DBS and Diathermy

Q: A 68-year-old male is recovering from community-acquired pneumonia (CAP) in the ICU. Patient has a Deep Brain Stimulator (DBS) implanted for his Parkinson's Disease. The patient's DBS is MRI-compatible and has had no issues in the past with his cardiac pacemaker. A physical therapist (PT) inquired with you about using diathermy for the patient to relieve his chronic muscle pain. Diathermy in a DBS patient can be used safely.

A) Yes

B) No

Answer: B

In the last few years, most DBSs have become MRI-compatible and can be safely inserted in patients with a cardiac pacemaker, though rechecking with the patient's home info packet is always needed prior to any such intervention.

Unfortunately, DBSs are incompatible with diathermy, which is frequently used during physical therapy sessions (and by chiropractors). Diathermy, as the name suggests, delivers heat to soft tissue using electrical energy. It increases blood circulation, decreases pain, and improves healing. Diathermy induces a radiofrequency current that may cause heating of the DBS electrodes and may cause life-threatening or disabling injury to the brain.

#procedures

References:

1. Capelle HH, Simpson RK Jr, Kronenbuerger M, et al. Long-term deep brain stimulation in elderly patients with cardiac pacemakers. J Neurosurg 2005; 102:53.

2. Nutt JG, Anderson VC, Peacock JH, et al. DBS and diathermy interaction induces severe CNS damage. Neurology 2001; 56:1384.

3. Boutet A, Chow CT, Narang K, Elias GJB, Neudorfer C, Germann J, Ranjan M, Loh A, Martin AJ, Kucharczyk W, Steele CJ, Hancu I, Rezai AR, Lozano AM. Improving Safety of MRI in Patients with Deep Brain Stimulation Devices. Radiology. 2020 Aug;296(2):250-262. doi: 10.1148/radiol.2020192291. Epub 2020 Jun 23. PMID: 32573388; PMCID: PMC7543718.

Body organ involved in IgAN besides kidney

Q: Which organ in the body may be related to IgA Nephropathy (IgN)? - select one

A) Adrenal gland

B) Brain

C) Cardia

D) Liver

E) Tonsils

Answer: E

Tonsillitis has been associated with hematuria and proteinuria in IgAN. Tonsils are considered a source of abnormal IgA that forms immune complexes and deposits in the glomeruli.

Although theoretically tonsillectomy can cure IgAN, there is limited evidence for this treatment; however, combining tonsillectomy with immunosuppressive therapy may be relatively more beneficial.

#nephrology

#immunology

References:

1. Hotta O, Miyazaki M, Furuta T, et al. Tonsillectomy and steroid pulse therapy significantly impact on clinical remission in patients with IgA nephropathy. Am J Kidney Dis 2001; 38:736.

2. Akagi H, Kosaka M, Hattori K, et al. Long-term results of tonsillectomy as a treatment for IgA nephropathy. Acta Otolaryngol Suppl 2004; :38.

3. Kochoyan ZS, Dobronravov VA. Tonsillectomy and immunosuppression improve outcomes in Caucasians with high-risk IgA nephropathy. Nephrol Dial Transplant 2026; 41:1284.

4. Rasche FM, Schwarz A, Keller F. Tonsillectomy does not prevent a progressive course in IgA nephropathy. Clin Nephrol 1999; 51:147.

Rapalogs and ACE-I-angioedema

Q: Post-transplant patients are at increased risk of ACE inhibitor-induced angioedema.

A) True

B) False

Answer: A

Post-transplant patients who take rapamycin (mTOR) inhibitors, commonly known as rapalogs such as sirolimus or everolimus, are at increased risk of Angiotensin-converting enzyme (ACE) inhibitor-induced angioedema when both are co-administered. Rapalogs reduce the metabolism of bradykinin. The effect appears to be dose-dependent for rapalog. 

Overall, all transplant patients are at increased risk of ACE inhibitor-induced angioedema because immunosuppressants decrease dipeptidyl peptidase 4 (DPP-4) levels, which is responsible for breaking down bradykinin, a key culprit in ACE inhibitor-related angioedema.

#toxicity

#pharmacology

#transplantation

References:

1. Duerr M, Glander P, Diekmann F, et al. Increased incidence of angioedema with ACE inhibitors in combination with mTOR inhibitors in kidney transplant recipients. Clin J Am Soc Nephrol 2010; 5:703.

2. Charmillon A, Deibener J, Kaminsky P, Louis G. Angioedema induced by angiotensin converting enzyme inhibitors, potentiated by m-TOR inhibitors: successful treatment with icatibant. Intensive Care Med 2014; 40:893.

3. Fuchs U, Zittermann A, Berthold HK, et al. Immunosuppressive therapy with everolimus can be associated with potentially life-threatening lingual angioedema. Transplantation 2005; 79:981.

4. Scott SI, Andersen MF, Aagaard L, Buchwald CV, Rasmussen ER. Dipeptidyl Peptidase-4 Inhibitor Induced Angioedema - An Overlooked Adverse Drug Reaction? Curr Diabetes Rev. 2018;14(4):327-333. doi: 10.2174/1573399813666170214113856. PMID: 28201967.

Paradoxes (and history) of LR

Q: Resuscitation with Lactated Ringer's (LR) may cause? - select one

A) Hypernatremia

B) Hyponatremia

Answer: B

Lactated Ringer's solution was accidentally invented in Dr. Ringer's laboratory in 1882 while his team was working on isolated frog hearts. De Ringer's laboratory assistant mistakenly used tap water instead of distilled water. It kept the heart beating longer than usual, and the team found that calcium in tap water (and other minerals) may be responsible. Also, they are safe and functional for tissues.

Over the years, with modifications, it is composed of

• Sodium (Na⁺): 130 mEq
• Chloride (Cl⁻): 109 mEq
• Potassium (K⁺): 4 mEq
• Calcium (Ca²⁺): 3 mEq
• Lactate: 28 mEq

Two Paradoxes of LR:

1. Though overall it is an isotonic solution, in terms of only Na, it is hyponatremic, as serum sodium isotonicity ranges from 135 to 145 mEq/L.

2. Although the PH of LR is 6.5, due to lactate in it, which converts to bicarbonate (HCO3), it causes metabolic alkalosis.

#electrolytes

#acid-base

References:

1. Sternbach G. Sydney Ringer: water supplied by the New River Water Company. J Emerg Med. 1988 Jan-Feb;6(1):71-4. doi: 10.1016/0736-4679(88)90254-5. PMID: 3283218.

2. Friedman JN; Canadian Paediatric Society, Acute Care Committee. Risk of acute hyponatremia in hospitalized children and youth receiving maintenance intravenous fluids. Paediatr Child Health. 2013 Feb;18(2):102-7. PMID: 24421667; PMCID: PMC3567908.

3. Park M, Sidebotham D. Metabolic alkalosis and mixed acid-base disturbance in anaesthesia and critical care. BJA Educ. 2023 Apr;23(4):128-135. doi: 10.1016/j.bjae.2023.01.002. Epub 2023 Feb 23. PMID: 36960435; PMCID: PMC10028421.

Pseudo-hypophosphatemia

Q: Intravenous (IV) mannitol may cause? - select one

A) pseudo-hypocalcemia 

B) pseudo-hypokalemia

C) pseudo-hypomagnesemia

D) pseudo-hyponatremia

E) pseudo-hypophosphatemia

Answer: E

The first step in the evaluation of pseudohypophosphatemia is to rule out spurious or pseudo-hypophosphatemia. Many well-known conditions and drugs may cause pseudohypophosphatemia either by the presence of paraproteins or by interference with the phosphate assay. Some of the causes are:

• multiple myeloma 
• other monoclonal gammopathies
• IV mannitol (usually in large or repeated doses)

#electrolytes

References:

1. Molinaris V, Bianchetti MG, Milani GP, et al. Interferences in the measurement of circulating phosphate: a literature review. Clin Chem Lab Med 2020; 58:1971.

2. Kerr S, Kindt J, Daram SR. Hypophosphatemia associated with paraproteinemia: a case report and review of the literature. WMJ 2007; 106:490.

3. Wen Wu L, Choi TS, Barbosa M, et al. PSEUDOHYPOPHOSPHATEMIA IN A PATIENT WITH MULTIPLE MYELOMA. AACE Clin Case Rep 2020; 6:e334.

4. Larner AJ. Pseudohyperphosphatemia. Clin Biochem. 1995 Aug;28(4):391-3. doi: 10.1016/0009-9120(95)00013-y. PMID: 8521592.

murmur of pulmonic stenosis

Q: The murmur of pulmonic stenosis can be best heard at? - select one

A) left upper sternal border

B) right upper sternal border

Answer: A

The murmur of pulmonic stenosis is a systolic ejection murmur and is best heard at the left upper sternal border. If the murmur varies with respiration, it is still considered mild. It radiates to the back, in the posterior lung fields. 

In severe cases, there is a prominent left parasternal lift, along with splitting of the second heart sound. As expected, there is a right-sided fourth heart sound over the left sternal border if pulmonic stenosis leads to right ventricular hypertrophy with diminished compliance. 

Cyanosis occurs only later in the most severe cases.

In Jugular Venous Pressure (JVP), there is a prominent "A" wave, but overall JVP remains in the normal range.

#cardiology

#physical-exam

References:

1. Marchini F, Meossi S, Passarini G, Campo G, Pavasini R. Pulmonary Valve Stenosis: From Diagnosis to Current Management Techniques and Future Prospects. Vasc Health Risk Manag. 2023 Jun 30;19:379-390. doi: 10.2147/VHRM.S380240. PMID: 37416511; PMCID: PMC10320808.

2. Heaton J, Horenstein MS, Kyriakopoulos C. Pulmonary Stenosis. 2024 Oct 6. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan–. PMID: 32809585.

3. Atiq M, Akhter S, Abdul Sattar S, Mohsin S, Aslam N. Murmur and Doppler alternans in critical pulmonary stenosis. Pediatr Cardiol. 2011 Oct;32(7):1004-7. doi: 10.1007/s00246-011-0033-6. Epub 2011 Jul 7. PMID: 21748495.

Treatment considerations in myasthenia gravis for the pregnant patient

Q: A 26-year-old female, first-time 30 weeks pregnant, and with a known history of Myasthenia Gravis (MG). pyridostigmine is preferred to be given? - select one

A) Intravenous (IV)

B) Oral

Answer: B

One of the first and mainstay treatments for MG is an acetylcholinesterase inhibitor such as pyridostigmine. Intravenous acetylcholinesterase inhibitors have the tendency to induce uterine contractions and are preferred to be given enterally, either by mouth or nasogastric tube. 

The other required precaution is a higher dose due to increased renal clearance, expanded maternal blood volume, delayed gastric emptying, and frequent emesis. The recommended way to increase the dose is to decrease the interval, or, if needed, to increase the dose and decrease the interval.

If the enteral route fails or labor ensues, IV administration is acceptable.

#ob-gyn

#neurology

References:

1. Norwood F, Dhanjal M, Hill M, et al. Myasthenia in pregnancy: best practice guidelines from a U.K. multispecialty working group. J Neurol Neurosurg Psychiatry 2014; 85:538.

2. Bansal R, Goyal MK, Modi M. Management of myasthenia gravis during pregnancy. Indian J Pharmacol. 2018 Nov-Dec;50(6):302-308. doi: 10.4103/ijp.IJP_452_17. PMID: 30783322; PMCID: PMC6364336.

3. Gilhus NE. Treatment considerations in myasthenia gravis for the pregnant patient. Expert Rev Neurother. 2023 Feb;23(2):169-177. doi: 10.1080/14737175.2023.2178302. Epub 2023 Feb 20. PMID: 36786092.

Katayama fever

Q: In acute schistosomiasis syndrome (Katayama fever), what should be given first?

A) Anthelminthic

B) Glucocorticoids

Answer: B

Acute schistosomiasis syndrome, popularly known as Katayama fever, is a highly inflammatory disease, and the first priority is to suppress inflammation via steroids.

Anthelmintic therapy, primarily praziquantel, is initiated once acute symptoms have fully resolved.

The idea behind this strategy is due to the following three facts;

1. Early treatment with praziquantel can be associated with recurrence of acute symptoms.
2. Glucocorticoids reduce plasma levels of praziquantel when given simultaneously
3. Praziquantel is effective only when given at least 8 weeks after exposure, once the infection is well established and the worms have fully matured

If the clinician decides to continue steroids with praziquantel due to fear of flare-up, it should be given two hours later due to the second reason given above.

#ID

#pharmacology

References:

1. Jauréguiberry S, Paris L, Caumes E. Acute schistosomiasis, a diagnostic and therapeutic challenge. Clin Microbiol Infect 2010; 16:225.

2. Ross AG, Vickers D, Olds GR, et al. Katayama syndrome. Lancet Infect Dis 2007; 7:218.

3. Jauréguiberry S, Paris L, Caumes E. Difficulties in the diagnosis and treatment of acute schistosomiasis. Clin Infect Dis 2009; 48:1163.

4. Neumayr AL, Tschirky B, Warren A, et al. Acute febrile respiratory reaction after praziquantel treatment during asymptomatic late form of acute schistosomiasis. J Travel Med 2012; 19:264.

TIPSS and HPS

Q: Transjugular intrahepatic portosystemic shunt (TIPSS) can cure Hepatopulmonary syndrome (HPS).

A) True

B) False

Answer: B

Transjugular intrahepatic portosystemic shunt (TIPSS) reduces the portal pressures. Previously, it has been advocated in HPS in several case reports, but recent evidence argues that it may worsen hepatic encephalopathy, may cause more pulmonary vasodilatation, shunting, and worsening of hypoxemia. It should be utilized as a last resort. 

#hepatology

#pulmonary

References:

1. Martinez-Palli G, Drake BB, Garcia-Pagan JC, et al. Effect of transjugular intrahepatic portosystemic shunt on pulmonary gas exchange in patients with portal hypertension and hepatopulmonary syndrome. World J Gastroenterol 2005; 11:6858.

2. Correa TL, Martins OC, Fernandes MV, et al. Effectiveness of Transjugular Intrahepatic Portosystemic Shunt Creation for the Treatment of Hepatopulmonary Syndrome. J Vasc Interv Radiol 2025; 36:1494.

HPP - underlying electrolyte pathophysiology

Q: Patients with hypokalemic Periodic Paralysis (HPP) usually have? - select one

A) Calcium channel disorders 

B) Potassium channel disorders

C) Sodium channel disorders 

Answer: A

Although HPP is a potassium-related pathophysiology, as the name suggests, the most common underlying gene mutation is a calcium channel disorder, involving the gene that codes for the alpha-1 subunit of the dihydropyridine-sensitive calcium channel in skeletal muscle.

The mechanism by which the calcium channel defect leads to episodic potassium influx into cells is not fully understood. The proposed mechanism, along with a few others, is that a gene disorder causes a decreased calcium current density and slower rate of activation. 

There could also be a pathology involving insulin sensitivity or hyperthyroidism.

Some patients may also have sodium channel disorders with a mutation in the skeletal muscle sodium channel, SCN4A, but this is uncommon. It affects males and females equally, in contrast to calcium channel disorders, which affect mostly males.

Some patients may not have either of the above channel disorders but may have other potentially associated mutations.

#electrolytes

#musculoskeletal

References:

1. Ptácek LJ, Tawil R, Griggs RC, et al. Dihydropyridine receptor mutations cause hypokalemic periodic paralysis. Cell 1994; 77:863.

2. Matthews E, Labrum R, Sweeney MG, et al. Voltage sensor charge loss accounts for most cases of hypokalemic periodic paralysis. Neurology 2009; 72:1544.

3. Ruff RL. Insulin acts in hypokalemic periodic paralysis by reducing inward rectifier K+ current. Neurology 1999; 53:1556.

4. Sternberg D, Maisonobe T, Jurkat-Rott K, et al. Hypokalaemic periodic paralysis type 2 caused by mutations at codon 672 in the muscle sodium channel gene SCN4A. Brain 2001; 124:1091.

Diabetes and ACE-induced Angioedema

Q: Diabetes increases the risk of ACE inhibitor-induced angioedema.

A) True

B) False

Answer: B

Diabetes is found to have a protective effect in Angiotensin-converting enzyme (ACE) inhibitor-induced angioedema. The underlying mechanism is unknown, though it has been proposed that diabetes increases levels of the enzyme Dipeptidyl peptidase-4 (DPP-IV), which breaks down bradykinin. Bradykinin is considered to be the main culprit in inducing angioedema due to ACE inhibitors.

Some known risk factors for ACE inhibitor-induced angioedema are older age, Aspirin or NSAID use, female sex, Smoking, history of allergies, Coronary artery disease (CAD), and history of ACE inhibitor-induced cough.

#pharmacology

#endocrinology

References:

1. Miller DR, Oliveria SA, Berlowitz DR, et al. Angioedema incidence in US veterans initiating angiotensin-converting enzyme inhibitors. Hypertension 2008; 51:1624.

2. Byrd JB, Touzin K, Sile S, et al. Dipeptidyl peptidase IV in angiotensin-converting enzyme inhibitor associated angioedema. Hypertension 2008; 51:141.

3. Ali HA, Lomholt AF, Mahmoudpour SH, Hermanrud T, Bygum A, von Buchwald C, Jakobsen MA, Rasmussen ER. Genetic susceptibility to angiotensin-converting enzyme-inhibitor induced angioedema: A systematic review and evaluation of methodological approaches. PLoS One. 2019 Nov 11;14(11):e0224858. doi: 10.1371/journal.pone.0224858. Erratum in: PLoS One. 2019 Dec 19;14(12):e0227056. doi: 10.1371/journal.pone.0227056. PMID: 31710633; PMCID: PMC6844479.

SCAD

Q: Spontaneous coronary artery dissection (SCAD) is more common in young? - select one

A) males

B) females

Answer: B

SCAD is a nontraumatic, noniatrogenic separation of the coronary arterial wall. It is more common in young females. Among females ≤50 years old with acute coronary syndrome (ACS), SCAD accounts for about one-quarter of cases. Lately, it is increasingly seen in older and postmenopausal females. 

The underlying mechanism of nonatherosclerotic SCAD is not fully understood. It is basically an intimal tear and bleeding of vasa vasorum, with intramedial hemorrhage, creation of a false lumen filled with intramural hematoma.

An inflammatory component is also described with histological findings of eosinophilic infiltrates in the adventitia. Coronary artery tortuosity may also play a role.

Pregnancy, multiparity, and postpartum stress, with hormonal changes, are considered major risk factors.

#cardiology

#ob-gyn

References:

1. Tam LM, Naderi S, Chi G, et al. Sex Differences in Spontaneous Coronary Artery Dissection: A Report of the iSCAD Registry. J Am Heart Assoc 2026; 15:e042773.

2. Saw J, Aymong E, Sedlak T, et al. Spontaneous coronary artery dissection: association with predisposing arteriopathies and precipitating stressors and cardiovascular outcomes. Circ Cardiovasc Interv 2014; 7:645.

3. Alfonso F. Spontaneous coronary artery dissection: new insights from the tip of the iceberg? Circulation 2012; 126:667.

4. Vijayaraghavan R, Verma S, Gupta N, Saw J. Pregnancy-related spontaneous coronary artery dissection. Circulation 2014; 130:1915.

Diabetes and ICH

Q: Diabetes increases the risk of spontaneous intracerebral hemorrhage.

A) True

B) False

Answer: A

Due to inherent underlying pathology of vasculature in diabetes, the risk of spontaneous as well as related to anticoagulation ICH is higher in diabetes.

Unfortunately, anticoagulant-associated intraocular bleed is also higher in patients with diabetic retinopathy.

#hematology

#neurology

#endocrinology

References:

1. Huhtakangas J, Tetri S, Juvela S, et al. Effect of increased warfarin use on warfarin-related cerebral hemorrhage: a longitudinal population-based study. Stroke 2011; 42:2431.

2. Boulanger M, Poon MT, Wild SH, Al-Shahi Salman R. Association between diabetes mellitus and the occurrence and outcome of intracerebral hemorrhage. Neurology 2016; 87:870.

3. Nentwich MM, Ulbig MW. Diabetic retinopathy - ocular complications of diabetes mellitus. World J Diabetes. 2015 Apr 15;6(3):489-99. doi: 10.4239/wjd.v6.i3.489. PMID: 25897358; PMCID: PMC4398904.

"dying-back" degeneration of large distal axons

Q: The "dying-back" degeneration of large distal axons is characteristic of which chemical toxicity? 

Answer: Organophosphate (OP) 

Although most critical care medicine curricula emphasize acute management of OP poisoning, one vital and delayed aspect of OP often goes unnoticed. =

OPIDN (OP-induced delayed neuropathy) is characterized by a painful "stocking-glove" paresthesias followed by a symmetrical motor polyneuropathy with flaccid weakness of the lower extremities that ascends to involve the upper extremities, primarily affecting distal muscles; in severe neurotoxicity, proximal muscle groups may also be affected. Sensory disturbances are usually mild. 

It occurs one to three weeks after OP exposure (delayed). Usually transient, but in severe cases, an upper motor neuron syndrome with spasticity of the lower extremities usually causes permanent disability. Electromyograms and nerve conduction studies reveal decreased firing of motor conduction units, and histopathologic sections of peripheral nerves show Wallerian degeneration, commonly known as "dying-back" degeneration, of large distal axons. The underlying mechanism involves inhibition of neuropathy target esterase (NTE), which is found in the brain, peripheral nerves, and lymphocytes, and is basically responsible for the metabolism of various esters in the cytoplasm. 

Other reported long-term effects of OP toxicity are either transient or permanent decreased memory, abstraction, attention, and Parkinsonism. Severity may differ with different brands of OP pesticides. 

#toxicity 

#neurology 

 References: 

 1. Aygun D, Onar MK, Altintop BL. The clinical and electrophysiological features of a delayed polyneuropathy developing subsequently after acute organophosphate poisoning and it's correlation with the serum acetylcholinesterase. Electromyogr Clin Neurophysiol 2003; 43:421. 

 2. Johnson MK. Organophosphorus esters causing delayed neurotoxic effects: mechanism of action and structure activity studies. Arch Toxicol 1975; 34:259. 

 3. Arima H, Sobue K, So M, et al. Transient and reversible parkinsonism after acute organophosphate poisoning. J Toxicol Clin Toxicol 2003; 41:67.

PAs visualization via TEE

Q: Which Pulmonary artery (PA) is relatively harder to visualize in transesophageal echocardiography (TEE)? - select one

A) Left

B) Right

Answer: A

The best level to visualize PAs, including main, right, and (?) left, during TEE is the midesophageal ascending aorta short-axis view. Unfortunately, left PA is relatively hard to visualize due to its proximity to the left main bronchus.

#procedures

#pulmonary

References:

1. Pruszczyk P, Torbicki A, Kuch-Wocial A, Szulc M, Styczynski G, Bochowicz A, Kostrubiec M. Visualization of the central pulmonary arteries by biplane transesophageal echocardiography. Exp Clin Cardiol. 2001 Winter;6(4):206-10. PMID: 20428260; PMCID: PMC2859001.

2. Hausmann D, Daniel WG, Mügge A, Heublein B, Hamm M, Schäfers HJ, Haverich A. Imaging of pulmonary artery and vein anastomoses by transesophageal echocardiography after lung transplantation. Circulation. 1992 Nov;86(5 Suppl):II251-8. PMID: 1424008.

 

RTA-3

Q: What is TYPE-3 renal tubular acidosis (RTA)?

Answer: Mix of RTA-1 and RTA-2

Academic books describe in detail Type I, 2 and 4 RTAs, but RTA-3 is rarely mentioned.

The term RTA-3 is used when both proximal and distal acidification defects coexist. It is a failure to reabsorb bicarbonate and an inability to acidify urine properly, resulting in systemic metabolic acidosis. 

In the pediatric population, it is associated with growth hormone deficiency.

#nephrology

#acid-base

References:

1. Goswami RP, Mondal S, Karmakar PS, Ghosh A. Type 3 renal tubular acidosis. Indian J Nephrol. 2012 Nov;22(6):466-8. doi: 10.4103/0971-4065.106058. PMID: 23439805; PMCID: PMC3573491.

2. Reddy P. Clinical approach to renal tubular acidosis in adult patients. Int J Clin Pract. 2011 Mar;65(3):350-60. doi: 10.1111/j.1742-1241.2009.02311.x. PMID: 21314872.

3. Liew YP, Rogers TA, Garb JL, Allen HF, Reiter EO, Campfield TJ, Dharnidharka VR, Braden GL. Type 3 renal tubular acidosis associated with growth hormone deficiency. J Pediatr Endocrinol Metab. 2017 Oct 26;30(10):1047-1053. doi: 10.1515/jpem-2016-0460. PMID: 28888090.

protamine reaction - types

Q: What are the three types of Protamine reaction?

Answer: The term "types of protamine reaction" is kind of a misnomer. In fact, it is the severity level.

Type I is a mild, transient reaction usually caused by rapid infusion. It is histamine-mediated and causes manageable vasodilation and hypotension.

Type II is characterized by a true anaphylactic or anaphylactoid hypersensitivity reaction (probably IgE-mediated), with features such as hypotension, bronchoconstriction, and urticaria.

Type III is a catastrophic pulmonary vasoconstrictive reaction characterized by complement/IgG activation, leading to sudden pulmonary hypertension, right ventricular failure, and severe noncardiogenic pulmonary edema.

Risk factors for such reactions are 

• prior protamine exposure 
• NPH insulin use
• fish allergies, and 
• vasectomy 

Management is usually supportive with pressors, IVF, and, in severe cases, ECMO.

#allergy-immunology

#pharmacology

#hemodynamics

References:

1. Pannu BS, Sanghavi DK, Guru PK, Reddy DR, Iyer VN. Fatal right ventricular failure and pulmonary hypertension after protamine administration during cardiac transplantation. Indian J Crit Care Med. 2016 Mar;20(3):185-7. doi: 10.4103/0972-5229.178185. PMID: 27076733; PMCID: PMC4810899.

2. Porsche R, Brenner ZR. Allergy to protamine sulfate. Heart Lung. 1999 Nov-Dec;28(6):418-28. doi: 10.1016/s0147-9563(99)70031-2. PMID: 10580216.

3. Weiss ME, Adkinson NF Jr. Allergy to protamine. Clin Rev Allergy. 1991 Fall-Winter;9(3-4):339-55. doi: 10.1007/BF02802312. PMID: 1782626.

Octreotide and chylothorax

Q: How does octreotide help in the management of chylothorax?

Answer: By decreasing intestinal fat absorption

Chylothorax continues to remain a challenging situation for both traumatic, including post-surgical, as well as non-traumatic etiologies. Various dietary, surgical, and pharmacological interventions have been tried with varying degrees of success.

Somatostatin analogs such as octreotide and lanreotide are known to decrease intestinal fat absorption. A short course of subcutaneous (SQ) octreotide, 50 to 200 micrograms every 8 hours for 1 to 2 weeks, has been proposed by experts, with caution to discontinue after 2 weeks regardless of the response. 

Caution should be exercised to monitor for cutaneous flushing, nausea, diarrhea, sinus bradycardia, injection-site pain, and elevated liver function tests.

#Pulmonary

References:

1. Mincher L, Evans J, Jenner MW, Varney VA. The successful treatment of chylous effusions in malignant disease with octreotide. Clin Oncol (R Coll Radiol) 2005; 17:118.

2. Evans J, Clark MF, Mincher L, Varney VA. Chylous effusions complicating lymphoma: a serious event with octreotide as a treatment option. Hematol Oncol 2003; 21:77.

3. Kalomenidis I. Octreotide and chylothorax. Curr Opin Pulm Med. 2006 Jul;12(4):264-7. doi: 10.1097/01.mcp.0000230629.73139.26. PMID: 16825878.

ACE-I with diuretics in AA patients

Q: African American (AA) patients, with the addition of a low dose of a thiazide diuretic to an ACE inhibitor, get a similar response to a fall in blood pressure (BP) as comparable to White patients.

A) True

B) False

Answer: A

It is conventionally and, to some extent, rightly believed that AA patients don't respond to ACE (angiotensin-converting enzyme) inhibitors as well as white patients. This notion has led to improper management of hypertension in AA patients many times. Evidence shows that the addition of just a low dose of a thiazide diuretic to an ACE inhibitor can give a comparable fall in BP as in White patients. 

Mechanism of action: ACE inhibitors and diuretics have a synergistic effect: diuretic-induced hypovolemia increases renin release and subsequent angiotensin II production. This effect is prevented by converting enzyme inhibition, resulting in a marked reduction in BP. A similar mechanism applies to the synergistic enhancement observed with dietary sodium restriction and an ACE inhibitor.

Other effects of adding ACE inhibitors to diuretics are:

• prevention of hypokalemia, as reduced angiotensin II formation induced by the ACE inhibitor decreases aldosterone secretion. 
• prevention of  glucose intolerance, hyperlipidemia, and hyperuricemia (some of the diuretic-induced effects)

#hemodynamics

References:

1. Townsend RR, Holland OB. Combination of converting enzyme inhibitor with diuretic for the treatment of hypertension. Arch Intern Med 1990; 150:1175.

2. Pollare T, Lithell H, Berne C. A comparison of the effects of hydrochlorothiazide and captopril on glucose and lipid metabolism in patients with hypertension. N Engl J Med 1989; 321:868.

3. Borghi C, Soldati M, Bragagni A, Cicero AFG. Safety implications of combining ACE inhibitors with thiazides for the treatment of hypertensive patients. Expert Opin Drug Saf. 2020 Dec;19(12):1577-1583. doi: 10.1080/14740338.2020.1836151. PMID: 33047990.

SAAG in CHF

Q: One of the advantages of the serum-to-ascites albumin gradient (SAAG) in congestive heart failure (CHF) is that it can predict treatment efficacy.

A) True

B) False

Answer: A

SAAG can predict portal hypertension with 97 percent accuracy. It is easy to calculate by subtracting the ascitic fluid albumin value from the serum albumin value, which should be obtained the same day. 

• gradient ≥1.1 g/dL (≥11 g/L) predicts portal hypertension with 97 percent accuracy
• gradient <1.1 g/dL (<11 g/L) negates portal hypertension

Patients with CHF can narrow their gradient during diuresis, but patients with cirrhosis rarely do unless blood pressure or portal pressure decreases significantly. This is an added advantage of SAAG in establishing a differential diagnosis.

#hepatology

#GI

#cardiology

References:

1. Runyon BA, Montano AA, Akriviadis EA, et al. The serum-ascites albumin gradient is superior to the exudate-transudate concept in the differential diagnosis of ascites. Ann Intern Med 1992; 117:215.

2. Hoefs JC. Serum protein concentration and portal pressure determine the ascitic fluid protein concentration in patients with chronic liver disease. J Lab Clin Med 1983; 102:260.

3. Goh ZNL, Teo RYL, Chung BK, Wong AC, Seak CJ. At the heart of the problem: congestive cardiac failure as a cause of ascites: A narrative review. Medicine (Baltimore). 2022 Aug 5;101(31):e29951. doi: 10.1097/MD.0000000000029951. PMID: 35945724; PMCID: PMC9351856.

DPP-4 with metformin

Q: Dipeptidyl peptidase 4 (DPP-4) inhibitors should not be combined with metformin to avoid the risk of severe hypoglycemia.

A) True

B) False

Answer: B

DPP-4 inhibitors, the most popular one in the USA is sitagliptin (trade name Januvia), have a low risk of hypoglycemia even when used as an add-on therapy with metformin. The risk of hypoglycemia is higher when combined with insulin or sulfonylureas, which are well-known to cause hypoglycemia by themselves. 

This characteristic of a lower rate of hypoglycemia is particularly useful in patients with chronic renal disease, including patients who require dialysis.

Similarly, good or bad, they have minimal effect on body weight.

#endocrinology

References:

1.  Nauck MA, Meininger G, Sheng D, et al. Efficacy and safety of the dipeptidyl peptidase-4 inhibitor, sitagliptin, compared with the sulfonylurea, glipizide, in patients with type 2 diabetes inadequately controlled on metformin alone: a randomized, double-blind, non-inferiority trial. Diabetes Obes Metab 2007; 9:194.

2. Gallwitz B, Rosenstock J, Rauch T, et al. 2-year efficacy and safety of linagliptin compared with glimepiride in patients with type 2 diabetes inadequately controlled on metformin: a randomised, double-blind, non-inferiority trial. Lancet 2012; 380:475.

3. Arjona Ferreira JC, Corry D, Mogensen CE, et al. Efficacy and safety of sitagliptin in patients with type 2 diabetes and ESRD receiving dialysis: a 54-week randomized trial. Am J Kidney Dis 2013; 61:579.

COVID-19, permissive hypercapnia,and permissive hypoxemia

Q: 72 years old male is admitted to the ICU with pneumonia and requires 12 L/min of oxygen flow. Respiratory culture from admission shows COVID-19. Targeting PaO2 ≥60 mmHg rather than ≥90 mmHg may result in more days alive without ventilatory support.

A) True

B) False

Answer: A

Permissive hypoxemia appears to have benefit in patients with COVID-19 who require mechanical ventilation. The HOT-COVID Randomized Clinical Trial, published in JAMA in 2024 at the tail end of the COVID-19 pandemic, went relatively unnoticed. It was a very strong trial with an average of 350 patients in each arm, showing that though there may not be a mortality benefit, patients receiving at least 10 L/minute of oxygen or mechanical ventilation, targeting PaO2 ≥60 mmHg, were associated with more days alive without ventilatory support compared with a target ≥90 mmHg.

The underlying mechanism of action may be due to the Bohr Effect, in which permissive hypercapnia, and thus concomitant permissive hypoxemia, may cause more O₂ to be released in metabolically active tissues.

#pulmonary

#ventilation

#ID

Reference:

1. Nielsen FM, Klitgaard TL, Siegemund M, et al. Lower vs Higher Oxygenation Target and Days Alive Without Life Support in COVID-19: The HOT-COVID Randomized Clinical Trial. JAMA 2024; 331:1185.

Social factors in suicide

Q: Immigrants are at higher risk for suicide than the citizens of the host country.

A) True

B) False

Answer: B

Contrary to popular belief, immigrants are at less risk for suicide than the citizens of the native country. Though no single theory can explain this, the postulation is that immigrants in a new country still have hope of doing better after leaving the hopelessness of their home country behind. On the other hand, natives may feel more hopeless with the given system. 

Although the data came from a European country (reference #1), it appears applicable to other contexts. Other social protective factors against suicide are:

• Being married
• Pregnant 
• A parent
• Socially connected
• Financially independent
• Religious 

#psychiatry

References:

1. Brennecke G, Stoeber FS, Kettner M, et al. Suicide among immigrants in Germany. J Affect Disord 2020; 274:435.

2. Hung GC, Cheng CT, Jhong JR, et al. Risk and protective factors for suicide mortality among patients with alcohol dependence. J Clin Psychiatry 2015; 76:1687.

3. Miola A, Tondo L, Pinna M, et al. Suicidal risk and protective factors in major affective disorders: A prospective cohort study of 4307 participants. J Affect Disord 2023; 338:189.

4. Qin P, Mortensen PB. The impact of parental status on the risk of completed suicide. Arch Gen Psychiatry 2003; 60:797.

RDW, RDW-SD and RDW-CV

Q: What's the difference between RDW, RDW-SD and RDW-SC?

Answer: 

Red cell distribution width (RDW) signifies either microcytosis (low RDW) or macrocytosis (high RDW). The two major causes of microcytosis, probably accompanied by hypochromia, are thalassemia and iron deficiency.

RDW- Standard Deviation (RDW-SD) measures the actual variation in size of red blood cells. A high RDW-SD means cells vary significantly in size. RDW-SD is an actual, physical measurement of the cell volume distribution curve at a level 20% above the baseline of the histogram.

RDW — Coefficient of Variation (RDW-CV) is a calculation influenced by average red blood cell size. It is usually considered less precise than RDW-SD because it measures the histogram at the midpoint.

RDW-SD, RDW-CV, and Mean Corpuscular Volume (MCV) should be read together for better understanding. 

#hematology

#laboratory science

References:

1. Sarma PR. Red Cell Indices. In: Walker HK, Hall WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths; 1990. Chapter 152. Available from: https://www.ncbi.nlm.nih.gov/books/NBK260/

2. Salvagno GL, Sanchis-Gomar F, Picanza A, Lippi G. Red blood cell distribution width: A simple parameter with multiple clinical applications. Crit Rev Clin Lab Sci. 2015;52(2):86-105. doi: 10.3109/10408363.2014.992064. Epub 2014 Dec 23. PMID: 25535770.

3. Yang K, Sun B, Zhang S, Pan Y, Fang J. RDW-SD is Superior to RDW-CV in Reflecting Liver Fibrosis Stage in Patients with Chronic Hepatitis B. Infect Drug Resist. 2023 Oct 27;16:6881-6891. doi: 10.2147/IDR.S427047. PMID: 37920477; PMCID: PMC10619233.

Plasmapheresis during pregnancy

Q: A 32-year-old female, first-time, 26 weeks pregnant, with a known history of Myasthenia Gravis (MG), presented with severe myasthenia crisis requiring intubation. Plasmapheresis should not be performed during pregnancy.

 

A) True

B) False

Answer: B

Two major rescue therapies for myasthenic crisis are:

• Plasmapheresis 
• High-dose intravenous immune globulin

They are both safe in pregnancy.

#Ob-gyn

#neurology

References:

1. Varner M. Myasthenia gravis and pregnancy. Clin Obstet Gynecol 2013; 56:372.

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

3. Watson WJ, Katz VL, Bowes WA Jr. Plasmapheresis during pregnancy. Obstet Gynecol 1990; 76:451.

SPS in hyperkalemia

Q: Sodium polystyrene sulfonate (SPS) or other cation-exchange resins should be utilized only in? - select one

A) acute hyperkalemia 

B) chronic hyperkalemia 

Answer: A

Sodium polystyrene sulfonate (SPS) or other cation-exchange resins are usually administered in combination with sorbitol to treat hyperkalemia. 

They were immensely popular in ICUs for the control of hyperkalemia, but evidence shows that they carry more harm than benefit, particularly causing potentially fatal intestinal necrosis and fluid overload as they exchange K for Na. 

Interestingly, some experts claim that the most effect comes from the laxative effect of added sorbitol. That's why SPS or other resins should be used only for short-term use and only in a semi-hyperkalemic emergency.

#electrolytes

References:

1. Hagan AE, Farrington CA, Wall GC, Belz MM. Sodium polystyrene sulfonate for the treatment of acute hyperkalemia: a retrospective study. Clin Nephrol. 2016 Jan;85(1):38-43. doi: 10.5414/CN108628. PMID: 26587776.

2. Rossignol P, Pitt B. Sodium polystyrene is unsafe and should not be prescribed for the treatment of hyperkalaemia: primum non nocere! Clin Kidney J. 2023 Apr 21;16(8):1221-1225. doi: 10.1093/ckj/sfad090. PMID: 37529653; PMCID: PMC10387396.

capsid inhibitor for HIV-1 treatment and prevention

Q: How do capsid inhibitors work in HIV?

Answer: They disrupt HIV capsid protein functions

Lenacapavir is the capsid inhibitor approved by the FDA in 2022. It has a unique mechanism of action that disrupts HIV capsid protein functions and impacts key protein-protein interactions necessary for viral entry and virion assembly.

It is very effective in patients with multidrug-resistant HIV, as well as in preventing HIV infection. It is administered in combination with an optimized background ART regimen. 

The beauty of this drug is that, after an initial induction regimen that includes an oral lenacapavir component, it is administered only every 6 months as a subcutaneous injection, thereby improving adherence, particularly in resource-limited countries.

#ID

#pharmacology

References:

1. Prather C, Lee A, Yen C. Lenacapavir: A first-in-class capsid inhibitor for the treatment of highly treatment-resistant HIV. Am J Health Syst Pharm. 2023 Dec 5;80(24):1774-1780. doi: 10.1093/ajhp/zxad223. PMID: 37767713.

2. Segal-Maurer S, DeJesus E, Stellbrink HJ, et al. Capsid Inhibition with Lenacapavir in Multidrug-Resistant HIV-1 Infection. N Engl J Med 2022; 386:1793.

3. De Clercq E, Zhang Y, Li G, Deng Y, Khouri R, Růžek D, Król E, Tan L. Lenacapavir: A capsid inhibitor for HIV-1 treatment and prevention. Biochem Pharmacol. 2025 Oct;240:117125. doi: 10.1016/j.bcp.2025.117125. Epub 2025 Jul 5. PMID: 40623458.

Brugada Syndrome in psychiatric disorder

Q: Which psychological condition is found to be associated with Brugada pattern ECGs? - Select one

A) Autism Spectrum Disorder  

B) Bipolar Disorder

C) Obsessive-Compulsive Disorders

D) Schizophrenia 

E) Social Anxiety

Answer: D

Brugada pattern ECGs are more significantly common in schizophrenia, and this association is without any significant impact of antipsychotic medications with sodium channel blocking activity.

Although the cause is not known, the same electrolyte channel dysfunction is suspected. It keeps the risk of sudden death in these patients high, an important element in the care of these patients, particularly when they are in hospitals and subject to various medications.

#psychiatry

#cardiology

References:

1. Blom MT, Cohen D, Seldenrijk A, et al. Brugada syndrome ECG is highly prevalent in schizophrenia. Circ Arrhythm Electrophysiol 2014; 7:384.

2. Rastogi A, Viani-Walsh D, Akbari S, Gall N, Gaughran F, Lally J. Pathogenesis and management of Brugada syndrome in schizophrenia: A scoping review. Gen Hosp Psychiatry. 2020 Nov-Dec;67:83-91. doi: 10.1016/j.genhosppsych.2020.09.003. Epub 2020 Oct 6. PMID: 33065406; PMCID: PMC7537626.

3. Treur JL, Thijssen AB, Smit DJA, Tadros R, Veeneman RR, Denys D, Vermeulen JM, Barc J, Bergstedt J, Pasman JA, Bezzina CR, Verweij KJH. Associations of schizophrenia with arrhythmic disorders and electrocardiogram traits: genetic exploration of population samples. Br J Psychiatry. 2025 Mar;226(3):153-161. doi: 10.1192/bjp.2024.165. Epub 2024 Nov 8. PMID: 39512114; PMCID: PMC7616879.

4. Sutterland AL, Blom MT, Ladee K, Lubbers JJM, Cohen D, de Haan L, Tan HL. Increased prevalence of ECG suspicious for Brugada Syndrome in recent onset schizophrenia spectrum disorders. Schizophr Res. 2019 Aug;210:59-65. doi: 10.1016/j.schres.2019.06.013. Epub 2019 Jun 24. PMID: 31248748.

AG in MM

Q: An anion gap (AG) in multiple myloma (MM) will be? - select one

A) high

B) low

Answer: B

Patients suspected of MM, typically with CRAB, i.e., hypercalcemia, renal insufficiency, anemia, and bone disease, would probably have a low anion gap. 

The two contributing factors to low AG are:

• Severe hypercalcemia acts as an unmeasured cation 
• A cationic IgG molecule

# electrolytes

#acid-base

References:

1. Mansoor S, Siddiqui I, Adil S, Nabi Kakepoto G, Fatmi Z, Ghani F. Anion gap among patients of multiple myeloma and normal individuals. Clin Biochem. 2007 Feb;40(3-4):226-9. doi: 10.1016/j.clinbiochem.2006.10.011. Epub 2006 Nov 1. PMID: 17156769.

2. Kraut JA, Madias NE. Serum anion gap: its uses and limitations in clinical medicine. Clin J Am Soc Nephrol 2007; 2:162.

3. De Troyer A, Stolarczyk A, De Beyl DZ, Stryckmans P. Value of anion-gap determination in multiple myeloma. N Engl J Med 1977; 296:858.

Aztreonam cross allergenicity

Q: Which cephalosporin allergy may also cause an allergy to aztreonam? - select one

A) Cefazolin 

B) Cefuroxime 

C) Ceftazidime 

D) Cefepime

E) Ceftaroline 

Answer: C

As a rule of thumb, there is no cross-allergenicity between aztreonam and other beta-lactam antibiotics, except ceftazidime. This cross-allergenicity between aztreonam and ceftazidime allergies is due to a shared side chain, called the R1 side chain.

#pharmacology

#ID

References:

Pérez Pimiento A, Gómez Martínez M, Mínguez Mena A, Trampal González A, de Paz Arranz S, Rodríguez Mosquera M. Aztreonam and ceftazidime: evidence of in vivo cross allergenicity. Allergy. 1998 Jun;53(6):624-5. doi: 10.1111/j.1398-9995.1998.tb03944.x. PMID: 9689350.

Gas explosion

Q: A gas explosion during a colonoscopy is a possibility.

A) True

B) False

Answer: A

A gas explosion during a colonoscopy is a rare but dreaded complication. Due to poor bowel prep, hydrogen or methane gas may be retained in the colonic lumen, and ignition from electrosurgical energy may cause a gas explosion. An alternative reason is the use of incompletely absorbable carbohydrate preparations, such as lactulose, mannitol, or sorbitol, which can serve as substrates for colonic bacteria, leading to fermentation and the production of high levels of combustible gases, including hydrogen and methane. 

One interesting case of a gas explosion is reported without the use of bowel preparation in a patient with colectomy for Gardner syndrome, who was found to have rectal polyps on proctoileoscopy. The polyps were treated with APC, which resulted in a gas explosion.

#procedures

#GI

References:

1. Manner H, Plum N, Pech O, et al. Colon explosion during argon plasma coagulation. Gastrointest Endosc 2008; 67:1123.

2. Tontini GE, Rimondi A, Pessarelli T, Ciprandi G, Kurihara H, Sorge A, Vecchi M. Clinical features and risk factors for colorectal gas explosion during digestive endoscopy and surgery: a systematic review. Surg Endosc. 2025 Jan;39(1):384-393. doi: 10.1007/s00464-024-11370-0. Epub 2024 Nov 15. PMID: 39548011; PMCID: PMC11666635.

3. Lin OS, Biehl T, Jiranek GC, Kozarek RA. Explosion from argon cautery during proctoileoscopy of a patient with a colectomy. Clin Gastroenterol Hepatol 2012; 10:1176.

4. Ladas SD, Karamanolis G, Ben-Soussan E. Colonic gas explosion during therapeutic colonoscopy with electrocautery. World J Gastroenterol. 2007 Oct 28;13(40):5295-8. doi: 10.3748/wjg.v13.i40.5295. PMID: 17879396; PMCID: PMC4171316.

Age's risk factor for acute renal transplant rejection

Q: Which of the following is at increased risk of acute kidney rejection post-transplant? - select one

A) older recipient and young donor

B) Younger recipient and older donor 

Answer: B

The following are the major risk factors for high immunologic risk of acute rejection.

• One or more human leukocyte antigen (HLA) mismatches
• Younger recipient and older donor age
• Presence of a donor-specific antibody (DSA)
• Blood group incompatibility
• Delayed onset of graft function
• Cold ischemia time greater than 24 hours
• Previous episode of rejection
• Receipt of a second or greater transplant
• Medication nonadherence

Younger patients' innate strong immunity may react vehemently to an older donor's organ.

#transplantation

#nephrology

References:

1. Kidney Disease: Improving Global Outcomes (KDIGO) Transplant Work Group. KDIGO clinical practice guideline for the care of kidney transplant recipients. Am J Transplant 2009; 9 Suppl 3:S1.