Crimean-Congo Hemorrhagic Fever (CCHF) - "Congo Virus"

What It Is

• Tintinalli's Emergency Medicine, p. 1127
• Henry's Clinical Diagnosis and Management by Laboratory Methods

Epidemiology

Transmission

1. Tick bite - most common route (Hyalomma tick bite)
2. Direct contact with blood/tissues of viremic animals (especially during slaughter - butchers, farmers, veterinarians at high risk)
3. Human-to-human - contact with blood or body fluids of infected patients (significant nosocomial risk; healthcare workers must use strict PPE)
4. Not transmitted by casual contact or airborne route

Clinical Phases

Phase 1 - Incubation

• 1-13 days (average ~5 days after tick bite; up to 13 days after blood exposure)

Phase 2 - Prehemorrhagic / Prodrome (Days 1-3)

• Abrupt onset high fever, severe headache, myalgia, dizziness
• Nausea, vomiting, abdominal pain
• Flushing of face/neck, conjunctival injection
• Possible altered mental status, photophobia

Phase 3 - Hemorrhagic Phase (Days 3-5, lasting 2-3 days)

• Nose (epistaxis)
• GI tract - hematemesis, melena, intra-abdominal bleeding
• Uterus - menometrorrhagia
• Urinary tract - hematuria
• Respiratory tract - hemoptysis
• Petechiae, ecchymoses, oozing from IV sites

Phase 4 - Recovery or Deterioration

• Survivors: defervescence begins ~Day 10-20
• Severe cases: shock, multiorgan failure, DIC, death

Laboratory Findings

Diagnosis

• RT-PCR (quantitative) on blood: first-line during acute phase (Days 1-7) when viral loads are highest
• Serology (ELISA for IgM antibodies, antigen detection): used after Day 7 and to increase sensitivity - important because extensive sequence diversity across 7 CCHFV clades can cause false negatives with single-target PCR assays
• Clinical diagnosis alone is strongly suggestive in endemic settings with appropriate exposure history

Treatment

• IV fluids, electrolyte correction
• Treatment of coagulopathy (FFP, platelets, cryoprecipitate)
• Respiratory support in severe cases
• Strict barrier nursing / infection control

• Oral or IV ribavirin for moderate-to-severe cases
• Duration: 10 days
• Remains the only approved antiviral, though evidence quality is moderate
• WHO recommends early use in suspected cases

• Monoclonal antibodies and heavy-chain antibodies (nanobodies) targeting CCHFV glycoproteins are under development (PMID: 41352535)
• Favipiravir and other nucleoside analogs under investigation

Prevention & Infection Control

• Personal protection against ticks: long clothing, repellents (DEET), tick checks
• Avoid unprotected contact with animal blood/carcasses in endemic areas
• Healthcare workers: full PPE (gown, gloves, eye protection, N95 mask) - nosocomial transmission is a major risk
• No licensed vaccine currently available (as of 2026), though candidates are in trials

Key Prognostic Markers of Fatal Outcome

• Viral load >10^8 copies/mL
• Severe thrombocytopenia (<20,000)
• Prolonged PT/aPTT
• Elevated AST/ALT >150 U/L
• Altered mental status early in illness

Recent Literature (2024-2026)

• Frank et al., Emerg Infect Dis 2024 (PMID: 38666548 & 38666553) - comprehensive two-part clinician review covering epidemiology, clinical features, diagnosis, and therapeutics
• Karanam et al., World J Virol 2025 (PMID: 40134837) - updated review on pathogenesis, transmission, and public health challenges
• Bulut et al., J Vector Borne Dis 2026 (PMID: 40485565) - updated treatment and management guidance

Midazolam - Side Effects & Precautions

What Is Midazolam?

Side Effects

1. Respiratory System (Most Significant)

• Respiratory depression - the most significant and dangerous adverse effect; can occur even at standard doses
• Apnea - especially with rapid IV administration or combination with opioids
• Hypoxemia - marked increase when combined with fentanyl (11 of 12 healthy volunteers developed hypoxemia in one study with midazolam + fentanyl combination)
• Risk is greatest in: elderly, debilitated patients, those with preexisting respiratory disease, and when combined with opioids

"Several fatalities have been reported after the use of midazolam, the majority of these being related to adverse respiratory events. In many of these cases, midazolam was used in combination with an opioid." - Barash's Clinical Anesthesia, 9e

2. Cardiovascular System

• Hypotension - small but consistent decrease in systolic BP; can be significant (19% of intubated patients had SBP <90 mmHg in one ED study)
• Bradycardia - less common
• Tachycardia - mild increase in heart rate is frequently seen
• Hypotension is dose-related and worsened by hypovolemia
• Cardiac index and coronary artery blood flow are generally not affected at usual doses

3. Central Nervous System

• Excessive sedation - particularly in elderly patients (prolonged psychomotor impairment)
• Anterograde amnesia - can be prolonged and undesirable postoperatively
• Paradoxical reactions - agitation, disinhibition, combativeness (rare)
• Altered mental status / confusion
• Residual sedation lasting 1-2 days can occur

4. Metabolite Accumulation

• Active metabolites (1-hydroxymidazolam, 4-hydroxymidazolam) accumulate with prolonged infusions
• In renal impairment, these metabolites are not cleared and can cause profound sedation
• In obese patients, prolonged elimination half-life due to adipose tissue distribution

5. Other Effects

• Hiccups (especially with rapid IV injection)
• Nausea/vomiting (mild)
• Local effects: pain on injection (less than diazepam as it is water-soluble - rarely causes phlebitis)
• Dependence and withdrawal with prolonged use - abrupt discontinuation after chronic use can precipitate withdrawal seizures

Precautions

Absolute Contraindications

Use with Caution in:

• Hypovolemia / volume depletion - hypotension is markedly exaggerated; avoid or reduce dose significantly
• Traumatic brain injury - hypotension is catastrophic; may worsen cerebral perfusion pressure
• Elderly patients - reduced clearance, prolonged sedation, greater sensitivity; use lower doses; context-sensitive half-time is approximately twice that of propofol
• Obesity - prolonged elimination due to adipose tissue distribution
• Hepatic cirrhosis / dysfunction - significantly reduced plasma clearance; dose reduction required
• Renal impairment - active metabolite accumulation causes prolonged/profound sedation; dose adjustment required (see renal dosing guidelines)
• Pulmonary disease / respiratory compromise - heightened risk of respiratory depression; use lower doses, ensure monitoring
• Neonates - use with caution; contains benzyl alcohol (injection) or sodium benzoate (oral syrup) which can be toxic in neonates; paradoxical excitation more common
• Congestive heart failure (CHF) - impaired hepatic blood flow affects clearance
• Critical illness - pharmacokinetics significantly altered; may require dose adjustment

Critical Drug Interactions

Reversal

• Flumazenil has a shorter half-life than midazolam - re-sedation can occur after reversal wears off; monitor for at least 1-2 hours
• Can precipitate acute withdrawal seizures in patients physically dependent on benzodiazepines
• Does NOT reverse the effects of opioids - co-administration with opioids still carries respiratory risk even after flumazenil

Administration Safety Points

• Always administer IV midazolam slowly (over at least 2 minutes); allow 2+ additional minutes to assess effect before re-dosing
• Never use outside a monitored setting without resuscitation equipment available (oxygen, bag-mask, flumazenil, suction)
• Continuous monitoring of respiratory rate, SpO2, blood pressure, heart rate is mandatory
• Start with the lowest effective dose; titrate to effect