Glomerular Disorders

Think of these things when you are investigating intrinsic renal failure.

FeNa < 1%, sodium retention, urine osm high (urine osm low in ATN)
Check 24 hr urine protein


NEPHRITIS
proteinuria
dysmorphic RBCs in urine
RBC casts
WBC casts granular material

Low complement levels - post streptococcal GN, endocarditis, lupus nephritis, & cryo)

Post streptococcal
- subepithelial deposit, humps
- C3, CH50 low for 6-8 wks
- 14 day latency after throat, skin infection
- usually no chronic RF
- check ASO titers
- treat with abx

Nl complement levels- Henoch-Schonlein, IgA nephropathy, Goodpastures, Wegeners

Will finish soon.

Acid/ Base: Quick and Dirty

Acid/Base problems can be really confusing. But, I am going to break it down for you. It will be quick and dirty.

Step 1. Figure out what you have. You know the basics. Metabolic Acidose, Metabolic Alkalosis, Respiratory Acidosis, Respiratory Alkalosis.

Step 2. Based on what you have, you have to do a few simple calculations. Here we go:

Metabolic Acidosis

1. Check the Anion Gap Na + (Cl + Bicarb)
If it is high, check the osmolality (Ya know, that formula you never remember: 2Na + Glucose/18 + BUN/2.8)

Then do calculated osm - measured osm, if it is > 20, then you got one of the ethalene glycol (calcium oxalate stones, woods lamp urine), methanols (oh MY eyes!), isopropyl alcohol (nailpolish remover breath), lactic acidosis or ketoacidosis- start fomepazole if you don't have a good history until you get lab results back

If it is high, also check the stupid delta AG/delta Bicarb gap to look for another "hidden" abnormality

If the patient has a ketoacidosis the ratio of the change in the AG and change in bicarb is usually 1:1, so if you take the change in the AG/1 and the value is less than the actual change in the bicarb (or the actual bicarb is higher), then you have a metabolic alkalosis along with the metabolic acidosis. If it the actual bicarb is lower, than you have a non-gap metabolic acidosis along with the primary disorder

If the patient has a ketoacidosis, the ratio of the change is 1:1.5, so if you take the AG/1.5 and if the value is less than the actual bicarb (or the actual bicarb is higher), then you have a hidden metabolic alkalosis. If the actual bicarb is lower, then you have a NG metabolic acidosis, too!

Another way to look at is Delta AG/Delta Bicarb > 1 -metabolic alkalosis, <1, style="COLOR: rgb(255,204,204)">2. Check if the lungs are working correctly
Winters formula: PCO2= 1.5 (Bicarb) + 8
If the measured PCO2 is higher than expected- respiratory acidosis
If the measured PCO2 is lower than expected- respiratory alkalosis

Metabolic Alkalosis

1. Check to see if the lungs are working
PCO2= 40 + 0.7 (HCO3- 24)
If the measured PCO2 is higher than expected- respiratory acidosis
If the measured PCO2 is lower than expected- respiratory alkalosis

2. Check the Urine Cl
If it is less than 10, saline sensitive, give fluids
If it is greater than 10, it is not saline sensitive and probably mineralocorticoid excess (usually hypertensive)

3. Check the AG and if it is high- go through the steps under the section of metabolic acidosis to make sure you don't have another disorder

4. Check the Delta/Delta gap if the AG is high and go through the process above

Respiratory Acidosis

Acute- the bicarb increases by 1 for every 10 the PCO2 is above 40, the pH decreases by 0.4 for each change of 10

Chronic- the bicarb increases by 3 for every 10 the PCO2 is above 40, the pH decreases by 0.8 for each change of 10

Respiratory Alkalosis

Acute- the bicarb decreases by 1 for every 10 the PCO2 is below 40, the pH increases by 0.4 for each change of 10

Chronic- the bicarb decreases by 5 for every 10 the PCO2 is below 40, the pH increases by 0.8 for each change of 10

Helpful Websites-
Acid Base Online Tutorial

Hypothyroidism

Symptoms: fatigue, wt gain, cold intolerance, constipation, myalgia, menstrual irregularities, depression, coarse features

Causes: Hashimoto’s thyroiditis, sick euthyroid syndrome, thyroidectomy, iodine deficiency or excess, drugs- lithium, amiodarone, infiltrative diseases- fibrous thyroiditis, hemachromatosis, sarcoidosis, congenital thyroid agenesis

Transient causes: painless (lymphocytic) thyroiditis, subacute granulomatous thyroiditis, post partum thyroiditis, subtotal thyroidectomy, following radioiodine for Graves’ dz,

Central hypothyroidism: TSH deficiency, TRH deficiency

3 HYPOTHALAMUS TRH

2 PITUITARY TSH

1 THYROID T4

0 BODY T3

First test TSH, if crazy high, repeat and get free T4

First Test TSH	Second Test Free T4	Clinical Status	Third Test
High	Low	1 Hypothyroidism	none
High	Normal	Subclinical hypothyroidism	TRH (if inc TSH, know it is not pituitary)
High	High	Pituitary hyperthyroidism	none

Screening: women ages 35-50 every 5 yrs

Treatment: T4 (synthroid, levothyroxine), check 3-6 wks for improvement in TSH
Treat subclinical hypothyroidism if sx, goiter, and TSH between 5-15, Treat elderly with low doses, Treat poorly compliant patients with weekly doses

Risk for over treatment: atrial fibrillation

Tips: if CK high, among other things, check TSH, if hyponatremic, check TSH, if hyperlipidemic, check TSH, if surgical patient has hypothyroidism, don’t have to hold surgery, but should treat

Myxedema Coma: treat aggressively, give T4 and T3. Give T3 until clinical improvement.

Sources: UpToDate, MedStudy Endocrinology section

Sepsis

Definitions

Systemic Inflammatory Response Syndrome (SIRS)

Two or more of the following:

Temp >38 or 100.4 or < 36 or 96.8

Heart rate >90/min

Respiratory rate >20/min or arterial blood PCO2 <32

Leukocyte count >12,000 or <4,000>

Sepsis= SIRS + known infection

Sever sepsis= sepsis associated with organ dysfunction, hypoperfusion, or hypotension

(lactic acidosis, oliguria, acute alteration in mental status)

Septic shock= sepsis-induced hypotension and perfusion abnormalities despite adequate fluid resuscitation

Pathophysiology

Abnormalities of coagulation and fibrinolysis which leads to a procoagulant state

Treatment

Treat the underlying cause, mostly with abx

Activated protein C (Xigris)- MHMC gives with strict precaution due to expense and bleeding tendency, need APACHE (Acute Physiology and Chronic Health Evaluation) score to be >24

Source- Infectious Disease Medicine in MKSAP

Hyponatremia: Quick & Dirty

Clinical Manifestations

Serum [Na] > 125 mmol/L

Usually asymptomatic

Serum [Na] 125-130 mmol/L

Predominantly GI symptoms (nausea, vomiting)

Serum [Na] <>

Lethargy, headache, ataxia, psychosis,weakness

Severe cerebral edema - seizures, coma, brain stem herniation, respiratory depression, death

Physiological Manifestations

↓ Serum [Na]

(in the presence of ↓ tonicity)

Shift of water from ECF → ICF

Water enters brain cells

Cerebral edema

Really good article

Adroque HJ, Madias NE. Hyponatremia. NEJM 2000, 342(21): 1581-9.

1. Figure out their volume status
1. Hypovolemic (thirsty, + orthostatics, dry mucus membranes, BUN/Cr)- diuretics, hypoaldosterone, salt-wasting nephropathy

Treat with fluids, hormones, salt

2. Hypervolemic (edema in legs, pulmonary edema)- CHF, Liver disease, nephrotic syndrome

Treat by diuresing, water restriction

3. Euvolemic (none of the above problems)- SIADH

inappropriately secretes ADH, so body doesn’t want to lose water, have very concentrated urine (urine osm- high, urine Na- high), so water stays in the body (serum osm- low)

need to make sure nothing is wrong with thyroid and adrenals (check TSH, cortisol)

treat by free water restriction and sometimes need to replace sodium, if chronic- demeclocycline

psychogenic polydipsia- need to drink 12-20 L a day and urine osm will be low

2. How to Treat
1. Too rapid- central pontine myelinosis
2. Rate of increase should not exceed 0.5 mEq/L/hr
3. In the case of neurologic emergency

Awesome Website

http://www.medcalc.com/sodium.html

Adrogue Formula:
Change in serum Na+ =	(infusate Na+ + infusate K+) - serum Na+
	_____________________________
	total body water + 1

Use the above formula to estimate the effect of 1 liter of any infusate containing sodium and potassium on serum sodium

Infusate Infusate Na+ (mmol/L) 5% NaCl 855 3% NaCl 513 0.9% NaCl (NS) 154 Lactate Ringer's 130 0.45% NaCl (½ NS) 77 0.2% NaCl (¼ NS) 34 5% Dextrose in water (D5W) 0

Total Body Water (in liters) : Children 0.6 x weight Women 0.5 x weight Men 0.6 x weight Elderly Women 0.45 x weight Elderly Men 0.5 x weight

Example

45 yr old 70 kg man, Na 110

Using 3% NS

Change in serum Na= (infusate Na + infusate K) – serum Na/ total body water + 1

= 513- 110/ 0.6 (70) + 1

= 403/ 43

= 9.7

So, 1 liter of 3% NS will bring up this patient’s serum Na by 9.7

Let’s use 0.9% NaCl

= 154 – 110/ 43

= 44/43

= 1

So, 1 liter of 0.9% NS will bring this patient’s serum sodium up by 1

Gen Med Floor Tips

1. Work as a Team- help each other out, start discharge summaries early, help the post-call person, get labs for people, etc…

2. Get organized- keep all of your patient’s info on a card so you’ll know everything on a day-to-day basis

3. Do not leave without signing out to the senior and on-call person

4. Come early and find out everything about what happened to your patient by talking to the on-call person and nurses, check the orders for that night

5. When doing an H&P in the PMHx section, please quantify everything. If patient has COPD, write their last PFTs, if patient has DM, write their last hemoglobin A1C, if patient is coming in for a pneumonia, write down their last few chest xray results (and get the xrays, of course). Write their echos in the the PMHx section. In the HPI section, towards the bottom, write down the vitals of the patient in the ED and write down what they did in the ED to treat the patient.

6. If you need help, are confused or overwhelmed, have a question, don’t hesitate to ask me anything. If you are on-call and unsure how to handle anything, call your senior. Nobody will think that you couldn’t handle it. Everyone will think you are wise to ask for help.

7. If you don’t know something during rounds, just say it. It is okay. But, get the information ASAP.

8. You will be the primary doctor for this patient. You need to write labs that are needed every morning. You will need to make sure social issues are met. Make sure things we ordered in the AM actually happened.

9. When cross-covering on the weekends, find out everything you need to know about the patient. Please don’t say, “This isn’t my patient, so I didn’t know.” Find out.

10. If you order a test, follow it up. Take the time to look at the echo with the cardiologists or watch the EGD.

11. Fill out orange med sheets when the patient is admitted.

12. Read, read, read about your patients. Keep a Washington’s Manual on you. Get a Pocket Medicine by the Mass Gen Hospital. (You have a book fund.)