐ACTH Ratio in Dogs with Hypoadrenocorticism,Dogs with Diseases Mimicking Hypoadrenocorticism and in Healthy Dogs

Background

The adrenocorticotropic hormone (ACTH) stimulation test is the gold standard for diagnosing hypoadrenocorticism (HA) in dogs. However, problems with the availability of synthetic ACTH (tetracosactrin/cosyntropin) and increased costs have prompted the need for alternative methods.

Objectives

To prospectively evaluate the cortisol‐to‐ACTH ratio (CAR) as a screening test for diagnosing canine HA.

Animals

Twenty three dogs with newly diagnosed HA; 79 dogs with diseases mimicking HA; 30 healthy dogs.

Methods

Plasma ACTH and baseline cortisol concentrations were measured before IV administration of 5 μg/kg ACTH in all dogs. CAR was calculated and the diagnostic performance of ACTH, baseline cortisol, CAR and sodium‐to‐potassium ratios (SPRs) was assessed based on receiver operating characteristics (ROC) curves calculating the area under the ROC curve.

Results

The CAR was significantly lower in dogs with HA compared to that in healthy dogs and in those with diseases mimicking HA (P < .0001). There was an overlap between HA dogs and those with HA mimicking diseases, but CAR still was the best parameter for diagnosing HA (ROC AUC 0.998), followed by the ACTH concentration (ROC AUC 0.97), baseline cortisol concentration (ROC AUC 0.96), and SPR (ROC AUC 0.86). With a CAR of >0.01 the diagnostic sensitivity and specificity were 100% and 99%, respectively.

Conclusion and Clinical Importance

Calculation of the CAR is a useful screening test for diagnosing primary HA. As a consequence of the observed overlap between the groups, however, misdiagnosis cannot be completely excluded. Moreover, additional studies are needed to evaluate the diagnostic reliability of CAR in more dogs with secondary HA.     

Plasma Antithrombin Activity as a Diagnostic and Prognostic Indicator in Dogs: A Retrospective Study of 149 Dogs

Background: Antithrombin (AT) is the major inhibitor of coagulation. In people, hypoantithrombinemia is associated with hypercoagulability, thrombosis, and poor prognosis. Veterinary studies, however, have not demonstrated similar prognostic significance. Thus, AT activity (ATA) in dogs currently is interpreted based on human medicine guidelines. Hypothesis: ATA can serve as a prognostic marker in dogs, as has been shown in people. Objectives: (1) To describe the clinical and clinicopathologic findings, diagnoses, and outcome of dogs with decreased versus normal ATA, (2) to identify diseases and mechanisms associated with hypoantithrombinemia, and (3) to assess ATA as a prognostic indicator. Animals and Methods: Retrospective study of 149 dogs with ATA measurement during their disease course. Results: Hypoantithrombinemic dogs had a higher proportion of leukocytosis, hemostatic abnormalities, hypoalbuminemia, and hyperbilirubinemia versus dogs with normal ATA. Hypoantithrombinemia commonly was present in immune‐mediated hemolytic anemia (IMHA), pancreatitis, hepatopathy, and neoplasia. It was associated with higher risk of mortality in the entire study population and for specific diseases (eg, IMHA, neoplasia). The odds ratio for mortality significantly and progressively increased when ATA was <60 and <30% (9.9, 14.7, respectively). A receiver operating characteristics analysis of ATA as a predictor of mortality showed an area under the curve of 0.7, and an optimal cutoff point of 60% yielded sensitivity and specificity of 58 and 85%, respectively. Conclusions and Clinical Importance: In dogs, ATA <60% indicates increased mortality risk, similarly to human patients, but ATA has limited value as a single discriminating factor in the outcome.