this explains about how to manage a patient with hypokalemia, especially investigation part

1. Approach to a patient with
HYPOKALEMIA
-P.shanmuga sundaram

2. APPROACH
• History of the patient
• Clinical features
• Physical Examination
• Investigation
- Laboratory test
- ECG
• Treatment

3. HISTORY
• Diarrhoea
• Periodic weakness
• Medications (eg: laxatives, diuretics, antibiotics)
• Diet and Dietary habits (eg: licorice )
• Arrhythmia

4. CLINICAL FEATURES
• Neuromuscular: Fatigue, myalgia, and muscular weakness of the
lower extremities.
– Smooth muscle involvement – Constipation, ileus, urinary retention
– progressive weakness, hypoventilation (due to respiratory
muscle involvement), and eventually complete paralysis
• Impaired ability of kidneys to concentrate urine – Polyuria, urine
with low osmolality, polydipsia
• GI manifestations:
– Anorexia, nausea, vomiting
– Constipation, Abdominal distension, paralytic ileus
• CVS – Arrhythmias
• Metabolic alkalosis

5. Drugs causing hypokalemia
• Loop diuretics (eg:furosemide)
• Thiazide diuretics (eg:hydrochlorothiazide)
• Antifungal
• Amphotericin B
• cisplatin

6. PHYSICAL EXAMINATION
Check for
• Blood pressure(hyper, hypotension)
• Volume status(hypovolaemia)
• Signs of
-hyperthyroidism
-cushing’s syndrome

7. INVESTIGATION
• Laboratory test
- electrolytes
- BUN
- urinary pH
- creatinine
- osmolality
• ECG
• Hormones

8. ELECTROLYTES
• Serum potassium level
normal  3.5-5.5 mMol/L
hypokalemia  < 3.5 mMol/L
mild  3.0 – 3.3 mMol/L
moderate  2.5 – 3.0 mMol/L
severe  <2.5 mMol/L
• Urinary pH
- Hypokalemic , alkaline (metabolic alkalosis)

12. Blood pressure

13. Blood pressure

14. • Creatinine
Urinary
K+: creatinine > 13 mMol/g of creatinine
• HORMONES
that decreases the ECF K+ are
-insulin
-aldosterone
-thyroid hormone

15. ECG Changes in Hypokalemia
 Early changes:
• Flattening or inversion of T waves
• Prominent U waves
• ST segment depression
• Prolonged QT interval
 Severe Potassium depletion:
• Prolonged PR interval
• Decreased voltage of QRS
• Widening of QRS complex
• Ventricular arrhythmia

16. The ecg changes are due to
DELAYED VENTRICULAR REPOLARIZATION
Diagnosis is therefore based on ST segment, T
wave & U wave abnormalities

18. Treatment
• Correct volume depletion & Rx of underlying etiology
• serum K+ drops by approximately 0.27 mM for every 100-mmol
reduction in total-body stores
• If mild hypokalemia - start oral K+ supplementation
• If severe hypokalemia – Start I.V K+ infusion
– At Rate of < 20 mEq/hr
Potassium infusion
– In peripheral vein < 40 mEq/L
– In central vein < 60 mEq/L
• Monitor K+ during therapy
• Search for & Rx hypomagnesemia

19. Treatment Contd...
• Preparations Available
– Various salts of K+ : Cl-
, HCO3
-
, Phosphate &
Gluconate salts
– KCl : More effective in hypokalemia with metabolic
alkalosis (e.g. Diuretic usage, Diarrhea)
– KHCO3 / K Citrate : Hypokalemia & metabolic acidosis
(e.g. RTA)

20. Etiology to be corrected
• Discontinue diuretics/laxatives
• Use potassium-sparing diuretics if diuretic
therapy is required (eg, severe heart failure)
• Treat diarrhea or vomiting
• Administer H2 blockers to patients receiving
nasogastric suction
• Control hyperglycemia if glycosuria is present

21. complication
severe hypokalemia
QT prolongation
torsades di pointes
ventricular fibrillation

22. Thank
you