Viral Infections

Dengue Shock Syndrome
Clinical Signs of Dengue Shock Syndrome:
• Cool extremities, delayed capillary refill time
• Lethargy or restlessness (which may be a sign of reduced brain perfusion)
• Tachypnoea or Kussmaul's breathing
• Tachycardia, weak pulse
• Narrow pulse pressure: Pulse pressure ≤20 mmHg with increased diastolic pressure, e.g. 100/80 mmHg •
Hypotension by age, defined as systolic pressure <80 mmHg for those aged <5 years or 80 to 90 mmHg for older children and adults

Evidence of Plasma Leakage (key differentiating point between Dengue and Dengue Haemorrhagic Fever)
Rise in Hct.: 20% (eg. In children 35 → 42 and in adults 40→48)
• Circulatory failure: Cold/cold clammy skin, CRFT>2 Sec, tachycardia, weak pulse, narrow pulse pressure <20, hypotension.
• Fluid accumulation - Ascites/ Pleural effusions
• Albumin <3.5 gm/dl

Nucleic acid vaccines
 COVID-19 (RNA vaccines)  Ebola virus (DNA in clinical trials)

Explanation: The most common cause of ulceration is genital herpes

Reference: Davidson 23rd; P-581

Warning Signs
• No clinical improvement or worsening of the situation just before or during the transition to afebrile phase or as the disease progresses.
• Persistent vomiting.
• Severe abdominal pain.
Lethargy and/or restlessness, sudden behavioural changes.
• Bleeding: Epistaxis , black stool, haematemesis, excessive menstrual bleeding, dark colored urine (haemoglobinuria) or haematuria.
Giddiness.
• Pale, cold and clammy hands and feet.
• Less/no urine output for 4-6 hours
• Liver enlargement > 2cm • Haematocrit >20%

Reference: Davidson 23rd, Box-11.35

Explanation: HIV mainly transmits through Blood transfusion (90%)

Explanation: Acute coryza is the most common URTI and is usually the result of rhinovirus infection

Molluscum contagiosum is caused by a DNA poxvirus skin infection. It is most common in children over the age of 1 year, particularly those with atopic dermatitis. It also occurs frequently in immunosuppressed patients, including those with HIV. Lesions are dome-shaped, ‘umbilicated’, skin-coloured papules with central punctum . They are often multiple and found at sites of apposition, such as the side of the chest and the inner arm.

Reference: Davidson 23rd , Page : 1239

Reference: Davidson 23rd; P-581

Explanation: Initial flushing faint macular rash in first 1–2 days. Maculopapular, scarlet morbilliform blanching rash from days 3–5 on trunk, spreading centrifugally and sparing palms and soles; onset often with fever defervescence. May desquamate on resolution or give rise to petechiae on extensor surfaces

Reference: Davidson 23rd; P-581

Investigations
1 to 5 days of fever : CBC, NS1 antigen, SGOT and SGPT (Not mandatory but helpful)
• After day7: IgM and IgG Antibodies (Day 5-7 window period)
• Follow up testing may be done on 1st afebrile day, but should be done daily when DHF is suspected
Haematocrit:
-A regular haematocrit is more important for management than the thrombocytopenia
-In severe dengue especially with shock hourly haematocrit is crucial for management

 The "steeple sign" refers to the narrowing of the subglottic trachea, resembling a church steeple, and is characteristic of croup (laryngotracheobronchitis). Davidson explains that croup is a viral respiratory illness, most often caused by parainfluenza viruses, and commonly affects young children. Harrison adds that the steeple sign is an important radiographic finding, though clinical diagnosis is usually sufficient.

Davidson 23rd; P-1121

Dengue virus, which has 4 distinct  serotypes, i.e. DENV-1, DENV-2, DENV-3,  DENV-4 is transmitted by Aedes aegypti  and Aedes albopictus to human

Indications of Colloid in Dengue
• Patients with massive plasma leakage
• Patients with shock with rising Hct.
• Those not responding to the maximum volume of crystalloid
• Those with pulse pressure < 10 mm Hg, who need urgent restore BP

Explanation: the most serious cause of viral encephalitis is herpes simplex which probably reaches the brain via the olfactory nerves. Varicella zoster is also an important cause.

Explanation: ‘Koplik’s spots’ seen on buccal mucosa in the early stages of clinical measles, is pathognomonic for measles