Irritable Bowel Syndrome (IBS)

A 29-year-old woman presents with a 6-month history of recurrent abdominal pain associated with bloating and altered bowel habits. She reports episodes of diarrhea alternating with constipation. Her symptoms are often worse during periods of stress and improve after defecation. She denies fever, weight loss, rectal bleeding, or nocturnal symptoms. Physical examination is unremarkable. Laboratory investigations including CBC, CRP, celiac serology, and stool studies are normal. Diagnosis?

Diagnosis is Irritable Bowel Syndrome (IBS).

1. Definition

1. Irritable bowel syndrome is a chronic functional gastrointestinal disorder.
2. It is characterized by:
1. Recurrent abdominal pain
2. Altered bowel habits
3. Absence of structural disease explaining symptoms
3. IBS is a positive clinical diagnosis based on Rome IV criteria.

2. Etiology / Associations

1. Exact cause is multifactorial and incompletely understood.
2. Contributing factors:
1. Altered gastrointestinal motility
2. Visceral hypersensitivity
3. Gut–brain axis dysfunction
4. Psychological stress and anxiety
5. Altered intestinal microbiota
6. Post-infectious changes
7. Low-grade intestinal inflammation
3. Associated conditions:
1. Anxiety disorders
2. Depression
3. Fibromyalgia
4. Chronic fatigue syndrome

3. Pathophysiology

1. Altered gut motility leads to diarrhea, constipation, or mixed bowel patterns
2. Visceral hypersensitivity causes exaggerated pain perception
3. Stress affects autonomic and enteric nervous system activity
4. Dysbiosis and low-grade mucosal inflammation may contribute
5. Increased intestinal permeability may trigger symptoms
6. Abnormal gut–brain interaction amplifies symptom severity

4. Clinical Features

4.1 Abdominal Symptoms

1. Recurrent abdominal pain or cramping
2. Pain related to defecation
3. Bloating and abdominal distension
4. Excessive flatulence

4.2 Bowel Habit Changes

1. Diarrhea (IBS-D)
2. Constipation (IBS-C)
3. Mixed bowel pattern (IBS-M)
4. Mucus in stool
5. Feeling of incomplete evacuation
6. Urgency

4.3 Associated Features

1. Fatigue
2. Anxiety or depression
3. Sleep disturbance
4. Urinary symptoms

4.4 Alarm Features (Red Flags)

1. Unintentional weight loss
2. Rectal bleeding
3. Iron deficiency anemia
4. Nocturnal diarrhea
5. Fever
6. Family history of colorectal cancer, celiac disease, or inflammatory bowel disease
7. Onset after age 50
8. Palpable abdominal or rectal mass

5. Diagnosis

5.1 Rome IV Criteria

1. Recurrent abdominal pain occurring at least 1 day/week in the last 3 months associated with two or more of the following:
1. Related to defecation
2. Associated with change in stool frequency
3. Associated with change in stool form
2. Symptom onset should be at least 6 months before diagnosis

5.2 IBS Subtypes

1. IBS-C: constipation predominant
2. IBS-D: diarrhea predominant
3. IBS-M: mixed diarrhea and constipation
4. IBS-U: unclassified

5.3 Investigations

1. Basic investigations are usually normal
2. Initial evaluation may include:
1. CBC
2. CRP or fecal calprotectin
3. Celiac serology
4. Stool studies if diarrhea predominant
3. Colonoscopy is indicated if:
1. Alarm features are present
2. Age-appropriate colorectal cancer screening is needed
3. Diagnosis is uncertain

6. Differential Diagnosis

1. Inflammatory bowel disease (IBD)
2. Celiac disease
3. Lactose intolerance
4. Colorectal cancer
5. Microscopic colitis
6. Chronic gastrointestinal infections
7. Hyperthyroidism or hypothyroidism
8. Malabsorption syndromes
9. Small intestinal bacterial overgrowth (SIBO)

7. Management

7.1 General Measures

1. Establish good physician–patient relationship
2. Reassurance and education
3. Stress reduction
4. Regular exercise
5. Adequate sleep

7.2 Dietary Therapy

1. Low-FODMAP diet may improve symptoms
2. Avoid trigger foods:
1. Caffeine
2. Alcohol
3. Fatty foods
4. Gas-producing foods
3. Increase soluble fiber (psyllium).
4. Avoid excessive insoluble fiber in some patients

7.3 Pharmacologic Therapy

IBS-C

1. Fiber supplements
2. Osmotic laxatives (polyethylene glycol)
3. Secretagogues:
1. Linaclotide
2. Lubiprostone

IBS-D

1. Loperamide
2. Bile acid binders
3. Rifaximin
4. Eluxadoline
1. Avoid in patients without a gallbladder or with pancreatitis risk

Pain / Bloating

1. Antispasmodics
2. Peppermint oil
3. Low-dose tricyclic antidepressants
4. SSRIs in selected patients

7.4 Psychological Therapy

1. Cognitive behavioral therapy
2. Gut-directed hypnotherapy
3. Stress management techniques

8. Monitoring

1. Monitor symptom severity and quality of life
2. Assess response to dietary and pharmacologic therapy
3. Reevaluate if alarm features develop
4. Avoid excessive unnecessary investigations

9. Complications

1. Reduced quality of life
2. Anxiety and depression
3. Work and social impairment
4. Frequent healthcare utilization
5. IBS does not increase mortality
6. IBS does not increase risk of colorectal cancer

10. Key Clinical Insight

1. Chronic recurrent abdominal pain associated with altered bowel habits and normal basic investigations strongly suggests IBS

11. Key Exam Points

1. IBS is diagnosed using Rome IV criteria
2. IBS is a positive clinical diagnosis in the absence of alarm features
3. Low-FODMAP diet is commonly beneficial
4. Psychological stress commonly worsens symptoms
5. IBS does not cause weight loss, bleeding, fever, or nocturnal diarrhea
6. Fecal calprotectin helps distinguish IBS from IBD
7. Colonoscopy is unnecessary in most young patients without red flags
8. IBS subtypes guide treatment
9. Reassurance and lifestyle modification are essential components of management

Kounis Syndrome

A 25 year old male develops acute onset chest pain, shortness of breath, and generalized urticaria shortly after receiving intravenous atropine for symptomatic bradycardia. He also reports palpitations, vomiting, and diaphoresis. On examination, he appears pale and diaphoretic, with diffuse wheezing on lung auscultation and generalized urticaria. Oxygen saturation is reduced. Electrocardiography shows ST-segment elevation in the inferolateral leads with reciprocal changes. Cardiac troponins may be mildly elevated. Emergency coronary angiography reveals normal coronary arteries, and echocardiography is normal with no regional wall motion abnormalities, consistent with transient coronary vasospasm. Symptoms and ECG changes resolve rapidly after treatment with corticosteroids, antihistamines, and supportive care. Diagnosis?

Diagnosis is Type I Kounis Syndrome triggered by atropine.

1. Definition

Kounis syndrome is an acute coronary syndrome triggered by an allergic or hypersensitivity reaction, resulting in coronary vasospasm, plaque rupture, or stent thrombosis.

2. Pathophysiology

1. Allergen exposure activates mast cells, basophils, and inflammatory pathways
2. Release of mediators such as histamine, leukotrienes, and platelet-activating factor
3. These mediators cause:
1. Coronary vasospasm
2. Plaque rupture in patients with underlying coronary artery disease
3. Stent thrombosis in previously stented patients

3. Classification

1. Type I
• Occurs in patients with normal coronary arteries
• Causes coronary vasospasm
• Troponin may be normal or mildly elevated
2. Type II
• Occurs in patients with pre-existing atherosclerotic disease
• Leads to plaque rupture and acute myocardial infarction
3. Type III
• Occurs in patients with coronary stents
• Leads to stent thrombosis

4. Clinical Features

4.1 Cardiac Features

1. Chest pain
2. Dyspnea
3. Palpitations
4. Nausea and vomiting

4.2 Allergic Features

1. Urticaria
2. Rash
3. Wheezing
4. Angioedema
5. Hypotension or anaphylaxis

5. Diagnosis

1. Clinical suspicion is key
• Acute coronary syndrome symptoms plus allergic manifestations
2. Electrocardiography
• ST elevation or depression
• Changes may be transient in Type I
3. Cardiac biomarkers
• Troponin may be normal or mildly elevated
4. Coronary angiography
• Normal coronaries in Type I
• Abnormal findings in Type II and III
5. Allergy markers
• Serum tryptase or IgE may support diagnosis

6. Key Clinical Insight

Chest pain with ECG changes in the presence of allergic features strongly suggests Kounis syndrome rather than primary acute coronary syndrome

7. Management

7.1 Core Principle

Simultaneously treat the allergic reaction and myocardial ischemia.

7.2 Allergic Component

1. Corticosteroids
2. Antihistamines (H1 and H2 blockers)
3. Oxygen therapy and intravenous fluids if required

7.3 Cardiac Component

Type I

1. Primary treatment is control of the allergic reaction
2. Nitrates or calcium channel blockers may be used for vasospasm if hemodynamically stable

Type II and III

1. Manage as acute coronary syndrome
2. Add steroids and antihistamines

7.4 Important Drug Considerations

1. Epinephrine
• Remains first line for life-threatening anaphylaxis
• Use with caution due to risk of worsening coronary vasospasm
2. Beta blockers
• Avoid in the acute phase due to risk of unopposed alpha-mediated vasoconstriction
3. Morphine
• Avoid due to histamine release and potential worsening of vasospasm

8. Prognosis

1. Type I generally has a favorable prognosis with prompt treatment
2. Type II and III depend on severity of underlying coronary disease
3. Early recognition reduces risk of myocardial infarction, arrhythmias, and death

9. Exam Level Pearls

1. Kounis syndrome = allergic reaction + acute coronary syndrome
2. Suspect when ACS symptoms occur with urticaria, wheeze, or anaphylaxis
3. Normal coronary angiography with ST elevation suggests Type I
4. Avoid beta blockers and morphine in acute phase
5. Use epinephrine cautiously but do not withhold in severe anaphylaxis
6. ECG changes often resolve after treatment of the allergic reaction

Leptospirosis

A 32-year-old male farmer presents with a 5-day history of high-grade fever, chills, severe myalgia, headache, and vomiting. He complains of intense pain in both calves and lower back. He also reports redness of both eyes without discharge and decreased urine output for the past 2 days. One week before symptom onset, he had been working barefoot in stagnant floodwater after heavy monsoon rains. On examination, he is febrile, tachycardic, mildly hypotensive, and dehydrated. Bilateral conjunctival suffusion and mild scleral icterus are noted. Laboratory investigations reveal thrombocytopenia, elevated bilirubin, mild to moderate transaminitis with AST predominance, serum creatinine 2.1 mg/dL, hyponatremia, hypokalemia, and elevated creatine phosphokinase (CPK). Diagnosis?

Diagnosis is Leptospirosis (severe icteric form, Weil’s disease).

1. Definition

1. Leptospirosis is a zoonotic bacterial infection caused by pathogenic Leptospira species.
2. It ranges from a mild self-limited febrile illness to severe multiorgan disease.
3. Severe disease (Weil’s disease) is characterized by:
1. Jaundice
2. Acute kidney injury (AKI)
3. Hemorrhage and/or pulmonary involvement

2. Etiology / Epidemiology

1. Caused by pathogenic Leptospira interrogans and related serovars
2. Reservoirs:
1. Rats (most important)
2. Dogs
3. Cattle
4. Pigs
3. Organisms are shed in animal urine contaminating:
1. Water
2. Soil
3. Mud
4. Transmission occurs via:
1. Skin abrasions
2. Mucosal surfaces
3. Conjunctiva
5. Risk factors:
1. Farmers
2. Sewage workers
3. Veterinarians
4. Flood exposure
5. Freshwater swimming
6. Common in tropical and subtropical regions, especially during monsoon seasons

3. Pathophysiology

1. Organisms enter through abraded skin or mucosa
2. Initial leptospiremic phase:
1. Hematogenous dissemination
2. Involvement of liver, kidneys, lungs, CNS, and heart
3. Immune phase occurs after antibody formation.
4. Vasculitis and endothelial injury cause:
1. Capillary leak
2. Hemorrhage
3. Organ dysfunction
5. Renal involvement commonly causes:
1. Non-oliguric AKI (classically)
2. Hypokalemia
6. Pulmonary hemorrhage and ARDS are major causes of mortality
7. Pulmonary involvement may occur even without jaundice

4. Clinical Features

4.1 General Features

1. Abrupt onset fever
2. Chills
3. Severe myalgia
4. Headache
5. Fatigue

4.2 Characteristic Features

1. Severe calf muscle tenderness
2. Conjunctival suffusion (conjunctival injection without purulent discharge)
3. Back and thigh pain

4.3 Gastrointestinal / Hepatic Features

1. Nausea
2. Vomiting
3. Abdominal pain
4. Jaundice
5. Hepatomegaly (occasionally)

4.4 Renal Features

1. Acute kidney injury
2. Non-oliguric AKI is classically seen, although oliguria may occur in severe disease
3. Electrolyte abnormalities:
1. Hypokalemia
2. Hyponatremia

4.5 Pulmonary Features

1. Cough
2. Hemoptysis
3. Pulmonary hemorrhage
4. ARDS

4.6 Neurological Features

1. Aseptic meningitis
2. Altered mental status
3. Encephalopathy

4.7 Cardiac Features

1. Myocarditis
2. Arrhythmias
3. Hypotension

5. Diagnosis

5.1 Clinical Suspicion

1. Acute febrile illness with:
1. Severe myalgia
2. Conjunctival suffusion
3. Floodwater or animal exposure
2. High suspicion in endemic tropical regions during monsoon season

5.2 Laboratory Findings

1. Leukocytosis
2. Thrombocytopenia
3. Elevated bilirubin
4. Mild to moderate transaminitis, often with AST predominance
5. Elevated creatinine
6. Hyponatremia and hypokalemia
7. Elevated CPK
8. Proteinuria or hematuria

5.3 Confirmatory Tests

1. IgM ELISA
2. Microscopic agglutination test (MAT)
3. PCR:
1. Blood in early disease
2. Urine later in disease
4. Culture (rarely used clinically)

5.4 Severity Indicators

1. Jaundice
2. AKI
3. Pulmonary hemorrhage
4. Hypotension
5. Altered sensorium
6. Respiratory failure

6. Differential Diagnosis

1. Dengue fever
2. Malaria
3. Scrub typhus
4. Typhoid fever
5. Viral hepatitis
6. Hantavirus infection
7. Rickettsial infections
8. Sepsis

7. Management

7.1 Mild Disease

1. Doxycycline 100 mg orally twice daily for 7 days
2. Alternatives:
1. Azithromycin
2. Amoxicillin
3. Antibiotics are most effective when started early in the leptospiremic phase

7.2 Severe Disease

1. Hospital admission
2. Ceftriaxone 1 to 2 g IV daily
3. Alternatives:
1. IV Penicillin G
2. Cefotaxime

7.3 Supportive Care

1. Intravenous fluids
2. Electrolyte correction
3. Dialysis for severe AKI
4. Oxygen or ventilatory support
5. Vasopressors if shock develops
6. Blood product transfusion if hemorrhage occurs

7.4 Special Considerations

1. Avoid doxycycline in pregnancy and young children
2. Jarisch Herxheimer reaction is uncommon but may occur after antibiotic initiation
3. Early antibiotic therapy reduces complications

8. Monitoring

1. Vital signs
2. Urine output
3. Renal function
4. Electrolytes
5. Platelet count
6. Liver function tests
7. Respiratory status

9. Complications

1. Acute kidney injury
2. Pulmonary hemorrhage
3. ARDS
4. Shock
5. Myocarditis
6. Arrhythmias
7. Meningitis
8. Disseminated intravascular coagulation (DIC)
9. Multiorgan failure

10. Prognosis

1. Mild disease usually resolves completely
2. Severe disease carries significant mortality
3. Mortality is highest in patients with pulmonary hemorrhage, ARDS, shock, or multiorgan failure
4. Early diagnosis and treatment improve outcomes

11. Prevention

1. Avoid contaminated water exposure
2. Use protective clothing and boots
3. Rodent control measures
4. Safe drinking water
5. Weekly doxycycline prophylaxis may be considered for short-term high-risk exposure, although evidence is limited

12. Key Clinical Insight

Fever + severe calf muscle pain + conjunctival suffusion + floodwater exposure strongly suggests leptospirosis

13. Key Exam Points

1. Conjunctival suffusion is a classic clue
2. Severe calf tenderness is highly characteristic
3. Weil’s disease = jaundice + AKI + hemorrhage
4. Pulmonary hemorrhage is the leading cause of death
5. Hypokalemia with AKI is a classic laboratory clue
6. IgM ELISA is commonly used for diagnosis
7. Do not delay empiric antibiotics if suspicion is high
8. Early treatment reduces complications and mortality