History of Presenting Illness

• Fever — noted on Day 1 of illness, for which he self-administered antibiotics (agent and dosage not specified)
• Nausea and vomiting — present for 2 days, non-bloody, no bilious content noted
• Loss of appetite — persistent throughout the entire 5 days of illness
• Diarrhoea — present for 4 days, non-bloody, no mucus noted

Past Medical & Surgical History

Summary Statement

Clinical note: The use of antibiotics prior to admission is worth documenting carefully — it may have partially masked the clinical picture (e.g. reduced fever, altered inflammatory markers) and is relevant to management planning, especially if conservative antibiotic management vs. surgical intervention is being considered for a possible periappendiceal abscess.

Differential Diagnoses — Right Hypochondriac (RUQ) Pain in a 16-Year-Old Male

🔴 Most Likely

1. Mesenteric Lymphadenitis

2. Gastroenteritis (Bacterial)

Yersinia enterocolitica in particular is notorious for causing right-sided abdominal pain with mesenteric adenitis — worth flagging to your team.

🟡 Moderately Likely

3. Acute Cholecystitis / Biliary Colic

4. Hepatitis (Viral — Hepatitis A or B)

5. Peptic Ulcer Disease / Gastritis

🟢 Less Likely but Worth Considering

6. Pancreatitis

7. Meckel's Diverticulitis

8. Renal Colic / Urinary Tract Pathology

9. Psoas Abscess

Summary Table

Clinical pearl: The combination of periumbilical → RUQ migration + diarrhoea + fever + age 16 in the absence of appendicitis should make mesenteric lymphadenitis secondary to Yersinia or viral gastroenteritis the working diagnosis at discharge. Ensure he has safety-netting advice and a clear plan for follow-up if symptoms return.

Provisional / Working Diagnosis

In Clinical Documentation Terms:

Applied to Your Patient:

"Provisional diagnosis: Mesenteric lymphadenitis / Acute gastroenteritis"

• No surgery was done → no histology to confirm appendicitis or Meckel's
• No endoscopy → can't confirm peptic ulcer
• He improved with conservative management (antibiotics, supportive care)
• He is being discharged, meaning the clinical team is satisfied with a non-surgical explanation

GENERAL EXAMINATION

ABDOMINAL EXAMINATION

Inspection

• Abdomen flat or mildly distended
• No visible peristalsis
• No surgical scars (confirmed — no prior surgery)
• No visible masses
• May show guarding on movement if pain still present

Palpation

Percussion

• Tympanic throughout (no ascites)
• No shifting dullness
• Liver dullness — normal span

Auscultation

• Bowel sounds present — may be hyperactive (gastroenteritis) or normal (resolving)
• No bruit

SPECIFIC SIGNS TO ELICIT (and expected results)

SYSTEMIC EXAMINATION

SUMMARY OF EXPECTED FINDINGS

A 16-year-old thin Malay boy, alert and cooperative, afebrile, mildly dehydrated, with mild RUQ tenderness on deep palpation, no peritoneal signs, no organomegaly, hyperactive bowel sounds, and negative specific appendicitis signs — consistent with resolving mesenteric lymphadenitis or gastroenteritis, ready for discharge with safety netting.

GENERAL EXAMINATION

ABDOMINAL EXAMINATION

Inspection

• Abdomen flat, moves with respiration
• No visible peristalsis
• No surgical scars
• No distension
• Patient may guard on movement due to RLQ pain

Palpation

Percussion

• Tympanic throughout
• No shifting dullness, no ascites

Auscultation

• Bowel sounds hyperactive (gastroenteritis) or returning to normal
• No bruit

SPECIFIC SIGNS — CORRECTED

SYSTEMIC EXAMINATION

CORRECTED SUMMARY

A 16-year-old thin Malay boy, alert and cooperative, afebrile, mildly dehydrated, with RLQ tenderness at and around McBurney's point, no peritoneal signs (no rigidity, no rebound, negative Rovsing's/Psoas/Obturator), no organomegaly, hyperactive bowel sounds — consistent with resolving mesenteric lymphadenitis or acute gastroenteritis, with appendicitis excluded clinically and/or radiologically by the treating team.

HOW CONSTIPATION CHANGES THE PICTURE

Differentials That Move UP in Priority

Differentials That Move DOWN

HOW EXAMINATION FINDINGS CHANGE

General Examination

Abdominal Palpation — Key Changes

Auscultation

MOST IMPORTANT CLINICAL POINT

A 16-year-old boy on a chronic low-fibre diet (instant noodles x 1 year) with RLQ pain, fever, vomiting, and constipation — the single most important differential to consider first is:

Fecaloma causing RLQ pain (Fecal impaction)

• Low fibre diet → chronic slow transit → hard stool accumulation in cecum/ascending colon → RLQ pain, distension, fever (secondary infection), vomiting
• Management: Enema, laxatives, dietary counselling — no surgery needed
• This fits perfectly with the conservative discharge without intervention

REVISED SUMMARY STATEMENT

A 16-year-old thin Malay boy presenting with RLQ pain, fever, vomiting, anorexia, and constipation on a background of chronic low-fibre diet — the leading differential is fecal impaction/fecaloma, followed by Meckel's diverticulitis, early appendicitis, and Crohn's disease. Intestinal obstruction must be excluded if patient has absolute constipation (no flatus or stool at all).

What Negative Special Signs Tell You

Collectively, all negative special signs = no acute surgical abdomen. This is exactly why the doctor is discharging him conservatively.

Revised Most Likely Diagnosis With All Negative Signs + Constipation

• ✅ RLQ pain
• ✅ Fever (resolving)
• ✅ Vomiting
• ✅ Constipation
• ✅ Anorexia
• ✅ Chronic low-fibre diet
• ❌ All special signs negative
• ❌ No peritonism
• ❌ No rigidity

#1 — Fecal Impaction / Fecaloma

#2 — Mesenteric Lymphadenitis

#3 — Functional Abdominal Pain

The Clinical Logic Chain

All negative special signs
        ↓
No peritoneal irritation
        ↓
No acute surgical abdomen
        ↓
Conservative management appropriate
        ↓
Safe for discharge with safety netting

What You Should Document

"All special abdominal signs including Rovsing's, Psoas, Obturator, and rebound tenderness were negative. No signs of peritonism or acute surgical abdomen. Consistent with provisional diagnosis of fecal impaction / mesenteric lymphadenitis. Patient discharged with dietary advice and safety netting."

What Changes Clinically

Revised Differential Diagnoses

🔴 Most Likely

1. Mesenteric Lymphadenitis

2. Omental Infarction

This is a diagnosis that is very commonly missed and almost exclusively seen in obese patients. It is the standout new differential here.

🟡 Moderately Likely

3. Acute Cholecystitis / Biliary Colic

Fat, Female, Forty, Fertile, Fair While this patient is male and 16, obesity alone significantly increases cholelithiasis risk even in adolescent males. Pain can radiate to RLQ. Murphy's sign may still be negative in mild or early cases.

4. Non-Alcoholic Fatty Liver Disease (NAFLD)

5. Meckel's Diverticulitis

6. Early / Resolving Appendicitis

🟢 Less Likely

7. Epiploic Appendagitis

8. Type 2 Diabetes / Insulin Resistance Complications

9. Inguinal Hernia

Revised Examination Findings in an Obese Patient

General Examination Changes

Abdominal Examination Changes

Key New Differentials Unique to Obesity

Summary Statement

An obese 16-year-old Malay boy with RLQ pain, fever, vomiting, constipation, negative special signs, and a balanced diet — the leading differentials are mesenteric lymphadenitis, omental infarction, and epiploic appendagitis. Acute cholecystitis and masked appendicitis must also be considered, as obesity significantly reduces the sensitivity of clinical abdominal signs. Conservative discharge is appropriate given negative special signs, but imaging (ultrasound) would have been ideal to exclude omental/epiploic pathology.

What Fever Tells You (And What Its Absence Means)

No fever = think mechanical, functional, or non-inflammatory causes first

Revised Differentials — Obese, Balanced Diet, No Fever, RLQ Pain

🔴 Most Likely

1. Omental Infarction

2. Epiploic Appendagitis

• No fever or only low-grade
• No peritonism
• Negative special signs
• Self-limiting
• Obese patients at higher risk

Epiploic appendagitis now becomes the #1 specific differential in an afebrile obese patient with RLQ pain and all negative signs.

3. Constipation / Fecal Loading

🟡 Moderately Likely

4. Biliary Colic (without Cholecystitis)

• Uncomplicated biliary colic has NO fever — fever only appears when it progresses to acute cholecystitis
• Obese adolescent → gallstones → colicky RUQ/RLQ pain triggered by fatty meals
• Vomiting present
• No fever, no peritonism
• Fits the afebrile picture well

5. Irritable Bowel Syndrome (IBS)

• RLQ cramping pain, altered bowel habit (constipation subtype here)
• No fever — purely functional
• Vomiting less typical but can occur
• Anorexia and stress-related
• Adolescents commonly affected
• Diagnosis of exclusion

6. Meckel's Diverticulitis

7. Inguinal / Femoral Hernia

• Reducible hernia causing intermittent RLQ pain and vomiting
• No fever unless strangulated
• Obesity increases risk
• Easily missed if groin not examined

🟢 Less Likely Without Fever

How Examination Findings Change Without Fever

The New Clinical Logic Chain

Obese + Balanced diet + RLQ pain
        ↓
No fever → No active infection/inflammation
        ↓
Negative special signs → No surgical abdomen
        ↓
Constipation present → Gut motility issue
        ↓
Vomiting → Visceral pain response
        ↓
Top diagnoses:
Epiploic appendagitis / Omental infarction / Biliary colic / IBS

Summary Statement

An obese, afebrile 16-year-old Malay boy with RLQ pain, vomiting, constipation, negative special signs, and no systemic inflammatory features — the most likely diagnoses are epiploic appendagitis or omental infarction (both obesity-related, afebrile, self-limiting), followed by biliary colic and IBS. The absence of fever effectively removes infectious and inflammatory causes from the top of the differential. Conservative management and discharge is fully justified.

Fever narrows differentials toward infection and inflammation. No fever narrows differentials toward mechanical, vascular, and functional causes.

What Changes Immediately

⚠️ FIRST AND MOST URGENT

Ectopic Pregnancy — Must Exclude Immediately

Until proven otherwise, any woman of reproductive age with RLQ pain = ectopic pregnancy until a pregnancy test is done.

• Irregular menstrual cycles → harder to date last menstrual period → easy to miss a missed period
• Ruptured ectopic = life-threatening emergency (haemoperitoneum, haemodynamic instability)
• Can present with no fever, localised RLQ pain, vomiting, anorexia
• Immediate urine/serum βhCG is mandatory before discharge

Revised Differentials — 29F, Irregular Cycles, RLQ Pain, Afebrile, Obese, Negative Special Signs

🔴 Most Likely

1. Ectopic Pregnancy (Exclude First)

• Irregular cycles = unreliable menstrual history
• RLQ pain, vomiting, anorexia
• No fever in unruptured cases
• Can have shoulder tip pain if bleeding into peritoneum
• βhCG + transvaginal ultrasound diagnostic

2. Ovarian Cyst / Torsion

• Ovarian cysts extremely common in women with irregular cycles (suggests PCOS or anovulation)
• Ovarian torsion: sudden severe RLQ pain, vomiting — can occur without fever if early
• Ruptured ovarian cyst: sharp pain, may be afebrile
• Negative special signs expected if no peritonism yet

3. Polycystic Ovarian Syndrome (PCOS)

• Irregular cycles + obesity = classic PCOS presentation
• Enlarged cystic ovaries → chronic pelvic/RLQ discomfort
• Associated: acanthosis nigricans, hirsutism, weight gain
• Not an acute emergency but explains the background

4. Endometriosis

• Irregular, painful periods + RLQ pain in a woman in her late 20s
• Cyclical pain worse around menstruation
• Can cause chronic RLQ pain, vomiting, bloating
• Often afebrile — not infective
• Frequently underdiagnosed — average delay 7–10 years

🟡 Moderately Likely

5. Pelvic Inflammatory Disease (PID)

• Ascending genital tract infection → salpingitis, oophoritis
• Usually presents with fever — but early or partially treated PID can be afebrile
• Irregular cycles, RLQ/bilateral pelvic pain, vomiting
• Cervical motion tenderness on bimanual examination — key sign
• She took antibiotics early → may have partially treated PID, masking fever

6. Mittleschmerz (Ovulation Pain)

• Mid-cycle pain from follicle rupture
• Afebrile, sharp, unilateral RLQ pain, self-limiting (hours to 1–2 days)
• Less likely given 5-day duration — but with irregular cycles, ovulation timing is unpredictable

7. Epiploic Appendagitis / Omental Infarction

• Still relevant — obesity remains a risk factor regardless of sex
• Afebrile, RLQ pain, negative special signs, self-limiting

8. Irritable Bowel Syndrome (IBS)

• More common in women than men
• Irregular bowel habits (constipation subtype), RLQ pain, bloating, vomiting
• Afebrile, no organic pathology — diagnosis of exclusion
• Hormonal fluctuations in irregular cycles can worsen IBS symptoms

🟢 Less Likely

9. Fibroid Degeneration

• Uterine fibroids common in women of reproductive age
• Degeneration → acute pain, low-grade or no fever, vomiting
• Associated with heavy/irregular menstruation

10. Tubo-Ovarian Abscess

• Complication of PID — but would expect fever to be present
• Less likely given afebrile status

Additional Examination Findings Specific to This Patient

General Examination — New Findings to Look For

Abdominal Examination

Mandatory Investigations Before Discharge

The New Clinical Logic Chain

29F + Irregular cycles + RLQ pain + Afebrile + Obese
            ↓
FIRST: Exclude ectopic pregnancy (βhCG)
            ↓
Irregular cycles + Obesity → PCOS → Ovarian cysts
            ↓
Afebrile → Less likely PID/infection
            ↓
Negative special signs → No acute surgical abdomen
            ↓
Top diagnoses:
Ovarian cyst/torsion | Endometriosis | PCOS-related | Epiploic appendagitis

Summary Statement

A 29-year-old obese female with irregular menstrual cycles presenting with RLQ pain, vomiting, constipation, no fever, and negative special signs — ectopic pregnancy must be excluded as the first priority with a βhCG before any discharge. Thereafter, the leading differentials are ovarian cyst/torsion, endometriosis, and PCOS-related pelvic pain, with epiploic appendagitis and IBS as secondary considerations. The irregular menstrual history combined with obesity strongly points toward an underlying PCOS as the root cause of both the menstrual irregularity and the recurrent abdominal symptoms.

In any woman of reproductive age with abdominal pain:

βhCG first. Always. No exceptions.