Transcript Hypokalaemia

Hypokalaemia
Normal levels in blood: 3.5 –
5.0mmol/L (Jones, 2011)
Hypokalaemia: symptoms
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Palpitations
Skeletal muscle weakness – cramps
Paralysis, paraesthesias
Constipation
Nausea, vomiting
Abdominal cramp
Polyuria, nocturia, polydispepsia
Psychosis, delerium, hallucinations
Depression
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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
Cushingoid appearence: oedema
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
Hypokalaemia: investigations (Garth et
al., 2009)
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Serum K+ level <3.5mmol/L
Creatinine
Magnesium
Digoxin use?
– Hypokalemia can potentiate digitalis induced arrythmia
• ECG
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T wave flattening
QT prolongation
ST segment depression
Ventricular and atrial arrythmia
• Thyroid function: TSH, free T3, free T4
• ABC
• Cardiac monitoring
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
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
Toxic colitis (Devuni et al., 2009)
• 1st criterion = x ray
• 2nd criterion = any 3 of:
– Fever
– Tachycardia >120bpm
– Leukocytosis
• 3rd criterion = any 1 of:
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Dehydration
Altered mental state
Electrolyte abnormality
hypotension
Toxic colitis (Devuni et al., 2009)
• Inflammatory causes
– Ulcerative colitis, Crohn’s disease,
pseudomembranous colitis
• Infectious colitis
– Salmonella, Shigella, Compylobacter, Yesinia, C. Diff.,
Entanoeba Histolytica, Cytomegalovirus
• Other causes
– Radiation colitis, ischaemic colitis, nonspecific colitis
secondary to chemotherapy, complication of
collangeous colitis (rare)
Toxic colitis: Investigations (Devuni et
al., 2009)
• Nutrition & coagulation panel (group & save) in
case surgery
• Imaging – x-ray then CT: loss of colinic
haustrations, 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
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
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
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
Toxic colitis: patient education(Devuni
et al., 2009)
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Patient Education:
Nutrition (increase K+: bananas, peaches)
IBD (Crohn’s + ulcerative colitis)
Ostomy usually permanent – stoma care team
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
References
• Devuni et al., (2009; online @ medscape). Toxic Megacolon: Clinical
presentation http://emedicine.medscape.com/article/181054overview
• 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_meta
bolic_disorders/electrolyte_disorders/disorders_of_potassium_con
centration.html?qt=disorder%20potassium&alt=sh