CBF and PaCO2

Q: Cerebral blood flow (CBF) decreases by what percentage per drop of each mm Hg in the arterial partial pressure of carbon dioxide (PaCO2)?



Answer:  2%

The objective of the above question is to highlight the relationship between respiratory alkalosis (R-Al) and cerebral blood flow. Hypocapnia in R-Al causes cerebral artery vasoconstriction, resulting in reduced cerebral blood flow. 

 CBF decreases by 2% for every 1 mm Hg drop in PaCO2.

#pulmonary
#neurology
#acid-base


Recommended reads:

1. Yoon S, Zuccarello M, Rapoport RM. pCO(2) and pH regulation of cerebral blood flow. Front Physiol. 2012;3:365. Published 2012 Sep 14. doi:10.3389/fphys.2012.00365 

2. Ito H, Kanno I, Ibaraki M, Hatazawa J, Miura S.Changes in human cerebral blood flow and cerebral blood volume during hypercapnia and hypocapnia measured by positron emission tomography. J Cereb Blood Flow Metab. 2003 Jun;23(6):665-70.

ETT exchange

Q: Video laryngoscopy is recommended for the Endo-tracheal tube (ETT) exchange? 

A) True
B) False



Answer: A

Exchange of ETT is a serious business as it can very quickly degenerate into a life-threatening situation with loss of airway leading to cardiac arrest. It should be carried out by an experienced provider or at least with an immediate backup of an expert. Usually, exchange of ETT is carried out in similar fashion as the placement of a new ETT. The same level of vigilance, preparation and medications should be used. It is usually of help to visualize the vocal cord prior to exchange of ETT with direct blade or video laryngoscope. 

At least one recent prospective study of 328 patients in whom the vocal cords were not easily visualized using direct blade laryngoscopy, comparing with historical controls, video laryngoscopy reduced the number of attempts for ETT exchange from 92 to 68 percent in first attempt, and lesser complications such as hypoxemia, esophageal intubation, bradycardia, and need for back up.

#procedure


Reference:

Mort TC, Braffett BH. Conventional Versus Video Laryngoscopy for Tracheal Tube Exchange: Glottic Visualization, Success Rates, Complications, and Rescue Alternatives in the High-Risk Difficult Airway Patient. Anesth Analg 2015; 121:440.

Fentanyl

Q; Fentanyl is? (select one) 

A) lipophilic 
B) hydrophilic


Answer: A

The objective of the above question is to emphasize the fact that though fentanyl is short-acting, due to its highly lipophilic state it rapidly gets distributed to highly perfused tissues i.e., brain, heart, kidney, and gastrointestinal tract followed by slower redistribution to muscle and fat tissues. This accumulated storage results in prolonged sedation and respiratory depression even when fentanyl is discontinued.

#pharmacology
#sedation
#analgesia


References:

1. Choi, Leena PhD; Ferrell, Benjamin A. MD; Vasilevskis, Eduard E. MD, MPH; Pandharipande, Pratik P. MD, MSCI; Heltsley, Rebecca PhD; Ely, E. Wesley MD, MPH; Stein, C. Michael MB, ChB; Girard, Timothy D. MD, MSCI - Population Pharmacokinetics of Fentanyl in the Critically Ill - Critical Care Medicine: January 2016 - Volume 44 - Issue 1 - p 64–72 

2. Kuip EJ, Zandvliet ML, Koolen SL, Mathijssen RH, van der Rijt CC. A review of factors explaining variability in fentanyl pharmacokinetics; focus on implications for cancer patients. Br J Clin Pharmacol. 2017;83(2):294–313. doi:10.1111/bcp.13129


3.Gourlay GK, Murphy TM, Plummer JL, Kowalski SR, Cherry DA, Cousins MJ: Pharmacokinetics of fentanyl in lumbar and cervical CSF following lumbar epidural and intravenous administration. Pain 1989; 38:253-9

Vitamin A intoxication

Q: 53 year old male with End-Stage renal Disease (ESRD) starts taking over the counter (OTC) multi-vitamin supplements. Patient presented with severe headache and is admitted to ICU after neurology service diagnosed him with pseudotumor cerebri. Patient was also found to have  Vitamin A intoxication. Patient is also likely to have? (select one)

A) Hypocalcemia
B) Hypercalcemia


Answer: B

Patients with ESRD should be prescribed or be cautioned against using OTC supplements. Vitamin A intoxication is a potential concern in these patients. Hypervitaminosis A may cause nausea, headache, fatigue, irritability, anorexia, hepatomegaly, and pseudotumor cerebri. It also causes hypercalcaemia due to the effect of vitamin A on bone, most likely an osteolytic effect.

#toxicology
#nephrology
#neurology


References:

1. Hammoud D, El Haddad B, Abdallah J. Hypercalcaemia secondary to hypervitaminosis a in a patient with chronic renal failure. West Indian Med J. 2014;63(1):105–108. doi:10.7727/wimj.2011.171 

2.  Lippe B, Hensen L, Mendoza G, Finerman M, Welch M. Chronic vitamin A intoxication. A multisystem disease that could reach epidemic proportions. Am J Dis Child. 1981;135:634–636.

3. Farrington K, Miller P, Varghese Z, Baillod RA, Moorhead JF. Vitamin A toxicity and hypercalcaemia in chronic renal failure. Br Med J (Clin Res Ed) 1981;282:1999–2002.

Symmers' pipestem fibrosis

Q: What is Symmers' pipestem fibrosis? 


Answer: The periportal fibrosis in Schistosomiasis is called Symmers' pipestem fibrosis.

The clinical course of Schistosomiasis is hallmarked by the host immune response to migrating eggs. Adult worms absorb host proteins and coat themselves with host antigens. This allows them to have a prolonged residence in the bloodstream evading immune attack. indolently, migration of eggs through tissues is associated with entrapment, inflammation, and subsequent fibrosis. Eggs are carried via the splanchnic venous system and may embolize to the liver, lungs, spleen, brain, or spinal cord.

#infectious-diseases
#hepatology


References: 

1. Gryseels B, Polman K, Clerinx J, Kestens L. Human schistosomiasis. Lancet 2006; 368:1106.

2. Pearce EJ. Priming of the immune response by schistosome eggs. Parasite Immunol 2005; 27:265.

3. Keating JH, Wilson RA, Skelly PJ. No overt cellular inflammation around intravascular schistosomes in vivo. J Parasitol 2006; 92:1365. 

4. Coutinho HM, Acosta LP, Wu HW, et al. Th2 cytokines are associated with persistent hepatic fibrosis in human Schistosoma japonicum infection. J Infect Dis 2007; 195:288.

Barthel Index

Q: What is Barthel Index? 

Answer: The Barthel Index (BI), developed almost 55 years ago, is an index of physical dependency after stroke. It accounts for 10  basic needs: 

1. Feeding 
2. Bathing 
3. Grooming 
4. Dressing 
5. Bowels 
6. Bladder 
7. Toilet use 
8. Transfers 
9. Mobility 
10. Stairs 

• A normal score is 100
• BI more than 60 is consistent with assisted independence 
• BI less than 40 represents severe dependency  

The reason for intensivists to be aware of this scale as it correlates with infarct size and may predict outcome after stroke. Also, it is frequently used as an outcome measure for stroke trials.

#Neurology


References:

1. MAHONEY FI, BARTHEL DW. FUNCTIONAL EVALUATION: THE BARTHEL INDEX. Md State Med J 1965; 14:61. 

2. Quinn TJ, Langhorne P, Stott DJ. Barthel index for stroke trials: development, properties, and application. Stroke 2011; 42:1146. 

3. Saver JL, Johnston KC, Homer D, et al. Infarct volume as a surrogate or auxiliary outcome measure in ischemic stroke clinical trials. The RANTTAS Investigators. Stroke 1999; 30:293.

4. Huybrechts KF, Caro JJ. The Barthel Index and modified Rankin Scale as prognostic tools for long-term outcomes after stroke: a qualitative review of the literature. Curr Med Res Opin 2007; 23:1627. 

Angiotensin II

Q: Which of the inotrope has a withdrawal of neurohormonal vasoconstrictor mechanisms such as angiotensin II and norepinephrine?    (select one)

A) milrinone 
B)) dobutamine 


Answer: B

Dobutamine and digoxin increase the cardiac output by the withdrawal of neurohormonal vasoconstrictor mechanisms such as angiotensin II and norepinephrine. In other words, they negate each other's effects. The objective of the above question is to bring to the attention its uses with Angiotensin II agonists. Angiotensin II infusions are now widely used in ICUs for different kinds of shocks. Drug interactions should be considered prior to combine the therapies in cardiogenic shock.


#hemodynamics


Recommended read:

Laurence W. Busse, Michael T. McCurdy, Osman Ali, Anna Hall, Huaizhen Chen & Marlies Ostermann The effect of angiotensin II on blood pressure in patients with circulatory shock: a structured review of the literature Critical Care volume 21, Article number: 324 (2017)

Amio in HD patients

Q: Amiodarone is dialyzable and may not be effective if a patient is on continuous renal replacement therapy  (CRRT)? (select one)

A) True
B) False


Answer: B

The objective of the above question is to clear the statements found at few places that Amiodarone is dialyzable. But it is only up to 5% and has barely any clinical significance. This is true for all forms of dialysis including CRRT, intermittent hemodialysis or peritoneal dialysis.

#nephrology
#pharmacology


References:

Khouri Y, Stephens T, Ayuba G, AlAmeri H, Juratli N, McCullough PA. Understanding and Managing Atrial Fibrillation in Patients with Kidney Disease. J Atr Fibrillation. 2015;7(6):1069. Published 2015 Apr 30. doi:10.4022/jafib.1069

Combining Aminoglycosides with antistaphylococcal penicillins or vancomycin in SA bacteremia

Q: Aminoglycosides should be combined with antistaphylococcal penicillins or vancomycin for the treatment of Staphylococcus aureus (SA) bacteremia due to their synergistic effect? (select one) 

A) Yes 
B) No


Answer: B

Although it is true and was a popular and a recommended practice to combine aminoglycosides with antistaphylococcal penicillins or vancomycin for treatment of S. aureus bacteremia, recent data and guidelines suggest against it. It may do more rapid clearing of bacteremia but found to be associated with a higher incidence of kidney dysfunction.

#infectious-diseases


References:

Fowler VG Jr, Boucher HW, Corey GR, et al. Daptomycin versus standard therapy for bacteremia and endocarditis caused by Staphylococcus aureus. N Engl J Med 2006; 355:653. 

Cosgrove SE, Vigliani GA, Fowler VG Jr, et al. Initial low-dose gentamicin for Staphylococcus aureus bacteremia and endocarditis is nephrotoxic. Clin Infect Dis 2009; 48:713.

PSH

Q: Paroxysmal sympathetic hyperactivity (PSH) after traumatic brain injury (TBI) is? (select one) 

A) symmetric 
B) asymmetric


Answer: A

Paroxysmal sympathetic hyperactivity (PSH), popularly known as sympathetic storm is a disorder of regulation of autonomic function commonly seen with severe traumatic brain injury. The presentation is usually very dramatic with tachycardia, systolic hypertension with elevated pulse pressures, tachypnea, diaphoresis, sometimes high fever, and in severe cases dystonic posturing which is typically symmetric.

#neurology




References:

Hughes JD, Rabinstein AA. Early diagnosis of paroxysmal sympathetic hyperactivity in the ICU. Neurocrit Care 2014; 20:454. 

 Perkes IE, Menon DK, Nott MT, Baguley IJ. Paroxysmal sympathetic hyperactivity after acquired brain injury: a review of diagnostic criteria. Brain Inj 2011; 25:925.

Rheolytic embolectomy

Q: What is Rheolytic embolectomy in pulmonary embolism (PE)?

 Answer: Data is very limited and efficacy is not fully established but rheolytic embolectomy consists of injecting pressurized saline through the catheter's distal tip while macerated thrombus is being aspirated through a catheter port.

This technique should be used in selected cases as it requires a venous cut-down for the insertion of the catheter. It is also suggested that the release of adenosine from disrupted platelets can lead to bradycardia, vasospasm, and hypoxia, and red blood cell fragmentation can result in hemoglobinuria. It is suggested to utilize this route when systemic thrombolysis fails in PE.

#procedures
#pulmonary


References:

1.  Kuo WT, van den Bosch MAAJ, Hofmann LV, et al. Catheter-directed embolectomy, fragmentation, and thrombolysis for the treatment of massive pulmonary embolism after failure of systemic thrombolysis. Chest 2008; 134:250. 

2. Chechi T, Vecchio S, Spaziani G, et al. Rheolytic thrombectomy in patients with massive and submassive acute pulmonary embolism. Catheter Cardiovasc Interv 2009; 73:506. 

3. Margheri M, Vittori G, Vecchio S, et al. Early and long-term clinical results of AngioJet rheolytic thrombectomy in patients with acute pulmonary embolism. Am J Cardiol 2008; 101:252. 

4. Ferrigno L, Bloch R, Threlkeld J, et al. Management of pulmonary embolism with rheolytic thrombectomy. Can Respir J 2011; 18:e52.

vecuronium and RSI

Q: Why Vecuronium is not recommended as an alternative to succinylcholine for Rapid Sequence Intubation (RSI) despite its good hemodynamic profile?


Answer: Vecuronium is not recommended as an alternative to succinylcholine for RSI due to its slower onset time of three to four minutes. The clinical duration of action is 25 to 50 minutes. Also, it is excreted both through the biliary and renal routes, and patients with renal or hepatic dysfunction may have a prolonged response to vecuronium. 

 If vecuronium is used for intubation, it requires a priming dose of 0.01 mg/kg at least three minutes prior to an intubating dose of 0.15 mg/kg.

#pharmacology
#procedures


Reference:

Baumgarten RK, Carter CE, Reynolds WJ, et al. Priming with nondepolarizing relaxants for rapid tracheal intubation: a double-blind evaluation. Can J Anaesth 1988; 35:5.

Naloxone dose

Q: In patients who go into cardiorespiratory arrest due to opioid overdose, the initial recommended dose of naloxone is?

A) .02 mg
B) .04 mg
C) .08  mg
D) 1 mg
E)  2 mg


Answer: E

Naloxone should be given in opioid toxicity depending on the clinical scenario. If a patient is spontaneously breathing, an initial dose of 0.04 mg intravenously (IV) is recommended. But if a patient is found to or near apnea, an initial dose of 1 mg can be tried to prevent impending respiratory failure and labor of ventilator. Patients in cardiorespiratory arrest due to opioid toxicity should receive an initial dose of a minimum of 2 mg.

#toxicology


Reference:

Berlot G, Gullo A, Romano E, Rinaldi A. Naloxone in cardiorespiratory arrest. Anaesthesia 1985; 40:819.

JVP

Q: 54 year old male is admitted to ICU with shortness of breath (SOB). On exam, the lower part of the right ear lobe is found to be pulsating. What is the probable cause of SOB?


Answer: Exacerbation of CHF

Examination of Jugular Venous Pressure (JVP) is essential in exacerbation of congestive heart failure (CHF). The objective of the above question is to highlight the fact that frequently very high JVP can be missed as the pulsation may be hidden high up in the neck! In such patients, it is not unusual to have a pulsatile lower part of the ear lobe. JVP is a reliable prognostic sign and its presence or absence has been found to be correlated with a subsequent increased risk of death.

#cardiology
#physical-exam


References:

1. Ambrosy AP, Pang PS, Khan S, et al. Clinical course and predictive value of congestion during hospitalization in patients admitted for worsening signs and symptoms of heart failure with reduced ejection fraction: findings from the EVEREST trial. Eur Heart J 2013; 34:835.


2. Sinisalo J, Rapola J, Rossinen J, Kupari M. Simplifying the estimation of jugular venous pressure. Am J Cardiol 2007; 100:1779.

anticoagulation in APS

Q: In patients with antiphospholipid syndrome (APS) who require anticoagulation, which of the following is preferred drug? 


A) warfarin 
B) rivaroxaban 
C) dabigatran 
D) apixaban 
E) edoxaban


Answer: A

Direct oral anticoagulants (DOACs) are fastly getting popular but there are few instances where either warfarin or heparin is still preferred. These include prosthetic heart valves, pregnancy, renal impairment, severe liver disease and antiphospholipid syndrome. 

In antiphospholipid syndrome (APS), warfarin is still a preferred anticoagulation as there is no substantial supportive data available in the favor of DOACs.

#pharmacology
#rheumatology 


Reference:

Garcia D, Erkan D. Diagnosis and Management of the Antiphospholipid Syndrome. N Engl J Med 2018; 378:2010-2021

dyspnea

Q: The official consensus definition of dyspnea from the American Thoracic Society includes all of the following factors except? 

A) physiological
B) psychological
C) anatomical
D) social
E) environmental 


Answer: C

The consensus statement from the American Thoracic Society defines dyspnea as: 

 "Dyspnea is a term used to characterize a subjective experience of breathing discomfort that is comprised of qualitatively distinct sensations that vary in intensity. The experience derives from interactions among multiple physiological, psychological, social, and environmental factors, and may induce secondary physiological and behavioral responses."

#pulmonary


Reference:

Parshall MB, Schwartzstein RM, Adams L, et al. An official American Thoracic Society statement: update on the mechanisms, assessment, and management of dyspnea. Am J Respir Crit Care Med 2012; 185:435.

Hydralazine in CHF

Q: 54 year old male is recovering in ICU from exacerbation of congestive heart failure (CHF). Hydralazine has been added to the drugs regimen. Which one test should be obtained?


Answer: Antinuclear antibody level

Hydralazine carries the risk of drug-induced lupus. It is recommended to check the baseline antinuclear antibody level before starting hydralazine. Also, it should be checked periodically while patient stays on hydralazine.

#pharmacology
#cardiology


References: 

1. Finks SW, Finks AL, Self TH. Hydralazine-induced lupus: maintaining vigilance with increased use in patients with heart failure. South Med J. 2006;99(1):18-22. 

2. Mansilla-Tinoco R, Harland SJ, Ryan PJ, et al. Hydralazine, antinuclear antibodies, and the lupus syndrome. Br Med J. 1982;284(6320):936-939.

ASA poisoning

Q: Salicylate poisoning causes? (select one)

A) Hyperpnea and tachypnea
B) Hypopnea and tachypnea


Answer: A

The objective of the above question is to highlight that in salicylate (aspirin) poisoning, one of the physical signs is not only the increased rate but also the increased depth of the respiration, called hyperpnea. This becomes more vital to identify as this is one of the earliest sign of salicylate poisoning. Later it may culminate into hypoventilation and respiratory failure due to muscles fatigue. This is a central effect due to the activation of the respiratory center of the medulla.

#toxicology
#pulmonary


References:

1. Hill JB. Salicylate intoxication. N Engl J Med 1973; 288:1110. 

2. Greenberg MI, Hendrickson RG, Hofman M. Deleterious effects of endotracheal intubation in salicylate poisoning. Ann Emerg Med 2003; 41:583.

NSF

Q: All of the following have been considered as risk factors for Nephrogenic systemic fibrosis (NSF) except? 

 A) high-dose erythropoietin treatment
B) metabolic acidosis
C) proinflammatory conditions
D) elevated calcium levels 
E) elevated phosphate levels


Answer: D 

Nephrogenic systemic fibrosis (NSF) though rare but can be a devastating side effect of gadolinium administration in patients with severe renal dysfunction. Awareness is still not very optimum for this condition. Literature is also very nascent as well. Few of the risk factors identified are high-dose erythropoietin treatment, metabolic acidosis, proinflammatory conditions, elevated iron, and phosphate levels. Gadolinium is itself a calcium channel blocker and high calcium level is not a risk factor identified yet.

#pharmacology
#nephrology


References:

Abu-Alfa AK. Nephrogenic systemic fibrosis and gadolinium-based contrast agents. Adv Chronic Kidney Dis 2011; 18:188.

Zhang B, Liang L, Chen W, et al. An Updated Study to Determine Association between Gadolinium-Based Contrast Agents and Nephrogenic Systemic Fibrosis. PLoS One 2015; 10:e0129720.

resuscitation endpoints

Q: Which of the following is found to be a better target for  resuscitation endpoints for improved  blood supply to abdominal viscera?

A) arterial pH
B) base deficit
C) arterial lactate
D) hourly urinary output 
E) abdominal perfusion pressure


Answer: E

Abdominal perfusion pressure (APP) is defined/calculated as the

 APP = MAP - IAP 

Where

• MAP = Mean Arterial Pressure, and 
• IAP = Intra-Abdominal Pressure

Studies have shown that APP is better than all other resuscitation endpoints as described in the first four choices of the question above. APP of at least 60 mm Hg is correlated with improved survival from Abdominal Compartment Syndrome (ACS) reflecting the improved blood supply to abdominal viscera.

#hemodynamics


References:

1. Schein M, Ivatury R. Intra-abdominal hypertension and the abdominal compartment syndrome. Br J Surg 1998; 85:1027. 

2. Caldwell CB, Ricotta JJ. Changes in visceral blood flow with elevated intraabdominal pressure. J Surg Res 1987; 43:14.

Anti-epilepsy drugs and suicide

Q: 21 year old female recently started on an anti-seizure medicine is admitted to ICU after a suicide attempt. Which of the anti-epilepsy drug is more associated with the increase suicidal ideation?

A) Carbamazepine 
B) Diazepam 
C) Phenytoin 
D) Lacosamide 
E) All of the anti-seizure drugs 


Answer: E

Unfortunately, less well known and very early side effect of any anti-seizure drug is an increased risk of suicidality. This effect is very high from day 7 to first six months of initiation of the treatment. This risk is shared by all antiseizure drugs and has been officially warned by the FDA. 

#psychiatry
#neurology
#pharmacology


References:

1. Bell GS, Gaitatzis A, Bell CL, et al. Suicide in people with epilepsy: how great is the risk? Epilepsia 2009; 50:1933. 

2. Andersohn F, Schade R, Willich SN, Garbe E. Use of antiepileptic drugs in epilepsy and the risk of self-harm or suicidal behavior. Neurology 2010; 75:335. 

3. Arana A, Wentworth CE, Ayuso-Mateos JL, Arellano FM. Suicide-related events in patients treated with antiepileptic drugs. N Engl J Med 2010; 363:542. 

4. Hesdorffer DC, Kanner AM. The FDA alert on suicidality and antiepileptic drugs: Fire or false alarm? Epilepsia 2009; 50:978. 

5. Mula M, Kanner AM, Schmitz B, Schachter S. Antiepileptic drugs and suicidality: an expert consensus statement from the Task Force on Therapeutic Strategies of the ILAE Commission on Neuropsychobiology. Epilepsia 2013; 54:199.

Hinchey classification system

Q: Hinchey classification system is for which disease?

A) Perforated peptic ulcer
B) Perforated diverticulitis
C) Perforated appendicitis
D) Perforated esophagus
E) Perforated tympanic membrane


Answer: B

Almost all patients with free perforated diverticulitis need surgical intervention. But the choice of techniques depends largely on level of peritoneal contamination. Hinchey described stages of perforated diverticulitis almost 40 years ago and is still considered a standard: 

• Stage I – Pericolic or mesenteric abscess 
• Stage II – Walled-off pelvic abscess 
• Stage III – Generalized purulent peritonitis 
• Stage IV – Generalized fecal peritonitis

#surgical-critical-care

#gastroenterology

Reference:

Hinchey EJ, Schaal PG, Richards GK. Treatment of perforated diverticular disease of the colon. Adv Surg 1978; 12:85.

noninvasive measures of ICP

Q: How ocular sonography can provide noninvasive measurement of intracranial pressure (ICP)? 

 
Answer: Various noninvasive methods have been suggested to estimate higher ICP. These include 

•  Transcranial Doppler (TCD) 
•  Tissue resonance analysis (TRA) 
•  Ocular sonography 
•  Intraocular pressure 
•  Tympanic membrane displacement

Ocular sonography provides a noninvasive estimate of high ICP by the measurement of optic nerve sheath diameter. Diameters of 5 to 6 mm is a reliable discriminate cutoff between normal and elevated ICP. This can be very helpful in patients with intracranial hemorrhage or traumatic brain injury.

#neuro-surgery
#opthalmology 


References:

1. Moretti R, Pizzi B, Cassini F, Vivaldi N. Reliability of optic nerve ultrasound for the evaluation of patients with spontaneous intracranial hemorrhage. Neurocrit Care 2009; 11:406. 

2. Dubourg J, Javouhey E, Geeraerts T, et al. Ultrasonography of optic nerve sheath diameter for detection of raised intracranial pressure: a systematic review and meta-analysis. Intensive Care Med 2011; 37:1059. 

3. Geeraerts T, Merceron S, Benhamou D, et al. Non-invasive assessment of intracranial pressure using ocular sonography in neurocritical care patients. Intensive Care Med 2008; 34:2062. 

4. Kimberly HH, Shah S, Marill K, Noble V. Correlation of optic nerve sheath diameter with direct measurement of intracranial pressure. Acad Emerg Med 2008; 15:201.

FAA

Case:  52 year old male is admitted to ICU with Right groin pain, fever, and palpable femoral artery. Patient had coronary angiogram via femoral artery a few months ago. Emergent duplex ultrasound shows Femoral Artery Aneurysm (FAA) with size 4 cm and of saccular morphology. What is the concern?


Answer: intramural FAA infection 

 The above question is designed to highlight the long term issues associated with femoral artery cannulation, a common procedure in ICU and other emergent settings. Studies have shown that the risk of complications related to FAA starts to increase once they start going beyond 3 cm and over 4 cm. As FAAs are more benign in nature, patients with smaller FAA can be followed clinically and with imagings. Any sign of rapid expansion, the development of intraluminal thrombus, or change of morphology to saccular aneurysm should prompt surgical evaluation, as this may be an indication of infection.

#surgical-critical-care
#infectious-diseases
#procedures


References:

1. Lawrence PF, Harlander-Locke MP, Oderich GS, et al. The current management of isolated degenerative femoral artery aneurysms is too aggressive for their natural history. J Vasc Surg 2014; 59:343.


2. Dawson J, Fitridge R. Update on aneurysm disease: current insights and controversies: peripheral aneurysms: when to intervene - is rupture really a danger? Prog Cardiovasc Dis 2013; 56:26.

effective solute

Q: Which of the following is considered effective solute? (select one)

A) Glucose
B) Urea



Answer: A

Although this concept was determined six decades ago but still is very valid and clinically relevant. Glucose is considered an effective osmole because glucose osmotically shifts water from cells. In contrast, urea is an ineffective osmole since there is little or no water shift across the cells.

Clinical significance: Glucose osmotically shifts water out from the cells, expands the extracellular fluid volume, dilutes the sodium concentration and may give erroneously (pseudo) hyponatremia. This does not happen with a rise in urea concentration as there is little water shift.

#electrolytes 


References:

1. EDELMAN IS, LEIBMAN J, O'MEARA MP, BIRKENFELD LW. Interrelations between serum sodium concentration, serum osmolarity and total exchangeable sodium, total exchangeable potassium and total body water. J Clin Invest 1958; 37:1236. 

2.  Roscoe JM, Halperin ML, Rolleston FS, Goldstein MB. Hyperglycemia-induced hyponatremia: metabolic considerations in calculation of serum sodium depression. Can Med Assoc J. 1975;112(4):452–453.

Hy's law

Q: What is "Hy's law" of Drug-Induced-Liver-Injury (DILI)?

 Answer: "Hy's law" is named after Dr. Hyman Zimmerman who proposed that 'if serum bilirubin is > 2 times the upper limit of normal in association with > 3 times elevation in serum aminotransferases, it predicts worse prognosis in DILI.'

#hepatology
#pharmacology



References:

1. Reuben A. Hy's law. Hepatology 2004; 39:574.
2. Björnsson E. Drug-induced liver injury: Hy's rule revisited. Clin Pharmacol Ther 2006; 79:521. 

plasma fibrinogen levels

Q: All of the following increase circulating plasma fibrinogen levels except? 

A) age
B) obesity
C) smoking
D) inflammation
E) alcoholism


Answer: E

Fibrinogen is an essential polypeptide in clot formation. It works via various mechanisms. It is the precursor to fibrin. It not only binds platelets but also supports platelet and thrombin aggregations. The most important thing is to be always mindful of the "fine balance" between fibrin clot formation and fibrinolysis. All other choices besides alcohol consumption increase the risk of clot formation and so of deep venous thrombosis (DVT).

#hematology


Reference:

Meade TW, Chakrabarti R, Haines AP, et al. Characteristics affecting fibrinolytic activity and plasma fibrinogen concentrations. Br Med J 1979; 1:153.

DVT prophylaxis in cirrhosis

Q: In patients with cirrhosis which of the following is preferred for Deep Venous Thrombosis (DVT) prophylaxis in ICU? (select one)

A) unfractionated heparin 
B) low molecular weight (LMW) heparin


Answer:  B 

 Unfractionated heparin requires antithrombin (AT) to inhibit thrombin and factor Xa. AT is synthesized in the liver. In patients with cirrhosis, their activity may be reduced. Low molecular weight (LMW) heparins are reliably effective for DVT prophylaxis in hospitalized patients. This also reinforce the fact that in patients with cirrhosis anti-factor Xa levels are not reliable to follow the anticoagulation activity.

#hepatology
#hematology


References:

1. Bechmann LP, Sichau M, Wichert M, et al. Low-molecular-weight heparin in patients with advanced cirrhosis. Liver Int 2011; 31:75. 

2. Fuentes A, Gordon-Burroughs S, Hall JB, et al. Comparison of anti-Xa and activated partial thromboplastin time monitoring for heparin dosing in patients with cirrhosis. Ther Drug Monit 2015; 37:40.

ESR and CRP in GCA

Q: 74-year-old male is admitted to ICU with headache and high fever. Patient gets diagnosed with Giant Cell Arteritis (GCA). Which of the following is more reliable to follow on the progress of GCA? (select one)

A) Erythrocyte sedimentation rate (ESR)
B) C-reactive protein (CRP)


Answer: B

Although ESR and CRP are not the perfect biomarkers of GCA, but CRP is more reliable. The C-reactive protein (CRP) is an hepatically synthesized acute phase reactant and is a sensitive marker of systemic inflammation. Practically, CRP is used in conjunction with the ESR but for academic sake CRP is a better marker.

#Rheumatology


Reference:

Kermani TA, Schmidt J, Crowson CS, et al. Utility of erythrocyte sedimentation rate and C-reactive protein for the diagnosis of giant cell arteritis. Semin Arthritis Rheum. 2012;41(6):866–871. 

Pharmacologic mydriasis

Q: Pharmacologic mydriasis is very common in ICU. How it can be confirmed?


Answer: Many drugs in ICU can cause mydriasis such as atropine, phenylephrine, clonidine, scopolamine patch, and aerosolized ipratropium. 

Pharmacologic mydriasis can be confirmed by demonstrating partial or no constriction by application of a 1% pilocarpine eye drop. In all other causes of the dilated pupil (except direct damage to pupillary sphincter from trauma or surgery), 1% pilocarpine will cause maximal pupillary constriction.

#pharmacology
#ophthalmology


References: 

 Iosson N. Images in clinical medicine. Nebulizer-associated anisocoria. N Engl J Med 2006; 354:e8. 

CARTER JH: Diagnosis of pupillary anomalies. J. Am. Optom. Assoc. (1979) 50(6):671–680.

resistant depression

Q: Which of the following drug has shown efficacy as an adjuvant treatment in resistant depression?

A) Thyroid replacements
B) Corticosteroids
C) Growth hormone
D) Estrogen replacements
E) Testosterone replacements


Answer: A

The exact mechanism is not cleared but this is proposed that antidepressants may have iatrogenic effects on the thyroid. Antidepressants may induce a change in iodine capture by thyroid cells or can make it unavailable for thyroid hormone synthesis. T3 is preferred over T4.

#psychiatry
#endocrinology



References:

 1. Nierenberg AA, Fava M, Trivedi MH, et al. A comparison of lithium and T(3) augmentation following two failed medication treatments for depression: a STAR*D report. Am J Psychiatry 2006; 163:1519.

2. Joffe RT, Singer W. A comparison of triiodothyronine and thyroxine in the potentiation of tricyclic antidepressants. Psychiatry Res 1990; 32:241.

3. Cooper-Kazaz R, Lerer B. Efficacy and safety of triiodothyronine supplementation in patients with major depressive disorder treated with specific serotonin reuptake inhibitors. Int J Neuropsychopharmacol 2008; 11:685.

4. Shelton RC, Osuntokun O, Heinloth AN, Corya SA. Therapeutic options for treatment-resistant depression. CNS Drugs 2010; 24:131.

5.  Sauvage MF, Marquet P, Rousseau A, Raby C, Buxeraud J, Lachâtre G. Relationship between psychotropic drugs and thyroid function: a review. Toxicol Appl Pharmacol. 1998 Apr;149(2):127-35.