Friday, April 20, 2018

premature occlusion of the coronary artery stents

Q: All of the following are the risk factors for the premature occlusion of the coronary artery stents except?

A) Premature cessation of dual anti-platelet therapy 

B) Smaller stent length 
C) Smaller vessel caliber
D) Left ventricular dysfunction 
E) Nonionic contrast media


Answer:  B

Premature cessation of dual anti-platelet therapy is the most common and the well known cause for the premature occlusion of the coronary artery stents but there is a long laundry list for this potentially life-threatening complication including proximal left anterior descending (LAD) stenting, side-branch stenting, diabetes mellitus, end-stage renal disease (ESRD), greater stent length, smaller vessel caliber, left ventricular dysfunction, use of nonionic contrast media, cocaine use, emergent stent placement, no aspirin at the time of the procedure, malignancy, multivessel disease.


References: 

1. Daemen J, Wenaweser P, Tsuchida K, et al. Early and late coronary stent thrombosis of sirolimus-eluting and paclitaxel-eluting stents in routine clinical practice: data from a large two-institutional cohort study. Lancet 2007; 369:667. 

2. Lagerqvist B, Carlsson J, Fröbert O, et al. Stent thrombosis in Sweden: a report from the Swedish Coronary Angiography and Angioplasty Registry. Circ Cardiovasc Interv 2009; 2:401. 

3.  Schühlen H, Kastrati A, Pache J, et al. Incidence of thrombotic occlusion and major adverse cardiac events between two and four weeks after coronary stent placement: analysis of 5,678 patients with a four-week ticlopidine regimen. J Am Coll Cardiol 2001; 37:2066. 

4. Scheller B, Hennen B, Pohl A, et al. Acute and subacute stent occlusion; risk-reduction by ionic contrast media. Eur Heart J 2001; 22:385.

Thursday, April 19, 2018

PDE5 inhibitors

Q: PDE5 inhibitors (Sildenafil, tadalafil or vardenafil) are now increasing used in ICU for the management of pulmonary hypertension. Their mechansim of action is? 

 A) Prolong the vasodilatory effect of nitric oxide 
B) Stimulates the nitric oxide receptor 
C) Selective antagonist of type A endothelin-1 receptor 
D) Nonselective endothelin receptor antagonist 
E) unexplained (found accidentally in patients with erectile dysfunction) 


 Answer:

Phosphodiesterase type 5 (PDE5) inhibitors prolong the vasodilatory effect of nitric oxide.

(Choice B) Riociguat is a Guanylate Cyclase stimulant (sGC) which increases the sensitivity of sGC to endogenous nitric oxide (NO) as well as directly stimulate the receptor to mimic the action of NO.

(choice C) Ambrisentan is an oral selective type A endothelin-1 receptor antagonist.

(Choice D) Bosentan is an oral nonselective endothelin receptor antagonist.

#pulmonary
#pharmacology



Reference:

Galiè N, Humbert M, Vachiery JL, et al. 2015 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension: The Joint Task Force for the Diagnosis and Treatment of Pulmonary Hypertension of the European Society of Cardiology (ESC) and the European Respiratory Society (ERS): Endorsed by: Association for European Paediatric and Congenital Cardiology (AEPC), International Society for Heart and Lung Transplantation (ISHLT). Eur Heart J 2016; 37:67.

Wednesday, April 18, 2018

Delirium

Q: Digoxin despite having normal (therapeutic) level can cause delirium? 

A) True 
B) False 


 Answer: A Objective of above question is to highlight the complexity of delirium. Any drug, environmental discordance, pain or any underlying disease process can cause delirium. 

 Those medications which require therapeutic level monitoring despite being at appropriate dose can still be the cause of delirium. 


Reference:

Francis J. Drug-induced delirium: Diagnosis and treatment. CNS Drugs 1996; 5:103.

Tuesday, April 17, 2018

laryngeal injury

Q: All of the following are risk factors for laryngeal injury via Endotracheal tube (ETT) except

A) Prolonged intubation 
B) Traumatic intubation 
C) Using a muscle relaxant during intubation
D) Unplanned extubation 
E) Presence of a nasogastric tube


Answer: C

The objective of above question is to highlight the importance of proper skills and techniques to be used during intubation. It is not uncommon to see that medical staff skip the use of a muscle relaxant during intubation for various reasons including unresponsiveness of a patient, fear of increasing the risk of myopathy, hyperkalemia, difficult intubation or desaturation.

Muscle relaxants should be employed during intubation unless absolutely contraindicated or risk is too high.


References:

1. Tadié JM, Behm E, Lecuyer L, et al. Post-intubation laryngeal injuries and extubation failure: a fiberoptic endoscopic study. Intensive Care Med 2010; 36:991. 

2. Santos PM, Afrassiabi A, Weymuller EA Jr. Risk factors associated with prolonged intubation and laryngeal injury. Otolaryngol Head Neck Surg 1994; 111:453. 

3. Colton House J, Noordzij JP, Murgia B, Langmore S. Laryngeal injury from prolonged intubation: a prospective analysis of contributing factors. Laryngoscope 2011; 121:596.

4. Friedman M, Baim H, Shelton V, et al. Laryngeal injuries secondary to nasogastric tubes. Ann Otol Rhinol Laryngol 1981; 90:469.  

Monday, April 16, 2018

CNS viral escape syndrome

Q: What is CNS viral escape syndrome?

 Answer: CNS viral escape syndrome is an HIV related phenomenon in which despite compliant treatment with antiretroviral therapy (ART), patients develop neurological deficits popularly known as HAND (HIV-associated neurocognitive disorders). Although viral load stays low in the plasma there is evidence of CNS HIV replication in the cerebrospinal fluid (CSF). This is due to drug resistance to the virus in the CSF. 

HAND is mostly characterized by difficulty with attention, lagging of memory, lack of cerebrating decisions and slowing down of cognitive and motor skills. 


#infectiousdiseases
#HIV
#Neurology


References: 

1. Peluso MJ, Ferretti F, Peterson J, et al. Cerebrospinal fluid HIV escape associated with progressive neurologic dysfunction in patients on antiretroviral therapy with well controlled plasma viral load. AIDS 2012; 26:1765. 

2. Canestri A, Lescure FX, Jaureguiberry S, et al. Discordance between cerebral spinal fluid and plasma HIV replication in patients with neurological symptoms who are receiving suppressive antiretroviral therapy. Clin Infect Dis 2010; 50:773. 

Sunday, April 15, 2018

Delta Toxin

Q: What is Delta toxin?

Answer: Delta toxin is a hemolytic peptide secreted by Staphylococcus aureus. This toxin is also known as Delta-lysin or septicolysin as it is lytic to cells by solubilization of their membranes. Also, it has direct and indirect effects on the activity of neutrophils and monocytes which confers to its proinflammatory property. 

#infectiousdiseases


 References:

 1. Dhople, V. M. and Nagaraj, R. Prot. Eng. 8, 315 (1995), Dhople, V. M. and Nagaraj, R. Peptides 26, 217 (2005). Send to J Infect Dis. 1997 Dec;176(6):1531-7. 

2. Schmitz FJ, Veldkamp KE, Van Kessel KP, Verhoef J, Van Strijp JA. Delta-toxin from Staphylococcus aureus as a costimulator of human neutrophil oxidative burst. J Infect Dis. 1997 Dec;176(6):1531-7. 

Saturday, April 14, 2018

ESBL

Q: which of the following group of antibiotics is a best bet against extended-spectrum beta-lactamases (ESBLs) producing organisms? 

 A) Penicillins
 B) Cephalosporins
 C) Monobactams 
 D) Carbapenems 
 E) Fluoroquinolones


Answer: D

Extended-spectrum beta-lactamases (ESBL) are enzymes that confer resistance to beta-lactam antibiotics which include penicillins, cephalosporins, and the monobactams. Carbapenems have been found to be the best treatment options in most of the studies. In case of increase risk from carbapenems such as in pregnancy or patients with underlying history of seizure, meropenem is considered as a good choice. Also, doripenem is another new promising carbapenem.


#infectiousdiseases


References:

1.  Tamma PD, Han JH, Rock C, et al. Carbapenem therapy is associated with improved survival compared with piperacillin-tazobactam for patients with extended-spectrum β-lactamase bacteremia. Clin Infect Dis 2015; 60:1319.

2. Kaniga K, Flamm R, Tong SY, et al. Worldwide experience with the use of doripenem against extended-spectrum-beta-lactamase-producing and ciprofloxacin-resistant Enterobacteriaceae: analysis of six phase 3 clinical studies. Antimicrob Agents Chemother 2010; 54:2119. 

Friday, April 13, 2018

Liver laceration

Q: Which of the following is the most reliable parameter of grading liver laceration/injury?

A) Aspartate aminotransferase (AST)
B) Alanine aminotransferase (ALT)
C) Level of Anemia
D) Blood Urea Nitrogen (BUN)
E) None of the above


Answer: E

None of the laboratory parameters are found to correlate well with the level of hepatic injury. This is a clinical diagnosis put together by history, physical exam and radiological workup such as a computed tomography (CT) with IV contrast, Focused Assessment with Sonography in Trauma (FAST), diagnostic peritoneal lavage (DPL) or diagnostic peritoneal aspiration (DPA) if clinically indicated, magnetic resonance imaging (MRI), and selectively arteriography.


Reference:

1. Koyama T, Hamada H, Nishida M, et al. Defining the optimal cut-off values for liver enzymes in diagnosing blunt liver injury. BMC Res Notes 2016; 9:41.

Thursday, April 12, 2018

Haptoglobin

Q: At what level of low haptoglobin it is considered due to hemolytic anemia?

 Answer:  Haptoglobin is an acute-phase reactant which goes up in infection and inflammation. But in clinical practice it is mostly used to predict hemolysis by it's low level. There are other reasons for low heptoglobin such as abdominal trauma and congenital ahaptoglobinemia but if haptoglobin level is less than 25 mg/dL, it is due to hemolysis proved otherwise. This should be read in conjunction with other labs such as high LDH and bilirubin but undetectable or extremely low haptoglobin itself is a good marker to consider hemolysis.

Normal haptoglobin level is 30-200 mg/dL.

#hematology


References:

1. Marchand A, Galen RS, Van Lente F. The predictive value of serum haptoglobin in hemolytic disease. JAMA 1980; 243:1909. 

2. Stahl WM. Acute phase protein response to tissue injury. Crit Care Med 1987; 15:545.

Wednesday, April 11, 2018

Half life of Protamine

Q: The half life of protamine is?

A) 5 minutes
B) 15 minutes
C) 30 minutes
D) 60 minutes
E) It correlates with heparin level in the plasma


Answer: A

Protamine is a known reversal of heparin. It has a very short  half-life of about five minutes. This information is clinically significant as recurrent anticoagulation may occur after initial reversal of heparin, and may require re-dosing of protamine. 



Reference:

Butterworth J, Lin YA, Prielipp RC, Bennett J, Hammon JW, James RL. Rapid disappearance of protamine in adults undergoing cardiac operation with cardiopulmonary bypass. .Ann Thorac Surg. 2002 Nov;74(5):1589-95.

Tuesday, April 10, 2018

Smoker's Paradox

Q; What is "smoker’s paradox"?

Answer: Smoker's paradox is a troubling phenomenon in cardiovascular patients. A population of patients who are nonsmokers may tend to have decrease response to clopidogrel, an essential treatment in most "stented patients". Smoking stimulates CYP1A2 and so enhances platelet inhibition by clopidogrel. Interestingly, once smoking is stopped, which is an universal recommendation, this benefit is lost.


References:

1. Desai NR, Mega JL, Jiang S, et al. Interaction between cigarette smoking and clinical benefit of clopidogrel. J Am Coll Cardiol 2009; 53:1273. 

2. Gurbel PA, Nolin TD, Tantry US. Clopidogrel efficacy and cigarette smoking status. JAMA 2012; 307:2495. 

3. The association of cigarette smoking with enhanced platelet inhibition by clopidogrel. J Am Coll Cardiol 2008; 52:531. 

4. Park KW, Kang SH, Kang J, et al. Enhanced clopidogrel response in smokers is reversed after discontinuation as assessed by VerifyNow assay: additional evidence for the concept of 'smokers' paradox'. Heart 2012; 98:1000. 

Monday, April 9, 2018

Pain in metastatic pancreatic cancer

Q: 52 year old male with a known diagnosis of metastatic pancreatic cancer is transferred from oncology floor after requiring intubation due to narcotic overdose. This is the second time patient required intubation due to the similar reason. Which of the following is a good option to relieve pain and prevent further such episodes?

A) Celiac plexus neurolysis (CPN)

B) Request patient to sign Do Not Resuscitate (DNR) papers
C) Tracheostomy
D) Placement of a stent across the area of biliary tract obstruction
E) Gabapentin



Answer: A

Celiac plexus neurolysis (CPN) has been found to be more effective than any other modality to relieve pain from metastatic pancreatic cancer. Other closest option is local radiation. It should be understood that CPN is not a denervation process, rather it inhibits synaptic pathways within the plexus. 

Choice B is unethical.
Choice C will not bring any comfort from pain.
Choice D may provide relief from pruritis and jaundice but not from pain.
Choice E may help but not be very effective in this scenario.


#palliativecare
#ethics


References:

1. Wong GY, Schroeder DR, Carns PE, et al. Effect of neurolytic celiac plexus block on pain relief, quality of life, and survival in patients with unresectable pancreatic cancer: a randomized controlled trial. JAMA 2004; 291:1092.  

2. Amr YM, Makharita MY. Neurolytic sympathectomy in the management of cancer pain-time effect: a prospective, randomized multicenter study. J Pain Symptom Manage 2014; 48:944.

Sunday, April 8, 2018

Berkson’s Bias

Q: What is Berkson’s Bias? 


Answer: Berkson’s Bias also known as Berkson Fallacy or Berksonian Bias was proposed in 1946 by Joseph Berkson. According to his theory, any study conducted in a medical care setting is exposed to bias as both exposure and disease status is affected. This is an extremely important form of selection bias which can potentially cloud any prospective or retrospective study. 



References/further readings:

1. Berkson J. Limitations of the Application of Fourfold Table Analysis to Hospital Data. Biometrics Bulletin. 1946;2(3):47–53.

2. Walter SD. Berkson's bias and its control in epidemiologic studies. J Chronic Dis 1980;33:721–25

3. Roberts RS, Spitzer WO, Delmore T, Sackett DL. An empirical demonstration of Berkson's bias. J Chronic Dis 1978;31:119–28

4. Schwartzbaum J, Ahlbom A, Feychting M. Berkson's bias reviewed. Eur J Epidemiol 2003;18:1109–12

5. Westreich D. Berkson's bias, selection bias, and missing data. Epidemiology 2012;23:159–64

Saturday, April 7, 2018

Steroid myopathy

Q: Concomitant use of which of the following medications decrease the intensity of dexamethasone induced myopathy?

A) Neuro-muscular blockers
B) Phenytoin
C) Erythromycin
D) Proton Pump Inhibitors 
E) Propofol


Answer: B

Patients with brain tumor usually use dexamethasone and phenytoin concomitantly to reduce vasogenic edema and risk of seizures respectively and get the unintended benefit of interaction between steroid and phenytoin. This interaction is due to the induction of hepatic metabolism of dexamethasone by phenytoin. On the reverse side, phenytoin level needs to be monitored as it may have an exaggerated effect.


Reference:


Pharm.D. Lisa A.Lawson, Pharm.D. Robert A.Blouin, Ph.D.Randal B.Smith Pharm.D. Robert P.Rapp, M.D. A. ByronYoung - Phenytoin-dexamethasone interaction: A previously unreported observation - Surgical Neurology Volume 16, Issue 1, July 1981, Pages 23-24 

Friday, April 6, 2018

GM-CSF connection

Q: 52 year old male is admitted to ICU with shortness of breath. Patient has a previous history of leukemia and  bone marrow transplantation. Pulmonologist look at the admitting CXR with alveolar opacities in mid and lower lung zones in a "bat wing distribution". Which of the following is the most likely diagnosis?

A) Pulmonary alveolar proteinosis (PAP)
B) Acute respiratory distress syndrome (ARDS)
C) Chronic Obstructive Pulmonary Disease (COPD) 
D) Cystic Fibrosis (CF)
E) Idiopathic Pulmonary Fibrosis (IPF)


Answer: A

The objective of the above question is to highlight the association between PAP and leukemia via GM-CSF deficiency or dysfunction. Pulmonary alveolar proteinosis (PAP) is a product of accumulation of lipoproteinaceous material in the distal air spaces. Classic CXR presentation is a "bat wing distribution" with bilateral symmetric alveolar opacities located centrally in mid and lower lung zones. 


#oncology
#pulmonary



References:

1. Tsushima K, Koyama S, Saitou H, et al. Pulmonary alveolar proteinosis in a patient with chronic myelogenous leukemia. Respiration 1999; 66:173. 

2. Ohmachi K, Ogiya D, Morita F, et al. Secondary pulmonary alveolar proteinosis in a patient with chronic myeloid leukemia in the accelerated phase. Tokai J Exp Clin Med 2008; 33:146. 

3. Yoshimura M, Kojima K, Tomimasu R, et al. ABL tyrosine kinase inhibitor-induced pulmonary alveolar proteinosis in chronic myeloid leukemia. Int J Hematol 2014; 100:611.

Thursday, April 5, 2018

antimicrobials in severe babesiosis

Q: All of the following antimicrobials are found to be effective in the treatment of severe babesiosis except?

A) Azithromycin 
B) Atovaquone
C) Clindamycin 
D) Levofloxacin
E) Quinine 


Answer: D

The most commonly used drug regimen for severe babesiosis is intravenous azithromycin plus oral atovaquone. Intravenous clindamycin plus oral quinine can be used as an alternative treatment. Therapy should be guided by the level of parasitemia and blood smears. 

Red blood cell exchange transfusion should be considered as an immediate life-saving therapy or if antimicrobial therapy fails.



References:


1. Vannier E, Krause PJ. Human babesiosis. N Engl J Med 2012; 366:2397. 

2.  Sanchez E, Vannier E, Wormser GP, Hu LT. Diagnosis, Treatment, and Prevention of Lyme Disease, Human Granulocytic Anaplasmosis, and Babesiosis: A Review. JAMA 2016; 315:1767. 

3. Kletsova EA, Spitzer ED, Fries BC, Marcos LA. Babesiosis in Long Island: review of 62 cases focusing on treatment with azithromycin and atovaquone. Ann Clin Microbiol Antimicrob 2017; 16:26.

Wednesday, April 4, 2018

NC and FiO2 oxygen conversion

Q: 6 L per minute of oxygen via low flow nasal cannula (NC) is approximately equal to?

A) 28% FiO2 of oxygen
B) 35% FiO2 of oxygen
C) 45% FiO2 of oxygen
D) 60% FiO2 of oxygen
E) It is hard to compare equivalency between NC and FiO2 level of oxygen


Answer:  C

Actually, there is a calculator developed to find equivalency of NC and FiO2 level of oxygen. This may be of help in converting or weaning patients from mask ventilation to nasal cannula.

Calculators can be found online but a simple rule of thumb is that the fraction of oxygen that is inspired (above 2I%) increases by 4% for every additional liter of oxygen flow administered.



Reference: 

AARC Clinical Practice Guideline, In Vitro pH and Blood Gas Analysis and Hemoximetry, Respiratory Care, 38:505-510, 1993

Tuesday, April 3, 2018

AIMS65 score

Q: All of the following are predictors of increased inpatient mortality in patients presenting with upper gastro-intestinal bleed (UGIB) except?

A) Albumin less than 3.0 g/dL 
B) INR higher than 2 
C) Mental status change
D) Systolic blood pressure less than 90 mmHg
E) 65 or older age 


Answer: B

Above question represents "AIMS65" score, which has been found to have an excellent accuracy for predicting hospital mortality for patients presenting with UGIB. The score was developed from the cohort of almost 62,000 patients. 


A = Albumin less than 3.0 g/dL 
I = INR higher than 1.5 
M = Mental status change 
S = Systolic blood pressure less than 90 mmHg 
65 = Age older

#Gastroenterology


References: 


1. Saltzman JR, Tabak YP, Hyett BH, et al. A simple risk score accurately predicts in-hospital mortality, length of stay, and cost in acute upper GI bleeding. Gastrointest Endosc 2011; 74:1215. 


2. Hyett BH, Abougergi MS, Charpentier JP, et al. The AIMS65 score compared with the Glasgow-Blatchford score in predicting outcomes in upper GI bleeding. Gastrointest Endosc 2013; 77:551.

3. Tang Y, Shen J, Zhang F, et al. Scoring systems used to predict mortality in patients with acute upper gastrointestinal bleeding in the ED. Am J Emerg Med 2018; 36:27.

Monday, April 2, 2018

Transient Global Amnesia

Q: Transient Global Amnesia (TGA) is an integral part of? 

 A) Stroke
B) Post-seizure 
C) Metabolic encephalopathy
D) Delirium
E) None of the above


Answer: E

TGA is a very distinct clinical condition of a transient "antegrade amnesia" for which no specific etiology has been determined but the site of dysfunction is the medial aspect of the temporal lobe. Epidemiologically, it appears to be an age-related condition. Two distinct clinical features in most cases are 1) disorientation to place and time and 2) repetitive questioning about whereabouts.


Patients with TGA have no increased risk of Transient Ischemic Attacks (TIAs), stroke and death. The episode usually lasts for six hours and can be easily confused by clinicians.

No treatment is recommended as overall it is a benign condition. There is no restriction to driving either in isolated cases.


References:

1. Quinette P, Guillery-Girard B, Dayan J, et al. What does transient global amnesia really mean? Review of the literature and thorough study of 142 cases. Brain 2006; 129:1640.

2. Miller JW, Petersen RC, Metter EJ, et al. Transient global amnesia: clinical characteristics and prognosis. Neurology 1987; 37:733.

3. Pantoni L, Bertini E, Lamassa M, et al. Clinical features, risk factors, and prognosis in transient global amnesia: a follow-up study. Eur J Neurol 2005; 12:350.

Sunday, April 1, 2018

Hunter's Algorithm - Serotonin Toxicity

Q: All of the following are parts of Serotonin Syndrome (SS) except?

A) Hyperthermia 

B) Ocular clonus
C) Deep tendon hyperreflexia 
D) Inducible muscle clonus 
E) Neuromuscular findings more pronounced in the upper extremities


Answer: E

SS is a clinical diagnosis. A wide range of clinical signs can be seen in SS including fluctuations in vital signs, hyperthermia, agitation, ocular clonus, muscle rigidity,  mydriasis, tremors, deep tendon hyperreflexia, inducible or spontaneous muscle clonus, dry mucous membranes, and diaphoresis. Neuromuscular findings are usually more pronounced in the lower extremities including bilateral Babinski signs.


Related: Hunter's Decision Rules (algorithm) for Diagnosis of Serotonin Toxicity at https://bit.ly/2GoSfl8


References:

Boyer EW, Shannon M. The serotonin syndrome. N Engl J Med 2005; 352:1112.

Saturday, March 31, 2018

Pupils in hypothermia

Q: Hypothermia causes? (select one)

A) Unreactive pupils
B) Hyperreactive pupils


Answer: A

In patients who present with hypothermia, this is an important clinical sign to know as it may quickly deceive the examiner and may lead to false diagnosis with other signs of hypothermia. A recent work from Mayo 1 shows that it may take at least up to 3 days before any definitive assessment can be made, and actually, a good outcome is possible in some of these patients.

#Neurology
#Physicalexam
#hypothermia



References:

1. Dhakal LP and et al - Early Absent Pupillary Light Reflexes After Cardiac Arrest in Patients Treated with Therapeutic Hypothermia. Ther Hypothermia Temp Manag. 2016 Aug;6(3):116-21.


2. Fischbeck KH, Simon RP. Neurological manifestations of accidental hypothermia. Ann Neurol 1981; 10:384.

Friday, March 30, 2018

Reflex orders

Q: 52 year old male admitted to ICU with End Stage Liver Disease (ESLD) and awaiting transplant continues complain of debilitating nausea. Which of the following anti-emetic should be used with caution in this patient?

A) Ondansetron
B) Metoclopramide
C) Dexamethsone
D) Prochlorperazine 
E) Olanzapine


Answer:  A

The objective of above question is to highlight the habit of "reflex orders" in hospitals.

ESLD patients suffer from nausea due to bilirubinemia, ascites, and various other circulating toxins. Ondansetron is one of the most widely used, and "reflexly ordered" anti-emetic in hospital but in ESLD patients the dose should not exceed 8 mg per day. In ESLD patients metoclopramide can be used up to 60 mg per 24 hours and is very effective.

#hepatology
#pharmacology


References:

1. Rhee C, Broadbent AM. Palliation and liver failure: palliative medications dosage guidelines. J Palliat Med 2007; 10:677. 

2. Uribe M, Ballesteros A, Strauss R, et al. Successful administration of metoclopramide for the treatment of nausea in patients with advanced liver disease. A double-blind controlled trial. Gastroenterology 1985; 88:757.

Thursday, March 29, 2018

TBI patients and dialysis

Q: Which of the following modality is preferred in hemodynamically stable patients with traumatic brain injury (TBI)? (select one)

A) Intermittent Hemodialysis (HD)
B) Continuous Renal Replacement Therapy (CRRT)


Answer: B

Most critically ill patients with renal failure who are hemodynamically stable can be served with less labor intense HD. But patients with traumatic brain injury (TBI) or at high risk of developing increased intracranial pressure (ICP) benefit more from CRRT. 

Intermittent HD can harm patients with TBI via two mechanisms.

1. Rapid removal of urea causes a rapid shift of water to the intracellular space resulting in worsen cerebral edema.


2. Drop in mean arterial pressure (MAP) during HD results in compensatory cerebral vasodilation resulting in worsening cerebral edema. 



#Nephrology
#Surgicalcriticalcare




Reference: 

Macedo E, Mehta RL. Continuous Dialysis Therapies: Core Curriculum 2016. Am J Kidney Dis 2016; 68:645.

Wednesday, March 28, 2018

High nasogastric suction tubes output, severe hypokalemia and acid-base disorder

Q: High output via nasogastric suction tubes in ICU patients may result in severe hypokalemia and which acid-base disorder?  

A) Metabolic acidosis
B) Respiratory acidosis
C) Metabolic alkalosis
D) Respiratory alkalosis
E) Triple acid base disorder


Answer: C

Severe hypokalemia results in metabolic alkalosis due to an intracellular shift or loss of hydrogen ion. This is chloride-responsive metabolic alkalosis, means it can be suspected if urine chloride is < 10 mEq/L. 


In ICU, high output via nasogastric suction tubes is the most common cause of severe hypokalemia due to loss of hydrochloric acid (H+ and Cl-). Concomitant hyponatremia leads kidney to compensate by retaining sodium in the collecting ducts at the expense of hydrogen ions.

#acidbase
#gastroenterology
#nephrology


Reference:

Hennessey, Iain. Japp, Alan.Arterial Blood Gases Made Easy. Churchill Livingstone 1 edition (18 Sep 2007).

Tuesday, March 27, 2018

uremic encephalopathy

Q; 52 year old male with End Stage Renal Disease (ESRD) missed his two dialysis sessions in a row and admitted to ICU with volume overload, hyperkalemia, acidosis and acute uremic encephalopathy. The patient required intubation. Emergent dialysis is instituted. The patient recovered from all symptoms but remained lethargic preventing his liberation from the ventilator. What is the usual lag time between an institution of hemodialysis and resolution of acute uremic encephalopathy?



Answer: 24 - 48 hours

Fortunately,  uremic encephalopathy is generally in direct proportion to the severity of azotemia. It takes about 24 to 48 hours in ESRD patients for mental status to be back to normal before uremic toxins clear.



#Neurology
#Nephrology


References:

Bolton, CF, Young, GB. Uremic encephalopathy. In: Bolton, CF, Young, GB, (Eds), Neurological Complications of Renal Disease, Buttersworth, Stoneham 1990. p.44.

Monday, March 26, 2018

PDSS and LAI-antipsychotics

Case: Psychiatric service is consulted for a 74 year old male patient in ICU with resistant delirium, not amenable to any pharmacology or non-pharmacology interventions. Psychiatric resident on call wrote orders for "olanzapine-LAI" (LAI = Long Acting Injectable). After receiving ordered drug, patient symptoms worsens with more confusion, disorientation, periods of excessive sedation, and patient start manifestation of extrapyramidal symptoms. Psychiatric attending was called and he diagnosed patient with "Postinjection delirium sedation syndrome" (PDSS)?


Answer: 

LAI anti-psychotics are not getting used with more frequency. Though rare, but they may present with undesirable effect of PDSS which can equally be frightening to house-staff and nurses at workplace. Before ordering and administrating LAIs, it should be known that providers, institutions, and pharmacies need to be registered and receive proper in-service for its dispension. Moreover, it is required to observe patient on one to one basis (1:1) for at least three hours after dispension of each dose. So far 6 antipsychotics have been approved for LAI forms. Probable cause of PDSS is extreme peak level of drug in the first hour of administration. 

#Delirium
#Psychiatry


References:

1. Citrome L. Olanzapine pamoate: a stick in time? A review of the efficacy and safety profile of a new depot formulation of a second-generation antipsychotic. Int J Clin Pract 2009; 63:140. 

2. Detke HC, McDonnell DP, Brunner E, et al. Post-injection delirium/sedation syndrome in patients with schizophrenia treated with olanzapine long-acting injection, I: analysis of cases. BMC Psychiatry 2010; 10:43. 


Sunday, March 25, 2018

Denervated donor heart

Q: Patients with previous heart transplant have (select one)

A) Supersensitive response to adenosine 
B) No response to adenosine


Answer: A

Contrary to popular belief, adenosine effect is exaggerated in patients who are heart transplant recipients. It reduces calcium influx into cardiac cells by antagonizing adenylate cyclase. It also increases potassium conductance.

Denervated donor heart has increased sensitivity to circulating catecholamine and adenosine.



#transplantation
#cardiology
Reference:

Koller-Strametz J, Kratochwill C, Grabenwöger M, et al. PR interval adaptation in the denervated transplanted heart. Pacing Clin Electrophysiol 1997; 20:1247.

Saturday, March 24, 2018

acute diverticulitis

Q; 72 year old male is admitted to ICU with sepsis, left lower quadrant (LLQ) pain and lower gastrointestinal (GI) bleed. Diagnosis of acute diverticulitis is made. Which of the following procedure should NOT be performed in this patient?

A) CT scan of abdomen 
B) Colonoscopy
C) Ultrasound of LLQ
D) insertion of left femoral central line
E) Angiography of mesenteric vessel



Answer: B

Out of all the procedures or workup, colonoscopy in acute phase of diverticulitis can harm the patient with very high risk of perforation. 


CT scan is required to establish the diagnosis (choice A). Ultrasound may have a low yield and may not be of help, but it is not contra-indicated (choice C) in acute diverticulitis. Lower body central line insertions are discouraged in general but are not contra-indicated (choice D). Angiography may be of help in case of massive bleeding to localize the site of bleeding (choice E).

Colonoscopy can be performed after few weeks of resolution of acute episode to rule out underlying malignancy.


#Gastroenterology
References:

1. Jacobs DO. Clinical practice. Diverticulitis. N Engl J Med 2007; 357:2057 

2.Sharma PV, Eglinton T, Hider P, Frizelle F. Systematic review and meta-analysis of the role of routine colonic evaluation after radiologically confirmed acute diverticulitis. Ann Surg 2014; 259:263.

Friday, March 23, 2018

Surgery in ulcerative colitis

Q: All of the following are indications for emergency surgery in ulcerative colitis except?

A) Colonic perforation

B), Life-threatening colorectal  bleeding
C) Toxic megacolon
D) Acute fulminant colitis if they fail medical therapy
E) All of the above


Answer: D

Surgical intervention for ulcerative colitis falls into three categories

1. emergency surgery
2. urgent surgery
3. elective surgery

Patients with colonic perforation, life-threatening gastrointestinal (GI) bleeding and toxic megacolon require emergency surgery.

Patients admitted to hospital who develop acute fulminant colitis  and do not respond to medical therapy are candidates for urgent surgery. Urgent surgery is defined as surgery on the same hospitalization.

Elective surgery should be decided on case to case basis as per indications for surgical guidelines from societies.



References: 

1.  Cima RR, Pemberton JH. Medical and surgical management of chronic ulcerative colitis. Arch Surg 2005; 140:300. 

2.  Andersson P, Söderholm JD. Surgery in ulcerative colitis: indication and timing. Dig Dis 2009; 27:335.

Thursday, March 22, 2018

Edentulousness in difficult bag-mask ventilation

Q: Edentulousness (no teeth) is one of the reason for the difficult bag-mask ventilation (BMV) before/during intubation? 

A) True 
B) False 

 Answer: A (True) 

A proper set of teeth supports the cheeks and provides a framework against which the mask fits. 

Learning objective of this question is to leave patient dentures in situ while BMV is underway. They can be removed just before direct laryngoscopy for intubation. 

Besides this, other indications for difficult BMV are prior radiation, obesity, age, male gender, and others.


#procedures   


Reference:

Conlon NP, Sullivan RP, Herbison PG, et al. The effect of leaving dentures in place on bag-mask ventilation at induction of general anesthesia. Anesth Analg 2007; 105:370.

Wednesday, March 21, 2018

Angioedema

Q: Besides face, lips, larynx, uvula, extremities, and genitalia, which of the following organs are more prone to get affected by Angiotensin-converting-enzyme -Inhibitor (ACE-I) Induced Angio-edema?

A) Bowels
B) Kidney
C) Liver
D) Brain
E) Prostate



Answer: A

Intestinal angioedema due to ACE-I usually goes unnoticed as they are not apparently visible and mostly presents with colicky and tender abdominal pain. It mostly affects the small intestine. It is important to recognize as these patients can be at higher risk for life-threatening laryngeal angioedema. CT scan is usually diagnostic.

#pharmacology
#gastroenterology



References:

1. Chase MP, Fiarman GS, Scholz FJ, MacDermott RP. Angioedema of the small bowel due to an angiotensin-converting enzyme inhibitor. J Clin Gastroenterol. 2000;31(3):254-257. 

2 Schmidt TD, McGarth KM. Angiotensin-converting enzyme inhibitor angioedema of the intestine: a case report and review of the literature. Am J Med Sci. 2002;324(2):106-108.

Tuesday, March 20, 2018

VIDD

Q:  Ventilator-induced diaphragmatic dysfunction (VIDD) can be evident as early as within first 24 hours of initiation of mechanical ventilation?

A) True
B) False


Answer: A (True)

It is now an established fact that mechanical ventilation can cause diaphragmatic muscle atrophy. The term designated for this phenomenon is known as ventilator induced diaphragmatic dysfunction (VIDD). Studies have shown that it may be evident as early as by the eighteenth hour of the initiation of positive pressure ventilation 1. When it comes to VIDD, any mechanical ventilation more than 24 hours is considered as a long-term mechanical ventilation! 2 VIDD is an umbrella term for muscle injury, atrophy, and proteolysis. The probable cause of VIDD is oxidative stress. This is a worrisome phenomenon as VIDD itself cause difficulty weaning from mechanical ventilation and ICU outcomes 3.


References:

1. Levine S, Nguyen T, Taylor N, et al. Rapid disuse atrophy of diaphragm fibers in mechanically ventilated humans. N Engl J Med 2008; 358:1327. 

2. Jaber S, Petrof BJ, Jung B, et al. Rapidly progressive diaphragmatic weakness and injury during mechanical ventilation in humans. Am J Respir Crit Care Med 2011; 183:364.  

Goligher EC, Dres M, Fan E, et al. Mechanical Ventilation-induced Diaphragm Atrophy Strongly Impacts Clinical Outcomes. Am J Respir Crit Care Med 2018; 197:204.