RTA

60 y/o pt presented with Polyuria, polydypsia...only abnormal finding is serum potassium 2.19 and hco3 12 and low ph----------------------------so pt is hving metabolic acidosis and AG is normal....
so two possibilities

1. GI loss
2. RTA

So now have to check Urine PH and Urine AG and Urine K+------------His Urine PH is 5 , UAG positive and urine k+ 30 which is > 25 MEq/l--------------


Type 1 RTA : Decrease H+ secretion from Distal Tubule. Most common cause is Autoimmune disorder Sjogren syndrome
Type 2 RTA: Decrease HCO3 reabsorption from PT .. mcc is multiple myeloma , carbonic anhydrase Inhibitor
Type 4 RTA: Hypoaldosteronism  so increase K+

this pt is having low K+ so obviously this ppt is not hving type 4 RTA....
so differentiate Type 1 vs Type 2 RTA----------give NaHCO3-----------type 1 will response and U HCO3 will be low while in type 2 coz of decreased HCO3 reabsorption ---------urine HCO3 will be high and blood PH also wont have much effect....

Treatment :
type 1: give NaHCO3,  K citrate
Type 2: Give NaHCO3( but wont have much effect coz of abnormal PT), so add  thiazide, K+ citrate
Type 4: give mineralo corticoid----fludrocortisone +/- cortisol , also add diuretic for edema.

Urine Anionic gap

Urine AG  =  Urine (Na  +  K  -  Cl)

measured in normalAG metabolic acidosis..--e.g in  GI loss

The urine AG has a negative value in most patients with a normal AG metabolic acidosis due to the appropriate increase in urinary ammonium in an attempt to excrete the excess acid. Ammonium is an unmeasured cation; as a result, an increase in its excretion as NH4Cl will lead to a rise in the urine Cl concentration and a negative urine AG, usually ranging from -20 to -50 meq/L.

In comparison, patients with renal failure, type 1 (distal) renal tubular acidosis (RTA), or hypoaldosteronism (type 4 RTA) are unable to excrete ammonium normally. As a result, the urine AG will have a positive value .

Urine K+ is also good finding---< 25 meq/L is normal response to GI loss of K+
but if it is > 25 MEq/l with hypokalemia---then suggest RTA type 2

Acidosis discussion

Case: 25 y/o male pt came to ER with altered mental status(AMS)-------
vitals: increased RR, PR and bp150/85
What test You should do in patient with AMS-----do basic metabolic panel(BMP), Urine analyis, Urine Drug screen, ABG.

Na- 139
K- 4
Cl- 102
hco3- 11
BUN 15
Cr 0.8
Glucose 110

ABG----------ph 7.19, Pco2- 24,  po2- 95

Urine drug screen---negative

So this patient is having ph 7.19 which is less then 7.35 so patient is having acidosis----------HCO3( normal 22-26)---11 which is low-----------------so It is metabolic acidosis-----------

Expected decrease in PCO2= 1.2 x ( decrease in HCO3) = 1.2 x  (24-11) = 1.2 x 13 = 16

this pt's PCO2= 24 -----and 40-16= 24------------so this is compensatory respi alkalosis.....

,
Next step is to calculate Anionic Gap= Na - ( HCO3- Cl) = 139- 113= 22
Normal AG = 3 to 12...
so this pt is hving AGmetabolic acisdosis

Causes of Met acidosis--------MUDPILES
this pt has normal S.cr so cant be uremia
normal glucose----so cant be DKA
So next step is t check serum Methanol, Ethanol, blood alcohol, lactic acid, salicylate level....
Blood alcohol , lactic acid and salicylate level normal and plasma osmolar gap is 25 ----so probably ethanol or methanol poisoning....

Management: check ABC, give fomipezol and hemodialysis( because of symptoms) and NaHCO3

Acidosis

Mg correction

Magnesium: normal value= 1.7-2.2 mg/dl

1. Supplement all Mg below 2.0 unless pt has renal failure (around 1.6 is fine, check with resident)

2. For every 0.5 deficit, give 1 g of Mg

3. Magnesium Sulfate 1 g IV (run over 1 hour) or 400mEq MgOxide po BID or TID

ER

1. Pt having Chest Pain- 
#1- Ask nurse for their vitals, if on monitor, ask if they are having EKG changes. Order Stat Cardiac enzymes, EKG, tell nurse to give pt Morphine, NTG, O2. 
#2- GO SEE THE PATIENT NOW!



2. Pt Aggitated/Mental status change- 
#1- Ask the nurse for vitals, Find out if this is baseline, or if this is new,
#2-Go see the patient, Check their meds and see if something you are giving might have caused it,
#3- Check UA (especially in older pts), ABG, Chem 7, #4- Haldol 5mg IV x1 if needed.

K+ correction

Potassium correction....
noraml value= 3.5 to 5 meq/l

Supplement K+ if it is below 3.5 meq/l
in Renal failure pt( look at s. cr...) supplement if k+ below 3.o meq/l

availble forms:
K-Dur 10mEq PO (tablet)
K-Lyte 25mEq PO (liquid): Has a lot of bicarb so if pt is alkolotic give KCl
K-Phos 2 tabs PO
K-Phos 10mmol IV (run over one hour)
Give 10mEq for every 0.1 below 4.0 so if K+ = 3 then give 100 meq
KCl 10mEq IV (run over one hour)

available forms: Potassium chloride (also citrate, acetate, bicarbonate, gluconate)
Adult
IV replacement: 10-40 mEq IV infused over 2-3 h; infusion rate not to exceed 40 mEq/h; may repeat q3-4h prn; modify infusion rate for specific requirements
PO supplementation: 50-100 mEq/d PO divided bid/tid or qd as SR formulation; larger doses may be needed in severe depletion to replenish potassium body storage

Pediatric
Usual dose for potassium replacement: 0.5-1 mEq/kg IV; not to exceed 30-40 mEq/dose
Infusion rate not to exceed 0.3-0.5 mEq/kg/h for noncritical hypokalemia; however, this rate may be inadequate in life-threatening hypokalemia
Infusion rates: >0.5 mEq/kg/h can be delivered but requires ECG monitoring to detect potentially fatal arrhythmia, especially ventricular dysrhythmia, because it can rapidly lead to cardiac arrest
PO supplementation is based on body weight, ranging from 2-4 mEq/kg/d PO in divided doses to avoid gastric distress

IV fluid and electrolytes management

I am gonna start with Fluid and electrolyte management….I know it’s quite a boring topic but we gotta know basic principle and am sure many of us are not aware of basics and do it blindly..so Lets start …

Case 1-50 y/o patient admitted to hospital for Pancreatitis so patient cant take anything PO to give rest to Pancreas and to decrease enzyme release from pancreas..

Case 2 -50 y/o patient admitted for diarrhea…with BP= 90/60 pr= 112 RR=14

So here we have two different pt..

1^st patient – patient is not hypovolemic but gonna be NPO so prophylactically we need to give MAINTENCE FLUID.

2^nd patient- seems hypovolemic so here we need to give something to replace lost body volume k/s REPLACEMENT THERAPY

Maintenance therapy: We need to give

1. Water—2L
2. Glucose: to prevent catabolism and anorexic ketoacidosis- 100 to 150 gm/day
3. Electrolyte mainly Na+ and K+-----------75 to 175 meq of Na+ in the form of NaCl and K+ 20 to 60 meq in the form of KCL in a day

Means as a maintenance therapy we need to give dextrose + ½ NS + KCl

Why ½ NS ?? why not NS??? ----------½ NS because water will go both ICF and ECF compartment while NaCl will go only in ECF… ½ NS = 77 meq of Na+ ---so 2 L of 1/2 NS will provide approx. 154 meq of NaCl so if we provide ½ NS ECF will get 154 Na+ and 1 L of water and ICF will get 1L of water

How to calculate rate of Maintenance IV fluid: Now usual requirement of water is 2L/day on average …so if we divide 2000ml/24 hours---roughly it is 83.33ml/hr…

( How did I calculate 2L/d fluid requirement??: Loss of fluid in a day: 800ml to 2200ml ~~ 1L urine+ 200ml stool+ 400-500 ml insensible loss – 200 ml gain of water because of endogenous metabolism--------- roughly 2L requirement)

Now 1 drop= 1/12 ml----------------------so if we give 83 ml in 1 hr-----------we have to give 83* 12 drops ~ 1000 drops/ hr-----------16 drops/min.

Replacement Therapy:

For replacement therapy we need to calculate loss of body volume:

Estimated Percentage Dehydration	Physical Examination Findings
<5	History of fluid loss but no findings on physical examination
5	Dry oral mucous membranes but no panting or pathological tachycardia
7	Mild to moderate decreased skin turgor, dry oral mucous membranes, slight tachycardia, and normal pulse pressure.
10	Moderate to marked degree of decreased skin turgor, dry oral mucous membranes, tachycardia, and decreased pulse pressure.
12	Marked loss of skin turgor, dry oral mucous membranes, and significant signs of shock.

We cant replace whole lost volume but need to replace just 80% of lost. Following is formula for deficit volme:

Deficit replacement volume (ml) = % dehydration x body weight (kg) x 1000 x 0.80

So in our pt, it would be------- 0.10 x 60 x 1000 x 0.80= 480 ml

So we need to give 480 ml bolus….

What is the rate of IV bolus-----------500ml/hr---------means 500 x 12= 6000 drops/hr-----------100drops/min

http://www.cvmbs.colostate.edu/clinsci/wing/fluids/fluids.htm