Non infectious causes of acidotic pleural fluid acidosis

Q: Beside infection give at least five causes of acidotic pleural fluid acidosis with or without low glucose?

Answer: Complicated parapneumonic pleural effusion or empyema is the leading and 'proven otherwise cause of pleural fluid acidosis (pH less than 7.2) and/or low glucose. But there are few other causes which may have the similar laboratory findings and may mislead the clinician. 

• Malignancy
• Rheumatoid pleuritis
• Lupus pleuritis
• Urinothorax
• Misplaced central venous catheter infusing isotonic fluid 

On side note one infectious cause, which may goes missed particularly in developed countries where epidemiology is on lower side is tuberculosis.

#procedures

#pulmonary

#ID

#rheumatology

#oncology

#urology

# laboratory-medicine

References:

1. Sahn SA. State of the art. The pleura. Am Rev Respir Dis 1988; 138:184.

2. Zheng WQ, Hu ZD. Pleural fluid biochemical analysis: the past, present and future. Clin Chem Lab Med. 2022 Nov 17;61(5):921-934. doi: 10.1515/cclm-2022-0844. PMID: 36383033.

Radial Artery in CABG

Q: In which subset of patients should the radial artery graft be used cautiously in cardiac arterial bypass surgery (CABG)?

Answer: Renal disease patients who are at risk for requiring dialysis

More and more heart centers and surgeons are increasingly using radial artery graft for CABG. One of the reasons for using radial graft along with the internal mammary graft, mostly left (LIMA) is due to literature showing higher long-term patency with two arterial grafts.

Intensivists should be aware of the fact that immediately after CABG surgery, many of these patients may develop spasm of the graft. Use of prophylactic vasodilator agent, such as intravenous (IV) nitro or calcium channel blocker (CCB), may help to prevent this complication.

As expected adequate ulnar artery flow to prevent the loss of hand function should be performed prior to making decision about use of radial artery via Allen test.

Also, post surgery, patient may feel forearm numbness and tingling, but these symptoms usually resolve with any clinical significance.

Renal patients who are at risk of going on dialysis should ideally be not get radial artery harvesting as it limits the creation of arterio-venous fistula or graft on the ipsilateral arm.

#surgical-critical-care

#vascular surgery

References:

1. Gaudino M, Benedetto U, Fremes S, et al. Radial-Artery or Saphenous-Vein Grafts in Coronary-Artery Bypass Surgery. N Engl J Med 2018; 378:2069.

2. Maniar HS, Sundt TM, Barner HB, et al. Effect of target stenosis and location on radial artery graft patency. J Thorac Cardiovasc Surg 2002; 123:45.

3. Iacò AL, Teodori G, Di Giammarco G, et al. Radial artery for myocardial revascularization: long-term clinical and angiographic results. Ann Thorac Surg 2001; 72:464.

renal failure treated by ACE-I

Q: Which type of renal failure is treated/managed by ACE inhibitors?

Answer: Scleroderma Renal Crisis!

Scleroderma Renal Crisis is one of the few rheumatological emergencies where early diagnosis and treatment can make a big difference in outcome. A wrong diagnosis may lead to the wrong management pathway and high mortality. SRC is heralded by a hypertensive crisis associated with acute renal failure. Still, the pearl is to avoid IV Labetolol or nitroprusside and gradually decrease blood pressure with PO angiotensin-converting enzyme (ACE) inhibitors. Calcium channel blockers may help. Renal dialysis is a last resort. It has been suggested that the use of steroids is associated with the onset of scleroderma renal crisis.

#rheumatology

References:

1. Cole A, Ong VH, Denton CP. Renal Disease and Systemic Sclerosis: an Update on Scleroderma Renal Crisis. Clin Rev Allergy Immunol. 2023 Jun;64(3):378-391. doi: 10.1007/s12016-022-08945-x. Epub 2022 Jun 1. PMID: 35648373; PMCID: PMC10167155.

2. Hudson M, Ghossein C, Steen V. Scleroderma renal crisis. Presse Med. 2021 Apr;50(1):104063. doi: 10.1016/j.lpm.2021.104063. Epub 2021 Feb 3. PMID: 33548376.

Thyroid and Recurrent Pregnancy loss connection

Case: 36 years old woman is admitted to the ICU for severe depression and suicidal ideation since she had three consecutive losses of pregnancy. All lab work appears relatively stable except for mild thyroid-stimulating hormone (TSH) elevation of 5.2 mIU/L.   

Discussion: Interestingly, thyroid health is highly related to pregnancy health. Even in mild and clinically asymptomatic hypothyroidism, the incidence of spontaneous miscarriage is high. 

Also, in euthyroid females with thyroid peroxidase (TPO) antibodie,s the risk can be doubled to tripled. 

Fortunately, with thyroid treatment, the risk can be minimized.

#ob-gyn

#endo

#psychiatry

References:

1. Negro R, Schwartz A, Gismondi R, et al. Increased pregnancy loss rate in thyroid antibody negative women with TSH levels between 2.5 and 5.0 in the first trimester of pregnancy. J Clin Endocrinol Metab 2010; 95:E44.

2. Chen L, Hu R. Thyroid autoimmunity and miscarriage: a meta-analysis. Clin Endocrinol (Oxf) 2011; 74:513.

3. Thangaratinam S, Tan A, Knox E, et al. Association between thyroid autoantibodies and miscarriage and preterm birth: meta-analysis of evidence. BMJ 2011; 342:d2616.

4. Bliddal S, Feldt-Rasmussen U, Rasmussen ÅK, et al. Thyroid Peroxidase Antibodies and Prospective Live Birth Rate: A Cohort Study of Women with Recurrent Pregnancy Loss. Thyroid 2019; 29:1465.

CRRT and Phosphate

Q: Which of the following may occur in continuous renal replacement therapy (CRRT)? - select one

A) Hyperphosphatemia

B) Hypophosphatemia 

Answer: B

Hypophosphatemia occurs in CRRT due to the removal of phosphate from effluent waste. It is common in the ICU to do aggressive CRRT via either high dialysate or replacement fluid flow rates. With high demand for CRRT in the ICU, frequent shortages of intravenous phosphate preparations have been reported in the United States. 

Said that Phosphate-containing dialysis solution may help in preventing hypophosphatemia during CRRT.

#nephrology

References:

1. Broman M, Carlsson O, Friberg H, et al. Phosphate-containing dialysis solution prevents hypophosphatemia during continuous renal replacement therapy. Acta Anaesthesiol Scand 2011; 55:39.

2. Hendrix RJ, Hastings MC, Samarin M, Hudson JQ. Predictors of Hypophosphatemia and Outcomes during Continuous Renal Replacement Therapy. Blood Purif. 2020;49(6):700-707. doi: 10.1159/000507421. Epub 2020 Apr 22. PMID: 32320987.

3. Bellomo R, Cass A, Cole L, Finfer S, Gallagher M, Kim I, Lee J, Lo S, McArthur C, McGuinness S, Norton R, Myburgh J, Scheinkestel C. The relationship between hypophosphataemia and outcomes during low-intensity and high-intensity continuous renal replacement therapy. Crit Care Resusc. 2014 Mar;16(1):34-41. Erratum in: Crit Care Resusc. 2014 Jun;16(2):139. McGuiness, Shay [corrected to McGuinness, Shay]. PMID: 24588434.

mannitol nephrotoxicity syndrome

Q: Acute Kidney Injury (AKI) developed due to mannitol therapy can be quickly reversed by hemodialysis (HD).

A) True

B) False

Answer: A (True)

If mannitol is used at a high dose, leading to an osmolal gap greater than 55 mosmol/kg, it may cause AKI by vasoconstriction. This phenomenon is known as mannitol nephrotoxicity syndrome.

AKI can be avoided by keeping the mannitol dose at the recommended lower level, i.e., 0.25 g/kg every four hours or 1.5 g/kg daily. Fortunately, this AKI is reversible either by stopping the mannitol or with a single or two sessions of HD. Without HD, it may take up to a week or so to get rid of excess mannitol. HD expedites the removal of excess mannitol.

#nephrology

#pharmacology

#toxicity

References:

1. Dorman HR, Sondheimer JH, Cadnapaphornchai P. Mannitol-induced acute renal failure. Medicine (Baltimore) 1990; 69:153.

2. Gadallah MF, Lynn M, Work J. Case report: mannitol nephrotoxicity syndrome: role of hemodialysis and postulate of mechanisms. Am J Med Sci 1995; 309:219.

3. Pérez-Pérez AJ, Pazos B, Sobrado J, et al. Acute renal failure following massive mannitol infusion. Am J Nephrol 2002; 22:573.

TAK

Q: Which of the following is NOT among the classic 1990 American College of Rheumatology (ACR) classification criteria for Takayasu arteritis (TAK)? - select one

A) Age at disease onset ≤40 years

B) Claudication of the extremities

C) Decreased pulsation of one or both brachial arteries

D) Bruit over one or both femoral arteries

E) Difference of at least 10 mmHg in systolic blood pressure between the arms

Answer: D

The 1990 American College of Rheumatology (ACR) classification criteria were developed to help distinguish one form of vasculitis from another. Patients are said to have TAK if at least three of the six criteria are present.

1. Age at disease onset ≤40 years
2. Claudication of the extremities
3. Decreased pulsation of one or both brachial arteries
4. Difference of at least 10 mmHg in systolic blood pressure between the arms
5. Bruit over one or both subclavian arteries or the abdominal aorta
6. Arteriographic narrowing or occlusion of the entire aorta, its primary branches, or large arteries in the proximal upper or lower extremities, not due to arteriosclerosis, fibromuscular dysplasia, or other causes

The criteria are criticized due to their possible limitations in clinical practice.

To update, the ACR/European Alliance of Associations for Rheumatology (EULAR) created new criteria for TAK using a weighted algorithm that includes clinical and imaging components (reference # 4).

Unfortunately, none of these criteria has been validated for establishing clinical diagnoses.

#rheumatology 

References:

1. Arend WP, Michel BA, Bloch DA, et al. The American College of Rheumatology 1990 criteria for the classification of Takayasu arteritis. Arthritis Rheum 1990; 33:1129.

2. Ishikawa K. Diagnostic approach and proposed criteria for the clinical diagnosis of Takayasu's arteriopathy. J Am Coll Cardiol 1988; 12:964.

3. Sharma BK, Jain S, Suri S, Numano F. Diagnostic criteria for Takayasu arteritis. Int J Cardiol 1996; 54 Suppl:S141.

4. Grayson PC, Ponte C, Suppiah R, et al. 2022 American College of Rheumatology/EULAR Classification Criteria for Takayasu Arteritis. Arthritis Rheumatol 2022; 74:1872.

PRES and CVA in SCD

Q: Which is more common in Sickle cell disease (SCD)? - Select one

A) PRES

B) Stroke

Answer: B

Posterior reversible encephalopathy (PRES), though usually described in accelerated hypertension with its constellation of symptoms like confusion, headache, visual symptoms, and seizures, may occur in other conditions, such as endothelial dysfunction. Its most interesting association is found in pediatric SCD patients with recent transfusion or hematopoietic stem cell transplantation. No clear explanation is available.

In SCD patients, stroke is more prevalent than PRES. This is the reason many times, PRES in SCD patients is misdiagnosed as stroke (see reference # 1). These patients are also prone to early dementia.

#neurology

#hematology

#pediatrics

References:

1. Solh Z, Taccone MS, Marin S, et al. Neurological PRESentations in Sickle Cell Patients Are Not Always Stroke: A Review of Posterior Reversible Encephalopathy Syndrome in Sickle Cell Disease. Pediatr Blood Cancer 2016; 63:983.

2. BinAmir HA, AlAhmari A, AlQahtani A, Mohamed G, Alotaibi F, AlShamrani M, AlSaeed A, AlGhanmi S, Heji A, Alreshaid A, AlKawi A, AlHazzani A, AlZawahmah M, Shuaib A, Al-Ajlan F, AlMohareb F. Posterior reversible encephalopathy syndrome post stem cell transplantation in sickle cell disease: case series and literature review. Front Med (Lausanne). 2024 May 1;11:1330688. doi: 10.3389/fmed.2024.1330688. PMID: 38751974; PMCID: PMC11094324.

3. Abboud MR. Cerebral vasculopathy in patients with sickle cell disease and stroke: now you see it, now you don't. Haematologica. 2024 Oct 1;109(10):3108-3109. doi: 10.3324/haematol.2024.285383. PMID: 38752274; PMCID: PMC11443402.

CCBs and clopidogrel

Case: 44 years old male was discharged 12 weeks ago on Dual Anti-Platelet Therapy (DAPT) from the hospital after acquiring a coronary stent due to an acute myocardial infarction. The patient presented to the ER with chest pain and an EKG similar to the previous presentation, with high suspicion of stent thrombosis. Patient reports 100% compliance with medications. The patient was recently started on Calcium channel blockers (CCBs) as an outpatient due to still uncontrolled hypertension (HTN). 

Discussion: Although clinically insignificant in most cases, CCBs may decrease the efficacy of clopidogrel because they inhibit CYP3A4. Still, it is very kosher to prescribe CCBs to patients on DAPT therapy due to the lack of concrete evidence and conflicting studies. 

An astute clinician should consider this possibility, as stent thrombosis can prove fatal.

#pharmacology

#cardiology

References:

1. Gremmel T, Steiner S, Seidinger D, et al. Calcium-channel blockers decrease clopidogrel-mediated platelet inhibition. Heart 2010; 96:186.

2. Siller-Matula JM, Lang I, Christ G, Jilma B. Calcium-channel blockers reduce the antiplatelet effect of clopidogrel. J Am Coll Cardiol 2008; 52:1557.

3. Olesen JB, Gislason GH, Charlot MG, et al. Calcium-channel blockers do not alter the clinical efficacy of clopidogrel after myocardial infarction: a nationwide cohort study. J Am Coll Cardiol 2011; 57:409.

4. Good CW, Steinhubl SR, Brennan DM, et al. Is there a clinically significant interaction between calcium channel antagonists and clopidogrel?: results from the Clopidogrel for the Reduction of Events During Observation (CREDO) trial. Circ Cardiovasc Interv 2012; 5:77.

Cocaine and adrenergic receptors

Q: Cocaine stimulates which adrenergic receptors? - select one

A) alpha-1

B) alpha-2

C) beta-1

D) beta-2 

E) All of the above

Answer: E

Cocaine is considered highly toxic as it stimulates all adrenergic receptors via increasing levels of norepinephrine, and to a lesser extent, epinephrine. Coronary syndromes occur via the alpha-adrenergic agonist's vasoconstrictive effect in both cardiac and peripheral vasculature.

Contrary to conventional belief, the central and euphoric effects occur via inhibition of neuronal serotonin reuptake, causing psychological addiction. The physiological addiction is primarily due to the dopamine reuptake effect on the dopamine-containing neuronal systems traveling from the limbic region to the frontal cortex. Also, the increased levels of the excitatory amino acids glutamate and aspartate have been described.

#toxicity

References:

1. Nestler EJ. The neurobiology of cocaine addiction. Sci Pract Perspect. 2005 Dec;3(1):4-10. doi: 10.1151/spp05314. PMID: 18552739; PMCID: PMC2851032.

2. Gawin FH. Cocaine addiction: psychology and neurophysiology. Science. 1991 Mar 29;251(5001):1580-6. doi: 10.1126/science.2011738. Erratum in: Science 1991 Aug 2;253(5019):494. PMID: 2011738.

3. Mahoney JJ 3rd, Haile CN, De La Garza R 2nd, Thakkar H, Newton TF. Electrocardiographic characteristics in individuals with cocaine use disorder. Am J Addict. 2017 Apr;26(3):221-227. doi: 10.1111/ajad.12524. Epub 2017 Mar 1. PMID: 28248441.

Older patients and suicide

Q: 87 years old male has been brought to the ER after a welfare check by his neighbor. The patient was found on the floor and appears to be hypovolemic and dehydrated. The neighbor also brought many empty bottles of prescription meds. The patient lives alone. After interviewing and examining the patient, the ER physician calls for admission with suspicion of suicidal ideation. ICU admission is warranted as older patients are more likely to complete suicide.

A) True

B) False

Answer: A (True)

Suicide in older patients is an under-recognised issue. They account for almost a quarter of all completed suicides. Though they attempt suicide less often than younger people, they are more successful at completion. In subgroups, males at age 85 or above have the highest rate of completed suicide. The list of risk factors is long, including:

• hopelessness
• insomnia
• restlessness
• impaired concentration
• active psychosis
• active alcohol use 
• unremitting pain
• comorbid physical illness
• terminal illness or worsening of physical illness
• widowhood 
• social isolation
• personality disorders
• prior suicide attempt
• family history of suicide

#psychiatry

#geriatrics

References:

1. Hoyert DL, Kochanek KD, Murphy SL. Deaths: final data for 1997. Natl Vital Stat Rep 1999; 47:1.

2. Waern M, Runeson BS, Allebeck P, et al. Mental disorder in elderly suicides: a case-control study. Am J Psychiatry 2002; 159:450.

3. Nguyen BL, Lyons BH, Forsberg K, et al. Surveillance for Violent Deaths - National Violent Death Reporting System, 48 States, the District of Columbia, and Puerto Rico, 2021. MMWR Surveill Summ 2024; 73:1.

4. Bruce ML, Ten Have TR, Reynolds CF 3rd, et al. Reducing suicidal ideation and depressive symptoms in depressed older primary care patients: a randomized controlled trial. JAMA 2004; 291:1081.

Diaphragm Dysfunction After Cardiac Surgery

Q: After Cardiothoracic surgery, which side of the diaphragm tends to have paralysis? - select one

A) left

B) right

Answer: A

During cardiothoracic surgery, stretching or cooling may cause phrenic nerve injury, resulting in unilateral diaphragmatic paralysis. The literature has described a wide range of occurrences, from 1.3 to 60 percent. Most are clinically not significant. 

This is because the Left Internal Mammary Artery (LIMA) is most often used in the bypass. Use of RIMA can cause similar pathology on the right side. 

Recovery may take up to one to two years.

#surgical-critical-care

#neurology

References:

1. Katz MG, Katz R, Schachner A, Cohen AJ. Phrenic nerve injury after coronary artery bypass grafting: will it go away? Ann Thorac Surg 1998; 65:32.

2. Canbaz S, Turgut N, Halici U, et al. Electrophysiological evaluation of phrenic nerve injury during cardiac surgery--a prospective, controlled, clinical study. BMC Surg 2004; 4:2.

3. Laghlam D, Lê MP, Srour A, Monsonego R, Estagnasié P, Brusset A, Squara P. Diaphragm Dysfunction After Cardiac Surgery: Reappraisal. J Cardiothorac Vasc Anesth. 2021 Nov;35(11):3241-3247. doi: 10.1053/j.jvca.2021.02.023. Epub 2021 Feb 11. PMID: 33736912.

Cardiac and Pulmonary Anatomical Shunt

Q: What are anatomic Pulmonary and Cardiac shunting?

Answer:  

Pulmonary anatomical shunting: The bronchial circulation provides oxygenation to the lung and is not oxygenated before it returns to the left heart. 

Cardiac anatomical shunting: Some blood flowing through some small cardiac veins empties back into the left heart without oxygenation.

#cardiology

#pulmonary

Further readings:

1. Cressoni M, Caironi P, Polli F, Carlesso E, Chiumello D, Cadringher P, Quintel M, Ranieri VM, Bugedo G, Gattinoni L. Anatomical and functional intrapulmonary shunt in acute respiratory distress syndrome. Crit Care Med. 2008 Mar;36(3):669-75. doi: 10.1097/01.CCM.0000300276.12074.E1. PMID: 18091555.

2. Tobler D, Greutmann M. Simple cardiac shunts in adults: atrial septal defects, ventricular septal defects, patent ductus arteriosus. Heart. 2020 Feb;106(4):307-314. doi: 10.1136/heartjnl-2019-314700. Epub 2020 Jan 7. PMID: 31911502.

3. Her C. Anatomical intrapulmonary shunt. Crit Care Med. 2008 Sep;36(9):2713; author reply 2714-5. doi: 10.1097/CCM.0b013e3181847321. PMID: 18728503.

4. Schmiel M, Ono M, Staehler H, Georgiev S, Burri M, Heinisch PP, Strbad M, Ewert P, Hager A, Hörer J. Impact of Anatomical Sub-types and Shunt Types on Aortopulmonary Collaterals in Hypoplastic Left Heart Syndrome. Semin Thorac Cardiovasc Surg. 2023 Winter;35(4):746-756. doi: 10.1053/j.semtcvs.2022.08.005. Epub 2022 Aug 23. PMID: 36007868.

Eye movements in Locked-in Syndrome

Q: In Locked-in syndrome, which of the eye movements remain intact? - select one

A) Horizontal

B) Vertical

Answer: B

Focal injury to the base of the pons, usually caused by embolic occlusion of the basilar artery, means the patient cannot move muscles in the limbs, trunk, or face.The only viable and intact function left is voluntary blinking and vertical eye movements. 

Horizontal eye movements are usually impaired due to damage to the paramedian pontine reticular formation (PPRF). In fact, early smooth horizontal eye movement is considered a favorable prognostic sign in locked-in syndrome.

#neurology

References:

1. Schnetzer L, McCoy M, Bergmann J, Kunz A, Leis S, Trinka E. Locked-in syndrome revisited. Ther Adv Neurol Disord. 2023 Mar 29;16:17562864231160873. doi: 10.1177/17562864231160873. PMID: 37006459; PMCID: PMC10064471.

2. Yang CC, Lieberman JS, Hong CZ. Early smooth horizontal eye movement: a favorable prognostic sign in patients with locked-in syndrome. Arch Phys Med Rehabil. 1989 Mar;70(3):230-2. PMID: 2923543.

3. Smith E, Delargy M. Locked-in syndrome. BMJ. 2005 Feb 19;330(7488):406-9. doi: 10.1136/bmj.330.7488.406. PMID: 15718541; PMCID: PMC549115.

ACE inhibitors/ARBs in migraine

Q: Angiotensin-converting enzyme (ACE) inhibitors and Angiotensin Receptor Blockers (ARBs) tend to make migraine? - select one

A) Better

B) Worse

Answer: A

Beta-blockers (BBs) and Calcium Channel Blockers (CCBs) are well known for their use in migraine treatment. Less well known is that ACE inhibitors/ARBs can also be used as an adjuvant treatment in migraine, particularly in hypertensive patients. Lisinopril has been found to be one of the most effective agents for reducing the number of hours, days, and severity of migraine. Candesartan, an ARB, is another good choice.

ACE inhibitors/ARBs are effective during treatment, but data regarding their effectiveness in preventing migraines is lacking.

#neurology

#pharmacology

References:

1. Tronvik E, Stovner LJ, Helde G, et al. Prophylactic treatment of migraine with an angiotensin II receptor blocker: a randomized controlled trial. JAMA 2003; 289:65.

2. Stovner LJ, Linde M, Gravdahl GB, et al. A comparative study of candesartan versus propranolol for migraine prophylaxis: A randomised, triple-blind, placebo-controlled, double cross-over study. Cephalalgia 2014; 34:523.

3. Schrader H, Stovner LJ, Helde G, et al. Prophylactic treatment of migraine with angiotensin converting enzyme inhibitor (lisinopril): randomised, placebo controlled, crossover study. BMJ 2001; 322:19.

APS - arterial thrombosis

Q: Which is the common site of arterial thrombosis in Antiphospholipid Syndrome (APS)? - select one

A) cerebral 

B) retinal

C) coronary

D) renal

E) mesenteric

Answer: A

Although venous thrombosis is commonly mentioned in APS, arterial thrombosis is also common. Cerebral vasculature is the most common site of arterial thrombosis. Retinal, coronary, renal, and mesenteric arteries can also get thrombosis, but are less common than the cerebral vasculature.

A young patient presenting with thrombotic stroke with no overt risk factors is APS-proven otherwise!

#rheumatology

#hematology

References:

1. Cervera R, Piette JC, Font J, et al. Antiphospholipid syndrome: clinical and immunologic manifestations and patterns of disease expression in a cohort of 1,000 patients. Arthritis Rheum 2002; 46:1019.

2. Andreoli L, Chighizola CB, Banzato A, et al. Estimated frequency of antiphospholipid antibodies in patients with pregnancy morbidity, stroke, myocardial infarction, and deep vein thrombosis: a critical review of the literature. Arthritis Care Res (Hoboken) 2013; 65:1869.

Sleep disturbance in cannabis withdrawal

Q: Which of the following is preferred for disabling sleep disturbances in Cannabis withdrawal? - select one

A) Zolpidem

B) Eszopiclone

C) Trazodone 

D) Doxylamine

E) L-tryptophan

Answer: A

Severe disabling sleep disturbance can occur in cannabis withdrawal, with a domino effect, with potentially fatal consequences.

Only a handful of medications, including zolpidem, dronabinol, and gabapentin, have been studied and shown to benefit.

The most studied and supportive evidence is available for Zolpidem. 

Nitrazepam, being a benzodiazepine, is usually discouraged due to its potential addiction issues. Nitrazepam is not available in the United States. 

#toxicity

#pharmacology

References:

1. Vandrey R, Smith MT, McCann UD, et al. Sleep disturbance and the effects of extended-release zolpidem during cannabis withdrawal. Drug Alcohol Depend 2011; 117:38.

2. Herrmann ES, Cooper ZD, Bedi G, et al. Effects of zolpidem alone and in combination with nabilone on cannabis withdrawal and a laboratory model of relapse in cannabis users. Psychopharmacology (Berl) 2016; 233:2469.

IVF in acute pancreatitis

Q: Which fluid is preferred in acute pancreatitis?

A) Lactated Ringer’s (LR)

B) normal saline (NS)

Answer: A

In the early phase of acute pancreatitis, the use of lactated Ringer’s has been found to reduce the length of stay and the risk of ICU admissions. And systemic inflammatory response syndrome (SIRS).

The only exception is that LR should be avoided in acute pancreatitis due to hypercalcemia as it contains 3 mEq/L calcium. 

#GI

References:

1. Aziz M, Ahmed Z, Weissman S, et al. Lactated Ringer's vs normal saline for acute pancreatitis: An updated systematic review and meta-analysis. Pancreatology 2021; 21:1217.

2. Wu BU, Hwang JQ, Gardner TH, et al. Lactated Ringer's solution reduces systemic inflammation compared with saline in patients with acute pancreatitis. Clin Gastroenterol Hepatol 2011; 9:710.

3. de-Madaria E, Herrera-Marante I, González-Camacho V, et al. Fluid resuscitation with lactated Ringer's solution vs normal saline in acute pancreatitis: A triple-blind, randomized, controlled trial. United European Gastroenterol J 2018; 6:63.

4. Choosakul S, Harinwan K, Chirapongsathorn S, et al. Comparison of normal saline versus Lactated Ringer's solution for fluid resuscitation in patients with mild acute pancreatitis, A randomized controlled trial. Pancreatology 2018; 18:507.

5. Lee A, Ko C, Buitrago C, et al. Lactated Ringers vs Normal Saline Resuscitation for Mild Acute Pancreatitis: A Randomized Trial. Gastroenterology 2021; 160:955.

6. Zhao G, Zhang JG, Wu HS, et al. Effects of different resuscitation fluid on severe acute pancreatitis. World J Gastroenterol 2013; 19:2044.

Anbx with neuromuscular blockade

Q: Which of the following antibiotics has a neuromuscular-blocking property? - select one

A) Ampicillin

B) Bactrim (trimethoprim-sulfamethoxazole)

C) Clindamycin

D) Doxycycline

E) Erythromycin

Answer: C

Clindamycin has neuromuscular-blocking properties and enhances the effects of neuromuscular blocking agents. At higher doses, it can independently cause neuromuscular blockade.

Clinical significance: It should be used cautiously in patients receiving neuromuscular-blocking agents.

#pharmacology

References:

1. al Ahdal O, Bevan DR. Clindamycin-induced neuromuscular blockade. Can J Anaesth. 1995 Jul;42(7):614-7. doi: 10.1007/BF03011880. PMID: 7553999.

2. Best JA, Marashi AH, Pollan LD. Neuromuscular blockade after clindamycin administration: a case report. J Oral Maxillofac Surg. 1999 May;57(5):600-3. doi: 10.1016/s0278-2391(99)90083-6. PMID: 10319836.

3. Becker LD, Miller RD. Clindamycin enhances a nondepolarizing neuromuscular blockade. Anesthesiology. 1976 Jul;45(1):84-7. doi: 10.1097/00000542-197607000-00015. PMID: 937756.

Rh antigen typing in renal transplant

Q: In Kidney transplant donors and recipients, matching for Rh antigens must be ensured as Rh antigen mismatching may lead to quick and early graft failure.

A) True

B) False

Answer: B (False)

Blood typing and crossmatching are performed per standard in all transplantations, including kidney transplants. Interestingly, though most institutions performed but matching for Rh antigens is not relevant in renal tranplant, as Rh antigens are not expressed on kidney tissue cell surfaces, Although, there may be a weak evidence that Rh antigen mismatching may cause a slight reduction in allograft survival, the overall risk is very low and Rh antigen system does not play a signficant role in allograft rejection. The highest risk exists for female Rh-negative recipients of childbearing age who are at risk for sensitization when the donor is Rh-positive.

Similarly, optimized HLA matching is very much desired; however, HLA matching between a particular donor and recipient is not required for successful transplantation. Some centers don't even perform HLA typing. The argument in favor is that with improved immunosuppressive regimens, the outcomes are acceptable (reference # 4).

In contrast, the ABO typing is required to be performed on two separate occasions before donation.

# transplantation

#kidney

References:

1. Organ Procurement and Transplantation Network: Policies. http://optn.transplant.hrsa.gov/governance/policies/ (Accessed on May 07, 2025).

2. Delmonico F, Council of the Transplantation Society. A Report of the Amsterdam Forum On the Care of the Live Kidney Donor: Data and Medical Guidelines. Transplantation 2005; 79:S53.

3. Bryan CF, Mitchell SI, Lin HM, et al. Influence of the Rh (D) blood group system on graft survival in renal transplantation. Transplantation 1998; 65:588.

4. Kim JJ, Fuggle SV, Marks SD. Does HLA matching matter in the modern era of renal transplantation? Pediatr Nephrol. 2021 Jan;36(1):31-40. doi: 10.1007/s00467-019-04393-6. Epub 2019 Dec 9. PMID: 31820146; PMCID: PMC7701071.

5. Kumbala D, Zhang R. Essential concept of transplant immunology for clinical practice. World J Transplant. 2013 Dec 24;3(4):113-8. doi: 10.5500/wjt.v3.i4.113. PMID: 24392315; PMCID: PMC3879520

NAC in COPD

Q: Inhaled N-acetylcysteine (NAC) is used as a mucolytic in COPD patients due to its quick effect within minutes. What's its drawback?

Answer: Bronchospasm

NAC can sever disulfide bonds in mucoproteins and DNA, reducing mucus viscosity. It also has an antioxidant property. It starts working within a minute and lasts up to 10 minutes.

That said, inhaled NAC may induce fatal bronchoconstriction, so it should be used with caution. It's recommended to add a bronchodilator with it.

Oral NAC largely bypasses this direct effect. The dose is 600 mg twice daily.

#pulmonary

References:

1. De Benedetto F, Aceto A, Dragani B, Spacone A, Formisano S, Pela R, Donner CF, Sanguinetti CM. Long-term oral n-acetylcysteine reduces exhaled hydrogen peroxide in stable COPD. Pulm Pharmacol Ther. 2005;18(1):41-7. doi: 10.1016/j.pupt.2004.09.030. Epub 2004 Dec 8. PMID: 15607126.

2. Sadowska AM, Verbraecken J, Darquennes K, De Backer WA. Role of N-acetylcysteine in the management of COPD. Int J Chron Obstruct Pulmon Dis. 2006;1(4):425-34. doi: 10.2147/copd.2006.1.4.425. PMID: 18044098; PMCID: PMC2707813.

3. Rhee CK, Lim SY, Lee WY, et al. The effect of nebulized N-acetylcysteine on the phlegm of chronic obstructive pulmonary disease: the NEWEST study. BMC Pulm Med 2024; 24:434.

sensual dysfunction in PD

Q: Which sensual dysfunction is considered to be a predictor or even the first sign of Parkinson's Disease (PD) for elderly adults? - select one

A) Olfactory 

B) Auditory

C) Tactile

D) visual

E) Dysgeusia

Answer: A

Olfactory dysfunction usually precedes motor symptoms. It is one of the earliest dysfunctions affecting all three components: odor identification, discrimination, and detection. Some experts consider it a first sign of PD (Reference #3). Usually, it gets missed, but it has an increased risk of PD in the next decade of life.

Although visual hallucinations, psychosis, delusions, and depression also occur in PD and are well known, they appear a little later or along with motor symptoms.

#neurology

#psychiatry

References:

1. Ponsen MM, Stoffers D, Booij J, et al. Idiopathic hyposmia as a preclinical sign of Parkinson's disease. Ann Neurol 2004; 56:173.

2. Ross GW, Petrovitch H, Abbott RD, et al. Association of olfactory dysfunction with risk for future Parkinson's disease. Ann Neurol 2008; 63:167.

3. Haehner A, Hummel T, Hummel C, et al. Olfactory loss may be a first sign of idiopathic Parkinson's disease. Mov Disord 2007; 22:839.

4. Fénelon G, Mahieux F, Huon R, Ziégler M. Hallucinations in Parkinson's disease: prevalence, phenomenology and risk factors. Brain 2000; 123 ( Pt 4):733.

Relative hypotension

Q: What is relative hypotension?

Answer: A drop in systolic blood pressure, taking into account the patient's baseline

This question aims to highlight the clinical importance of the frequently ignored consideration of the patient's baseline blood pressure value.

Over time, literature has employed various terms to describe hypotension, depending on the underlying pathology and clinical scenarios. The most important ones are:

Absolute hypotension: systolic blood pressure <90 mmHg or mean arterial pressure <65 mmHg

Relative hypotension: A drop in systolic blood pressure >40 mmHg from the patient's baseline (some experts narrow it down to merely a drop of > 7 mmHg (reference # 2)

Orthostatic hypotension: A drop >20 mmHg in systolic pressure or >10 mmHg drop in diastolic pressure with standing

Profound hypotension: requiring vasopressor

#hemodynamic

References:

1. Schenk J, van der Ven WH, Schuurmans J, Roerhorst S, Cherpanath TGV, Lagrand WK, Thoral P, Elbers PWG, Tuinman PR, Scheeren TWL, Bakker J, Geerts BF, Veelo DP, Paulus F, Vlaar APJ; Cardiovascular Dynamics Section of the ESICM. Definition and incidence of hypotension in intensive care unit patients, an international survey of the European Society of Intensive Care Medicine. J Crit Care. 2021 Oct;65:142-148. doi: 10.1016/j.jcrc.2021.05.023. Epub 2021 Jun 18. PMID: 34148010.

2. van Oppen JD, Owen RK, Jones W, Beishon L, Coats TJ. The effect of relative hypotension on 30-day mortality in older people receiving emergency care. Intern Emerg Med. 2024 Apr;19(3):787-795. doi: 10.1007/s11739-023-03468-5. Epub 2023 Nov 8. PMID: 37940793; PMCID: PMC11039506.

3. Panwar R. Untreated Relative Hypotension Measured as Perfusion Pressure Deficit During Management of Shock and New-Onset Acute Kidney Injury-A Literature Review. Shock. 2018 May;49(5):497-507. doi: 10.1097/SHK.0000000000001033. PMID: 29040214.

4. Kotani Y, Yoshida T, Kumasawa J, Kamei J, Taguchi A, Kido K, Yamaguchi N, Kariya T, Nakasone M, Mikami N, Koga T, Nakayama I, Shibata M, Yoshida T, Nashiki H, Karatsu S, Nogi K, Tokuhira N, Izawa J. The impact of relative hypotension on acute kidney injury progression after cardiac surgery: a multicenter retrospective cohort study. Ann Intensive Care. 2021 Dec 20;11(1):178. doi: 10.1186/s13613-021-00969-4. PMID: 34928430; PMCID: PMC8686086.

TPO-RAs

Q: 58 years old male with a history of end-stage liver cirrhosis is admitted to the ICU with upper gastrointestinal bleed (UGIB) due to esophageal varices. Labs showed a platelet count of only 10K PLT/µL. Before placing a large-bore central line, a medical student suggested administering thrombopoietin receptor agonists (TPO-RA). Considering the risk of bleeding and ongoing hematemesis, this appears to be a good idea.

A) True

B) False

Answer: B (False)

The FDA has approved two TPO-RAs for use in patients with chronic liver disease and thrombocytopenia who are undergoing high-risk invasive surgeries, such as spinal or cardiac surgery. However, there are many caveats regarding the use of TPO-RA.

It needs to be administered 10 to 13 days before the procedure. The total course time is 5 to 7 days, administered daily. The effect is transient.

It is not used in emergent and low-risk procedures such as central line placement, thoracentesis, paracentesis, or pigtail placements.

Two commercial TPO-RAs approved in the USA are Avatrombopag and Lusutrombopag.

#hematology

#procedures

References:

1. Nanchal R, Subramanian R, Karvellas CJ, et al. Guidelines for the Management of Adult Acute and Acute-on-Chronic Liver Failure in the ICU: Cardiovascular, Endocrine, Hematologic, Pulmonary, and Renal Considerations. Crit Care Med 2020; 48:e173.

2. O'Shea RS, Davitkov P, Ko CW, et al. AGA Clinical Practice Guideline on the Management of Coagulation Disorders in Patients With Cirrhosis. Gastroenterology 2021; 161:1615.

3. Terrault N, Chen YC, Izumi N, et al. Avatrombopag Before Procedures Reduces Need for Platelet Transfusion in Patients With Chronic Liver Disease and Thrombocytopenia. Gastroenterology 2018; 155:705.

Cryoprecipitation

Q: Cryoprecipitation occurs below? - select one

A) 37°C

B) 35°C

C) 33°C

Answer: A

Precipitation of blood proteins at temperatures below 37°C is called cryoprecipitation.

This lower margin level is clinically significant, as surgical and non-surgical patients frequently arrive in the ICU with temperatures well below this temperature threshold. Cryoprecipitation occurs in two forms:

- Cryoglobulinemia, i.e., precipitation of blood proteins from serum and plasma. These patients may develop hyperviscosity or thrombosis. 

-Cryofibrinogenemia, i.e., precipitation of proteins from plasma. These patients may develop thrombosis.

#hematology

#hypothermia

Reference:

Ken Zafren, Daniel F Danzl, Michael Ganetsky - Nonfreezing cold water (trench foot) and warm water immersion injuries - https://www.uptodate.com/contents/nonfreezing-cold-water-trench-foot-and-warm-water-immersion-injuries (last accessed April 27, 2025) - © 2025 UpToDate, Inc. and/or its affiliates. All Rights Reserved.

Nocturnal dialysis and sleep

Q: Sleep quality in End-Stage Renal Disease (ESRD) patients undergoing home nocturnal hemodialysis usually improves.

A) True

B) False

Answer: A

Contrary to popular belief, sleep quality tends to improve during home nocturnal hemodialysis, with minimal disturbance. Preexisting sleep apnea shows significant improvement, with a notable decrease in apnea and hypopnea episodes (from 46 to 9 per hour). It also increases oxygen saturation, from the baseline average of 89.2% to 94.1%. 

Despite such improvement, no decrease in periodic limb movements and daytime sleepiness is noted.

#nephrology

#sleep

References:

1. Perl J, Unruh ML, Chan CT. Sleep disorders in end-stage renal disease: 'Markers of inadequate dialysis'? Kidney Int 2006; 70:1687.

2. Hanly PJ, Pierratos A. Improvement of sleep apnea in patients with chronic renal failure who undergo nocturnal hemodialysis. N Engl J Med 2001; 344:102.

3. Hanly PJ, Gabor JY, Chan C, Pierratos A. Daytime sleepiness in patients with CRF: impact of nocturnal hemodialysis. Am J Kidney Dis 2003; 41:403.

jolt accentuation maneuver

Q: What is a "jolt accentuation maneuver" to rule out meningitis?

Answer: Kernig's sign and Brudzinski's sign are well-known in Meningitis. The "jolt accentuation maneuver" also helps to rule out meningitis in patients with fever and headache. The patient is instructed to rapidly rotate their head horizontally; if this does not worsen the headache, meningitis is unlikely.

#ID

#neurology

#physical-exam

Recommended readings:

1. Afhami S, Dehghan Manshadi SA, Rezahosseini O. Jolt accentuation of headache: can this maneuver rule out acute meningitis? BMC Res Notes. 2017 Oct 30;10(1):540. doi: 10.1186/s13104-017-2877-1. PMID: 29084605; PMCID: PMC5663092.

2. Iguchi M, Noguchi Y, Yamamoto S, Tanaka Y, Tsujimoto H. Diagnostic test accuracy of jolt accentuation for headache in acute meningitis in the emergency setting. Cochrane Database Syst Rev. 2020 Jun 11;6(6):CD012824. doi: 10.1002/14651858.CD012824.pub2. PMID: 32524581; PMCID: PMC7386453.

3. Akaishi T, Kobayashi J, Abe M, Ishizawa K, Nakashima I, Aoki M, Ishii T. Sensitivity and specificity of meningeal signs in patients with meningitis. J Gen Fam Med. 2019 Jul 15;20(5):193-198. doi: 10.1002/jgf2.268. PMID: 31516806; PMCID: PMC6732499.

ODS

Q 44 years old homeless male was admitted to the ICU with severe hyponatremia a week ago, due to psychogenic polydipsia. Unfortunately, after five days of treatment, patient developed dysarthria, quadriparesis, behavioral disturbances, and seizures. Patient required intubation. It was determined that patient has probably developed osmotic demyelination syndrome (ODS) due to rapid correction of sodium. In osmotic demyelination syndrome, the initial severity of the illness is a good predictor of long-term prognosis.

A) True

B) False

Answer: B 

There are three objectives of this question.

First, to emphasize that in ODS, formerly called central pontine myelinolysis (CPM), symptoms can be delayed up to six days.

Second, although conventionally, ODS has been thought to be an irreversible process, evidence has shown that, with good support, meaningful recovery is possible up to eight weeks after the event.

Third, the initial severity of the illness is not predictive of long-term prognosis.

The most dreaded outcome of ODS is the potential "locked-in" syndrome.

#electrolytes

#neurology

References:

1. Lambeck J, Hieber M, Dreßing A, Niesen WD. Central Pontine Myelinosis and Osmotic Demyelination Syndrome. Dtsch Arztebl Int. 2019 Sep 2;116(35-36):600-606. doi: 10.3238/arztebl.2019.0600. PMID: 31587708; PMCID: PMC6804268.

2. Sterns RH, Riggs JE, Schochet SS Jr. Osmotic demyelination syndrome following correction of hyponatremia. N Engl J Med 1986; 314:1535.

3. Menger H, Jörg J. Outcome of central pontine and extrapontine myelinolysis (n = 44). J Neurol 1999; 246:700.

4. Louis G, Megarbane B, Lavoué S, et al. Long-term outcome of patients hospitalized in intensive care units with central or extrapontine myelinolysis*. Crit Care Med 2012; 40:970.