VNJ Volume 40 (1) February 2025 | Page 25

Plus-Hex CLINICAL

Patient presentation

A young male labrador retriever was presented to the medical team at a referral centre . The owners informed the team that the patient had developed a reluctance to eat and drink over the previous week . They had noticed muscle twitches , hindlimb paresis and ataxia . These episodes had progressed over the week and become more frequent and severe . Multiple episodes noted by the owners were described as seizures with partial or full loss of consciousness lasting up to 3 min . On clinical examination , the patient presented as quiet and ataxic , with visible tremors and poor overall body and muscle condition . Several abnormalities were identified during the examination , as detailed in Table 1 .

Diagnosis

Venous blood samples were taken to perform analyses , including a blood gas analysis , using an epoc system . Full results of this analysis can be seen in Table 2 , which highlights the parameters outside their reference ranges , including severe hypocalcaemia [ 3 ] . The pO 2 and cSO 2 are severely below the reference ranges due to this sample being a venous blood sample . It is important to consider whether a sample is venous or arterial blood when interpreting the results . All other biochemistry parameters analysed were within their reference ranges . Further blood samples were sent to an external laboratory for measurement of vitamin B12 , folate and parathyroid hormone ( PTH ), and full haematology , including a complete blood count . The PTH results later confirmed the differential diagnosis of primary hypoparathyroidism .

Treatment

A 20 G intravenous catheter was placed in the cephalic vein to provide emergency calcium supplementation and maintenance fluid therapy . The patient was started on 1 ml / kg calcium gluconate 10 % solution intravenously ( IV ) over 30 min . Oral ( PO ) vitamin D ( alfacalcidol ) every 24 hours and PO calcium gluconate ( 500 mg elemental calcium ) every 6 hours were also administered .

Table 2 . Overview of the clinical examination , including normal ranges for an adult dog . *, value outside the reference range .

Parameter ( unit ) Result Reference range pH 7.391 7.350 – 7.450

pCO 2

( mmHg ) 33.1 * 34 – 40

pO 2

( mmHg ) 28 * 85 – 100

cHCO 3

–

( mmol / l ) 23.1 20.0 – 24.0 Base excess ( mmol / l ) – 1.9 – 5 – 0

cSO 2

(%) 52.5 * > 90 Na + ( mmol / l ) 146 139 – 150 K + ( mmol / l ) 4.1 3.4 – 4.9 Ca 2 + ( mmol / l ) 0.53 * 1.12 – 1.40 Cl – ( mmol / l ) 111 106 – 127

cTCO 2

( mmol / l ) 22.3 17 – 25 Haematocrit (%) 50 35 – 50 % cHgb ( g / dl ) 16.9 12.0 – 17.0 Glucose ( mmol / l ) 7.5 * 3.33 – 6.38 Lactate ( mmol / l ) 0.59 * 0.6 – 2.90 BUN ( mg / dl ) 12 10 – 26 Urea ( mmol / l ) 4.3 3.6 – 8.3 Creatinine (µ mol / l ) 86 44 – 115

pCO 2

, partial pressure of carbon dioxide ; pO 2 , partial pressure of oxygen ; cHCO 3

–

, calculated bicarbonate ; cSO 2

, oxygen saturation ; Na + , sodium ; K + , potassium ; Ca ² + , calcium ; Cl – , chloride ; TCO 2

, total carbon dioxide ; cHgb , calculated haemoglobin ; BUN , blood urea nitrogen .

The patient experienced two seizures while in the hospital . The first seizure was successfully managed with diazepam administered IV at a dose of 0.5 mg / kg . Following the second seizure , levetiracetam was administered IV at 30 mg / kg , and oral levetiracetam at 20 mg / kg was then given every 8 hours . This treatment effectively prevented further seizures .

Volume 40 ( 1 ) • February 2025

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