Hypokalaemia

1. Hypokalaemia Normal levels in blood: 3.5 – 5.0mmol/L (Jones, 2011)

2. Hypokalaemia: symptoms • Palpitations • Skeletal muscle weakness – cramps • Paralysis, paraesthesias • Constipation • Nausea, vomiting • Abdominal cramp • Polyuria, nocturia, polydispepsia • Psychosis, delerium, hallucinations • Depression

3. Physical findings consistent with severe hypokalaemia(Garth et al., 2009) • Ileus • Hypotension • Ventricular arrhythmia • Cardiac arrest • Bradycardia or tachycardia • Premature atrial or ventricular beats • Hypoventilation, respiratory distress • Respiratory failure • Lethargy • Decreased muscle strength • Decreased tendon reflexes • Cushingoidappearence: oedema

4. Hypokalaemia: causes (Garth et al., 2009) • Renal losses and leukemia • GI losses • Diarrhoea and vomiting • Enema, laxative use • Ileal loop • Medications • Diuretics • Beta adrenergic agonists • Steroids • Transcellular shift • Insulin • Alkalosis • Malnutrition • Decreased intake inc. Anorexia nervosa • Parenteral nutrition

5. Hypokalaemia: investigations (Garth et al., 2009) • Serum K+ level <3.5mmol/L • Creatinine • Magnesium • Digoxin use? • Hypokalemia can potentiate digitalis induced arrythmia • ECG • T wave flattening • QT prolongation • ST segment depression • Ventricular and atrialarrythmia • Thyroid function: TSH, free T3, free T4 • ABC • Cardiac monitoring

6. Hypokalemia: treatment (The Merck Manual; online) • 1) oral potassium • Mild to moderate hypokalemia (2.5-3.5mmol/L) • Large dose = GI irritation so give divided doses • Wax impregnated preps better tolerated than liquid preps – take with or after food • 2) IV potassium • Severe hypokalemia: ECG changes or severe symptoms • K+ solution irritate peripheral veins • Concentration should not be more than 40mmol/L • 3) If Hypokalemia induced arrythmia can give more than 40mmol/L must use central vein or multiple peripheral veins • MUST HAVE CONTINUOUS CARDIAC MONITORING AND HOURLY SERUM POTASSIUM • Do not use glucose preparation due to insulin interference (may decrease K+ levels further) • Normally between 100-120mmol/L K+ in 24 hours • Regular Mg and Ca levels

7. Toxic megacolon (Devuni et al., 2009) • a.k.a Toxic Megacolon: clinical term for acute toxic colitis • “toxic colitis” preferred as possible without megacolon dilatation • Potentially lethal • Systemic toxicity • Colonic dilatation = transverse colon >6cm

8. Toxic colitis (Devuni et al., 2009) • 1st criterion = x ray • 2nd criterion = any 3 of: • Fever • Tachycardia >120bpm • Leukocytosis • 3rd criterion = any 1 of: • Dehydration • Altered mental state • Electrolyte abnormality • hypotension

9. Toxic colitis (Devuni et al., 2009) • Inflammatory causes • Ulcerative colitis, Crohn’s disease, pseudomembranous colitis • Infectious colitis • Salmonella, Shigella, Compylobacter, Yesinia, C. Diff., EntanoebaHistolytica, Cytomegalovirus • Other causes • Radiation colitis, ischaemic colitis, nonspecific colitis secondary to chemotherapy, complication of collangeous colitis (rare)

10. Toxic colitis: Investigations (Devuni et al., 2009) • Nutrition & coagulation panel (group & save) in case surgery • Imaging – x-ray then CT: loss of colinichaustrations, possible thumbprinting • Other – ESR, CRP (usually increased). Nb. These findings are supportive not specific • Do not do barium studies due to risk of perforation • CBC counts • Abdominal x-rays every 12 hours

11. Treatment of toxic colitis (Devuni et al., 2009) • 1) reduce colonic distortion • 2) correct fluid and electrolyte imbalance • 3) treat toxemia and precipitating factors • Fluid and electrolyte replenishment should be aggressive at first • Start broad spectrum IV antibiotic e.g. Ampicillin • Stop all meds that reduce colonic mobility e.g. Narcotics, antidiarrhoeals, anticholinergics • Bowel rest consider NG tube. Can use long suction tube but needs fluro placement • Start IV steroids –IV hydrocortisone for pts on steroids • Rolling techniques to redistribute gas • Cyclosporin A: last choice before surgery or if surgery not viable because hideous side effects

12. Toxic colitis: surgical intervention (Devuni et al., 2009) • Early surgical consultation • Consider if no improvement following 48-72 hrs with medical therapy • Perform surgical resection • Subtotal colectomy preferred: • Patient very ill; shorter procedure • Possibilty of ileoanal pouch formation • Approx. 50% Crohn’s patients no rectum involvement

13. Toxic colitis: surgical intervention (Devuni et al., 2009) • Complications: • Perforation after dilatation has reduced • Peritonitis not obvious if steroid use • If only do med management = poor prognosis • Surgical intervention before perforation = excellent results

14. Toxic colitis: patient education(Devuni et al., 2009) • Patient Education: • Nutrition (increase K+: bananas, peaches) • IBD (Crohn’s + ulcerative colitis) • Ostomy usually permanent – stoma care team

15. Toxic colitis: Nursing Priorities • Careful and frequent monitoring • Manual BP and pulse especially if GI patient: monitoring for bleeds (Christine Whitehead lecture – if patient tachy, monitor for BP drop - call doctor!) • Fluid balance – I/O • X-rays • Repeat K bloods +Mg & Ca • NG tube placement • Rolling techniques • Stoma care team involvement/referral if surgery an option • Patient education

16. References • Devuni et al., (2009; online @ medscape). Toxic Megacolon: Clinical presentation http://emedicine.medscape.com/article/181054-overview • Garth, D. Et al (2009; online @ medscape). Hypokalemia in Emergency Medicine: Clinical Presentation. http://emedicine.medscape.com/article/767448-overview • Jones, H. (2011) Nursing and Health – Medical Abbreviations & Normal Ranges: Survival Guide. Pearson Education Ltd. • Merck Manual (online) Disorders of potassium concentration: electrolyte disorders http://www.merckmanuals.com/professional/endocrine_and_metabolic_disorders/electrolyte_disorders/disorders_of_potassium_concentration.html?qt=disorder%20potassium&alt=sh