On physical exam - a dying art

Q: What is uremic frost?

Answer: Uremic frost is a dermatological manifestation of severe azotemia. When the blood urea nitrogen level is high, the concentration of urea in sweat increases greatly. Evaporation of sweat causes urea to crystallize and deposit on the skin.

Q: Beside central diabetes, nephrogenic and gestational diabetes insipidus - what is Dipsogenic Diabetes Insipidus (DI)?


Answer: Dipsogenic DI is due to a defect or damage to the thirst mechanism, which is located in the hypothalamus. This defect results in an abnormal increase in thirst and fluid intake that suppresses ADH secretion and increases urine output.

Clinical significance: Desmopressin (or other drugs) should not be used to treat dipsogenic diabetes insipidus because they may decrease urine output but not thirst and fluid intake. This fluid "overload" can lead to water intoxication, leading to hyponatremia and so brain damage.

There is no effective treatment but some recommends small doses of DDAVP at bedtime to relieve nocturia.

Q: 28 year old patient is admitted to ICU after traumatic brain injury. While evaluating films with radiologist he shows concerns of ischemia to pituitary gland, hypothalamus and surrounding structures. Which treatments you need to be worried if symptoms of Panhypopituitarism develops?


Answer: Pituitary hormones of clinical significance include

• adrenocorticotropic hormone (ACTH),
• follicle-stimulating hormone (FSH),
• luteinizing hormone (LH),
• growth hormone (GH),
• prolactin,
• thyroid-stimulating hormone (TSH), and
• antidiuretic hormone (ADH)

4 essential treatments to keep in mind:

1. Desmopressin acetate (DDAVP) if Diabetes insipidus develops.
2. Hydrocortisone: Should be initiated even before workup is initiated.
3. Levo-thyroxine
4. Reproductive hormones (Estrogen or Testosterone)

Growth hormone is not routinely replaced in adults.

Q: Describe 5 functions of angiotensin II ?


Answer: One of the functions of the kidney is to monitor blood pressure.

Kidney secretes renin.

Renin acts on angiotensinogen, splitting off a fragment called angiotensin I.

angiotensin I is cleaved by a angiotensin converting enzyme (ACE) — producing angiotensin II.

Angiotensin II

• constricts the walls of arterioles closing down capillary beds
• stimulates the proximal tubules in the kidney to reabsorb sodium ions
• stimulates the adrenal cortex to release aldosterone. (Aldosterone causes the kidneys to reclaim still more sodium and water).
• increases the strength of the heartbeat;
• stimulates the pituitary to release the vasopressin.

Q: Name 3 conditions each which may make fibrinogen level to go up or down?


Answer:

Conditions/drugs which may cause decrease fibrinogen levels:

• Anabolic steroids,
• Phenobarbital and
• Valproic acid

Conditions/drugs which may cause increase fibrinogen levels:

• Pregnancy,
• Cigarette smoking, and
• Estrogen

Q: 54 year old male developed life threatening GI bleeding after Fondaparinux (arixtra) administration post orthopedic surgery. FFP and pRBC is ordered and volume resuscitation started. What else can be done to counter effect of Fondaparinux (Arixtra)?




Answer: Recombinant Factor VIIa

Low-molecular-weight heparins are inhibitors of factor Xa, but have small therapeutic window and has the risk of bleeding. Fondaparinux has a long elimination half-life.

rFVIIa overcome the inhibition of thrombin generation and normalize the fondaparinux-induced prolongation of aPTT and PT. Sensitive thrombin-generation assays demonstrated the efficacy of rFVIIa in restoring impaired thrombin formation after fondaparinux administration. rFVIIa reverses not only the anticoagulant effect of fondaparinux but also the profibrinolytic effects of this agent, probably through activation of thrombin-activatable fibrinolysis inhibitor (TAFI).




Reference:

Ability of Recombinant Factor VIIa to Reverse the Anticoagulant Effect of the Pentasaccharide Fondaparinux in Healthy Volunteers - Circulation. 2002;106: 2550

Q: Which is more sensitive bedside diagnostic in ruling out Pneumothorax - CXR or ultrasound (Choose one)?


Answer: Ultrasound

It is now pretty much establish that bedside ultrasound (can be easily learn and perform by intensivist) is more sensitive in detecting pneumothorax.

(see video in this regard in our videos section)



Reference:

Wilkerson RG, Stone MB (January 2010). "Sensitivity of bedside ultrasound and supine anteroposterior chest radiographs for the identification of pneumothorax after blunt trauma". Acad. Emerg. Med. 17 (1): 11–17

Chest tube insertion (2 Parts)

Q: 34 year old male with no medical access in past presented to ER with severe hypertension. On lab workup found to have hypokalemia and metabolic alkalosis. Your first diagnosis?

Hint: Triad of HTN, Hypokalemia and metabolic alkalosis

Answer: Primary hyperaldosteronism

Aldosterone hypersecretion acts on the cortical collecting duct to stimulate potassium secretion into the tubular fluid, enhancing renal potassium wasting.The metabolic alkalosis is due to increased renal hydrogen ion loss mediated by hypokalemia and aldosterone.

A short note on Dopexamine

Dopexamine is basically a β2-adrenergic receptor agonist. It is considered an inotropic agent. It can be use in heart failure for afterload reduction with positive inotropicity. Beside beta2-adrenergic stimulation it also stimulates peripheral dopamine (DA1 and DA2) receptors. Also it inhibits neuronal reuptake of noradrenaline (uptake-1).

Net effect is increase cardiac output through positive inotropism and reduce afterload through increased flow to renal and mesenteric beds. It improves gastric mucosal oxygenation.

Dose is infusion at 0.5 microgram per kg per minute increasing up to 6 micrograms per kg per minute. Central line infusion is recommended. As always with similar drugs patients receiving dopexamine should be monitored with EKG, hemodynamics, urine output etc. It may cause hypotension.

Dopexamine is not approved for use currently in the US or Canada.

Q: One advantage of Dronedarone (Multaq) over Amiodarone is removal of iodine moieties from its compound which decreases the side effects to thyroid, lung and nervous system. What other advantage it is said to have over Amiodarone?



Answer: It has much shorter half life.

Dronedarone is less lipophilic and so has an elimination half-life of only 24 hours in contrast to amiodarone which has half life extended over several weeks.

Q: Can Amiodarone be given to a patient with documented allergy to shellfish or contrast media due to its iodine content?


Answer: Yes - usually its safe


Documented allergies to contrast media or shellfish should not imply that a patient is allergic to iodine. Reactions to contrast media are due to the high osmolar or ionic content of the dye. The primary allergen in shellfish is tropomyosin. No known association exists between amiodarone and reactions to contrast media or shellfish. Unless until true allergy exist specifically for iodine, Amiodarone is usually a very safe medicine from this perspective.