Q: Which test can rule out Psychogenic coma or Malingering?


Answer: Cold caloric test

Cold caloric test (oculovestibular reflex) can rule out psychogenic coma or malingering with very high sensitivity and specificity. Irrigation of ear with 60-100mL of ice water can have 3 kinds of response

• A slow tonic deviation of the eye toward the ice happens in true coma with an intact brainstem. 
• No response means damage to the brainstem 
• Fast phase nystagmus away from the cold ear happens in an awake patient.

Q: Which electrolyte imbalance is common in Ecstasy (MDMA) intoxication?

A) Hyperkalemia
B) Hypernatremia
C) Hypokalemia
D) Hyponatremia
E) Hypocalcemia


Answer: D

MDMA has dual effect. It not only causes direct drug-induced inappropriate secretion of ADH decreasing water excretion but also causes polydipsia. Major cause of death in Ecstasy is hyponatremia. It is found to be more common in female gender.



References: 

1. Hartung TK, Schofield E, Short AI, et al. Hyponatraemic states following 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy') ingestion. QJM 2002; 95:431. 

2. Budisavljevic MN, Stewart L, Sahn SA, Ploth DW. Hyponatremia associated with 3,4-methylenedioxymethylamphetamine ("Ecstasy") abuse. Am J Med Sci 2003; 326:89. 

Q: In all of the following conditions intravenous (IV) ketorolac should be use with very caution except? 

A) Spine surgery 
B)  Patients with active smoking history
C) Previous long-term NSAID use
D) Creatinine more than or equal to 2 mg/dL.
E)  Age more than 65


Answer:  A

Actually IV ketorolac is an indication to use in spinal surgery, particularly in first 48 hours with dosing recommendations of 15 to 30 mg every six to eight hours, with maximum daily dose of 60 mg.  IV ketorolac decreases need for narcotics and subsequently it side effects.

Concern has been raised about use of IV Ketorolac and spinal nonunion. Though literature nullifies this concern, surgeon should be kept informed with its use.

IV ketorolac should be use with caution in other said conditions.


 Reference: 

Pradhan BB, Tatsumi RL, Gallina J, et al. Ketorolac and spinal fusion: does the perioperative use of ketorolac really inhibit spinal fusion? Spine 2008; 33:2079.

A note on Visceral Perfusion Pressure

As predicted alike Cerebral Perfusion, Intra-Abdominal Pressure's (IAP) ultimate goal is to keep visceral perfusion intact.

Visceral Perfusion Pressure(VPP) = MAP-IAP

It is found that VPP with a target above 60 mmHg correlates  with improved survival.


Reference: 

 Cheatham ML. Intraabdominal pressure monitoring during fluid resuscitation. Curr Opin Crit Care 2008; 14: 327–33.

Q: What is one added advantage of High Flow Nasal Cannula Oxygen Therapy?


Answer:  It provides Positive Pressure Ventilation (PEEP effect)

Despite being an open system, high flow itself overcomes some of the resistance of expiratory flow and increases airway pressure. One added trick is to instruct patient to keep mouth closed which helps in increasing pharyngeal pressure, which in return not only increases lung volume but may also recruits collapsed alveoli. Interestingly, higher the BMI higher is the effect.



References: 

 1.  Parke R, McGunness S, Eccleston M. Nasal high-flow therapy delivers low level positive airway pressure. Br J Anaesth. 2009;103:886–90.

2. Groves N, Tobin A. High flow nasal oxygen generates positive airway pressure in adult volunteers. Aust Crit Care. 2007;20:126–31

Role of intravenous lipid emulsion (ILE) in drug toxicity

Intravenous lipid emulsion (ILE) has been proposed in lipophilic drugs like beta-blockers, calcium channel blockers or tricyclic antidepressants. Help from hospital pharmacy should be obtained. Evidence for its use is weak and should be kept for unstable patients and should be used after due consideration of risks and benefits. Proposed mechanism is sinking of lipophilic drug by surrounding it.

Dosing: IV bolus of 1 to 1.5 mL/kg given over 1-3 minutes of a 20 percent lipid emulsion solution. Boluses can be repeated every 5 minutes upto maximum of 3 times - and if found effective, infusion can be continued at 0.25 to 0.5 mL/kg per minute untill patient becomes hemodynamically stable.



References:

1.  Jamaty C, Bailey B, Larocque A, et al. Lipid emulsions in the treatment of acute poisoning: a systematic review of human and animal studies. Clin Toxicol (Phila) 2010; 48:1. 

2. Young AC, Velez LI, Kleinschmidt KC. Intravenous fat emulsion therapy for intentional sustained-release verapamil overdose. Resuscitation 2009; 80:591. 

3. Sirianni AJ, Osterhoudt KC, Calello DP, et al. Use of lipid emulsion in the resuscitation of a patient with prolonged cardiovascular collapse after overdose of bupropion and lamotrigine. Ann Emerg Med 2008; 51:412. 

4. Doepker B, Healy W, Cortez E, Adkins EJ. High-dose insulin and intravenous lipid emulsion therapy for cardiogenic shock induced by intentional calcium-channel blocker and Beta-blocker overdose: a case series. J Emerg Med 2014; 46:486. 

5. Bologa C, Lionte C, Coman A, Sorodoc L. Lipid emulsion therapy in cardiodepressive syndrome after diltiazem overdose--case report. Am J Emerg Med 2013; 31:1154.e3. 

Q: Name at least 3 joints which are mostly involved and actually may be first clinical clue of septic arthritis secondary to endocarditis?



Answer: 

• Sacroiliac 
• Pubic
• Manubriosternal 

Osteo-Articular-Infection in  Infective endocarditis  may involve vertebrae, stemoclavicular joint, sacroiliac joint, knees, and wrist joints. Interestingly, many times, they are the first clinical findings in infective Endocarditis

Q: 62 year old male with known history of HIV presented to ER with SOB. CXR revealed unilateral spontaneous pneumothorax, otherwise parenchyma on both sides appears normal. What would be your concern?



Answer:  Pneumothoraces in HIV patients should be read as PCP (Pneumocystis jirovecii) infection, proved otherwise. Prompt evaluation should be initiated, and treatment should not be delayed. About 25% of HIV patients with PCP may have normal chest x-rays at least in the beginning of the disease.


Reference: 

DeLorenzo LJ, Huang CT, Maguire GP, Stone DJ. Roentgenographic patterns of Pneumocystis carinii pneumonia in 104 patients with AIDS. Chest 1987; 91:323.

Q: What is Reynolds Pentad?


Answer:  In acute cholangitis if all of the following five are presents, it probably speaks for suppurative cholangitis and carries very high morbidity and mortality.

• Fever
• Abdominal pain
• Jaundice 
• Confusion and 
• Hypotension 

Q: Inhaled Nitric Oxide(NO) increases the risk of injury to which of the following organs

A) Liver
B) Bone marrow
C) Kidney
D) Brain
E) Adrenals



Answer:  C

A meta-analysis published by Afshari A. and Coll. showed that inhaled NO increases the risk of renal injury. It should continue to be used only as a short-term rescue therapy in right heart failure, pulmonary hypertension or in refractory hypoxemia. Also, methemoglobin levels should be monitored closely in those patients.



Reference:

Afshari A, Brok J, Møller AM, Wetterslev J. Inhaled nitric oxide for acute respiratory distress syndrome (ARDS) and acute lung injury in children and adults. Cochrane Database Syst Rev 2010; :CD002787

A note on pericardiocentesis, severe pulmonary hypertension, right heart failure and left heart failure

Pericardial tamponade itself is a life threatening disease process and rarely it's risk outweighs the benefit. But patients with severe pulmonary hypertension may carry higher risk and chance of dying by procedure itself. Actually, effusion in pericardial chamber sometime is lifesaving in patients with severe pulmonary hypertension as they may be preventing dilatation of the right ventricle (RF failure). Drainage of that fluid may cause acute RV dilatation/failure and collapse of hemodynamics, rarely salvageable.

Unlikely but pericardiocentesis may cause left heart failure with cardiogenic pulmonary edema. This is probably due to sudden increase in venous return atop on underlying left ventricular(LV) dysfunction. But acute left ventricular failure is usually managed and salvaged in contrast to acute right ventricular failure. It is a very rare complication of pericardiocentesis and should not prevent the procedure.


References:

1.  Acute right ventricular dilation and echocardiographic volume overload following pericardiocentesis for relief of cardiac tamponade. Am Heart J 1984; 107:1266.

2.Wolfe MW, Edelman ER. Transient systolic dysfunction after relief of cardiac tamponade. Ann Intern Med 1993; 119:42. 

Q: Intra-Aortic-Balloon-Pump (IABP) associated thrombocytopenia is usually benign. It is common to have intravenous infusion of Heparin along with IABP. Studies have shown very safe profile even if both modalities of treatments are applied together. But, at what point Heparin Induced Thrombocytopenia (HIT) should become a concern?


Answer: HIT occurs in about 3% of patients who receive both IABP and heparin simultaneously. IABP-associated thrombocytopenia usually stabilized after 72-96 hours of counterpulsation. But if it does not stabilizes or continue to fall after that time-period, HIT should be considered due to its lethal implications.




Reference: 

Bream-Rouwenhorst HR1, Hobbs RA, Horwitz PA.J - Thrombocytopenia in patients treated with heparin, combination antiplatelet therapy, and intra-aortic balloon pump counterpulsation. - .J Interv Cardiol. 2008 Aug;21(4):350-6.

Q: 34 year old male with long history of myasthenia gravis went for elective thymectomy. Inadvertently patient had blood loss of 2 liters. What would be your concern? 


Answer: Postoperative myasthenic crisis

High Estimated Blood Loss (EBL), at least more than one litre itself is a risk factor for postoperative myasthenic crisis in patients with long standing myasthenia. Other risk factors are well known as low vital capacity, baseline need of high pyridostigmine dose or poor functional status.



Reference:

Watanabe A, Watanabe T, Obama T, et al. Prognostic factors for myasthenic crisis after transsternal thymectomy in patients with myasthenia gravis. J Thorac Cardiovasc Surg 2004; 127:868.

Q: What is the biggest advantage of applying BiPAP (non-invasive positive pressure ventilation) via standard type of ventilators?


Answer: Standard type of ventilators by default have separate inspiratory and expiratory tubing which minimizes the rebreathing of carbon dioxide. Also, more reliable and precise concentration of oxygen can be delivered.


References: 

 Ferguson GT, Gilmartin M. CO2 rebreathing during BiPAP ventilatory assistance. Am J Respir Crit Care Med 1995; 151:1126.

Q: Which mode of ventilation is preferred during one-lung ventilation?


Answer:  Pressure-controlled ventilation 

Conventional ventilation with SIMV (Synchronized Intermittent Minute Ventilation)  or AC (Assist Controlled) will not prevent ventilated lung from having high peak pressure.  Damage to ventilated lung like pneumothorax will be immediately life-threatening.  

Q: Which valve with vegetation in endocarditis has the highest risk of sequelae? 

A) Tricuspid valve
B) Aortic valve
C) Pulmonic valve
D) Anterior mitral leaflet 
E) on papillary muscles


Answer: D

As expected left sided vegetation in endocarditis carries more risk of complications like CVA, ophthalmic complications, ischemia of the extremities or to organs like renal or spleen, PE or even acute MI. But, in comparison to Aortic valve the risk is highest among patients with a vegetation on the anterior mitral leaflet. It is assumed that this is due to broad and abrupt leaflet excursion of the anterior mitral leaflet.



References: 

 1. Bayer AS, Bolger AF, Taubert KA, et al. Diagnosis and management of infective endocarditis and its complications. Circulation 1998; 98:2936. 

2. Rohmann S, Erbel R, Görge G, et al. Clinical relevance of vegetation localization by transoesophageal echocardiography in infective endocarditis. Eur Heart J 1992; 13:446.

Q: What is "duckbill" mechanism?

Answer: "Duckbill" mechanism is applied in the IntraBronchial Valve (IBV) which allows air and secretions to pass through a central orifice that opens during exhalation but stay close on inhalation preventing air to enter. It is a kind of a non-surgical version of  lung volume reduction surgery (LVRS) for severe emphysema.

Q: Which of the following uncontrolled disease process may results in overestimation of oxygen saturation by pulse-ox 

A) Diabetes
B) Hypertension
C) Congestive Heart Failure
D) Sickle Cell Trait
E) Sleep Apnea Syndrome


Answer:  A

In diabetic patients with HbA1C more than 7 may cause overestimation of oxygen saturation by pulse-ox. This is probably due to an increased hemoglobin oxygen affinity.



 References: 

 Pu LJ, Shen Y, Lu L, et al. Increased blood glycohemoglobin A1c levels lead to overestimation of arterial oxygen saturation by pulse oximetry in patients with type 2 diabetes. Cardiovasc Diabetol 2012; 11:110.

A note on use of plasmapheresis  for central pontine myelinolysis(CPM) 

Data is limited but plasmapheresis has shown promising clinical benefit on CPM (also known as osmotic demyelination syndrome) if implement quickly on diagnosis, though MRI may not show any improvement. If nothing to loose, plasmapheresis could be of worth trying in such situations.



References: 

1.  Bibl D, Lampl C, Gabriel C, et al. Treatment of central pontine myelinolysis with therapeutic plasmapheresis. Lancet 1999; 353:1155. 

2. Grimaldi D, Cavalleri F, Vallone S, et al. Plasmapheresis improves the outcome of central pontine myelinolysis. J Neurol 2005; 252:734. 

3. Saner FH, Koeppen S, Meyer M, et al. Treatment of central pontine myelinolysis with plasmapheresis and immunoglobulins in liver transplant patient. Transpl Int 2008; 21:390.

Q: What are the 2 methods by which Intermittent pneumatic compression boots prevent Deep Venous Thrombosis (DVT)? 


Answer:  Intermittent pneumatic compression boots prevent DVT not only by enhancing blood flow or  preventing venous stasis in the deep veins of the legs, but also by  increasing endogenous fibrinolytic activity via reducing plasminogen activator inhibitor-1.


Reference: 

 Comerota AJ, Chouhan V, Harada RN, et al. The fibrinolytic effects of intermittent pneumatic compression: mechanism of enhanced fibrinolysis. Ann Surg 1997; 226:306.

Q: Beside clot formation what is another caveat of nonpulsatile cardiac devices?

Answer: It may cause poor microcirculation perfusion and may cause overall end-organ dysfunctions.

A note on Urine Albumin-to-Creatinine Ratio (UACR) 

The addition of albuminuria staging to GFR staging is relatively a new endeavor, added for further micromanaging and to identify patients with renal disease relatively earlier. Another advantage of this staging is use of a spot urine albumin-to-creatinine ratio (UACR). 24 hour collection is not necessary.

 Urine albumin (mg/dL) / Urine creatinine (g/dL) = UACR in mg/g

Grading is done as per following

1. A1 = UACR less than 30 mg/g 
2.  A2 = UACR 30 to 299 mg/g 
3.  A3 = ACR more than/equal to300 mg/g

 Studies have shown that UACR along with eGFR provide a better predictor of patients at risk for ESRD.



 Reference: 

Hallan SI, Ritz E, Lydersen S, et al. Combining GFR and albuminuria to classify CKD improves prediction of ESRD. J Am Soc Nephrol 2009; 20:1069.

Q: Out of following which medicine should be avoided at end of life care?

A) Morphine
B) Dexmedetomidine
C) Glycopyrrolate
D) Cisatracurium 
E)  Ondansetron



Answer:  D

Cisatracurium is a neuromuscular blockade and it provides no beneficial effect  at end of life. Rather it can mask patient's symptoms, hasten and make death more painful and may prevent providers from effectively deliver comfort care. 

Another objective of above question is to bring in light the role of sedatives in palliative care (Choice B). More and more literature now favours comforting sedation for patient's at end of life.


Recommended Reading:

Palliative Sedation in End-of-Life Care - Susan D. Bruce, RN, BSN, OCN; and coll. - Journal of Hospice and Palliative Nursing. 2006;8(6):320-327.

Q; What is the major pitfall in using glucose level via arterial line sampling?


Answer: Iatrogenic hypoglycemia

As per "Guidelines for arterial line blood sampling: preventing hypoglycaemic brain injury 2014 - from The Association of Anaesthetists of Great Britain and Ireland", published in september 2014

"Drawing samples from an indwelling arterial line is the method of choice for frequent blood analysis in adult critical care areas. Sodium chloride 0.9% is the recommended flush solution for maintaining the patency of arterial catheters, but it is easy to confuse with glucose-containing bags on rapid visual examination. The unintentional use of a glucose-containing solution has resulted in artefactually high glucose concentrations in blood samples drawn from the arterial line, leading to insulin administration causing hypoglycaemia and fatal neuroglycopenic brain injury."


Full Guideline can be read @

https://www.aagbi.org/sites/default/files/Arterial%20line%20blood%20sampling.pdf

A note on water soluble contrast (Gastrografin) as a treatment in small bowel obstruction

Use of water soluble contrast (Gastrografin) has shown therapeutic modality in patients with partial non mechanical small bowel obstruction, along with NPO, nasogastric decompression, hydration and electrolyte replacement. Water soluble contrast (Gastrografin) is a hypertonic solution, decreases intestinal wall edema and increases intestinal peristalsis. If it works, there should be an improvement in symptoms within 24 hours.


Reference: 

Abbas SM, Bissett IP, Parry BR. Meta-analysis of oral water-soluble contrast agent in the management of adhesive small bowel obstruction. Br J Surg 2007; 94:404.

Q: What is considered to be the gold assay for Heparin Induced Thrombocytopenia (HIT)?


Answer: Serotonin release assay 

The 5 components required to do this test are

• Donor platelets 
• 14C-serotonin radiolabel
•  Patient's serum 
•  Heparin at therapeutic concentrations (0.1 units/mL)
•  Heparin at excessive concentrations (100 units/mL)

First, platelets from normal donors are radiolabeled with 14C-serotonin. Incubation is done with patient serum plus heparin at therapeutic as well as at excessive concentrations. A positive test is the release of 14C-serotonin when therapeutic heparin concentrations are used, but not with excessive heparin concentrations. This sounds odd but it reflects the fact that the binding of HIT antibodies is only seen at certain ratios of heparin to PF4.

Q: Bicarbonate therapy is usually not indicated in DKA(Diabetic Ketoacidosis). At what level of PH in DKA, bicarbonate therapy is recommended? 


Answer: 6.9 

Bicarbonate therapy in DKA should be used only if PH goes below 6.90. Also, it needs to be remembered that bicarbonate may decrease potassium level, so potassium should be replaced if level is less than 5.3 mEq/L.

Q: What is Pusher syndrome? 

Answer:  CVA patients tends to passively prefer weight-bearing on their nonhemiparetic side. But one subset of patients with CVA actively try to push their weight away from the nonhemiparetic side to the hemiparetic side. It may be due to lesions involved in the brain in posterior thalamus or multiple areas of the right cerebral hemisphere.

Clinical significance:  Rehabilitation may take longer in these patients.



References:

1.  Pedersen PM, Wandel A, Jørgensen HS, Nakayama H, Raaschou HO, Olsen TS (January 1996). "Ipsilateral pushing in stroke: incidence, relation to neuropsychological symptoms, and impact on rehabilitation. The Copenhagen Stroke Study". Arch Phys Med Rehabil 77 (1): 25–8

2. Babyar SR, Peterson MG, Bohannon R, Pérennou D, Reding M (July 2009). "Clinical examination tools for lateropulsion or pusher syndrome following stroke: a systematic review of the literature". Clin Rehabil 23 (7): 639–50.