1. Pontine bleed: priorities

• Anticoagulant or antiplatelet use.
• Platelets, INR and aPTT.
• Cavernous malformation, which is common in the pons. Consider MRI/MRV once he is stable.

• SBP above 200 mmHg.
• Pinpoint pupils.
• Abnormal corneal or oculocephalic reflexes.

• Secure the airway and breathing early if GCS is low, there are bulbar signs, or breathing is irregular.
• Give no antithrombotics. Reverse any anticoagulant.
• Give a short-acting IV antihypertensive: nicardipine, clevidipine or labetalol. Goldman-Cecil advises a rapid-onset, short-acting agent to avoid BP lability.
• Surgery rarely helps a pontine bleed. Obstructive hydrocephalus from a fourth ventricle bleed may need an EVD.
• Use mannitol or hypertonic saline only for edema with clinical deterioration. Avoid steroids.
• Treat seizures only if they occur. Don't give prophylaxis.
• Use pneumatic compression for DVT prevention. Add LMWH later if he is stable. Control glucose and fever. Screen for dysphagia.

2. Electrolytes: low K, Ca and PO4 with creatinine 1.6 and hypertension

• Magnesium. This is the most useful single test. Low Mg causes low K, low Ca and low phosphate together. About 40% of hypomagnesemic patients are hypokalemic, and 20% have low Ca, low phosphate or low Na. The hypokalemia can be refractory until Mg is replaced (National Kidney Foundation Primer, Clinical Manifestations of Hypomagnesemia; Brenner and Rector's The Kidney, Electrolyte Homeostasis). Harrison's also notes that low Ca with low Mg may be partly from vitamin D deficiency.
• Albumin or ionized calcium. Correct the calcium. Also check an ECG for QTc and U waves.
• Drugs. Loop or thiazide diuretics, PPIs, laxatives and alcohol can all contribute.

• Malnutrition, malabsorption or alcohol use. Beware refeeding if nutrition is started.
• Vitamin D deficiency with secondary hyperparathyroidism. This lowers Ca and phosphate. It can coexist with CKD, though CKD alone usually raises phosphate.
• Proximal tubulopathy (Fanconi pattern). Look for low K, low phosphate, low urate, glycosuria and metabolic acidosis.
• Hypertension with low K raises the possibility of primary aldosteronism or another mineralocorticoid excess state.
  • Send renin and aldosterone later. Results are unreliable acutely and on many drugs.
  • Check urine K and Cl and the acid-base status.
• Acute brain injury itself can cause renal K and Mg wasting and a catecholamine-driven shift of K into cells.

3. Replacement with eGFR of about 45-50

• Mg first, IV magnesium sulfate. Reduce the dose and monitor levels given his reduced GFR.
• K: replace carefully, IV KCl at no more than 10 mEq/h peripherally (up to 20 mEq/h via central line with monitoring). Recheck every 4-6 hours.
• Fluids: use isotonic fluids and avoid dextrose. Dextrose drives K and phosphate into cells. Avoid hypotonic fluids because they worsen cerebral edema.
• Ca: give IV calcium gluconate if he is symptomatic, QTc is prolonged or Ca is severely low. Correct Mg and vitamin D too.
• Phosphate: replace modestly and cautiously, as the kidneys clear it less well. This matters more if he is ventilated or on nutrition. Monitor for overshoot.
• Keep Na stable. If giving hypertonic saline or mannitol, check Na and osmolality every 4-6 hours.
• Low K, Ca and Mg together prolong the QT interval and raise the risk of arrhythmia and seizures. Keep him on telemetry.

4. Recent evidence

1. Pontine bleed

• Anticoagulant or antiplatelet use.
• Platelets, INR and aPTT.
• A cavernous malformation, which is common in the pons. Consider MRI once he is stable.

• SBP above 200 mmHg.
• Pinpoint pupils.
• Abnormal corneal or oculocephalic reflexes.

• Secure the airway early if GCS is low, there are bulbar signs, or breathing is irregular.
• Give no antithrombotics. Reverse any anticoagulant.
• BP: Use a short-acting IV agent such as nicardipine, clevidipine or labetalol.
  • The book's target is SBP of about 140 mmHg when presenting SBP is 150-220.
  • Going lower, to 110-139, adds no benefit and raised renal adverse events (Goldman-Cecil). That matters with his creatinine of 1.6.
  • Avoid nitroprusside because of raised ICP and thiocyanate accumulation.
• Surgery rarely helps a pontine bleed. Obstructive hydrocephalus from a fourth ventricle bleed may need an EVD.
• Use mannitol or hypertonic saline only for edema with clinical deterioration. Avoid steroids.
• Treat seizures only if they occur. Don't give prophylaxis.
• Use pneumatic compression for DVT prevention. Add LMWH later if he is stable.
• Control glucose and fever. Screen for dysphagia.

2. Electrolytes

• Loop or thiazide diuretics, PPIs, laxatives and alcohol.
• Malnutrition or malabsorption.
• Vitamin D deficiency with secondary hyperparathyroidism. CKD alone usually raises phosphate, so low phosphate points elsewhere.
• Proximal tubulopathy (Fanconi pattern). Look for glycosuria, low urate and metabolic acidosis.
• Primary aldosteronism or another mineralocorticoid excess state, given hypertension with low K. Renin and aldosterone are unreliable acutely, so send them later.
• Acute brain injury itself, which can cause K and Mg wasting and a catecholamine-driven shift of K into cells.

• Mg, albumin or ionized Ca, phosphate, PTH, 25-OH vitamin D, and bicarbonate or ABG.
• Urine K, Na, Cl, glucose and Mg.
• ECG for QTc and U waves.

3. Replacement with eGFR of about 45-50

• Mg first: Give IV magnesium sulfate at a reduced dose, and monitor levels because of his reduced GFR.
• K: Give IV KCl at no more than 10 mEq/h peripherally, or up to 20 mEq/h via a central line with monitoring. Recheck every 4-6 hours.
• Fluids: Use isotonic fluids and avoid dextrose, which drives K and phosphate into cells. Avoid hypotonic fluids because they worsen cerebral edema.
• Ca: Give IV calcium gluconate if he is symptomatic, QTc is prolonged or Ca is severely low. Correct Mg and vitamin D as well.
• Phosphate: Replace modestly and cautiously, as the kidneys clear it less well. Monitor for overshoot.
• If you use mannitol or hypertonic saline, check Na and osmolality every 4-6 hours.
• Low K, Ca and Mg together prolong the QT interval and raise the risk of arrhythmia and seizures. Keep him on telemetry.