Lab Case 46

A 70 year old man presents after feeling acutely unwell a few hours ago. He complains of weakness, lethargy and a painful knee. On examination he is diaphoretic and looks unwell.

He is currently on treatment for diabetes, heart failure, AF, HTN


BP 160/50

PR 50/min

RR 22/min

T 36 celsius

His blood results are as follows:

Na        124 mmol/l  (134-145)

K          >8.0 mmol/l  (3.4-5.5)

Cl          87 mmol/l  (95-108)

HCO3   16 mmol/l  (22-32)

Urea     25 mmol/l  (3-8)

Creat    286 umol/l  (40-120)

Lactate   15.7  mmol/l  (< 2)

Glucose  40 mmol/l   (4-6)

pH    7.20  (7.36-7.44)

pCO2  43  mmHg (36-44)

urine ketones ++


1. Describe the abnormalities

2. Interpret your findings

3. What are your priorities in treatment?

4. What complications would you consider?




6 thoughts on “Lab Case 46

  1. Moderate acidaemia
    Moderate metabolic acidosis
    Expected pCO2 is 16×1.5 + 8 = 32
    but can’t really comment if venous gas, if arterial, has mild resp acidosis also.

    Strong ion difference = 37 is fine (normal is 38)
    Anion gap is raised at 21
    Delta ratio is 9/8, so isolated HAGMA, with respiratory as mentioned above.

    Critical hyperkalaemia. Expected K for pH is 5.0 + 2×0.5 = 6.0
    Hyponatraemia. Expected Na for Glucose is 35/3 + 124 = 133.
    Severe hyperlactaemia: A – hypoperfusion/shock – from DKA, dehydration
    B1 from sepsis, ?septic joint
    B2 – toxins. Diabetic, ?metformin, but likely T1DM with DKA

    Hypochloraemia – due to hyponatraemia
    Glucose 40, DKA

    Urea, creatinine raised.
    Renal failure, check old results.
    Urea:creat ratio <100. Not pre-renal (but should be with DKA!)

    Ketones in urine – ?DKA, ?starvation

    Moderate metabolic acidosis.
    Unclear re compensation given unknown if venous or arterial gas.

    Likely DKA from septic joint, may not have mounted a fever due to age, not tachy
    due to probable beta-blockers.
    Embolus to limb less likely given history, but a possibility with AF.

    Rehydrate, CSL. Judicious with hx of heart failure.
    ECG, check blood ketones.
    Ca gluconate 10ml 10%
    Ca resonium 30g PR
    Insulin 10units IV (for potassium)
    Bloods, consider knee aspirate for Gram stain, MC+S
    Antibiotics for knee with discussion with ortho.

    Then insulin infusion post fluid, until clearance of ketones.

    100% O2, given very high lactate, check carbon monoxide and cyanide is always a

    High risk of arrhythmia also.

  2. in addition to what simon says, could this be hyperglycaemic hyper osmotic state with profound dehydration and AKI rather than dka.

  3. Abnormalities and Interpretation
    1) Apparent hyponatraemia in context of hyperglycaemia, with a corrected Na of 135
    2) Hyperkalaemia from combination dehydration, renal failure, hyperglycaemia
    3) High anion gap metabolic acidosis. With both ketones and lactate but no significant acidaemia and no ketones mentioned in blood. Osmolality 313. Likely HHS.
    4) Renal failure contributions possibly from dehydration and diabetic nephropathy
    5) high glucose with ketones in urine but no significant acidosis. Likely HHS
    6) leg pain. Arterial thrombus known to complicate HHS. Perhaps secondary to a mural thrombus.

    Priorities in treatment
    1) Give IVH will assist the renal function, help correct the K as well as the hyperglycaemic state.
    2) Correct K, keep in mind that as the BSL lowers so too will the K. Give IV calcium gluconate, bicarbonate, salbutamol neb, Insulin/dextrose as well as resonium
    4) Give insulin infusion to correct hyperglycaemia and also to treat hyperkalaemia
    5) Consider anticoagulation depending on further testing including troponin, doppler US and echo.

    Complications considered
    1) MI and peripheral arterial thrombus (linked to HHS)
    2) Development into DKA which can result in obtundation and the need for intubation
    3) Complications relating to worsening renal failure including oliguria, worsening acidosis, worsening hyperkalaemia requiring dialysis

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