Missed Perforated Appendicitis in a Nonverbal Patient with Autism and Duchenne Muscular Dystrophy

1. Introduction

Acute appendicitis is one of the most common pediatric emergencies and timely diagnosis is essential to prevent complications such as perforation and abscess formation [1]. Diagnosis typically relies on history and physical exam findings, with the classic presentation including migration of pain from the periumbilical region to the right lower quadrant, vomiting, and fever [2]. In younger children, however, these classic features may be absent, contributing to delayed diagnosis [3,4,5].

Diagnostic challenges are amplified in children with autism spectrum disorder (ASD), particularly those who are nonverbal. Rather than verbalizing discomfort or localizing pain, these children may express distress through deviations from their baseline behavior, including increased irritability, aggression, self-injurious behaviors, or altered facial expressions [6,7]. Consequently, their behavioral manifestations are often misunderstood, leading to higher rates of complications from acute appendicitis [8,9]. Furthermore, commonly used visual self-report pain assessment tools like the Wong-Baker FACES Pain Rating Scale may have limited utility in pediatric populations with ASD or cognitive delays. This inaccuracy stems from developmental barriers that limit their ability to map their internal sensory experiences onto abstract pictorial representations of emotion [6,10].

Diagnosing appendicitis in children with Duchenne muscular dystrophy (DMD) is complicated by the fact that classic peritoneal signs, such as abdominal rigidity and guarding, may be attenuated due to characteristic progressive muscle weakness, limiting abdominal wall contraction [11]. Moreover, the chronic use of steroids in patients with DMD may both increase susceptibility to infection and blunt inflammatory responses, including fever and leukocytosis, potentially masking appendicitis [12].

Herein, we present the case of a 4-year-old nonverbal boy with the coexistence of level 3 ASD and DMD on chronic steroid therapy whose atypical presentation resulted in a delayed diagnosis of acute appendicitis leading to perforation and abscess formation. This case highlights the importance of maintaining a high index of suspicion for appendicitis in medically complex children who present with behavioral changes or nonspecific symptoms despite initially reassuring evaluations.

2. Case Presentation

A 4-year-old nonverbal boy with level 3 ASD and DMD (deletion of introns 53-60), managed with prednisone 10 mg daily, presented to his pediatrician with a five-day history of fever, poor oral intake, decreased stool output, frequent crying and poor sleep. Serial vital signs, laboratory results, imaging findings, and key clinical events are summarized in Table 1.

On initial evaluation, he was irritable, combative, and unable to cooperate with the physical examination. His temperature was 38.3°C, with otherwise normal vital signs. He was referred to the emergency department for further evaluation, where repeat temperature was 36.4°C. Abdominal examination was reportedly benign, with normal bowel sounds and no tenderness, guarding or rigidity. His Wong-Baker FACES Pain Rating Scale was 0. Chest radiograph was normal. Given the absence of concerning physical examination findings, he was diagnosed with presumed gastroenteritis and discharged with supportive care.

The following day, he returned to the emergency department due to persistent fever, irritability, poor oral intake, vomiting and four days without a bowel movement. His temperature was 38.9°C and his Wong-Baker FACES Pain Rating Scale was 2. Repeat abdominal examination remained benign, demonstrating a soft, nondistended, nontender abdomen with normal bowel sounds and no organomegaly or palpable masses. Abdominal radiograph indicated a nonspecific bowel gas pattern with a mild stool burden and no free air or appendicolith. He was treated for constipation and discharged with instructions to continue supportive care.

Two days later, he presented for a third time with persistent symptoms and worsening fever to 39.4°C. Physical examination revealed abdominal distension and hypoactive bowel sounds. Computed tomography (CT) demonstrated perforated appendicitis with a walled-off abscess (Figure 1). He was admitted for nonoperative management with broad-spectrum antibiotics and supportive care. Four days after admission, progressive abdominal distension prompted abdominal ultrasonography, revealing multiple intra-abdominal abscesses. He subsequently underwent percutaneous drainage with catheter placement by interventional radiology and continued antibiotic therapy. The drains were removed four days later, and he was discharged after a 10-day hospitalization with an additional seven-day course of oral antibiotics. Two months later, he underwent an uncomplicated laparoscopic appendectomy, which showed persistent appendicitis with perforation (Figure 2).

Figure 1. Axial contrast-enhanced Computed Tomography (CT) findings. (a) Inflamed appendix with surrounding periappendiceal inflammatory changes. (b) Periappendiceal abscess measuring 38.8 × 24.2 mm.

Figure 1. Axial contrast-enhanced Computed Tomography (CT) findings. (a) Inflamed appendix with surrounding periappendiceal inflammatory changes. (b) Periappendiceal abscess measuring 38.8 × 24.2 mm.

Figure 2. Cross Section of Appendix. (a) H&E stain at 2x. The entire surface mucosa has been replaced by inflammation; inflammation is seen spreading relatively close to the outer surface of the appendiceal wall; no residual appendiceal mucosa is present in this section. Nodules of residual normal lymphoid aggregates are present. (b) H&E stain at 20x demonstrating occasional multinucleate giant cells (*).

Figure 2. Cross Section of Appendix. (a) H&E stain at 2x. The entire surface mucosa has been replaced by inflammation; inflammation is seen spreading relatively close to the outer surface of the appendiceal wall; no residual appendiceal mucosa is present in this section. Nodules of residual normal lymphoid aggregates are present. (b) H&E stain at 20x demonstrating occasional multinucleate giant cells (*).

Table 1. Summary of Emergency Department Visits and Inpatient management. .

Date	6/11/2024	6/12/2024	6/14/24	6/18/2024	8/23/2024
Temperature (celcius)	36.4	38.9	39.4	36.8	-
Blood Pressure (mmHg)	-	99/68	-	109/85	-
Heart Rate (beats/ minute)	134	159	-	150	-
Respiratory Rate (Breaths/ minute)	24	22	24	22	-
Wong Baker/ FACES	0	2	-	-	-
White Blood Cell Count (WBC)	-	-	13.3 x 10e6/L	-	-
Absolute Neutrophil Count (as percentage of WBC)	-	-	48%3	-	-
Band Count (as percentage of WBC)	-	-	17%4	-	-
Anion Gap	-	-	17 mmol/L	-	-
Lactic Acid	-	-	1.0 mmol/L	-	-
Imaging	CXR1	AXR2	CT scan5	Abdominal US6	-
Diagnosis	Gastroenteritis	Constipation	Perforated appendicitis with Abscess	Perforated Appendicitis with multiple abscesses	Perforated appendicitis for interval appendectomy
Treatment	ondansetron, ibuprofen and oral fluids	ondansetron, ibuprofen alternating with acetaminophen	Interval appendectomy pathway	percutaneous drain	Laparoscopic Appendectomy.
Pathology Report	-	-	-		Perforated vermiform appendix7

*¹ No acute cardiopulmonary disease. ² No free air, air fluid levels or appendicolith identified. ³ Absence of significant neutrophilia, possibly related to chronic steroid use. ⁴ Left shift with bandemia consistent with acute infection. Bandemia remains a useful marker of infection in patients on steroids. ⁵ Perforated appendix with walled off abscess (See Figure 1). ⁶ Multiple intraabdominal abscesses. ⁷ See Figure 2.

Table 1. Summary of Emergency Department Visits and Inpatient management. .

Date	6/11/2024	6/12/2024	6/14/24	6/18/2024	8/23/2024
Temperature (celcius)	36.4	38.9	39.4	36.8	-
Blood Pressure (mmHg)	-	99/68	-	109/85	-
Heart Rate (beats/ minute)	134	159	-	150	-
Respiratory Rate (Breaths/ minute)	24	22	24	22	-
Wong Baker/ FACES	0	2	-	-	-
White Blood Cell Count (WBC)	-	-	13.3 x 10e6/L	-	-
Absolute Neutrophil Count (as percentage of WBC)	-	-	48%3	-	-
Band Count (as percentage of WBC)	-	-	17%4	-	-
Anion Gap	-	-	17 mmol/L	-	-
Lactic Acid	-	-	1.0 mmol/L	-	-
Imaging	CXR1	AXR2	CT scan5	Abdominal US6	-
Diagnosis	Gastroenteritis	Constipation	Perforated appendicitis with Abscess	Perforated Appendicitis with multiple abscesses	Perforated appendicitis for interval appendectomy
Treatment	ondansetron, ibuprofen and oral fluids	ondansetron, ibuprofen alternating with acetaminophen	Interval appendectomy pathway	percutaneous drain	Laparoscopic Appendectomy.
Pathology Report	-	-	-		Perforated vermiform appendix7

*¹ No acute cardiopulmonary disease. ² No free air, air fluid levels or appendicolith identified. ³ Absence of significant neutrophilia, possibly related to chronic steroid use. ⁴ Left shift with bandemia consistent with acute infection. Bandemia remains a useful marker of infection in patients on steroids. ⁵ Perforated appendix with walled off abscess (See Figure 1). ⁶ Multiple intraabdominal abscesses. ⁷ See Figure 2.

3. Discussion

This case illustrates how the combination of severe ASD, DMD, and chronic corticosteroid therapy obscured the clinical presentation of acute appendicitis and contributed to delayed diagnosis.

Our patient lacked the classic history associated with acute appendicitis, including periumbilical pain migrating to the right lower quadrant and exacerbation of pain with movement. This diagnostic challenge stemmed from the atypical presentation of pain in children with ASD as well as his inability to localize pain. In this population, visceral pain frequently manifests as acute behavioral changes, such as heightened irritability, self-injurious behaviors, or aggression along with poor cooperation with physical examination [6,7]. Caregiver interviews are therefore essential to establish the child’s behavioral baseline and identify meaningful deviations. Furthermore, clinicians should be aware that standard self-report pain assessment tools like the Wong-Baker FACES Pain Rating Scale can be difficult to interpret in neurodivergent children, who may have difficulty associating abstract pictorial expressions with their internal sensory experiences [10]. Despite the absence of classic localized pain findings, our patient demonstrated other signs of advanced peritonitis —such as anorexia, vomiting, and decreased bowel output—which may reflect secondary paralytic ileus and should prompt careful reassessment [11].

Classic peritoneal signs, including abdominal rigidity and guarding, were absent in our patient. Although causality cannot be established, coexisting DMD may have contributed to the absence of these findings. Clinicians should recognize that patients with advanced DMD may lack these classic signs because progressive weakness of the abdominal wall musculature may diminish protective muscle contraction [12,13]. Nevertheless, secondary signs of peritonitis, including abdominal distension and hypoactive bowel sounds, were evident.

Chronic corticosteroid therapy may attenuate fever and leukocytosis while increasing susceptibility to infection, making appendicitis more difficult to recognize [13]. Although corticosteroid-induced demargination can complicate interpretation of the leukocyte count, bandemia remains an important indicator of acute bacterial infection, as was observed in our patient. Emerging evidence suggests that procalcitonin may be less affected by corticosteroid therapy than C-reactive protein (CRP) and may therefore serve as a useful adjunctive biomarker for evaluating bacterial infection [14].

Plain abdominal radiography has limited diagnostic utility in suspected acute appendicitis and should not be used to exclude the diagnosis [15]. In our patient, the initial abdominal radiograph demonstrated only a nonspecific bowel gas pattern and mild stool burden, contributing little to the diagnostic evaluation. When clinical suspicion persists despite a reassuring physical examination or nondiagnostic radiographs, particularly in children with communication barriers or neuromuscular disorders, clinicians should maintain a low threshold for ultrasonography or CT.

Nonoperative management with antibiotics is an accepted treatment strategy for perforated appendicitis with localized abscess formation [16]. However, careful patient selection and close clinical monitoring remain essential. In our patient, a localized abscess progressed despite antibiotic therapy, ultimately requiring percutaneous drainage of multiple intra-abdominal abscesses. This case illustrates that medically complex or immunosuppressed children undergoing nonoperative management may require escalation of care despite appropriate initial therapy.

4. Conclusions

This case highlights the diagnostic and management challenges of acute appendicitis in a nonverbal child with coexisting ASD and DMD. Communication barriers, atypical pain behaviors, and attenuation of classic abdominal findings contributed to delayed recognition and subsequent perforation with abscess formation. Clinicians should maintain a high index of suspicion for serious intra-abdominal pathology in children with neurodevelopmental and neuromuscular disorders and consider early advanced imaging when symptoms persist or deviations from baseline behavior are present despite an initially reassuring evaluation. This case underscores the importance of close monitoring during nonoperative management of perforated appendicitis in medically complex children, as escalation of care may be required.