Back

Maggots | Foreign Bodies And Others | Nose | Otorhinolaryngology (Ear Nose Throat / E.N.T) | 4th Year (Fourth Year) | MBBS | Detailed Free Notes

Views 0

1. EXAM-READY DEFINITION

  • Nasal myiasis is an infestation of the nasal cavity by larvae (maggots) of flies, resulting in progressive destruction of nasal mucosa and underlying tissues, with severe local morbidity if untreated.

  • It is classically seen in tropical and subtropical regions, particularly among debilitated, elderly, unhygienic, or unconscious patients.

One-Line University Answer

Nasal myiasis is infestation of the nasal cavity by fly larvae causing tissue destruction and foul-smelling nasal discharge.

2. TERMINOLOGY & CLASSIFICATION CONTEXT

2.1 TERMINOLOGY

  • Myiasis = infestation by fly larvae

  • Nasal myiasis = myiasis involving the nasal cavity

2.2 CLASSIFICATION OF MYIASIS (VIVA-FAVORITE)

A. BASED ON SITE

  • Nasal myiasis

  • Aural myiasis

  • Oral myiasis

  • Cutaneous myiasis

B. BASED ON LARVAL BEHAVIOR

  • Obligatory myiasis – larvae require living tissue

  • Facultative myiasis – larvae feed on necrotic tissue

  • Accidental myiasis – incidental ingestion/invasion

Exam Pearl

  • Nasal myiasis is usually facultative.

3. EPIDEMIOLOGY (EXAM-RELEVANT)

3.1 GEOGRAPHICAL DISTRIBUTION

  • Common in:

    • Tropical regions

    • Developing countries

  • Increased prevalence in:

    • Rural areas

3.2 PREDISPOSING POPULATION

  • Elderly

  • Bedridden patients

  • Mentally challenged individuals

  • Alcoholics

  • Patients with:

    • Atrophic rhinitis

    • Nasal malignancy

    • Poor hygiene

3.3 SEASONAL VARIATION

  • More common in:

    • Summer months

  • Due to:

    • Increased fly population

4. APPLIED ANATOMY (VERY HIGH-YIELD)

4.1 NASAL CAVITY STRUCTURES AT RISK

  • Nasal septum

  • Inferior turbinate

  • Floor of nasal cavity

  • Vestibule

4.2 WHY NOSE IS VULNERABLE

  • Warm, moist environment

  • Presence of necrotic tissue or crusts

  • Easy access for flies

  • Reduced protective reflexes in debilitated patients

5. ETIOLOGY (STEP-WISE, EXAM-ORIENTED)

5.1 CAUSATIVE ORGANISMS

  • Common flies:

    • Chrysomya bezziana

    • Musca domestica

    • Lucilia sericata

5.2 MODE OF INFESTATION

  • Fly lays eggs in:

    • Crusted nasal cavity

    • Foul-smelling discharge

  • Eggs hatch into larvae

  • Larvae burrow into tissues

5.3 PREDISPOSING FACTORS

  • Poor personal hygiene

  • Atrophic rhinitis

  • Chronic nasal discharge

  • Nasal malignancy

  • Unconsciousness

  • Low socioeconomic status

Exam Line

Atrophic rhinitis is the most common predisposing condition for nasal myiasis.

6. PATHOGENESIS (CORE EXAM SECTION)

6.1 BASIC MECHANISM

  • Eggs deposited in nasal cavity →

  • Larvae hatch →

  • Maggots penetrate mucosa →

  • Secrete proteolytic enzymes →

  • Tissue necrosis →

  • Progressive destruction

6.2 STEP-BY-STEP PATHOGENESIS

  1. Egg deposition by fly

  2. Larval hatching

  3. Mechanical tissue penetration

  4. Enzymatic digestion of tissue

  5. Necrosis and sloughing

  6. Secondary bacterial infection

6.3 WHY TISSUE DESTRUCTION IS SEVERE

  • Larvae:

    • Have backward-directed hooks

    • Burrow deeply

  • Continuous movement causes:

    • Mechanical trauma

    • Bleeding

    • Necrosis

7. MORPHOLOGY OF MAGGOTS (EXAM-RELEVANT)

  • Whitish, cylindrical larvae

  • Segmented body

  • Anterior hooks

  • Posterior spiracles for respiration

  • Actively motile

8. PATHOLOGICAL EFFECTS ON NASAL STRUCTURES

8.1 LOCAL EFFECTS

  • Mucosal ulceration

  • Necrosis

  • Septal erosion

  • Turbinate destruction

8.2 DEEP EXTENSION (SEVERE CASES)

  • Palate

  • Paranasal sinuses

  • Orbit

  • Rare intracranial extension

9. CLINICAL FEATURES — SYMPTOMS (WITH LOGIC)

9.1 NASAL DISCHARGE

  • Profuse

  • Foul-smelling

  • Blood-stained

9.2 SENSATION OF MOVEMENT

  • Patient may complain of:

    • Crawling sensation in nose

9.3 NASAL PAIN

  • Severe

  • Due to tissue destruction

9.4 EPISTAXIS

  • Due to mucosal erosion

9.5 FACIAL SWELLING

  • Due to inflammation and secondary infection

10. SIGNS ON EXAMINATION

10.1 ANTERIOR RHINOSCOPY

  • Visible live maggots

  • Necrotic tissue

  • Crusting

  • Foul odor

10.2 ENDOSCOPY

  • Reveals:

    • Extent of infestation

    • Posterior nasal cavity involvement

11. DIFFERENTIATING FEATURES (EARLY RECOGNITION)

  • Visible maggots

  • Severe foul smell

  • Rapid tissue destruction

  • Occurs in debilitated patients

12. DIAGNOSIS — INTRODUCTORY OVERVIEW

  • Primarily clinical

  • Imaging used to assess:

    • Extent

    • Complications

(Investigations, management, complications, OSCE, viva, examiner traps in PART 2)

Written And Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 7 Distinctions And 11 World Records For Educate A Change MBBS 4th Year (Fourth Year / Professional) Otorhinolaryngology (ENT) Free Material

13. INVESTIGATIONS (STEP-WISE, EXAM-ORIENTED)

13.1 CLINICAL DIAGNOSIS (PRIMARY & MOST IMPORTANT)

  • Diagnosis is predominantly clinical

  • Based on:

    • Visualization of live larvae on anterior rhinoscopy/endoscopy

    • Severe foul-smelling discharge

    • Necrotic tissue within nasal cavity

  • History often reveals:

    • Poor hygiene

    • Atrophic rhinitis

    • Debilitating illness

Exam Line

Nasal myiasis is primarily a clinical diagnosis.

13.2 NASAL ENDOSCOPY

  • Essential to:

    • Assess extent of infestation

    • Identify posterior nasal cavity, choana, nasopharynx involvement

    • Guide complete removal

  • Often repeated over successive days

13.3 IMAGING (WHEN INDICATED)

CT SCAN PARANASAL SINUSES

  • Indications:

    • Suspected deep extension

    • Orbital symptoms

    • Palatal or sinus involvement

    • Non-visualized posterior disease

  • Findings:

    • Mucosal destruction

    • Sinusitis

    • Bony erosion (pressure/necrosis, not malignant)

Exam Pearl

  • Imaging is not routine, but mandatory in complicated cases

13.4 LABORATORY TESTS

  • CBC:

    • May show anemia (chronic bleeding)

    • Leukocytosis (secondary infection)

  • Culture:

    • Rarely required

  • Species identification:

    • Academic interest only, not exam-essential

14. DIFFERENTIAL DIAGNOSIS (VERY HIGH-YIELD TABLE)

Feature Nasal Myiasis Rhinolith Malignancy Atrophic Rhinitis
Onset Acute–subacute Very chronic Progressive Chronic
Odor Extremely foul Foul Variable Foul
Pain Severe Mild Severe Mild
Visible larvae Present Absent Absent Absent
Tissue destruction Rapid Pressure erosion Invasive Minimal
Bleeding Common Occasional Common Rare

Examiner Trap

  • Severe foul smell + pain + necrosis → think myiasis, not rhinolith

15. MANAGEMENT (CORE ENT EXAM SECTION)

15.1 PRINCIPLES OF MANAGEMENT

  • Immediate removal of all larvae

  • Kill or immobilize maggots

  • Treat secondary infection

  • Prevent complications

  • Improve hygiene and underlying condition

15.2 INITIAL MEASURES (BEFORE REMOVAL)

15.2.1 LARVICIDAL / SUFFOCATING AGENTS

Applied to force maggots to surface:

  • Turpentine oil (traditional)

  • Liquid paraffin

  • Chloroform in olive oil (1:4)

  • Ether (with caution)

Mechanism

  • Blocks spiracles → larvae come out for air

Exam Line

Turpentine oil is used to suffocate larvae before removal.

15.3 MECHANICAL REMOVAL (MAIN TREATMENT)

15.3.1 METHOD

  • Removal under:

    • Good illumination

    • Nasal endoscopy

  • Use:

    • Tilley’s forceps

    • Suction

  • Procedure is:

    • Repeated daily

    • Until nasal cavity is free of larvae

15.3.2 ANESTHESIA

  • Local anesthesia:

    • Cooperative patients

  • General anesthesia:

    • Uncooperative patients

    • Children

    • Extensive infestation

15.4 PHARMACOLOGICAL THERAPY

15.4.1 IVERMECTIN (VERY IMPORTANT)

  • Oral ivermectin:

    • Single dose or short course

  • Mechanism:

    • Paralyses larvae by interfering with neural transmission

  • Reduces:

    • Larval burden

    • Duration of treatment

Exam Pearl

  • Ivermectin is now standard adjunct therapy.

15.4.2 ANTIBIOTICS

  • Broad-spectrum antibiotics

  • Indicated when:

    • Secondary infection present

    • Necrosis extensive

15.4.3 ANALGESICS & SUPPORTIVE CARE

  • Pain control

  • Hydration

  • Nutritional support

16. POST-REMOVAL CARE

  • Daily nasal toileting

  • Saline irrigation

  • Topical antibiotic ointment

  • Endoscopic reassessment

  • Address predisposing factors:

    • Treat atrophic rhinitis

    • Improve hygiene

    • Manage malignancy if present

17. COMPLICATIONS (EXAM-SCORING SECTION)

17.1 LOCAL COMPLICATIONS

  • Septal perforation

  • Turbinate destruction

  • Palatal perforation

17.2 REGIONAL COMPLICATIONS

  • Sinusitis

  • Orbital cellulitis

  • Facial cellulitis

17.3 LIFE-THREATENING COMPLICATIONS (RARE)

  • Cavernous sinus thrombosis

  • Intracranial extension

  • Septicemia

Exam Line

Untreated nasal myiasis can be life-threatening.

18. OSCE / PRACTICAL STATIONS

18.1 SPOT DIAGNOSIS

  • Live larvae in nasal cavity
    Answer: Nasal myiasis

18.2 MANAGEMENT STATION

  • Apply turpentine oil

  • Mechanical removal

  • Ivermectin

18.3 COUNSELLING STATION

  • Explain hygiene importance

  • Treat underlying disease

  • Prevent recurrence

19. LONG CASE (UNIVERSITY FORMAT)

History

  • Elderly patient

  • Severe foul nasal discharge

  • Pain and bleeding

Examination

  • Maggots visible

  • Necrotic nasal mucosa

Diagnosis

  • Nasal myiasis

Management

  • Larvicidal agents

  • Endoscopic removal

  • Ivermectin + antibiotics

20. MCQs (EXAM-FOCUSED)

1. Most common predisposing condition for nasal myiasis:
A. Sinusitis
B. Atrophic rhinitis
C. Allergic rhinitis
D. Nasal polyp
Correct Answer: B

2. Drug used to paralyze larvae:
A. Metronidazole
B. Albendazole
C. Ivermectin
D. Amoxicillin
Correct Answer: C

21. VIVA QUESTIONS

  • Define nasal myiasis

  • Common predisposing factors

  • Why turpentine oil is used?

  • Role of ivermectin

  • Complications

22. EXAMINER TRAPS

  • Removing larvae without suffocation

  • Missing posterior extension

  • Ignoring underlying atrophic rhinitis

  • Inadequate follow-up

23. CLINICAL PEARLS (EXAM GOLD)

  • Seen in debilitated patients

  • Severe foul smell + pain + necrosis

  • Mechanical removal is key

  • Ivermectin is effective

  • Prevention = hygiene + early care

Written And Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 7 Distinctions And 11 World Records For Educate A Change MBBS 4th Year (Fourth Year / Professional) Otorhinolaryngology (ENT) Free Material

24.1 WHY THIS CORRELATION IS IMPORTANT IN EXAMS

  • Nasal myiasis is not just infestation, it is a destructive pathological process

  • Radiology explains:

    • Depth of invasion

    • Complications

    • Why urgent treatment is required

  • Pathology explains:

    • Rapid tissue necrosis

    • Severe pain and bleeding

24.2 RADIOLOGICAL FINDINGS EXPLAINED

CT SCAN (PNS / FACE)

  • Findings:

    • Soft-tissue density within nasal cavity

    • Mucosal thickening

    • Air pockets due to tissue destruction

    • Sinus involvement

    • Possible palatal or septal erosion

  • Bone changes:

    • Irregular erosions due to necrosis

    • Not smooth pressure erosion (unlike rhinolith)

Exam Line

Bone destruction in nasal myiasis is due to necrosis, not malignancy.

24.3 PATHOLOGICAL BASIS OF FINDINGS

  • Proteolytic enzymes secreted by larvae

  • Mechanical burrowing by hooks

  • Secondary bacterial infection

  • Result:

    • Rapid necrosis

    • Sloughing

    • Bleeding

24.4 CLINICAL CORRELATION

Pathology Radiology Clinical Feature
Tissue necrosis Mucosal destruction Foul discharge
Vascular injury Irregular erosions Epistaxis
Sinus spread Sinus opacification Facial pain
Septal damage Septal erosion Nasal deformity

25. ADVANCED COMPLICATIONS (COMPLETE CLASSIFICATION)

25.1 LOCAL COMPLICATIONS

  • Septal perforation

  • Turbinate destruction

  • Vestibular necrosis

  • Crusting and synechiae

25.2 REGIONAL COMPLICATIONS

  • Maxillary sinusitis

  • Ethmoid sinusitis

  • Orbital cellulitis

  • Facial cellulitis

25.3 DEEP AND LIFE-THREATENING COMPLICATIONS

  • Cavernous sinus thrombosis

  • Meningitis

  • Brain abscess

  • Septicemia

Exam Line

Death can occur if nasal myiasis is untreated.

26. MANAGEMENT CHALLENGES & PRACTICAL PITFALLS

26.1 WHY COMPLETE REMOVAL IS DIFFICULT

  • Larvae hide deep in tissues

  • Posterior nasal cavity involvement

  • Continuous migration of larvae

  • Patient intolerance due to pain

26.2 COMMON MISTAKES

  • Single-day removal only

  • No endoscopic examination

  • No ivermectin use

  • Ignoring underlying disease

26.3 HOW TO ENSURE SUCCESSFUL TREATMENT

  • Daily endoscopic inspection

  • Repeated larvicidal application

  • Adequate analgesia

  • Correction of predisposing factors

27. PROGNOSIS

  • Good if treated early

  • Excellent after complete removal

  • Poor prognosis if:

    • Delayed diagnosis

    • Orbital or intracranial spread

    • Severe malnutrition

28. PREVENTION (PUBLIC HEALTH & COUNSELLING)

28.1 INDIVIDUAL LEVEL

  • Personal hygiene

  • Regular nasal cleaning

  • Early treatment of rhinitis

28.2 COMMUNITY LEVEL

  • Fly control

  • Proper waste disposal

  • Health education in rural areas

28.3 HOSPITAL LEVEL

  • Proper nursing care of:

    • Unconscious patients

    • ICU patients

  • Covering nose and mouth

29. OSCE / PRACTICAL STATIONS (FULL SET)

29.1 SPOTTER

  • Specimen showing maggots
    Diagnosis: Nasal myiasis

29.2 PROCEDURE STATION

  • Demonstrate steps of maggot removal:

    1. Apply turpentine oil

    2. Mechanical removal

    3. Endoscopic clearance

29.3 COUNSELLING STATION

  • Explain disease cause

  • Hygiene importance

  • Need for follow-up

30. LONG CASE (UNIVERSITY STYLE)

History

  • Elderly, poor hygiene

  • Severe foul nasal discharge

  • Pain and bleeding

Examination

  • Live larvae visible

  • Necrotic nasal tissue

Investigations

  • Clinical diagnosis

  • CT scan for extension

Diagnosis

  • Nasal myiasis

Management

  • Turpentine oil application

  • Endoscopic removal

  • Ivermectin

  • Antibiotics

  • Supportive care

31. MCQs (FINAL SET)

1. Most effective drug in nasal myiasis:
A. Metronidazole
B. Albendazole
C. Ivermectin
D. Ciprofloxacin
Correct Answer: C

2. Most common predisposing condition:
A. Allergic rhinitis
B. Sinusitis
C. Atrophic rhinitis
D. DNS
Correct Answer: C

3. Mechanism of tissue damage:
A. Pressure
B. Immune reaction
C. Proteolytic enzymes
D. Ischemia
Correct Answer: C

32. VIVA QUESTIONS (RAPID-FIRE)

  • Define nasal myiasis

  • Name common flies

  • Predisposing factors

  • Why turpentine oil is used

  • Complications

  • Prevention

33. EXAMINER TRAPS (VERY IMPORTANT)

  • Confusing with rhinolith

  • Not examining posterior nose

  • No ivermectin prescription

  • Ignoring systemic condition

  • Assuming condition is harmless

34. CLINICAL PEARLS (EXAM GOLD)

  • Seen in elderly, debilitated, poor hygiene

  • Severe foul smell + pain + necrosis

  • Diagnosis is clinical

  • Mechanical removal is key

  • Ivermectin improves outcome

  • Prevention is crucial

Written And Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 7 Distinctions And 11 World Records For Educate A Change MBBS 4th Year (Fourth Year / Professional) Otorhinolaryngology (ENT) Free Material

Hunain Zia

Hunain Zia has previously achieved considerable success in the high-school educational stream, gaining a massive 154 Total A Grades and 7 Major Distinctions, a process in which he broke/ set 11 different world records, including the most A grades ever achieved, most subjects ever appeared in, most distinctions, gaining distinctions across two separate boards (Pearson Edexcel and CAIE) within the same year/ ever, and even 19 hours of constant examination. All records stand intact today. Hunain pursued his Honors Accounting Degree from the prestigious Bentley University, and then completed an LLB (in Honors) from University of London. Currently, he manages multiple social and commercial projects, has founded digital streams and works tirelessly in the education sector.

Educate A Change focuses on truly bringing change in the educational sector worldwide. All our courses are designed to ensure success, and provide complete preparation without requiring any other external material. Therefore, it takes away the expense of academies, books, past paper compilations and other miscellaneous items. Instead, by just the courses we offer, the student can prepare fully for the best grades in their CAIEs, Edexcel and other high-school exams. The earnings from our course-sales are invested in social projects and growing the free educational activities of Educate A Change.