Decompression SicknessMANAGEMENT

ENVIRONMENTAL AND EXPOSURE PRESENTATIONS · 12 SECTIONS

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668 items

☷ Legend

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Cardiovascular Presentations71▾

Respiratory Presentations52▾

Neurological Presentations83▾

Gastrointestinal Presentations74▾

Genitourinary and Reproductive Presentations48▾

Infectious Disease Presentations148▾

Trauma Presentations89▾

Toxicologic Presentations80▾

Psychiatric Presentations26▾

Musculoskeletal and Rheumatologic Presentations96▾

Dermatology Presentations23▾

Environmental and Exposure Presentations27▾

Acute Mountain Sickness Arterial Gas Embolism Bee-Wasp Sting (Anaphylaxis)Chilblains Ciguatera Fish Poisoning Coral Cut Decompression Sickness Electrical Burn Injury Envenomation (snake, spider, insect)High Altitude Cerebral Edema (HACE)High Altitude Pulmonary Edema (HAPE)High-altitude illness Hypothermia Hypothermia (Mild)Hypothermia (Severe)Immersion Foot Lightning Strike Injury Scombroid Fish Poisoning Scorpion Envenomation Sea Urchin Injury Shark Bite Snake Envenomation Spider Bite (Black Widow)Spider Bite (Brown Recluse)Stingray Spine Injury Tick paralysis White Phosphorus Burn

Hematologic and Oncologic Presentations36▾

Pediatric-Specific Presentations19▾

Endocrine and Metabolic Presentations45▾

ENT and Maxillofacial Presentations27▾

Ophthalmologic Presentations19▾

Obstetric Presentations23▾

Systemic and Miscellaneous Presentations17▾

01Approach to the Critical Patient/attcp69

Immediate priorities

›Airway and breathing threats

›Respiratory compromise from massive pulmonary venous gas emboli

›Dyspnea at rest

›Retrosternal chest pain with cough — the chokes

›Hemodynamic instability

›Hypotension from hemoconcentration and endothelial leak

›Shock physiology in severe DCS

›If SpO2 < 90% or respiratory distress, immediate 100% oxygen via nonrebreather mask

›Class I recommendation

›Demand valve delivery preferred if available

›Neurological threat recognition

›Spinal cord DCS

›Paraparesis or paraplegia

›Urinary retention

›Girdle pain as premonitory sign

›Cerebral DCS or arterial gas embolism

›Altered consciousness

›Seizure

›Focal cortical deficits

›Inner ear DCS

›Acute vertigo and nystagmus

›Hearing loss and tinnitus

›All neurological presentations: urgent recompression is the definitive treatment

›Do not delay for imaging

›ACEP Level B recommendation for recompression without delay

›Stabilization before transfer

›100% oxygen continuously during transfer

02History/hx71

Dive profile

›Dive parameters

›Maximum depth reached

›DCS essentially absent at depths < 6 m

›Risk increases substantially > 21 m

›Bottom time and repetitive dives

›Total cumulative dive time

›Number of dives in preceding 24 hours

›Ascent rate and decompression compliance

›Missed safety stops

›Rapid ascent or out-of-air emergency

›Gas mixture used

›Standard air vs nitrox vs trimix

›Oxygen partial pressure

›Dive computer data

›Download if available for objective profile

Symptom onset and characterization

›Onset timing

›73% of mild cases present within 1 hour of surfacing

›98% of severe cases present within 1 hour of surfacing

›99% of all cases present within 6 hours

›CNS cases present fastest — 56% within 10 minutes of surfacing

›Symptom types

›Joint and musculoskeletal pain — the bends

›Deep boring ache, commonly shoulder, elbow, hip, knee

›Present in 50 to 65% of cases

›Pain not worsened by movement distinguishes from injury

›Neurological symptoms

03Physical Exam/exam66

Vital signs and general

›Stability snapshot

›Blood pressure

›Hypotension as hemoconcentration or shock marker

›SBP < 90 mmHg is emergency

›Heart rate

›Tachycardia from volume depletion or pain

›Oxygen saturation

›Room air baseline then response to 100% oxygen

›Respiratory rate

›Tachypnea with pulmonary venous gas emboli

›Temperature

›Hypothermia from cold water exposure

Neurological exam

›Complete neurological assessment mandatory

›Mental status and cognition

›Executive dysfunction often missed on casual exam

›GCS

›Cranial nerves

›Nystagmus in inner ear DCS

›Visual field deficits in cerebral DCS

›Motor strength

›Paraparesis or quadriparesis — spinal cord DCS

›Focal limb weakness — cerebral DCS or AGE

›Sensory exam

›Nondermatomal hypoesthesia — characteristic and easily missed

›Proprioception loss — dorsal column vulnerability

›Coordination

04Differential Diagnosis/ddx43

Life-threatening causes

›Arterial gas embolism

›ICD-10 T70.3XXA

›Onset typically within minutes of surfacing

›Altered consciousness, seizure, focal cortical signs

›Can coexist with DCS — treatment is the same recompression

›Spinal cord DCS

›ICD-10 T70.3XXA

›Paraparesis, urinary retention, saddle anesthesia

›Highest disability risk of all DCS subtypes

›Pulmonary barotrauma

›ICD-10 T70.1XXA

›Pneumothorax — tension physiology possible

›Pneumomediastinum, subcutaneous emphysema

›Lung overexpansion during ascent mechanism

Diving-related mimics

›Inner ear barotrauma

›Vertigo and hearing loss from middle or inner ear pressure injury

›More common in shallow dives without decompression violation

›Dive profile and onset timing key to differentiation

›Immersion pulmonary edema

›Dyspnea during or shortly after diving

›Bilateral infiltrates, hypertension common

›ICD-10 J81.0

›Marine envenomation

›Skin pain or numbness from jellyfish, stonefish

›Exposure history and distribution of findings

05Laboratory Tests/lt37

Core labs

›Diagnostic role

›DCS is a clinical diagnosis — no specific biomarkers exist

›Labs guide severity assessment and fluid management

›Labs must not delay recompression

›Complete blood count and hematocrit

›Hemoconcentration as endothelial leak marker

›Guides fluid resuscitation in severe cases

›Hematocrit rise proportional to plasma extravasation

›Thrombocytopenia in severe DCS

›Comprehensive metabolic panel

›Renal function and electrolytes

›Dehydration assessment

›Fluid management inputs

›Glucose

›Avoid hyperglycemia — worsens neurological injury

›Avoid glucose-containing IV fluids

Coagulation and inflammation

›Coagulation studies

›Severe DCS with suspected coagulopathy

›PT, aPTT, fibrinogen

›DIC screen if clinical concern

›Creatine kinase

›Elevated CK may suggest pulmonary barotrauma or AGE

›Differentiation from isolated DCS not required before recompression

›Baseline useful for monitoring

›Arterial blood gas

›PaO2 and PaCO2 in mmHg for respiratory failure assessment

06Diagnostic Tests/dt75

Scoring Systems

›DCS classification — Decompression Sickness Type I and Type II

›Type I — musculoskeletal and cutaneous

›Joint pain — the bends

›Cutaneous — pruritus, cutis marmorata, lymphedema

›Generally better prognosis

›Type II — neurological, vestibular, and cardiopulmonary

›Spinal cord — most common severe neurological form

›Cerebral — focal cortical deficits

›Inner ear — vertigo and hearing loss

›The chokes — pulmonary venous gas emboli

›Highest risk of permanent disability

›Bubble grade scoring — Spencer and Kissman-Masurel scales

›Used by researchers and hyperbaric units

›Grade based on Doppler-detected venous gas emboli quantity

›Not used routinely in ED

›Precordial Doppler for venous gas emboli detection

›Higher bubble grade associated with higher DCS risk

›Research tool; not required for treatment decision

MRI

›MRI brain and spine role

›Low sensitivity for acute spinal cord DCS

›Significant functional deficits possible with normal MRI

›Negative MRI does not exclude spinal cord DCS

›Corpus callosum T2 and FLAIR hyperintensities in cerebral DCS

›Not pathognomonic — can be seen in other conditions

›Spinal cord T2 signal change in severe cases

›Posterior column involvement pattern

›Cervical and thoracic cord most affected

›Imaging must not delay recompression

›MRI only if strong concern for alternative diagnosis

›Cerebral hemorrhage exclusion if anticoagulation planned

›Post-recompression MRI

›Resolution of T2 signal correlates with clinical improvement

›Follow-up imaging for persistent deficits

›PFO evaluation planning using MRI brain for silent infarcts

›CT head role

›Not sensitive for arterial gas embolism or DCS

›Air emboli may be visible in acute AGE — transient

›Cerebral hemorrhage exclusion before anticoagulation

›When to obtain CT head

›Altered consciousness with diagnostic uncertainty

›Concern for intracranial hemorrhage

›Do not delay recompression for CT

›CT chest role

›Pulmonary barotrauma evaluation

›Pneumothorax before recompression if clinically indicated

›Pneumomediastinum assessment

›Tension pneumothorax must be drained before recompression

›Recompression worsens pneumothorax

›Class I recommendation

›CT chest findings in barotrauma

›Subcutaneous emphysema

›Pneumomediastinum air tracking

›Pleural air collections

Ultrasound

›Point-of-care ultrasound

›Lung POCUS

›Pneumothorax exclusion before recompression

›Absent lung sliding and lung point

›Sensitive for pneumothorax — ACEP Level B recommendation

›Cardiac POCUS

›RV dilation and septal flattening with massive venous gas emboli

›Gross LV function assessment

›Pericardial effusion screen

›Volume status assessment

›IVC collapsibility for fluid responsiveness estimation

›Limited by breathing variation

›Bubble contrast echocardiography — post-stabilization

›Transthoracic echo with agitated saline for PFO screening

›Recommended after unexplained or recurrent DCS

›Especially neurological, cutaneous, or inner ear DCS

›PFO prevalence markedly higher in unexplained DCS

›Transcranial Doppler with bubble contrast

›Alternative PFO screening method

›Performed after recompression and recovery

›Audiometry and electronystagmography

›Inner ear DCS assessment — defer until after recompression

07Disposition/dispo43

Recompression and transfer

›All DCS cases require hyperbaric oxygen evaluation

›Immediate transfer to nearest hyperbaric oxygen facility

›Contact DAN hotline for facility locating: (919) 684-8111

›Ground transport preferred to avoid altitude exposure

›Maintain 100% oxygen throughout transfer

›Reduces nitrogen bubble load in transit

›Continuous monitoring during transport

›Type II DCS and AGE — highest urgency

›Neurological symptoms require urgent recompression

›Delay worsens prognosis

›Do not wait for imaging unless hemorrhage exclusion mandatory

›The chokes — immediate recompression

›Cardiovascular collapse risk if delayed

Admission indications

›Inpatient admission criteria

›Neurological DCS requiring recompression therapy course

›Multiple recompression sessions often needed

›Physical therapy and rehabilitation planning

›Spinal cord DCS

›Urinary catheter management

›DVT prophylaxis for immobile patients

›Fractionated heparin for spinal cord DCS

›Hemodynamic instability or severe hemoconcentration

›IV fluid resuscitation monitoring

›Pulmonary barotrauma requiring intervention

Discharge and follow-up

›Discharge criteria — mild Type I DCS only

08Treatment/t82

Immediate oxygen therapy

›100% normobaric oxygen

›Nonrebreather mask at 10 to 15 L/min

›First-line for all DCS presentations

›14% achieve complete symptom relief

›51% achieve partial symptom reduction

›Demand valve oxygen delivery

›Higher fraction of inspired oxygen than NRB

›Preferred when available

›Duration of normobaric oxygen

›Continue until recompression available

›Continue throughout transport

›Contraindications to note

›Nitrous oxide absolutely contraindicated — causes bubble expansion

›Avoid glucose-containing IV fluids — worsens neurological injury

›Avoid hypotonic fluids — promote intracellular edema

Hyperbaric oxygen therapy

›US Navy Treatment Table 6 — standard first-line recompression

›Pressurization to 2.8 atm (18 m equivalent)

›100% oxygen breathing periods

›Air breaks to prevent oxygen toxicity

›Total session approximately 4 hours 45 minutes

›Indications

›All Type II DCS — neurological, vestibular, pulmonary

›Type I DCS not resolving with normobaric oxygen

›Class I recommendation based on expert consensus

›US Navy Treatment Table 5 — mild DCS

›Pressurization to 2.8 atm

›Shorter duration than Table 6

›Total session approximately 2 hours

›Indications

›Mild Type I DCS with complete resolution at pressure

›Repetitive recompression sessions

›Multiple sessions often required for neurological DCS

›Spinal cord DCS may need 5 to 10 or more sessions

›Response assessed clinically after each session

›Tenoxicam adjunct reduces median sessions from 3 to 2

›NSAID RCT evidence supporting adjunctive use

Fluid resuscitation

›Hydration protocol

›Oral rehydration if conscious and tolerating

›Isotonic noncarbonated noncaffeinated noncalcoholic fluid

›Water acceptable if preferred option unavailable

›IV isotonic crystalloid for moderate to severe DCS

›Normal saline 0.9% or lactated Ringer's

›Initial bolus 500 to 1000 mL for dehydration

›Titrate to hemodynamic stability

›Avoid glucose-containing solutions

›Risk of hyperglycemia worsening neurological injury

›Avoid hypotonic solutions

›Promote intracellular edema in neurological injury

Adjunctive medications

›NSAIDs

›Tenoxicam

›Reduced median recompression sessions from 3 to 2 in RCT

›Standard oral NSAID dosing

›Adjunct to recompression — not monotherapy

›Other NSAIDs

›Ibuprofen reasonable alternative

›Avoid in renal impairment or hemorrhagic risk

›DVT prophylaxis for immobile patients

›Fractionated heparin subcutaneous

›Enoxaparin 40 mg SC daily

›For spinal cord DCS with immobility

›Begin after hemorrhagic complications excluded

›IV lidocaine — selected severe neurological AGE

›Neuroprotective in animal models

›Not standard of care — limited human evidence

›Considered by hyperbaric specialists in refractory cases

›Medications without evidence or contraindicated

›Steroids — historically used, lack evidence, not standard

›Aspirin — not formally studied, not recommended routinely

›Nitrous oxide — absolutely contraindicated

Bladder and nursing care

›Urinary catheterization

›For urinary retention from spinal cord DCS

›Foley catheter placement

›Monitor urine output

›Positioning

›Supine positioning preferred

›Historical left lateral decubitus no longer recommended

›Trend position does not improve outcomes

›Head of bed neutral for neurological DCS

›Serial neurological examination

›Document deficits before and after each recompression session

›Sensory map documentation

›Motor strength grading

09Special Populations/sp59

Pregnancy

›Pregnancy-specific considerations

›Fetal risk from gas bubbles

›Fetal circulation does not filter venous gas emboli as efficiently

›Fetal decompression sickness is a theoretical concern

›Diving not recommended during pregnancy

›Hyperbaric oxygen in pregnancy

›Relative contraindication — fetal oxygen toxicity risk

›Risk-benefit analysis required

›General consensus: treat mother if DCS is life-threatening

›Teratogenic risk of HBO lower than risk of untreated severe DCS

›Medication adjustments

›NSAIDs — avoid after 30 weeks gestation

›IV isotonic crystalloid safe for resuscitation

›Enoxaparin — standard pregnancy dosing for DVT prophylaxis

›Fetal monitoring

›Viable gestation: continuous fetal monitoring during HBO

›Obstetrics consult immediately

›Imaging considerations

›MRI preferred over CT for neurological evaluation

›CXR with shielding if pneumothorax excluded required

Geriatric

›Older adult considerations

›Increased nitrogen solubility and tissue loading

›Higher body fat percentage — increased nitrogen storage

›Reduced cardiac output — slower denitrogenation

›Comorbidity burden

›Higher PFO prevalence with atrial septal changes

10Background/b73

Epidemiology

›Incidence and scope

›Recreational scuba diving DCS incidence 0.4 to 1 per 10,000 dives

›Risk increases substantially with deeper, longer, or repetitive dives

›Decompression violation greatly amplifies risk

›Military and commercial diving higher risk population

›Deeper operational profiles

›Greater decompression obligations

›Aviation and spaceflight DCS

›Altitude decompression sickness at altitudes above 5,500 m

›Astronaut extravehicular activity risk

›Demographics and outcomes

›Male divers predominate but female-specific risk factors exist

›Menstrual cycle phase may influence bubble formation

›Prior DCS is a risk factor for recurrence

›PFO prevalence in DCS cohorts markedly elevated

›97.2% PFO in divers with unprovoked DCS vs 35.5% controls

›Disability outcomes

›Spinal cord DCS has highest permanent disability rate

›Early recompression improves long-term outcomes substantially

Pathophysiology

›Gas bubble formation mechanism

›Nitrogen dissolved under pressure per Henry's Law

›Increased ambient pressure during diving increases dissolved nitrogen

›Rapid ascent causes supersaturation — gas comes out of solution

›Bubble nucleation sites

›Blood vessel lumen — venous gas emboli

›Tissue planes — musculoskeletal and neurological DCS

›Extravascular bubbles — joint and spinal cord

›Bubble effects

›Mechanical obstruction of blood flow

›Endothelial injury and inflammatory cascade

›Hemoconcentration from plasma extravasation

›Platelet activation and coagulopathy in severe cases

›Patent foramen ovale role

›Right-to-left shunt bypasses pulmonary filtration

›Venous bubbles enter arterial circulation

›Arterial gas embolism to brain, spinal cord, coronary vessels

›Bubble load threshold

›Large bubble loads overwhelm pulmonary filtering — the chokes

›Spinal cord vulnerability

›Epidural venous plexus — Batson's plexus

›Valveless, susceptible to bubble trapping

›Thoracolumbar cord most commonly affected

›Autochthonous bubble formation

›Bubbles form within cord tissue directly

›Not only embolic from venous gas emboli

Therapeutic Considerations

›Recompression rationale

›Increased pressure reduces bubble volume — Boyle's Law

›Bubble volume decreases as pressure increases

›Facilitates bubble reabsorption

›Hyperoxia accelerates nitrogen washout

›100% oxygen increases nitrogen diffusion gradient

›Reduces bubble nitrogen content

›Anti-inflammatory effect of HBO

›Reduces neutrophil adhesion

›Attenuates endothelial injury cascade

›Normobaric oxygen — interim therapy

›Partial reduction of bubble load before recompression

›Significant symptom relief in 65% of cases

›Should never replace recompression for Type II DCS

›Prevention strategies

›Pre-dive hydration reduces venous gas emboli load

›Animal model evidence

›Practical recommendation: well hydrated before diving

›Conservative dive profiles

›Slower ascent rates

›Mandatory safety stops at 5 m for 3 minutes minimum

›Post-dive altitude avoidance

›No flying within 12 to 18 hours of single no-decompression dive

›No flying within 24 hours of repetitive or decompression dives

›PFO closure consideration

›Percutaneous closure for divers with recurrent unexplained DCS

›Especially neurological, inner ear, and cutaneous DCS

›Shared decision-making with diving medicine and cardiology

11Patient Discharge Instructions/pdi27

copy discharge instructions

›Decompression sickness home care after treatment

›Rest for at least 24 to 48 hours after recompression

›Drink plenty of water — avoid alcohol and carbonated drinks

›Take all prescribed medications as directed

›Do not dive again until cleared by a diving medicine specialist

›Do not fly or travel to altitude until fully asymptomatic and cleared

›Warning signs — return to emergency department immediately

›Any new or returning weakness, numbness, or tingling

›Difficulty walking or loss of balance

›Difficulty urinating or loss of bladder control

›Worsening or new joint pain

›Shortness of breath or chest pain

›Confusion, difficulty thinking, or personality change

›Vision changes or hearing loss

›Skin rash that looks mottled or blotchy returning

›Follow-up instructions

›Diving medicine or hyperbaric specialist within 48 to 72 hours

›Heart bubble test (echocardiogram with bubble study) may be recommended

›Tests for a small hole in the heart that can increase DCS risk

›Do not return to diving until a diving physician has cleared you

›Bring your dive computer to your follow-up appointment

›Prevention for future dives

›Always dive within your dive computer or table limits

›Perform safety stops at 5 m for 3 minutes on every dive

›Stay well hydrated before diving

›Avoid flying or going to altitude within 18 hours of diving

›Dive conservatively — ascend slowly, limit repetitive dives

12References/r23

Guidelines and key sources

›Primary guidelines and societies

›Divers Alert Network clinical guidelines for DCS management

›DAN hotline: (919) 684-8111 — 24-hour specialist access

›Undersea and Hyperbaric Medical Society clinical guidelines

›Indications for hyperbaric oxygen therapy

›US Navy Diving Manual — Treatment Tables 5 and 6

›Standard recompression protocols for DCS and AGE

›Key evidence sources

›Bennett et al — systematic review of DCS epidemiology and treatment

›Incidence 0.4 to 1 per 10,000 recreational dives

›Symptom onset timing data: 73% mild, 98% severe within 1 hour

›Blatteau et al — RCT of tenoxicam adjunctive therapy

›Reduced median recompression sessions from 3 to 2

›Cartoni et al and Torti et al — PFO and DCS risk

›PFO prevalence 97.2% in unexplained DCS vs 35.5% controls

›High-grade PFO increases DCS risk 3- to 13-fold

›Moon and Gorman — normobaric oxygen interim therapy

›14% complete relief, 51% symptom reduction

›Coding standards

›ICD-10 T70.3XXA — effects of high pressure on sinuses and ears

›Used for DCS and arterial gas embolism

›ICD-10 T70.1XXA — sinus barotrauma

›SNOMED CT decompression sickness disorder concept

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Reviewed by SymptomDx Medical Team · Last reviewed August 18, 2026

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