Infectious diseases,...

Question 1

Investigations to be done when a patient is presented with fever

Answer 1

1. a full blood count
2. urea and electrolytes, liver function tests, blood glucose and muscle enzymes
3. Inflammatory markers, ESR, CRP
4. Auto antibodies and antibodies to HIV 1
5. chest x-ray and ECG
6. urine culture
7. blood culture, throat swab
8. PCR
9. other specimens history and examination
10. Specific tests geographical location

Question 2

Prominent causes of pyrexia of unknown origin in old age

Answer 2

1. TB
2. Intra-abdominal Abscesses
3. Complicated urinary tract infections
4. Infective endocarditis
5. Poly myalgia rheumatica
6. Temporal arteritis and tumours
   A small fraction of cases remain undiagnosed than young people

Question 3

Management of fever

Answer 3

Buy paracetamol and by tepid sponging to cool the skin
Replacement of salt and water is important in patients with drenching sweats
Further management is based on underlying cause

Question 4

Diurnal variation of body temperature

Answer 4

Oral temperature is 37.2°C at 6 AM and 37.7°C at 4 PM that is it varies between 98.9°F and 99.9°F

Question 5

Methods of monitoring temperature

Answer 5

Peripheral methods:
Tympanic membrane temporal artery axillary, and oral thermometry

Central methods:
Pulmonary artery catheter, urinary bladder, oesophageal and rectal thermometer

Question 6

Differences between the various temperatures of the body

Answer 6

1. Rectal temperature is higher then oral by .4°C. Oral temperature is lower due to mouth breathing
2. Unadjusted tympanic membrane readings are 0.8°C or 1.6 F lower than rectal temperature

Question 7

Hyperthermia

Answer 7

It is defined as the elevation of core body temperature above the normal diurnal range of 36 to 37.5°C due to failure of thermoregulation
Severe hypothermia is when the temperature is above 40°C or 104° F

Question 8

Malignant hyperthermia

Nature and causes

Answer 8

Malignant hyperthermia is a autosomal dominant disorder that manifests often following treatment with anaesthetic agents most commonly succinylcholine and halothane
Pathological and controllable increase of heat production

Question 9

Features of malignant hyperthermia

Answer 9

1. Initial muscle rigidity especially masseter stiffness
2. Sinus tachycardia
3. Hypercarbia and skin cyanosis

Marked hyperthermia up to 45°C or 113° F occurs a few minutes to hours later

Question 10

Neuroleptic malignant syndrome (NMS)

Answer 10

Life threatening neurological emergency associated with the use of antipsychotic neuroleptic agents
Clinical syndrome of mental status change rigidity ,fever and dysautonomia

Question 11

Neuroleptic malignant syndrome (NMS) is caused by the antipsychotic agents

Answer 11

Haloperidol
Fluphenazine
Chlorpromazine
Clozapine
Risperdone 
Metoclopramide
Promethazine

Question 12

Hyperpyrexia

Answer 12

Fever more than 41.5°C or 106.7° F

Severe infections, central nervous system or haemorrhages

Question 13

Set point of hypothalamus is raised by

Answer 13

PGE2
This activates:
1. neurons in the vasomotor centre for vasoconstriction
2. warm sensing neutrons to slow their firing rate and increase heat production in the periphery

Question 14

Methods of heat production in humans

Answer 14

1. Shivering thermogenesis
2. Non-shivering thermogenesis (eg brown adipose tissue)
3. Increased metabolic activity
4. Behavioural changes

Question 15

Causes of hypothalamic fever

Answer 15

1. Local trauma
2. Haemorrhage
3. Tumour
4. Intrinsic hypothalamic malfunction

Question 16

Examples of pyrogens

Answer 16

1. Exogenous-toxins
   Endotoxins from E. coli and Klebsiella
   Enterotoxins from S. aureus and S. pyogenes
2. Endogenous-cytokines like IL-1 beta, TNF – alpha, IL-6

Question 17

Continuous or sustained fever

Answer 17

Continuous or sustained fever is defined as fever that does not fluctuate more than 1•C (1.5•F) during 24 hours, but at no time touches normal

Question 18

Examples of continuous or sustained fever

Answer 18

1. Lobar and gram negative pneumonia
2. Typhoid
3. Acute bacterial meningitis
4. Urinary tract infection

Question 19

Step ladder fever

Answer 19

Fever characterised by slow step wise temperature rise and the high plateau
Classical of typhoid fever

Question 20

Intermittent fever

Answer 20

The fever is present only for several hours during the day
Examples:
Malaria, Kala Azar
Pyogenic infections, lymphoma , septicaemia
Tuberculosis, Schistosomiasis
Leptospira, Borrelia

Question 21

The various periodicities of malarial fever

Answer 21

Quotidian: 24 hr-P. falciparum
Tertian: 48 hr-P. ovale
Quartan: 72 hr-P. malariae

Question 22

Pel Ebstein fever

Answer 22

Pel Ebstein fever is an intermittent low grade fever characterised by 3-10 days of fever with subsequent a febrile period of 3-10 days

Typical rare manifestation of Hodgkin’s lymphoma

Question 23

Remittent fever

Answer 23

Remittent fever is defined as fever with daily fluctuations exceeding 2°C but at no time touches normal

Question 24

Examples of remittent fever

Answer 24

Infective endocarditis
Rickettsial infections
Brucellosis

Question 25

Relapsing fever

Answer 25

Relapsing fevers refer to those that are recurring and separated with low grade fever or no fever

Question 26

Relapsing fevers are seen in

Answer 26

``` Malaria Lymphoma Borrelia Cyclic neutropenia Rat bite fever ```

Question 27

Recurrent fevers

Answer 27

Partial treatment of deep-seated infections like abscesses Due to recurrent exposure to allergens in hypersensitivity pneumonitis Drug fever Cyclic neutropenic fevers Cancer and pulmonary embolism – tissue necrosis Relapsing fever is due to episodic spirochetemia

Question 28

Fever defervescence range

Answer 28

Effective antimalarial therapy leads to fever defervescence by crisis (within hours) whereas in typhoid fever resolution occurs by lysis (gradually over days) following effective antibiotics

Question 29

Aseptic fever is caused by

Answer 29

``` Non Infectious cases like: Drugs –rifampicin, methyl dopa Connective-tissue disease Malignancy Thyroid storm Heat stroke Pontine haemorrhage Radiation sickness Overatropinisation ```

Question 30

Fever with rash

Answer 30

``` Measles – fourth day of fever Infectious mononucleosis Meningococcaemia Scarlet fever Rubella- 2/3 rd day fever Enteric fever – end of first week Dengue Scrub typhus ```

Question 31

Naprosyn test

Answer 31

``` When naprosyn (naproxen 375 mg twice daily), or other NSAIDS [51], is given for three days, fevers due to cancers display a rapid and sustained decline while little or no changes was observed in fever due to infectious diseases ```

Question 32

Temperature – pulse dissociation or relative bradycardia is seen in (Faget’s sign or violation of the Liebermeister’s rule)

Answer 32

``` Typhoid fever Brucellosis Leptospirosis Leishmaniasis Legionnaires disease Psittacosis Yellow fever Drug induced fever Factitious fever ```

Question 33

Nociceptor cough

Answer 33

``` Via C-fibre nociceptor By: 1. Local anaesthetics 2. TRPV1 antagonists 3. TRPA1 antagonists 4. Na+ channel blockers 5. Opioids ```

Question 34

Mechanoreceptor cough

Answer 34

1. Local anaesthetics 2. Cl- channel blockers 3. Na+/K+ ATPase inhibitors

Question 35

Causes of impaired cough

Answer 35

1. Decreased respiratory muscle strength 2. Chest wall or abdominal pain 3. Chest wall deformity 4. Impaired glottis closure or tracheostomy 5. Tracheobronchomalacia 6. Abnormal airway secretions 7. Central respiratory depression (anaesthesia, sedation, coma)

Question 36

Etiology of cough

Answer 36

``` 1. Acute: 3 weeks RTI, aspiration, chemical inhalation 2. Sub acute: 3-8 weeks Irritation persisting after tracheobronchitis, pertussis 3. Chronic: 8 weeks ```

Question 37

Chronic cough with normal CXR

Answer 37

* ACE inhibitor therapy * Air pollution * GERD * Post-nasal drip * Cough-variant asthma * Chronic eosinophilic bronchitis * Cough hypersensitivity syndrome

Question 38

Hemoptysis can be of ___ types (based on causes)

Answer 38

* Infectious * Vascular * Malignancy * Mechanical/others

Question 39

Central cyanosis characteristics

Answer 39

* Generalised * Warm affected parts * Does not disappear on application of warmth * Cyanosis may disappear in pulmonary case (except in right to left shunt) when oxygen is supplied * Tongue is always involved

Question 40

Characteristics of peripheral cyanosis

Answer 40

* Localised * Cold affected part * Disappear on application of warmth or when oxygen is supplied * Tongue is never involved

Question 41

Causes of central cyanosis

Answer 41

``` 1. Decreased arterial oxygen saturation A. Decreased atmospheric pressure B. Impaired alveolar function C. Anatomical stunts D. Hb with low affinity for oxygen ``` 2. Hb abnormalities

Question 42

Peripheral cyanosis

Answer 42

1. Reduced cardiac output 2. Cold exposure 3. Redistribution of blood flow from extremities 4. Arterial obstruction 5. Venous obstruction