deep venous thrombosis ( dvt ) is a common condition that affects approximately 1 in 1000 persons / year . dvt has a prevalence of 10.5 - 11.9% in patients who are admitted in intensive care unit ( icu ) among indian patients . upper limb dvt is increasingly being recognized as a clinical entity with potential for considerable morbidity . it usually refers to thrombosis of the axillary or subclavian veins , occurs spontaneously or sometimes develops as a complication of pacemaker use , long - term central venous catheter ( cvc ) use , or cancer . approximately , 10% of all cases of deep - vein thrombosis involve the upper extremities , resulting in an annual incidence of 0.4 - 1 case/10,000 people . here , we are presenting two cases who had developed upper limb dvt while resolving phase of their sepsis with reactive thrombocytosis . a 37-year - old man referred to our icu with acute respiratory distress syndrome ( ards ) and septic shock on the 23 day of his illness . he had h1n1 influenza viral infection , confirmed by reverse transcription polymerase chain reaction method . at admission , vitals were : heart rate 140/min , blood pressure ( mean ) 70 mmhg on noradrenaline infusion ( 20 g / min ) . his ventilatory requirement was positive end - expiratory pressure ( peep ) of 14 cm h2o and fio2 of 0.70 with pao2/fio2(p / f ) ratio 160 . his laboratory parameters on admission was hemoglobin 12 g / dl , total leukocyte count ( tlc ) 18,000 and platelet count of 165 ( 10/l ) . before   admission , he had platelet count ranging from 83 to 163 ( 10/l ) . lung protective ventilation was continued and prone position ventilation sessions were given to improve p / f ratios . by day 7 of icu stay his hemodynamics improved with no further need of vasopressor . during follow - up , he had thrombocytosis during 2 week ( 622 - 707  10/l ) . he was receiving dvt prophylaxis in appropriate doses . on day 14 of his stay swelling , was noted in the right upper limb . bedside doppler ultrasonography of bilateral jugular veins revealed thrombosed right internal jugular vein ( ijv ) suggestive of acute thrombus with no flow along entire length of cervical ijv extending into right subclavian vein . magnetic resonance imaging venogram confirmed the findings ; and thromboelastography ( teg ) was done , which showed hypercoagulability [ figure 1 ] . he was started on injection enoxaparin 60 mg subcutaneous 12 hourly , with antiplatelet ( aspirin ) . later on , he had an uneventful course in the icu and was discharged on oral anti - coagulant . the thrombus had recanalized with no residual limb edema and his platelet counts were back to normal . ( a ) the magnetic resonance venogram depicting thrombus in right internal jugular vein extending to right subclavian vein . ( b ) thromboelastogram showing hypercoagulability the second case is about a 29-year - old male patient who was admitted on the 12 day of his illness with acute viral encephalitis . on admission in icu , vitals were : heart rate 110/min , mean blood pressure 82 mm of hg ( on noradrenaline infusion 10 g / min ) . he required ventilatory support due to encephalopathy , and kept on synchronized intermittent mandatory ventilation mode with peep of 6 of cm h2o . his arterial blood gas showed ph 7.34 , po2100 mmhg and pco242 mmhg on fio2 of 0.4 with p / f ratios around 250 . he was fluid resuscitated along with other supportive care , which resulted in improvement in shock and stopping of vasopressor within 48 h of admission . his laboratory parameters were hemoglobin 10 g / dl , tlc 13,000 , platelet 140 ( 10/l ) , creatinine 0.7 mg / dl . he continued to stay in the icu in the view of difficult weaning due to his muscle weakness . he showed persistent thrombocytosis ( 537 - 827  10/l ) after 2 weeks of admission . on day 46 in icu swelling was noted in his right arm . doppler of his upper limb showed evidence of thrombosis in both right subclavian vein and right ijv [ figure 2 ] . he was started on therapeutic doses of low molecular weight heparin along with aspirin . in at follow - up after 1-month , his thrombosis gradually resolved with recanalization of the vein , decrease in limb edema , and he is still on oral anti - coagulant . ( a ) doppler ultrasonography showing thrombus in right internal jugular vein with no flow . a 37-year - old man referred to our icu with acute respiratory distress syndrome ( ards ) and septic shock on the 23 day of his illness . he had h1n1 influenza viral infection , confirmed by reverse transcription polymerase chain reaction method . at admission , vitals were : heart rate 140/min , blood pressure ( mean ) 70 mmhg on noradrenaline infusion ( 20 g / min ) . his ventilatory requirement was positive end - expiratory pressure ( peep ) of 14 cm h2o and fio2 of 0.70 with pao2/fio2(p / f ) ratio 160 . his laboratory parameters on admission was hemoglobin 12 g / dl , total leukocyte count ( tlc ) 18,000 and platelet count of 165 ( 10/l ) . before   admission , he had platelet count ranging from 83 to 163 ( 10/l ) . lung protective ventilation was continued and prone position ventilation sessions were given to improve p / f ratios . by day 7 of icu stay his hemodynamics improved with no further need of vasopressor . during follow - up , he had thrombocytosis during 2 week ( 622 - 707  10/l ) . he was receiving dvt prophylaxis in appropriate doses . on day 14 of his stay swelling , was noted in the right upper limb . bedside doppler ultrasonography of bilateral jugular veins revealed thrombosed right internal jugular vein ( ijv ) suggestive of acute thrombus with no flow along entire length of cervical ijv extending into right subclavian vein . magnetic resonance imaging venogram confirmed the findings ; and thromboelastography ( teg ) was done , which showed hypercoagulability [ figure 1 ] . he was started on injection enoxaparin 60 mg subcutaneous 12 hourly , with antiplatelet ( aspirin ) . later on , he had an uneventful course in the icu and was discharged on oral anti - coagulant . the thrombus had recanalized with no residual limb edema and his platelet counts were back to normal . ( a ) the magnetic resonance venogram depicting thrombus in right internal jugular vein extending to right subclavian vein . ( b ) thromboelastogram showing hypercoagulability the second case is about a 29-year - old male patient who was admitted on the 12 day of his illness with acute viral encephalitis . on admission in icu , vitals were : heart rate 110/min , mean blood pressure 82 mm of hg ( on noradrenaline infusion 10 g / min ) . he required ventilatory support due to encephalopathy , and kept on synchronized intermittent mandatory ventilation mode with peep of 6 of cm h2o . his arterial blood gas showed ph 7.34 , po2100 mmhg and pco242 mmhg on fio2 of 0.4 with p / f ratios around 250 . he was fluid resuscitated along with other supportive care , which resulted in improvement in shock and stopping of vasopressor within 48 h of admission . his laboratory parameters were hemoglobin 10 g / dl , tlc 13,000 , platelet 140 ( 10/l ) , creatinine 0.7 mg / dl . he continued to stay in the icu in the view of difficult weaning due to his muscle weakness . he showed persistent thrombocytosis ( 537 - 827  10/l ) after 2 weeks of admission . on day 46 in icu swelling was noted in his right arm . doppler of his upper limb showed evidence of thrombosis in both right subclavian vein and right ijv [ figure 2 ] . he was started on therapeutic doses of low molecular weight heparin along with aspirin . in at follow - up after 1-month , his thrombosis gradually resolved with recanalization of the vein , decrease in limb edema , and he is still on oral anti - coagulant . ( a ) doppler ultrasonography showing thrombus in right internal jugular vein with no flow . a 37-year - old man referred to our icu with acute respiratory distress syndrome ( ards ) and septic shock on the 23 day of his illness . he had h1n1 influenza viral infection , confirmed by reverse transcription polymerase chain reaction method . at admission , vitals were : heart rate 140/min , blood pressure ( mean ) 70 mmhg on noradrenaline infusion ( 20 g / min ) . his ventilatory requirement was positive end - expiratory pressure ( peep ) of 14 cm h2o and fio2 of 0.70 with pao2/fio2(p / f ) ratio 160 . his laboratory parameters on admission was hemoglobin 12 g / dl , total leukocyte count ( tlc ) 18,000 and platelet count of 165 ( 10/l ) . before   admission , he had platelet count ranging from 83 to 163 ( 10/l ) . lung protective ventilation was continued and prone position ventilation sessions were given to improve p / f ratios . by day 7 of icu stay his hemodynamics improved with no further need of vasopressor . during follow - up , he had thrombocytosis during 2 week ( 622 - 707  10/l ) . he was receiving dvt prophylaxis in appropriate doses . on day 14 of his stay swelling , was noted in the right upper limb . bedside doppler ultrasonography of bilateral jugular veins revealed thrombosed right internal jugular vein ( ijv ) suggestive of acute thrombus with no flow along entire length of cervical ijv extending into right subclavian vein . magnetic resonance imaging venogram confirmed the findings ; and thromboelastography ( teg ) was done , which showed hypercoagulability [ figure 1 ] . he was started on injection enoxaparin 60 mg subcutaneous 12 hourly , with antiplatelet ( aspirin ) . later on , he had an uneventful course in the icu and was discharged on oral anti - coagulant . the thrombus had recanalized with no residual limb edema and his platelet counts were back to normal . ( a ) the magnetic resonance venogram depicting thrombus in right internal jugular vein extending to right subclavian vein . the second case is about a 29-year - old male patient who was admitted on the 12 day of his illness with acute viral encephalitis . on admission in icu , vitals were : heart rate 110/min , mean blood pressure 82 mm of hg ( on noradrenaline infusion 10 g / min ) . he required ventilatory support due to encephalopathy , and kept on synchronized intermittent mandatory ventilation mode with peep of 6 of cm h2o . his arterial blood gas showed ph 7.34 , po2100 mmhg and pco242 mmhg on fio2 of 0.4 with p / f ratios around 250 . he was fluid resuscitated along with other supportive care , which resulted in improvement in shock and stopping of vasopressor within 48 h of admission . his laboratory parameters were hemoglobin 10 g / dl , tlc 13,000 , platelet 140 ( 10/l ) , creatinine 0.7 mg / dl . he continued to stay in the icu in the view of difficult weaning due to his muscle weakness . he showed persistent thrombocytosis ( 537 - 827  10/l ) after 2 weeks of admission . on day 46 in icu swelling was noted in his right arm . doppler of his upper limb showed evidence of thrombosis in both right subclavian vein and right ijv [ figure 2 ] . he was started on therapeutic doses of low molecular weight heparin along with aspirin . in at follow - up after 1-month , his thrombosis gradually resolved with recanalization of the vein , decrease in limb edema , and he is still on oral anti - coagulant . ( a ) doppler ultrasonography showing thrombus in right internal jugular vein with no flow . thrombocytosis , that is , platelet count more than 450  10/l , can be primary or reactive ( secondary ) in etiology . reactive thrombocytosis is common and reported in various conditions such as inflammation , postsplenectomy , hematopoietic disorder , surgery and cancer . in these conditions , elevated endogenous levels of interleukin-6 ( il-6 ) , interferon gamma ( ifn- ) are responsible for the thrombocytosis . il-6 contributes to inflammatory thrombopoiesis predominantly by stimulating the hepatic production of thrombopoietin ( tpo ) ; while , ifn- has its effect on megakaryocytes growth . furthermore , there is enhanced production of tpo , messenger ribonucleic acid and protein by stimulation of hepatocytes with il-6 . in icu patients ' thrombocytosis is a commonly seen phenomenon , it 's found in nearly 21% of patients admitted to an icu . due to relatively lesser platelet count and smaller mean platelet volume , pathologic thrombus is not so common in reactive thrombocytosis in comparison to primary thrombocytosis ; unless it is aggravated by underlying disease process or any condition peculiar to the patient , e.g. arthrosclerosis . in the pathogenesis of dvt of upper extremity , presence of the indwelling catheter ( cvcs , pacemaker , or defibrillator leads ) , cancer , surgery or trauma of the arm or shoulder are common and major risk factors . the prevalence of cvc - related upper limb dvt in cancer patients varies from 11.7% to 44% . in presented both cases , cvc were inserted in both neck vessels ( ijv and subclavian vein ) before diagnosis of dvt , and were not inserted after diagnosis of thrombosis and managed with catheter in the femoral vein . presented both cases , though patients had a risk factor of having cvcs previously at the site of thrombosis ; the association of increased platelet count can not be ruled out in pathogenesis of thrombosis . in further evaluation , teg had increased maximum amplitude : 77.8 mm in the first patient and 78.1 mm in the second patient with a reference range 5166 mm . the  angle was within normal limits depicting that the hypercoagulability is due to platelet and not enzyme activity . after the detection of dvt these patients were given the therapeutic doses of anti - coagulant for dvt along with anti - platelet ( aspirin ) . there was no evidence of any more dvt or any other site of thrombosis in both these patients . intensive care unit patient having reactive thrombocytosis during the recovery phase of sepsis must be kept in priority for screening to rule out dvt , so that timely therapeutic intervention could avoid a life - threatening pulmonary embolism .
deep venous thrombosis ( dvt ) is not an uncommon condition in the intensive care unit ( icu ) , and having high morbidity and mortality . 
 upper limb dvt also is increasingly being recognized as a clinical entity . 
 the presence of the indwelling catheter in neck veins is a risk for developing venous thrombus , which may be further aggravated by presence of thrombocytosis . in icu patients with sepsis , 
 reactive thrombocytosis has been found during the recovery phase . here , we are presenting two cases , having thrombocytosis and central venous catheter who developed upper limb dvt .