Wednesday, January 29, 2020

PO T4 in ICU

Q: What is the caveat of prescribing oral thyroid replacement therapy in ICU patients who are on continuous tube feed?

Answer:  

Thyroid replacement (T4 or Thyroxine) in either of its forms like gel, capsule or tablet should be ideally taken as an empty stomach. It becomes only of academic importance as many times it is impossible to time the thyroid replacement in ICU patients particularly those who are on continuous tube feeds. Although this may decrease some efficacy of thyroid replacement, it still provides sufficiently required clinical action. 

Another viable option is to provide thyroid replacement in an intravenous (IV) form. According to guidelines, the equivalent IV dose is approximately 75% of the previously established oral dosage
.


#endocrinology


References:


1. PDR: https://www.pdr.net/drug-summary/Synthroid-levothyroxine-sodium-26 (last accessed January 12, 2020) 


2. Bolk N, Visser TJ, Nijman J, et al. Effects of evening vs morning levothyroxine intake: a randomized double-blind crossover trial. Arch Intern Med 2010; 170:1996. 


3. Skelin M, Lucijanić T, Liberati-Čizmek AM, et al. Effect of timing of levothyroxine administration on the treatment of hypothyroidism: a three-period crossover randomized study. Endocrine 2018; 62:432.

Tuesday, January 28, 2020

Liver flow and cardiac tamponade

Q: How hepatic venous flow abnormalities can help in the diagnosis of pericardial tamponade?

Answer: 

Using abdominal ultrasound in cardiac tamponade help in two ways.

1. Hepatic: Although it can be seen only in one-third of patients, hepatic venous flow abnormalities have a high positive (82%) and negative (88%) predictive values for cardiac tamponade. It is seen as

  • blunting or frank reversal of diastolic flow with expiration, and 
  • systolic venous flow predominance
2. Inferior Vena Cava (IVC) plethora: Dilatation and less than a 50 percent reduction in the diameter of the dilated IVC during inspiration, reflects a marked elevation in central venous pressure (CVP). If an IVC plethora is present with pulses paradoxus, there is more than a 90% probability that a patient will require pericardial drainage. Unfortunately, though it is a highly sensitive sign but has no specificity.

#cardiology

#POCUS


References:


1. Mercé J, Sagristà-Sauleda J, Permanyer-Miralda G, et al. Correlation between clinical and Doppler echocardiographic findings in patients with moderate and large pericardial effusion: implications for the diagnosis of cardiac tamponade. Am Heart J 1999; 138:759. 


2.  Himelman RB, Kircher B, Rockey DC, Schiller NB. Inferior vena cava plethora with blunted respiratory response: a sensitive echocardiographic sign of cardiac tamponade. J Am Coll Cardiol 1988; 12:1470. 

Monday, January 27, 2020

"open abdomen" in refractory intracranial hypertension

Q: "open abdomen"  should be given consideration in refractory intracranial hypertension? (select one)

A) True
B) False


Answer: A

In cases of refractory intracranial hypertension mostly after traumatic brain injury, consideration should be given to 'open abdomen' surgery. This is based on the idea that the abdominal decompression lowers the venous pressures, and subsequently augments the venous outflow from the head, resulting in decreased intracranial pressure.


#neurosurgery

#trauma
#surgical-critical-care


Reference:


Joseph DK, Dutton RP, Aarabi B, Scalea TM. Decompressive laparotomy to treat intractable intracranial hypertension after traumatic brain injury. J Trauma 2004; 57:687.

Sunday, January 26, 2020

ET-CO2

Q: End-Tidal CO2 is measured at? (select one)

A) Beginning of inhalation
B) Beginning of exhalation



Answer: A

An end-tidal CO2 is basically a simple graphic measurement of how much CO2 a person is exhaling, so it is the amount of CO2 at the beginning of the inhalation, a peak with maximum CO2. Although ET-CO2 is used in a wide range of pathologies, in ICU they are very helpful in 


  •  Verification and maintenance of placement of the endotracheal tube (ETT) 
  •  Effectiveness of CPR 
  •  Indicator of ROSC during chest compressions 
  •  Determining the adequacy of ventilation

#pulmonary
#ventilators


References:

1. Bhavani-Shankar K, Philip JH. Defining segments and phases of a time capnogram. Anesth Analg. 2000;91(4):973-7.

2. DiCorpo JE, Schwester D, Dudley LS, et al. A wave as a window. Using waveform capnography to achieve a bigger physiological patient picture. JEMS. 2015;40(11):32-35. 


3. Link MS, Berkow LC, Kudenchuk PJ, et al. Part 7: Adult advanced cardiovascular life support: 2015 American Heart Association guidelines update for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation. 2015;132(18 Suppl 2):S444-464. 


4. Gravenstein JS, Jaffe MB, Gravenstein N, et al., editors. Capnography. Cambridge University Press: Cambridge, UK, 2011.

Saturday, January 25, 2020

rebound hypercalcemia in rhabdomyolysis

Q: What is rebound hypercalcemia in rhabdomyolysis?

Answer:  Calcium level go through a rollercoaster ride in rhabdomyolysis. The initial phase is marked by potentially significant hypocalcemia. This is due to 
  • calcium entry into damaged myocytes, 
  • deposition of calcium salts in damaged muscle, and 
  • decreased bone responsiveness to parathyroid hormone
Recovery phase in rhabdomyolysis is characterized by potentially life-threatening rebound hypercalcemia taking a detour of normocalcemia. This is due to 
  • release of calcium from injured muscle, 
  • hyperparathyroidism from the acute renal failure, and 
  • an increase in calcitriol (1,25-dihydroxyvitamin D)

#electrolytes
#musculoskeletal


References:

1. Llach F, Felsenfeld AJ, Haussler MR. The pathophysiology of altered calcium metabolism in rhabdomyolysis-induced acute renal failure. Interactions of parathyroid hormone, 25-hydroxycholecalciferol, and 1,25-dihydroxycholecalciferol. N Engl J Med 1981; 305:117.

2. Akmal M, Bishop JE, Telfer N, et al. Hypocalcemia and hypercalcemia in patients with rhabdomyolysis with and without acute renal failure. J Clin Endocrinol Metab 1986; 63:137.


Friday, January 24, 2020

Necrotizing fasciitis and sodium

Q: Necrotizing fasciitis is more commonly associated with?

A) Hyponatremia
B) Hypernatremia


Answer: A

Although logic argues that sepsis and hypovolemia should cause hypernatremia, laboratory findings in necrotizing fascitis are more commonly associated with hyponatremia. In fact, the degree of hyperkalemia and hyponatremia correlates with the aggressiveness of the disease and should prompt clinicians to expedite the management.


Hyponatremia and part of hyperkalemia occur due to the degree of renal failure which is the surrogate of multiorgan failure. Hyponatremia is also exacerbated by fluid sequestration in affected soft tissue infections.


#nephrology

#infectious-diseases
#electrolytes


References:


1. Espandar R, Sibdari SY, Rafiee E, Yazdanian S. Necrotizing fasciitis of the extremities: a prospective study. Strategies Trauma Limb Reconstr. 2011;6(3):121–125. doi:10.1007/s11751-011-0116-1 

2. Ogilvie CM, Miclau T. Necrotizing soft tissue infections of the extremities and back. Clin Orthop Relat Res. 2006;447:179–186. doi: 10.1097/01.blo.0000218734.46376.89.

Thursday, January 23, 2020

Seizure in ETOH withdrawal

Q: Seizure in alcohol withdrawal syndrome if left untreated can very quickly degenerate into status epilepticus?

A) True
B) False



Answer: B


Status epilepticus is not a feature of alcohol withdrawal-associated seizures. Actually, an astute clinician should quickly start investigating other associated etiologies common in this scenario such as central structural or infectious processes. Seizure in alcohol withdrawal syndrome is usually single or a brief flurry of seizures over a short period. If left untreated, one-third of seizures progress to delirium tremens (DT). Treatment is use of benzodiazepines, phenobarbital, or propofol. Phenytoin is ineffective. Carbamazepine and levetiracetam have been used but their efficacy is not established.

#toxicology

#neurology


References:


1. Victor M, Brausch C. The role of abstinence in the genesis of alcoholic epilepsy. Epilepsia 1967; 8:1. 


 2. Rathlev NK, D'Onofrio G, Fish SS, et al. The lack of efficacy of phenytoin in the prevention of recurrent alcohol-related seizures. Ann Emerg Med 1994; 23:513.

Wednesday, January 22, 2020

ECT

Q: Name a non-psychiatric disease for which electro-convulsive therapy (ECT) can be used?



Answer: Neuroleptic Malignant Syndrome (NMS)

Most of the literature in this regard is anecdotal and based on less than 100 case-reports. ECT can be considered as a last resort for treatment in NMS when drug therapy fails. Although some relationship is suspected with underlying psychiatric disorders particularly catatonia or medications on a patient's profile, the response is found to be not predictable on the basis of age, gender, psychiatric diagnosis or any particular feature of NMS including catatonia. 


#psychiatry

#neurology


References:


1. Trollor JN, Chen X, Chitty K, Sachdev PS. Comparison of neuroleptic malignant syndrome induced by first- and second-generation antipsychotics. Br J Psychiatry. 2012 Jul. 201(1):52-6. 2. 


2. Morcos, N; Rosinski, A; Maixner, D. F. Electroconvulsive Therapy for Neuroleptic Malignant Syndrome. A Case Series. The Journal of ECT: December 2019 - Volume 35 - Issue 4 - p 225–230

Tuesday, January 21, 2020

IVF in DKA & HHNK

Q: Infusion of intravenous (IV) saline in Diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS) serves two main purposes. One is to expand the extracellular volume to achieve euvolemia. What is the second? 


Answer:  Increase of insulin responsiveness.

IV fluid infusion is the most important first treatment required in DKA and HHS (also known as hyperosmotic hyperglycemic nonketotic state - HHNK). Indeed, it achieves the primary goal of expanding vascular volume but a relatively less known effect is the increase of insulin responsiveness. This occurs via three mechanisms 


  •  lowering of plasma osmolality 
  • lowering the vasoconstriction  & improving perfusion 
  • lowering the stress hormone levels

#endocrinology


References:

1. Bratusch-Marrain PR, Komajati M, Waldhausal W. The effect of hyperosmolarity on glucose metabolism. Pract Cardiol 1985; 11:153. 

2. Kitabchi AE, Umpierrez GE, Murphy MB. Diabetic ketoacidosis and hyperglycemic hypersmolar state. In: International Textbook of Diabetes Mellitus, 3rd, DeFronzo RA, Ferrannini E, Keen H, Zimmet P (Eds), John Wiley & Sons, Chichester, UK 2004. p.1101.

Monday, January 20, 2020

Intubating patient with metabolic acidosis

Q: Patients with severe metabolic acidosis may not be able to tolerate Rapid Sequence Intubation (RSI). What is the exact etiology behind it?

Answer:  Patients with severe Metabolic acidosis can deteriorate within seconds, even with a very short apnea episode during RSI. Apnea abruptly halts the compensatory elimination of carbon dioxide, leading to hemodynamic collapse, hard to salvage.

Related podcast:  Intubating the patient with Severe Metabolic Acidosis


Linkhttps://emcrit.org/?powerpress_pinw=37-podcast   (Scott Weingart M.D)


#procedures



References: 

 1. Scott Weingart. Podcast 3 – Laryngoscope as a Murder Weapon (LAMW) Series – Ventilatory Kills – Intubating the patient with Severe Metabolic Acidosis. EMCrit Blog. Published on May 22, 2009. Accessed on January 3rd 2020. 

2. Available at [https://emcrit.org/emcrit/tube-severe-acidosis/. Grant S et al. Ventilator-Assisted Preoxygenation: Protocol for Combining Non-Invasive Ventilation and Apnoeic Oxygenation Using a Portable Ventilator. EMA 2016; 28: 67 – 72. PMID: 26764895

Sunday, January 19, 2020

NBTE and NIE

Q) Which endocarditis is more prone to cause dislodged? 

A) infective endocarditis 
B) non-bacterial thrombotic endocarditis (NBTE) 


 Answer: B

This is due to the fact that vegetations in NBTE (popularly know as Libman-Sacks endocarditis) can get easily dislodged as there is a very little inflammatory reaction at the site of attachment. Subsequently, this can lead to massive cerebral infarction. In systemic lupus erythematosus (SLE) the odds ratio for such event is as high as 13.4 if vegetation is present.


#cardiology

#rheumatology
#infectious-diseaes


Reference:


Roldan CA, Sibbitt WL Jr, Qualls CR, et al. Libman-Sacks endocarditis and embolic cerebrovascular disease. JACC Cardiovasc Imaging 2013; 6:973.

Saturday, January 18, 2020

Propofol in PONV

Q: What is the dose of propofol in postoperative nausea and vomiting (PONV)? 

 
Answer: Propofol can be successfully used as off-label in PONV. The recommended dose is 15 to 20 mg one time. It can be repeated under strict supervision due to the potential of respiratory depression, particularly in post-op patients. A similar dose has also been used with success in chemotherapy-induced resistant N&V.

This also reduces the morphine-induced pruritus, an added advantage in such scenarios. 


#surgical-critical-care

#pharmacology



References: 

 1. Chatterjee S, Rudra A, Sengupta S. Current concepts in the management of postoperative nausea and vomiting. Anesthesiol Res Pract. 2011;2011:748031. 


 2. Chua WY, Wan Mat WR, Md Nor N, Mohammad Yusof A, Masdar A, Abdul Rahman R. Comparing sub-hypnotic doses of propofol to prevent intrathecal morphine-induced pruritus in caesarean delivery. Anesth Analg. 2016;123(3s):p63.

Friday, January 17, 2020

Anti-hypertensive in Marfan

Q: Which group of anti-hypertensives showed to decrease the risks of acute aortic complications in Marfan syndrome by directly improving the elastic properties of the aorta?



Answer: Beta-blockers

Beta-blockers are unique as it has shown not only to decrease the myocardial contractility and pulse pressure but has shown to improve the elastic properties of the aorta, particularly in patients with an increased aortic root diameter.  
The dose is targetted to maintain the heart rate after submaximal exercise to keep less than 100 beats/minute.


Calcium Channel Blockers (CCBs) should be avoided in Marfan syndrome.

#cardiology

#pharmacology
#surgical-critical-care


References:


1. Hiratzka LF, Bakris GL, Beckman JA, et al. 2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine. Circulation 2010; 121:e266. 


2. Loeys BL, Dietz HC, Braverman AC, et al. The revised Ghent nosology for the Marfan syndrome. J Med Genet 2010; 47:476.

Thursday, January 16, 2020

How the "Myasthenic crisis" is defined?

Q: How the "myasthenic crisis" is defined? 

 Answer:  According to International consensus guidance for management of myasthenia gravis (2016), "myasthenic crisis" is defined by increasing respiratory muscle and/or bulbar muscle weakness from the disorder that is severe enough to necessitate intubation.

"Impending myasthenic crisis" is defined as a rapid clinical worsening of myasthenia gravis that, in opinion of the treating clinician, could lead to a crisis in short term (days to weeks).

#neurology




Reference:

Sanders DB, Wolfe GI, Benatar M, et al. International consensus guidance for management of myasthenia gravis: Executive summary. Neurology 2016; 87:419.

Wednesday, January 15, 2020

Off label uses of Gabapentin

Q: Name at least 7 off-label uses of Gabapentin?

Answer: Gabapentin is a versatile drug in the sense that it can be used in many nerve-related situations where the etiology of pain is not clear or the pain is refractory. It includes
  • Chronic refractory cough
  • Fibromyalgia
  • Hiccups
  • Postoperative pain
  • Pruritus including chronic, brachioradial, malignancy-related and uremic
  • Restless legs syndrome
  • Menopause associated vasomotor symptoms
  • Alcohol withdrawal
All of these off labels uses may utilize different doses via different routes. A pharmacy should be consulted before prescribing it, particularly in patients with renal insufficiency and with other medications on board. 

#pharmacology


References:

1. Alonso-Navarro H, Rubio L, Jiménez-Jiménez FJ. Refractory hiccup: successful treatment with gabapentin. Clin Neuropharmacol. 2007;30(3):186-187.


2. American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 141: management of menopausal symptoms [published correction appears in Obstet Gynecol. 2016;127(1):166]. Obstet Gynecol. 2014;123(1):202-216.


3. Arnold LM, Goldenberg DL, Stanford SB, et al. Gabapentin in the treatment of fibromyalgia: a randomized, double-blind, placebo-controlled, multicenter trial. Arthritis Rheum. 2007;56(4):1336-1344.


4. Aurora RN, Kristo DA, Bista SR, et al; American Academy of Sleep Medicine. The treatment of restless legs syndrome and periodic limb movement disorder in adults—an update for 2012: practice parameters with an evidence-based systematic review and meta-analyses: an American Academy of Sleep Medicine clinical practice guideline. Sleep. 2012;35(8):1039-1062.


5. Brower KJ, Myra Kim H, Strobbe S, Karam-Hage MA, Consens F, Zucker RA. A randomized double-blind pilot trial of gabapentin versus placebo to treat alcohol dependence and comorbid insomnia. Alcohol Clin Exp Res. 2008;32(8):1429-1438.


6. Carvalho S, Sanches M, Alves R, Selores M. Brachioradial pruritus in a patient with cervical disc herniation and Parsonage-Turner syndrome. An Bras Dermatol. 2015;90(3):401-402.


7. Cobin RH, Goodman NF; AACE Reproductive Endocrinology Scientific Committee. American Association of Clinical Endocrinologists and American College of Endocrinology position statement on menopause—2017 update [published correction appears in Endocr Pract. 2017;23(12):1488]. Endocr Pract. 2017;23(7):869-880


8. Demierre MF, Taverna J. Mirtazapine and gabapentin for reducing pruritus in cutaneous T-cell lymphoma. J Am Acad Dermatol. 2006;55(3):543-544


9. Furieri FA, Nakamura-Palacios EM. Gabapentin reduces alcohol consumption and craving: a randomized, double-blind, placebo-controlled trial. J Clin Psychiatry. 2007;68(11):1691-1700.


10. Garcia-Borreguero D, Ferini-Strambi L, Kohnen R, et al; European Federation of Neurological Societies; European Neurological Society; European Sleep Research Society. European guidelines on management of restless legs syndrome: report of a joint task force by the European Federation of Neurological Societies, the European Neurological Society and the European Sleep Research Society. Eur J Neurol. 2012;19(11):1385-1396
 


11. Gibson P, Wang G, McGarvey L, Vertigan AE, Altman KW, Birring SS; CHEST Expert Cough Panel. Treatment of unexplained chronic cough: CHEST guideline and expert panel report. Chest. 2016;149(1):27-44. 


12.  
Pande AC, Davidson JR, Jefferson JW, et al. Treatment of social phobia with gabapentin: a placebo-controlled study. J Clin Psychopharmacol. 1999;19(4):341-348.

Tuesday, January 14, 2020

A- line technique

Q: While inserting arterial line which approach has the better chance of first stick success?

A) Direct puncture

B) Use of a guidewire


Answer:  B

Studies have shown that the guidewire approach either separate-guidewire or integral-guidewire has a better chance of success on the first stick than a direct puncture. 


Also, direct puncture takes longer to perform, and more attempts with the use of more catheters.


#procedures




References:


Beards SC, Doedens L, Jackson A, Lipman J. A comparison of arterial lines and insertion techniques in critically ill patients. Anaesthesia 1994; 49:968. 


Mangar D, Thrush DN, Connell GR, Downs JB. Direct or modified Seldinger guide wire-directed technique for arterial catheter insertion. Anesth Analg 1993; 76:714.

Monday, January 13, 2020

CAS and heart valve disease association

Q: Which cardiac valvular disease is found to be a risk factor for poor outcomes in carotid artery stenting (CAS)? (select one)

A) Aortic stenosis
B) Aortic regurgitation


Answer: A

CAS requires an experienced hand as many factors affect the outcome of the procedure including age older than 80, female gender, the burden of calcification and ulceration of carotid plaque, contra-lateral carotid stenosis, prior neck irradiation, high hemoglobin A1C, renal insufficiency, anti-coagulation on board, and emergency admission.


As far as cardiac valvular disease is concerned, aortic stenosis is found to be associated with a higher risk for CAS poor outcomes.


#surgical-critical-care



References:


1. Hofmann R, Niessner A, Kypta A, et al. Risk score for peri-interventional complications of carotid artery stenting. Stroke 2006; 37:2557. 


2. Jackson BM, English SJ, Fairman RM, et al. Carotid artery stenting: identification of risk factors for poor outcomes. J Vasc Surg 2008; 48:74. 


3. Howard VJ, Voeks JH, Lutsep HL, et al. Does sex matter? Thirty-day stroke and death rates after carotid artery stenting in women versus men: results from the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST) lead-in phase. Stroke 2009; 40:1140. 


4.  Donahue M, Visconti G, Focaccio A, et al. Acute Kidney Injury in Patients With Chronic Kidney Disease Undergoing Internal Carotid Artery Stent Implantation. JACC Cardiovasc Interv 2015; 8:1506. 

Sunday, January 12, 2020

snake bite

Q: How the snake bite area should be immobilized in the context of the heart level?

Answer: Immobilization of the snake bite area depends on the type of the snake well known in the local territory. In Australia, where snakes are known to cause neurotoxicity, the bite wound should be kept below the level of the heart. The objective is to minimize the absorption of the venom in the lymphatic system. In North America, snake bites tend to cause more local tissue damage. And, the bite wound may be placed at the level of the heart to manage local swelling but not encourage systemic absorption. Splinting should be applied to minimize the pressure on the tissues

 In any case, some old known and frequently shown treatments in movies are not recommended and should be avoided. It includes incise and sucks out the venom, applying ice or electric shock and, above all applying the tourniquet.


In the United States, the number to call to seek immediate help in case of snakebite is 1-800-222-1222.

#snake-bite

#toxicology


References:


1. Gold BS, Dart RC, Barish RA. Bites of venomous snakes. N Engl J Med 2002; 347:347.


2. Warrell DA. Envenoming and injuries by venomous and nonvenomous reptiles worldwide. In: Wilderness Medicine, 6th Edition, Auerbach PS (Ed), Elsevier Mosby, Philadelphia 2012. p.1040. 


3. Chudnofsky C. Splinting techniques. In: Clinical Procedures in Emergency Medicine, Roberts J, Hedges J (Eds), WB Saunders, Philadelphia, 1998. p.852. 


4. Alberts MB, Shalit M, LoGalbo F. Suction for venomous snakebite: a study of "mock venom" extraction in a human model. Ann Emerg Med 2004; 43:181.

Saturday, January 11, 2020

Meropenem

Q: Meropenem has the advantage of no seizure risk over Imipenem?

A) True
B) False


Answer: B

There is some confusion of Meropenem's advantage over Imipenem that it is preferable due to no seizure risk. It is not proven, though the risk may be lower. The only proven advantage meropenem has over imipenem is it's broader gram-negative and anaerobe coverage. Also, it does not require co-administration with cilastatin. It can be used for bacterial meningitis.


#infectious-diseases



Reference:


Cannon JP, Lee TA, Clark NM, et al. The risk of seizures among the carbapenems: a meta-analysis. J Antimicrob Chemother 2014; 69:2043.

Friday, January 10, 2020

L-sided non-tunneled internal jugular vein central venous dialysis catheter and infection

Q: The left-sided non-tunneled internal jugular (IJ) central venous dialysis catheter has a higher rate of infection in comparison to right-sided?

A) True

B) False

Answer: A

The left-sided non-tunneled internal jugular vein dialysis catheter not only has a higher rate of malfunction but also has a higher rate of infection in comparison to right-sided IJ catheter. The catheter has to make two bends from the insertion site to reach its destination just above the right atrium, one at the clavicular level and other at the superior vena cava (SVC) level. This can causes a higher level of malfunction (flow issues), particularly during Continous renal replacement therapy (CRRT). Subsequently, clinical staff tends to touch/manipulate/handle the catheter relatively more which leads to more infection rates.


#procedures

#infectious-diseases
#nephrology


Reference:


Engstrom BI, Horvath JJ, Stewart JK, et al. Tunneled internal jugular hemodialysis catheters: impact of laterality and tip position on catheter dysfunction and infection rates. J Vasc Interv Radiol 2013; 24:1295.

Thursday, January 9, 2020

Phentolamine to make the diagnosis of Pheochromocytoma

Q: How the Phentolamine is used to make the diagnosis of Pheochromocytoma? 

Answer: 

Since advances in laboratory tests, the use of phentolamine to diagnose pheochromocytoma has become more of academic interest. Said that, it is still of importance for a physician to know its modus operandi for the sake of better comprehension of the disease.

If a physician decides to run a phentolamine test to evaluate pheochromocytoma, it should ideally be performed in an ICU setting as it may mark life-threatening hemodynamic instability. The patient should be put in a supine position in a comfortable non-stimulus environment. Blood pressure should be monitored every 10 minutes for at least 30 minutes, and till patient is at his known hypertensive level. A drop in blood pressure more than 35 mm Hg in systolic, and more than 25 mm Hg in diastolic is considered a positive response. If blood pressure does not change, or decrease is not more than 35 mm Hg in systolic and more than 25 mm Hg in diastolic, the test is considered negative. This is not a confirmatory teat but has a good predictive value. 

With a rapid intravenous injection, the response is expected to be brisk. Blood pressure should be monitored immediately after IV push of phentolamine and every 30 seconds for 3 minutes, and then every minute for 7 minutes. The maximum response is generally achieved within 2 minutes. Phentolamine effect lasts for 15 to 30 minutes.


#cardiology

#procedures


References:


1. Marik PE and Varon J. Hypertensive Crises: challenges and management. Chest. 2007;131:1949-1962. 


2.  McMillian WD, Trombley BJ, Charash WE, et al. Phentolamine Continuous infusion in a patient with pheochromocytoma. Am J Health-Syst Pharm. 2011;68:130-134.

Wednesday, January 8, 2020

AFE definition

Q: Whats the diagnostic criteria of Amniotic Fluid Embolism (AFE)? 

 Answer: 


 Working group of the Society for Maternal-Fetal Medicine (SMFM) and the Amniotic Fluid Embolism Foundation proposed a definition of AFE based on the presence of four diagnostic criteria, all of which must be present


  • Sudden onset of cardiorespiratory arrest or hypotension (systolic blood pressure < 90) with evidence of respiratory compromise
  • Documentation of overt DIC using the scoring system of the Scientific and Standardization Committee on DIC of the International Society on Thrombosis and Haemostasis (ISTH), modified for pregnancy (see reference # 2)
  • Clinical onset during labor or within 30 minutes of placental delivery. 
  •  Absence of fever (≥38°C) during labor

#ob-gyn



References:

1. Clark SL, Romero R, Dildy GA, et al. Proposed diagnostic criteria for the case definition of amniotic fluid embolism in research studies. Am J Obstet Gynecol 2016; 215:408. 


2. Toh CH, Hoots WK, SSC on Disseminated Intravascular Coagulation of the ISTH. The scoring system of the Scientific and Standardisation Committee on Disseminated Intravascular Coagulation of the International Society on Thrombosis and Haemostasis: a 5-year overview. J Thromb Haemost 2007; 5:604. 


3. Stafford IA, Moaddab A, Dildy GA, et al. Evaluation of proposed criteria for research reporting of amniotic fluid embolism. Am J Obstet Gynecol 2019; 220:285.

Tuesday, January 7, 2020

steroid in HCPS

Q: Given the pathology of 'capillary leak' in hantavirus cardiopulmonary syndrome (HCPS) - high dose glucocorticoids are valuable in its management? 

A) True 
B) False


Answer: B

Despite increased risk of cardiopulmonary collapse and respiratory failure due to capillary leak in hantavirus cardiopulmonary syndrome, glucocorticoids failed to show any benefit and are not recommended as an adjunctive treatment.


#Infectious-diseases



Reference:


1. Vial PA, Valdivieso F, Ferres M, et al. High-dose intravenous methylprednisolone for hantavirus cardiopulmonary syndrome in Chile: a double-blind, randomized controlled clinical trial. Clin Infect Dis 2013; 57:943.

Monday, January 6, 2020

D-Dimer in PE during pregnancy

Q: Negative D-Dimer rules out the pulmonary embolism (PE) in pregnancy?

A) True
B) False


Answer: B

D-dimer has a high false-negative rate in pregnancy. It also has a high false-positive rate in pregnancy. D-Dimer has no utility to rule out PE in pregnancy. D-Dimer is a physiologic response in pregnancy and rises during the course of a normal pregnancy. It declines slowly postpartum, and has no normal reference range!


#pulmonary

#OB-Gyn
#hematology


References:


1. Damodaram M, Kaladindi M, Luckit J, Yoong W. D-dimers as a screening test for venous thromboembolism in pregnancy: is it of any use? J Obstet Gynaecol 2009; 29:101. 


2.  To MS, Hunt BJ, Nelson-Piercy C. A negative D-dimer does not exclude venous thromboembolism (VTE) in pregnancy. J Obstet Gynaecol 2008; 28:222.

Sunday, January 5, 2020

murmur in atrial myxoma

Q: Auscultation of murmur in left atrial myxoma sounds to be like murmur of which cardiac valvular disease? 



Answer: mitral stenosis (MS)

Murmur in atrial myxoma occurs when the tumor is moved toward the left atrium through the mitral orifice, and when the flow across the valve is still continuing. The best way to distinguish the murmur of MS and atrial myxoma is by altering patient's position. In experienced hand/ear, the sound of "tumor plop" point towards the diagnosis of left atrial myxoma. ECHO is needed to confirm the diagnosis. 


Similarly, on the other side, right atrial myxoma which is less common than left atrial myxoma has auscultatory findings similar to tricuspid stenosis.


#cardiology

#physical-exam


Reference:


Nasser WK, Davis RH, Dillon JC, et al. Atrial myxoma. I. Clinical and pathologic features in nine cases. Am Heart J 1972; 83:694.

Saturday, January 4, 2020

Modanifil

Q: Modafinil is indicated for shift workers like ICU nurses, intensivists or ED nurses/physicians? (select one)

A) One hour before shift
B) One hour after shift


Answer: A

Modafinil binds to the dopamine transporter and inhibits dopamine reuptake, and increases dopamine levels in different parts of the brain. Said that this mechanism of action is demonstrated in the animal models. Its primary mechanism of action remains elusive.


The prescription should be obtained after thorough workup and under the supervision of an experienced/trained physician. 

#pharmacology




References:


1. Gerrard P, Malcolm R. Mechanisms of modafinil: A review of current research. Neuropsychiatr Dis Treat. 2007;3(3):349–364.


2.  Alertec (modafinil) [product monograph]. Toronto, Ontario, Canada: Teva Canada Limited; June 2019.

Friday, January 3, 2020

AUB and NSAIDS

Q; 32 year old female is admitted to ICU due to hypovolemic shock after having a severe uterine bleed. OB-Gyn service has been called to assist in management. Besides other standard treatment Nonsteroidal anti-inflammatory drug (NSAIDs) has been prescribed as an adjuvant treatment. How the NSAIDS directly help in abnormal uterine bleed (AUB)?

Answer:  NSAIDs decrease the volume of menstrual blood by causing a decline in the rate of prostaglandin synthesis in the endometrium, leading to vasoconstriction and consequently reduced bleeding. Mostly prescribed NSAIDs are Mefenamic acid, Naproxen, and Ibuprofen.

#OB-GYN



References:


1. Rees MC, DiMarzo V, Tippins JR, et al. Leukotriene release by endometrium and myometrium throughout the menstrual cycle in dysmenorrhoea and menorrhagia. J Endocrinol 1987; 113:291. 


2. Smith SK, Abel MH, Kelly RW, Baird DT. Prostaglandin synthesis in the endometrium of women with ovular dysfunctional uterine bleeding. Br J Obstet Gynaecol 1981; 88:434.

Thursday, January 2, 2020

forms of potassium

Q: Which form of potassium administration gives the fastest potassium repletion?

A) Potassium phosphate 
B)  Potassium chloride 
C) Potassium bicarbonate


Answer: B

Out of all three preparations of potassium repletion, potassium chloride raises serum potassium concentration fastest. This is due to the fact that chloride is primarily an extracellular anion and only partially crosses the cell membrane. This is also advantageous in patients who develop hypokalemia from either diuretic therapy or vomiting, and are also chloride deficient. The administration of non-chloride potassium salts provides only 40% of the administrated potassium.


#pharmacology




References:


1. Mount DB. Disorders of Potassium Balance. In: Brenner and Rector's The Kidney, 10, Elsevier, 2016. 


2. KASSIRER JP, BERKMAN PM, LAWRENZ DR, SCHWARTZ WB. THE CRITICAL ROLE OF CHLORIDE IN THE CORRECTION OF HYPOKALEMIC ALKALOSIS IN MAN. Am J Med 1965; 38:172. 


3. Villamil MF, Deland EC, Henney RP, Maloney JV Jr. Anion effects on cation movements during correction of potassium depletion. Am J Physiol 1975; 229:161.